chore(deps): bump github.com/miekg/dns from 1.1.50 to 1.1.53 (#449)

Bumps [github.com/miekg/dns](https://github.com/miekg/dns) from 1.1.50 to 1.1.53.
- [Release notes](https://github.com/miekg/dns/releases)
- [Changelog](https://github.com/miekg/dns/blob/master/Makefile.release)
- [Commits](https://github.com/miekg/dns/compare/v1.1.50...v1.1.53)

---
updated-dependencies:
- dependency-name: github.com/miekg/dns
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.dockerignore

@@ -1,3 +1,7 @@
-example
+.examples
+Dockerfile
 .github
 .idea
+.git
+web/app
+*.db

.examples/docker-compose-grafana-prometheus/README.md

@@ -0,0 +1,41 @@
+## Usage
+Gatus exposes Prometheus metrics at `/metrics` if the `metrics` configuration option is set to `true`.
+
+To run this example, all you need to do is execute the following command:
+```console
+docker-compose up
+```
+Once you've done the above, you should be able to access the Grafana dashboard at `http://localhost:3000`.
+
+![Gatus Grafana dashboard](../../.github/assets/grafana-dashboard.png)
+
+
+## Queries
+By default, this example has a Grafana dashboard with some panels, but for the sake of verbosity, you'll find
+a list of simple queries below. Those make use of the `key` parameter, which is a concatenation of the endpoint's
+group and name.
+
+### Success rate
+```
+sum(rate(gatus_results_total{success="true"}[30s])) by (key) / sum(rate(gatus_results_total[30s])) by (key)
+```
+
+### Response time
+```
+gatus_results_duration_seconds
+```
+
+### Total results per minute
+```
+sum(rate(gatus_results_total[5m])*60) by (key)
+```
+
+### Total successful results per minute
+```
+sum(rate(gatus_results_total{success="true"}[5m])*60) by (key)
+```
+
+### Total unsuccessful results per minute
+```
+sum(rate(gatus_results_total{success="false"}[5m])*60) by (key)
+```

.examples/docker-compose-grafana-prometheus/config/config.yaml

@@ -1,16 +1,19 @@
 metrics: true
-services:
-  - name: TwiNNatioN
-    url: https://twinnation.org/health
-    interval: 30s
-    conditions:
-      - "[STATUS] == 200"
-  - name: GitHub
-    url: https://api.github.com/healthz
+endpoints:
+  - name: website
+    url: https://twin.sh/health
     interval: 5m
     conditions:
       - "[STATUS] == 200"
-  - name: Example
+
+  - name: example
     url: https://example.com/
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+
+  - name: github
+    url: https://api.github.com/healthz
+    interval: 5m
     conditions:
       - "[STATUS] == 200"

.examples/docker-compose-grafana-prometheus/docker-compose.yml

@@ -1,14 +1,13 @@
-version: '3.7'
-
+version: "3.9"
 services:
   gatus:
     container_name: gatus
     image: twinproduction/gatus
     restart: always
     ports:
-      - 8080:8080
+      - "8080:8080"
     volumes:
-      - ./config.yaml:/config/config.yaml
+      - ./config:/config
     networks:
       - metrics
 
@@ -18,7 +17,7 @@ services:
     restart: always
     command: --config.file=/etc/prometheus/prometheus.yml
     ports:
-      - 9090:9090
+      - "9090:9090"
     volumes:
       - ./prometheus/prometheus.yml:/etc/prometheus/prometheus.yml
     networks:
@@ -31,7 +30,7 @@ services:
     environment:
       GF_SECURITY_ADMIN_PASSWORD: secret
     ports:
-      - 3000:3000
+      - "3000:3000"
     volumes:
       - ./grafana/grafana.ini/:/etc/grafana/grafana.ini:ro
       - ./grafana/provisioning/:/etc/grafana/provisioning/:ro

.examples/docker-compose-grafana-prometheus/grafana/provisioning/dashboards/gatus.json

@@ -0,0 +1,582 @@
+{
+  "annotations": {
+    "list": [
+      {
+        "builtIn": 1,
+        "datasource": "-- Grafana --",
+        "enable": true,
+        "hide": true,
+        "iconColor": "rgba(0, 211, 255, 1)",
+        "name": "Annotations & Alerts",
+        "type": "dashboard"
+      }
+    ]
+  },
+  "editable": true,
+  "gnetId": null,
+  "graphTooltip": 0,
+  "id": 3,
+  "links": [],
+  "panels": [
+    {
+      "cacheTimeout": null,
+      "datasource": null,
+      "description": "Number of successful results compared to the total number of results during the current interval",
+      "gridPos": {
+        "h": 8,
+        "w": 12,
+        "x": 0,
+        "y": 0
+      },
+      "id": 9,
+      "links": [],
+      "options": {
+        "fieldOptions": {
+          "calcs": [
+            "mean"
+          ],
+          "defaults": {
+            "mappings": [
+              {
+                "id": 0,
+                "op": "=",
+                "text": "N/A",
+                "type": 1,
+                "value": "null"
+              }
+            ],
+            "max": 1,
+            "min": 0,
+            "nullValueMode": "connected",
+            "thresholds": [
+              {
+                "color": "red",
+                "value": null
+              },
+              {
+                "color": "semi-dark-orange",
+                "value": 0.6
+              },
+              {
+                "color": "yellow",
+                "value": 0.8
+              },
+              {
+                "color": "dark-green",
+                "value": 0.95
+              }
+            ],
+            "unit": "percentunit"
+          },
+          "override": {},
+          "values": false
+        },
+        "orientation": "horizontal",
+        "showThresholdLabels": false,
+        "showThresholdMarkers": false
+      },
+      "pluginVersion": "6.4.4",
+      "targets": [
+        {
+          "expr": "sum(rate(gatus_results_total{success=\"true\"}[30s])) by (key) / sum(rate(gatus_results_total[30s])) by (key)",
+          "hide": false,
+          "legendFormat": "{{key}}",
+          "refId": "B"
+        }
+      ],
+      "timeFrom": null,
+      "timeShift": null,
+      "title": "Success rate",
+      "type": "gauge"
+    },
+    {
+      "aliasColors": {},
+      "bars": false,
+      "cacheTimeout": null,
+      "dashLength": 10,
+      "dashes": false,
+      "datasource": null,
+      "fill": 1,
+      "fillGradient": 0,
+      "gridPos": {
+        "h": 8,
+        "w": 12,
+        "x": 12,
+        "y": 0
+      },
+      "id": 11,
+      "legend": {
+        "avg": false,
+        "current": false,
+        "max": false,
+        "min": false,
+        "show": true,
+        "total": false,
+        "values": false
+      },
+      "lines": true,
+      "linewidth": 1,
+      "links": [],
+      "nullPointMode": "null as zero",
+      "options": {
+        "dataLinks": []
+      },
+      "percentage": false,
+      "pluginVersion": "6.4.4",
+      "pointradius": 2,
+      "points": false,
+      "renderer": "flot",
+      "seriesOverrides": [],
+      "spaceLength": 10,
+      "stack": false,
+      "steppedLine": false,
+      "targets": [
+        {
+          "expr": "gatus_results_duration_seconds",
+          "format": "time_series",
+          "instant": false,
+          "interval": "",
+          "intervalFactor": 1,
+          "legendFormat": "{{key}}",
+          "refId": "A"
+        }
+      ],
+      "thresholds": [],
+      "timeFrom": null,
+      "timeRegions": [],
+      "timeShift": null,
+      "title": "Response time",
+      "tooltip": {
+        "shared": true,
+        "sort": 0,
+        "value_type": "individual"
+      },
+      "type": "graph",
+      "xaxis": {
+        "buckets": null,
+        "mode": "time",
+        "name": null,
+        "show": true,
+        "values": []
+      },
+      "yaxes": [
+        {
+          "format": "short",
+          "label": null,
+          "logBase": 1,
+          "max": null,
+          "min": null,
+          "show": true
+        },
+        {
+          "format": "short",
+          "label": null,
+          "logBase": 1,
+          "max": null,
+          "min": null,
+          "show": true
+        }
+      ],
+      "yaxis": {
+        "align": false,
+        "alignLevel": null
+      }
+    },
+    {
+      "aliasColors": {},
+      "bars": false,
+      "cacheTimeout": null,
+      "dashLength": 10,
+      "dashes": false,
+      "datasource": null,
+      "fill": 1,
+      "fillGradient": 0,
+      "gridPos": {
+        "h": 8,
+        "w": 12,
+        "x": 0,
+        "y": 8
+      },
+      "id": 10,
+      "legend": {
+        "avg": false,
+        "current": false,
+        "max": false,
+        "min": false,
+        "show": true,
+        "total": false,
+        "values": false
+      },
+      "lines": true,
+      "linewidth": 1,
+      "links": [],
+      "nullPointMode": "connected",
+      "options": {
+        "dataLinks": []
+      },
+      "percentage": false,
+      "pluginVersion": "6.4.4",
+      "pointradius": 2,
+      "points": true,
+      "renderer": "flot",
+      "seriesOverrides": [],
+      "spaceLength": 10,
+      "stack": false,
+      "steppedLine": false,
+      "targets": [
+        {
+          "expr": "sum(rate(gatus_results_total{success=\"true\"}[30s])) by (key) / sum(rate(gatus_results_total[30s])) by (key)",
+          "format": "time_series",
+          "instant": false,
+          "interval": "",
+          "intervalFactor": 1,
+          "legendFormat": "{{key}}",
+          "refId": "A"
+        }
+      ],
+      "thresholds": [],
+      "timeFrom": null,
+      "timeRegions": [],
+      "timeShift": null,
+      "title": "Success rate",
+      "tooltip": {
+        "shared": true,
+        "sort": 0,
+        "value_type": "individual"
+      },
+      "type": "graph",
+      "xaxis": {
+        "buckets": null,
+        "mode": "time",
+        "name": null,
+        "show": true,
+        "values": []
+      },
+      "yaxes": [
+        {
+          "format": "short",
+          "label": null,
+          "logBase": 1,
+          "max": null,
+          "min": null,
+          "show": true
+        },
+        {
+          "format": "short",
+          "label": null,
+          "logBase": 1,
+          "max": null,
+          "min": null,
+          "show": true
+        }
+      ],
+      "yaxis": {
+        "align": false,
+        "alignLevel": null
+      }
+    },
+    {
+      "aliasColors": {},
+      "bars": false,
+      "dashLength": 10,
+      "dashes": false,
+      "datasource": null,
+      "description": "Number of results per minute",
+      "fill": 1,
+      "fillGradient": 0,
+      "gridPos": {
+        "h": 8,
+        "w": 12,
+        "x": 12,
+        "y": 8
+      },
+      "id": 2,
+      "interval": "",
+      "legend": {
+        "alignAsTable": false,
+        "avg": false,
+        "current": false,
+        "hideEmpty": false,
+        "hideZero": false,
+        "max": false,
+        "min": false,
+        "rightSide": false,
+        "show": true,
+        "total": false,
+        "values": false
+      },
+      "lines": true,
+      "linewidth": 1,
+      "nullPointMode": "null",
+      "options": {
+        "dataLinks": []
+      },
+      "percentage": false,
+      "pointradius": 2,
+      "points": false,
+      "renderer": "flot",
+      "seriesOverrides": [],
+      "spaceLength": 10,
+      "stack": false,
+      "steppedLine": false,
+      "targets": [
+        {
+          "expr": "sum(rate(gatus_results_total[5m])*60) by (key)",
+          "format": "time_series",
+          "hide": false,
+          "instant": false,
+          "interval": "30s",
+          "intervalFactor": 1,
+          "legendFormat": "{{key}}",
+          "refId": "A"
+        }
+      ],
+      "thresholds": [],
+      "timeFrom": null,
+      "timeRegions": [],
+      "timeShift": null,
+      "title": "Total results per minute",
+      "tooltip": {
+        "shared": true,
+        "sort": 0,
+        "value_type": "individual"
+      },
+      "type": "graph",
+      "xaxis": {
+        "buckets": null,
+        "mode": "time",
+        "name": null,
+        "show": true,
+        "values": []
+      },
+      "yaxes": [
+        {
+          "decimals": null,
+          "format": "short",
+          "label": null,
+          "logBase": 1,
+          "max": null,
+          "min": null,
+          "show": true
+        },
+        {
+          "format": "short",
+          "label": null,
+          "logBase": 1,
+          "max": null,
+          "min": null,
+          "show": true
+        }
+      ],
+      "yaxis": {
+        "align": false,
+        "alignLevel": null
+      }
+    },
+    {
+      "aliasColors": {},
+      "bars": false,
+      "dashLength": 10,
+      "dashes": false,
+      "datasource": null,
+      "fill": 1,
+      "fillGradient": 0,
+      "gridPos": {
+        "h": 7,
+        "w": 12,
+        "x": 0,
+        "y": 16
+      },
+      "id": 5,
+      "legend": {
+        "avg": false,
+        "current": false,
+        "max": false,
+        "min": false,
+        "show": true,
+        "total": false,
+        "values": false
+      },
+      "lines": true,
+      "linewidth": 1,
+      "nullPointMode": "null",
+      "options": {
+        "dataLinks": []
+      },
+      "percentage": false,
+      "pointradius": 2,
+      "points": false,
+      "renderer": "flot",
+      "seriesOverrides": [],
+      "spaceLength": 10,
+      "stack": false,
+      "steppedLine": false,
+      "targets": [
+        {
+          "expr": "sum(rate(gatus_results_total{success=\"true\"}[5m])*60) by (key)",
+          "instant": false,
+          "interval": "30s",
+          "legendFormat": "{{key}}",
+          "refId": "A"
+        }
+      ],
+      "thresholds": [],
+      "timeFrom": null,
+      "timeRegions": [],
+      "timeShift": null,
+      "title": "Successful results per minute",
+      "tooltip": {
+        "shared": true,
+        "sort": 0,
+        "value_type": "individual"
+      },
+      "type": "graph",
+      "xaxis": {
+        "buckets": null,
+        "mode": "time",
+        "name": null,
+        "show": true,
+        "values": []
+      },
+      "yaxes": [
+        {
+          "decimals": null,
+          "format": "short",
+          "label": null,
+          "logBase": 1,
+          "max": null,
+          "min": null,
+          "show": true
+        },
+        {
+          "format": "short",
+          "label": null,
+          "logBase": 1,
+          "max": null,
+          "min": null,
+          "show": true
+        }
+      ],
+      "yaxis": {
+        "align": false,
+        "alignLevel": null
+      }
+    },
+    {
+      "aliasColors": {},
+      "bars": false,
+      "dashLength": 10,
+      "dashes": false,
+      "datasource": null,
+      "fill": 1,
+      "fillGradient": 0,
+      "gridPos": {
+        "h": 7,
+        "w": 12,
+        "x": 12,
+        "y": 16
+      },
+      "id": 3,
+      "legend": {
+        "avg": false,
+        "current": false,
+        "max": false,
+        "min": false,
+        "show": true,
+        "total": false,
+        "values": false
+      },
+      "lines": true,
+      "linewidth": 1,
+      "nullPointMode": "null",
+      "options": {
+        "dataLinks": []
+      },
+      "percentage": false,
+      "pointradius": 2,
+      "points": false,
+      "renderer": "flot",
+      "seriesOverrides": [],
+      "spaceLength": 10,
+      "stack": false,
+      "steppedLine": false,
+      "targets": [
+        {
+          "expr": "sum(rate(gatus_results_total{success=\"false\"}[5m])*60) by (key)",
+          "interval": "30s",
+          "legendFormat": "{{key}} ",
+          "refId": "A"
+        }
+      ],
+      "thresholds": [],
+      "timeFrom": null,
+      "timeRegions": [],
+      "timeShift": null,
+      "title": "Unsuccessful results per minute",
+      "tooltip": {
+        "shared": true,
+        "sort": 0,
+        "value_type": "individual"
+      },
+      "type": "graph",
+      "xaxis": {
+        "buckets": null,
+        "mode": "time",
+        "name": null,
+        "show": true,
+        "values": []
+      },
+      "yaxes": [
+        {
+          "format": "short",
+          "label": null,
+          "logBase": 1,
+          "max": null,
+          "min": null,
+          "show": true
+        },
+        {
+          "format": "short",
+          "label": null,
+          "logBase": 1,
+          "max": null,
+          "min": null,
+          "show": true
+        }
+      ],
+      "yaxis": {
+        "align": false,
+        "alignLevel": null
+      }
+    }
+  ],
+  "refresh": "1m",
+  "schemaVersion": 20,
+  "style": "dark",
+  "tags": [],
+  "templating": {
+    "list": []
+  },
+  "time": {
+    "from": "now-1h",
+    "to": "now"
+  },
+  "timepicker": {
+    "refresh_intervals": [
+      "5s",
+      "10s",
+      "30s",
+      "1m",
+      "5m",
+      "15m",
+      "30m",
+      "1h",
+      "2h",
+      "1d"
+    ]
+  },
+  "timezone": "",
+  "title": "Gatus",
+  "uid": "KPI7Qj1Wk",
+  "version": 2
+}

.examples/docker-compose-mattermost/config/config.yaml

@@ -0,0 +1,15 @@
+alerting:
+  mattermost:
+    webhook-url: "http://mattermost:8065/hooks/tokengoeshere"
+    insecure: true
+
+endpoints:
+  - name: example
+    url: https://example.org
+    interval: 1m
+    conditions:
+      - "[STATUS] == 200"
+    alerts:
+      - type: mattermost
+        description: "health check failed 3 times in a row"
+        send-on-resolved: true

.examples/docker-compose-mattermost/docker-compose.yml

@@ -0,0 +1,23 @@
+version: "3.9"
+services:
+  gatus:
+    container_name: gatus
+    image: twinproduction/gatus:latest
+    ports:
+      - "8080:8080"
+    volumes:
+      - ./config:/config
+    networks:
+      - default
+
+  mattermost:
+    container_name: mattermost
+    image: mattermost/mattermost-preview:5.26.0
+    ports:
+      - "8065:8065"
+    networks:
+      - default
+
+networks:
+  default:
+    driver: bridge

.examples/docker-compose-multiple-config-files/config/backend.yaml

@@ -0,0 +1,21 @@
+endpoints:
+  - name: check-if-api-is-healthy
+    group: backend
+    url: "https://twin.sh/health"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+      - "[BODY].status == UP"
+      - "[RESPONSE_TIME] < 1000"
+
+  - name: check-if-website-is-pingable
+    url: "icmp://example.org"
+    interval: 1m
+    conditions:
+      - "[CONNECTED] == true"
+
+  - name: check-domain-expiration
+    url: "https://example.org"
+    interval: 6h
+    conditions:
+      - "[DOMAIN_EXPIRATION] > 720h"

.examples/docker-compose-multiple-config-files/config/frontend.yaml

@@ -0,0 +1,8 @@
+endpoints:
+  - name: make-sure-html-rendering-works
+    group: frontend
+    url: "https://example.org"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+      - "[BODY] == pat(*<h1>Example Domain</h1>*)" # Check for header in HTML page

.examples/docker-compose-multiple-config-files/config/global.yaml

@@ -0,0 +1,8 @@
+metrics: true
+debug: false
+ui:
+  header: Example Company
+  link: https://example.org
+  buttons:
+    - name: "Home"
+      link: "https://example.org"

.examples/docker-compose-multiple-config-files/docker-compose.yml

@@ -0,0 +1,10 @@
+version: "3.8"
+services:
+  gatus:
+    image: twinproduction/gatus:latest
+    ports:
+      - "8080:8080"
+    environment:
+      - GATUS_CONFIG_PATH=/config
+    volumes:
+      - ./config:/config

.examples/docker-compose-postgres-storage/config/config.yaml

@@ -0,0 +1,42 @@
+storage:
+  type: postgres
+  path: "postgres://username:password@postgres:5432/gatus?sslmode=disable"
+
+endpoints:
+  - name: back-end
+    group: core
+    url: "https://example.org/"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+      - "[CERTIFICATE_EXPIRATION] > 48h"
+
+  - name: monitoring
+    group: internal
+    url: "https://example.org/"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+
+  - name: nas
+    group: internal
+    url: "https://example.org/"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+
+  - name: example-dns-query
+    url: "8.8.8.8" # Address of the DNS server to use
+    interval: 5m
+    dns:
+      query-name: "example.com"
+      query-type: "A"
+    conditions:
+      - "[BODY] == 93.184.216.34"
+      - "[DNS_RCODE] == NOERROR"
+
+  - name: icmp-ping
+    url: "icmp://example.org"
+    interval: 1m
+    conditions:
+      - "[CONNECTED] == true"

.examples/docker-compose-postgres-storage/docker-compose.yml

@@ -0,0 +1,29 @@
+version: "3.9"
+services:
+  postgres:
+    image: postgres
+    volumes:
+      - ./data/db:/var/lib/postgresql/data
+    ports:
+      - "5432:5432"
+    environment:
+      - POSTGRES_DB=gatus
+      - POSTGRES_USER=username
+      - POSTGRES_PASSWORD=password
+    networks:
+      - web
+
+  gatus:
+    image: twinproduction/gatus:latest
+    restart: always
+    ports:
+      - "8080:8080"
+    volumes:
+      - ./config:/config
+    networks:
+      - web
+    depends_on:
+      - postgres
+
+networks:
+  web:

.examples/docker-compose-sqlite-storage/config/config.yaml

@@ -0,0 +1,42 @@
+storage:
+  type: sqlite
+  path: /data/data.db
+
+endpoints:
+  - name: back-end
+    group: core
+    url: "https://example.org/"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+      - "[CERTIFICATE_EXPIRATION] > 48h"
+
+  - name: monitoring
+    group: internal
+    url: "https://example.org/"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+
+  - name: nas
+    group: internal
+    url: "https://example.org/"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+
+  - name: example-dns-query
+    url: "8.8.8.8" # Address of the DNS server to use
+    interval: 5m
+    dns:
+      query-name: "example.com"
+      query-type: "A"
+    conditions:
+      - "[BODY] == 93.184.216.34"
+      - "[DNS_RCODE] == NOERROR"
+
+  - name: icmp-ping
+    url: "icmp://example.org"
+    interval: 1m
+    conditions:
+      - "[CONNECTED] == true"

.examples/docker-compose-sqlite-storage/docker-compose.yml

@@ -0,0 +1,9 @@
+version: "3.9"
+services:
+  gatus:
+    image: twinproduction/gatus:latest
+    ports:
+      - "8080:8080"
+    volumes:
+      - ./config:/config
+      - ./data:/data/

.examples/docker-compose/config/config.yaml

@@ -1,6 +1,6 @@
-services:
+endpoints:
   - name: example
-    url: http://example.org
+    url: https://example.org
     interval: 30s
     conditions:
       - "[STATUS] == 200"

.examples/docker-compose/docker-compose.yml

@@ -0,0 +1,8 @@
+version: "3.8"
+services:
+  gatus:
+    image: twinproduction/gatus:latest
+    ports:
+      - 8080:8080
+    volumes:
+      - ./config:/config

.examples/docker-minimal/config.yaml

@@ -1,6 +1,6 @@
-services:
+endpoints:
   - name: example
-    url: http://example.org
+    url: https://example.org
     interval: 30s
     conditions:
       - "[STATUS] == 200"

.examples/kubernetes/gatus.yaml

@@ -1,23 +1,43 @@
 apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: gatus
+  namespace: kube-system
 data:
   config.yaml: |
     metrics: true
-    services:
-      - name: TwiNNatioN
-        url: https://twinnation.org/health
-        interval: 1m
+    endpoints:
+      - name: website
+        url: https://twin.sh/health
+        interval: 5m
         conditions:
           - "[STATUS] == 200"
-      - name: GitHub
+          - "[BODY].status == UP"
+
+      - name: github
         url: https://api.github.com/healthz
         interval: 5m
         conditions:
           - "[STATUS] == 200"
-      - name: Example
+
+      - name: cat-fact
+        url: "https://cat-fact.herokuapp.com/facts/random"
+        interval: 5m
+        conditions:
+          - "[STATUS] == 200"
+          - "[BODY].deleted == false"
+          - "len([BODY].text) > 0"
+          - "[BODY].text == pat(*cat*)"
+          - "[STATUS] == pat(2*)"
+          - "[CONNECTED] == true"
+
+      - name: example
         url: https://example.com/
         conditions:
           - "[STATUS] == 200"
-kind: ConfigMap
+---
+apiVersion: v1
+kind: ServiceAccount
 metadata:
   name: gatus
   namespace: kube-system
@@ -31,14 +51,16 @@ spec:
   replicas: 1
   selector:
     matchLabels:
-      k8s-app: gatus
+      app: gatus
   template:
     metadata:
-      labels:
-        k8s-app: gatus
       name: gatus
       namespace: kube-system
+      labels:
+        app: gatus
     spec:
+      serviceAccountName: gatus
+      terminationGracePeriodSeconds: 5
       containers:
         - image: twinproduction/gatus
           imagePullPolicy: IfNotPresent
@@ -49,11 +71,27 @@ spec:
               protocol: TCP
           resources:
             limits:
-              cpu: 200m
-              memory: 50M
+              cpu: 250m
+              memory: 100M
             requests:
               cpu: 50m
-              memory: 20M
+              memory: 30M
+          readinessProbe:
+            httpGet:
+              path: /health
+              port: 8080
+            initialDelaySeconds: 5
+            periodSeconds: 10
+            successThreshold: 1
+            failureThreshold: 3
+          livenessProbe:
+            httpGet:
+              path: /health
+              port: 8080
+            initialDelaySeconds: 10
+            periodSeconds: 10
+            successThreshold: 1
+            failureThreshold: 5
           volumeMounts:
             - mountPath: /config
               name: gatus-config
@@ -74,4 +112,4 @@ spec:
       protocol: TCP
       targetPort: 8080
   selector:
-    k8s-app: gatus
+    app: gatus

.gitattributes

@@ -1 +1 @@
-* text=lf
+* text=auto eol=lf

.github/FUNDING.yml

@@ -0,0 +1 @@
+github: [TwiN]

.github/assets/gatus-diagram.drawio

@@ -0,0 +1 @@
+<mxfile host="app.diagrams.net" modified="2022-12-07T04:00:31.242Z" agent="5.0 (Windows)" etag="4-CttOJPoGYGt_6RMEMf" version="20.5.3" type="device"><diagram id="oCf8YAkR0GE5Fy88uv5t" name="Page-1">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</diagram></mxfile>

.github/codecov.yml

@@ -0,0 +1,12 @@
+ignore:
+  - "watchdog/watchdog.go"
+  - "storage/store/sql/specific_postgres.go" # Can't test for postgres
+
+coverage:
+  status:
+    patch: off
+    project:
+      default:
+        target: 75%
+        threshold: null
+

.github/dependabot.yml

@@ -0,0 +1,15 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    labels: ["dependencies"]
+    schedule:
+      interval: "weekly"
+      day: "wednesday"
+  - package-ecosystem: "gomod"
+    directory: "/"
+    open-pull-requests-limit: 1
+    labels: ["dependencies"]
+    schedule:
+      interval: "weekly"
+      day: "wednesday"

.github/workflows/benchmark.yml

@@ -0,0 +1,30 @@
+name: benchmark
+on:
+  workflow_run:
+    workflows: [publish-latest]
+    branches: [master]
+    types: [completed]
+  workflow_dispatch:
+    inputs:
+      repository:
+        description: "Repository to checkout. Useful for benchmarking a fork. Format should be <owner>/<repository>."
+        required: true
+        default: "TwiN/gatus"
+      ref:
+        description: "Branch, tag or SHA to checkout"
+        required: true
+        default: "master"
+jobs:
+  build:
+    name: benchmark
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/setup-go@v4
+        with:
+          go-version: 1.19
+          repository: "${{ github.event.inputs.repository || 'TwiN/gatus' }}"
+          ref: "${{ github.event.inputs.ref || 'master' }}"
+      - uses: actions/checkout@v3
+      - name: Benchmark
+        run: go test -bench=. ./storage/store

.github/workflows/build.yml

@@ -1,27 +0,0 @@
-name: build
-on:
-  pull_request:
-    paths-ignore:
-      - '*.md'
-  push:
-    branches:
-      - master
-    paths-ignore:
-      - '*.md'
-jobs:
-  build:
-    name: Build
-    runs-on: ubuntu-latest
-    timeout-minutes: 5
-    steps:
-      - name: Set up Go 1.15
-        uses: actions/setup-go@v1
-        with:
-          go-version: 1.15
-        id: go
-      - name: Check out code into the Go module directory
-        uses: actions/checkout@v2
-      - name: Build binary to make sure it works
-        run: go build -mod vendor
-      - name: Test
-        run: go test -mod vendor -cover ./...

.github/workflows/publish-experimental.yml

@@ -0,0 +1,26 @@
+name: publish-experimental
+on: [workflow_dispatch]
+jobs:
+  publish-experimental:
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Get image repository
+        run: echo IMAGE_REPOSITORY=$(echo ${{ secrets.DOCKER_USERNAME }}/${{ github.event.repository.name }} | tr '[:upper:]' '[:lower:]') >> $GITHUB_ENV
+      - name: Login to Docker Registry
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v4
+        with:
+          platforms: linux/amd64
+          pull: true
+          push: true
+          tags: ${{ env.IMAGE_REPOSITORY }}:experimental

.github/workflows/publish-latest-to-ghcr.yml

@@ -0,0 +1,38 @@
+name: publish-latest-to-ghcr
+on:
+  workflow_run:
+    workflows: [test]
+    branches: [master]
+    types: [completed]
+concurrency:
+  group: ${{ github.workflow }}
+  cancel-in-progress: true
+jobs:
+  publish-latest-to-ghcr:
+    runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'success' }}
+    permissions:
+      contents: read
+      packages: write
+    timeout-minutes: 60
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Get image repository
+        run: echo IMAGE_REPOSITORY=$(echo ghcr.io/${{ github.actor }}/${{ github.event.repository.name }} | tr '[:upper:]' '[:lower:]') >> $GITHUB_ENV
+      - name: Login to Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v4
+        with:
+          platforms: linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64
+          pull: true
+          push: true
+          tags: ${{ env.IMAGE_REPOSITORY }}:latest

.github/workflows/publish-latest.yml

@@ -0,0 +1,34 @@
+name: publish-latest
+on:
+  workflow_run:
+    workflows: [test]
+    branches: [master]
+    types: [completed]
+concurrency:
+  group: ${{ github.workflow }}
+  cancel-in-progress: true
+jobs:
+  publish-latest:
+    runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'success' }}
+    timeout-minutes: 60
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Get image repository
+        run: echo IMAGE_REPOSITORY=$(echo ${{ secrets.DOCKER_USERNAME }}/${{ github.event.repository.name }} | tr '[:upper:]' '[:lower:]') >> $GITHUB_ENV
+      - name: Login to Docker Registry
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v4
+        with:
+          platforms: linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64
+          pull: true
+          push: true
+          tags: ${{ env.IMAGE_REPOSITORY }}:latest

.github/workflows/publish-release-to-ghcr.yml

@@ -0,0 +1,37 @@
+name: publish-release-to-ghcr
+on:
+  release:
+    types: [published]
+jobs:
+  publish-release-to-ghcr:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    timeout-minutes: 60
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Get image repository
+        run: echo IMAGE_REPOSITORY=$(echo ghcr.io/${{ github.actor }}/${{ github.event.repository.name }} | tr '[:upper:]' '[:lower:]') >> $GITHUB_ENV
+      - name: Get the release
+        run: echo RELEASE=${GITHUB_REF/refs\/tags\//} >> $GITHUB_ENV
+      - name: Login to Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v4
+        with:
+          platforms: linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64
+          pull: true
+          push: true
+          tags: |
+            ${{ env.IMAGE_REPOSITORY }}:${{ env.RELEASE }}
+            ${{ env.IMAGE_REPOSITORY }}:stable
+            ${{ env.IMAGE_REPOSITORY }}:latest

.github/workflows/publish-release.yml

@@ -0,0 +1,34 @@
+name: publish-release
+on:
+  release:
+    types: [published]
+jobs:
+  publish-release:
+    name: publish-release
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    steps:
+      - uses: actions/checkout@v3
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+      - name: Get image repository
+        run: echo IMAGE_REPOSITORY=$(echo ${{ secrets.DOCKER_USERNAME }}/${{ github.event.repository.name }} | tr '[:upper:]' '[:lower:]') >> $GITHUB_ENV
+      - name: Get the release
+        run: echo RELEASE=${GITHUB_REF/refs\/tags\//} >> $GITHUB_ENV
+      - name: Login to Docker Registry
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v4
+        with:
+          platforms: linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64
+          pull: true
+          push: true
+          tags: |
+            ${{ env.IMAGE_REPOSITORY }}:${{ env.RELEASE }}
+            ${{ env.IMAGE_REPOSITORY }}:stable
+            ${{ env.IMAGE_REPOSITORY }}:latest

.github/workflows/test.yml

@@ -0,0 +1,33 @@
+name: test
+on:
+  pull_request:
+    paths-ignore:
+      - '*.md'
+      - '.examples/**'
+  push:
+    branches:
+      - master
+    paths-ignore:
+      - '*.md'
+      - '.github/**'
+      - '.examples/**'
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/setup-go@v4
+        with:
+          go-version: 1.19
+      - uses: actions/checkout@v3
+      - name: Build binary to make sure it works
+        run: go build
+      - name: Test
+        # We're using "sudo" because one of the tests leverages ping, which requires super-user privileges.
+        # As for the 'env "PATH=$PATH" "GOROOT=$GOROOT"', we need it to use the same "go" executable that
+        # was configured by the "Set up Go" step (otherwise, it'd use sudo's "go" executable)
+        run: sudo env "PATH=$PATH" "GOROOT=$GOROOT" go test ./... -race -coverprofile=coverage.txt -covermode=atomic
+      - name: Codecov
+        uses: codecov/codecov-action@v3.1.1
+        with:
+          files: ./coverage.txt

.gitignore

@@ -1,2 +1,20 @@
-bin
-.idea
+# IDE
+*.iml
+.idea
+.vscode
+
+# OS
+.DS_Store
+
+# JS
+node_modules
+
+# Go
+/vendor
+
+# Misc
+*.db
+*.db-shm
+*.db-wal
+gatus
+config/config.yml

Dockerfile

@@ -1,16 +1,19 @@
 # Build the go application into a binary
 FROM golang:alpine as builder
-WORKDIR /app
-ADD . ./
-RUN CGO_ENABLED=0 GOOS=linux go build -mod vendor -a -installsuffix cgo -o gatus .
 RUN apk --update add ca-certificates
+WORKDIR /app
+COPY . ./
+RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o gatus .
+
+# Run Tests inside docker image if you don't have a configured go environment
+#RUN apk update && apk add --virtual build-dependencies build-base gcc
+#RUN go test ./... -mod vendor
 
 # Run the binary on an empty container
 FROM scratch
 COPY --from=builder /app/gatus .
 COPY --from=builder /app/config.yaml ./config/config.yaml
-COPY --from=builder /app/static static/
 COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
 ENV PORT=8080
 EXPOSE ${PORT}
-ENTRYPOINT ["/gatus"]
+ENTRYPOINT ["/gatus"]

LICENSE

@@ -199,3 +199,4 @@
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
+

LICENSE.md

@@ -1,201 +0,0 @@
-                                 Apache License
-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
-
-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-   1. Definitions.
-
-      "License" shall mean the terms and conditions for use, reproduction,
-      and distribution as defined by Sections 1 through 9 of this document.
-
-      "Licensor" shall mean the copyright owner or entity authorized by
-      the copyright owner that is granting the License.
-
-      "Legal Entity" shall mean the union of the acting entity and all
-      other entities that control, are controlled by, or are under common
-      control with that entity. For the purposes of this definition,
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-      outstanding shares, or (iii) beneficial ownership of such entity.
-
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-      exercising permissions granted by this License.
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-      including but not limited to software source code, documentation
-      source, and configuration files.
-
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-      transformation or translation of a Source form, including but
-      not limited to compiled object code, generated documentation,
-      and conversions to other media types.
-
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-
-   APPENDIX: How to apply the Apache License to your work.
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-      To apply the Apache License to your work, attach the following
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Makefile

@@ -0,0 +1,40 @@
+BINARY=gatus
+
+# Because there's a folder called "test", we need to make the target "test" phony
+.PHONY: test
+
+install:
+	go build -mod vendor -o $(BINARY) .
+
+run:
+	GATUS_CONFIG_PATH=./config.yaml ./$(BINARY)
+
+clean:
+	rm $(BINARY)
+
+test:
+	go test ./... -cover
+
+
+##########
+# Docker #
+##########
+
+docker-build:
+	docker build -t twinproduction/gatus:latest .
+
+docker-run:
+	docker run -p 8080:8080 --name gatus twinproduction/gatus:latest
+
+docker-build-and-run: docker-build docker-run
+
+
+#############
+# Front end #
+#############
+
+frontend-build:
+	npm --prefix web/app run build
+
+frontend-run:
+	npm --prefix web/app run serve

alerting/alert/alert.go

@@ -0,0 +1,96 @@
+package alert
+
+import (
+	"errors"
+	"strings"
+)
+
+var (
+	// ErrAlertWithInvalidDescription is the error with which Gatus will panic if an alert has an invalid character
+	ErrAlertWithInvalidDescription = errors.New("alert description must not have \" or \\")
+)
+
+// Alert is a core.Endpoint's alert configuration
+type Alert struct {
+	// Type of alert (required)
+	Type Type `yaml:"type"`
+
+	// Enabled defines whether the alert is enabled
+	//
+	// Use Alert.IsEnabled() to retrieve the value of this field.
+	//
+	// This is a pointer, because it is populated by YAML and we need to know whether it was explicitly set to a value
+	// or not for provider.ParseWithDefaultAlert to work.
+	Enabled *bool `yaml:"enabled,omitempty"`
+
+	// FailureThreshold is the number of failures in a row needed before triggering the alert
+	FailureThreshold int `yaml:"failure-threshold"`
+
+	// Description of the alert. Will be included in the alert sent.
+	//
+	// This is a pointer, because it is populated by YAML and we need to know whether it was explicitly set to a value
+	// or not for provider.ParseWithDefaultAlert to work.
+	Description *string `yaml:"description"`
+
+	// SendOnResolved defines whether to send a second notification when the issue has been resolved
+	//
+	// This is a pointer, because it is populated by YAML and we need to know whether it was explicitly set to a value
+	// or not for provider.ParseWithDefaultAlert to work. Use Alert.IsSendingOnResolved() for a non-pointer
+	SendOnResolved *bool `yaml:"send-on-resolved"`
+
+	// SuccessThreshold defines how many successful executions must happen in a row before an ongoing incident is marked as resolved
+	SuccessThreshold int `yaml:"success-threshold"`
+
+	// ResolveKey is an optional field that is used by some providers (i.e. PagerDuty's dedup_key) to resolve
+	// ongoing/triggered incidents
+	ResolveKey string `yaml:"-"`
+
+	// Triggered is used to determine whether an alert has been triggered. When an alert is resolved, this value
+	// should be set back to false. It is used to prevent the same alert from going out twice.
+	//
+	// This value should only be modified if the provider.AlertProvider's Send function does not return an error for an
+	// alert that hasn't been triggered yet. This doubles as a lazy retry. The reason why this behavior isn't also
+	// applied for alerts that are already triggered and has become "healthy" again is to prevent a case where, for
+	// some reason, the alert provider always returns errors when trying to send the resolved notification
+	// (SendOnResolved).
+	Triggered bool `yaml:"-"`
+}
+
+// ValidateAndSetDefaults validates the alert's configuration and sets the default value of fields that have one
+func (alert *Alert) ValidateAndSetDefaults() error {
+	if alert.FailureThreshold <= 0 {
+		alert.FailureThreshold = 3
+	}
+	if alert.SuccessThreshold <= 0 {
+		alert.SuccessThreshold = 2
+	}
+	if strings.ContainsAny(alert.GetDescription(), "\"\\") {
+		return ErrAlertWithInvalidDescription
+	}
+	return nil
+}
+
+// GetDescription retrieves the description of the alert
+func (alert Alert) GetDescription() string {
+	if alert.Description == nil {
+		return ""
+	}
+	return *alert.Description
+}
+
+// IsEnabled returns whether an alert is enabled or not
+// Returns true if not set
+func (alert Alert) IsEnabled() bool {
+	if alert.Enabled == nil {
+		return true
+	}
+	return *alert.Enabled
+}
+
+// IsSendingOnResolved returns whether an alert is sending on resolve or not
+func (alert Alert) IsSendingOnResolved() bool {
+	if alert.SendOnResolved == nil {
+		return false
+	}
+	return *alert.SendOnResolved
+}

alerting/alert/alert_test.go

@@ -0,0 +1,85 @@
+package alert
+
+import (
+	"testing"
+)
+
+func TestAlert_ValidateAndSetDefaults(t *testing.T) {
+	invalidDescription := "\""
+	scenarios := []struct {
+		name                     string
+		alert                    Alert
+		expectedError            error
+		expectedSuccessThreshold int
+		expectedFailureThreshold int
+	}{
+		{
+			name: "valid-empty",
+			alert: Alert{
+				Description:      nil,
+				FailureThreshold: 0,
+				SuccessThreshold: 0,
+			},
+			expectedError:            nil,
+			expectedFailureThreshold: 3,
+			expectedSuccessThreshold: 2,
+		},
+		{
+			name: "invalid-description",
+			alert: Alert{
+				Description:      &invalidDescription,
+				FailureThreshold: 10,
+				SuccessThreshold: 5,
+			},
+			expectedError:            ErrAlertWithInvalidDescription,
+			expectedFailureThreshold: 10,
+			expectedSuccessThreshold: 5,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.name, func(t *testing.T) {
+			if err := scenario.alert.ValidateAndSetDefaults(); err != scenario.expectedError {
+				t.Errorf("expected error %v, got %v", scenario.expectedError, err)
+			}
+			if scenario.alert.SuccessThreshold != scenario.expectedSuccessThreshold {
+				t.Errorf("expected success threshold %v, got %v", scenario.expectedSuccessThreshold, scenario.alert.SuccessThreshold)
+			}
+			if scenario.alert.FailureThreshold != scenario.expectedFailureThreshold {
+				t.Errorf("expected failure threshold %v, got %v", scenario.expectedFailureThreshold, scenario.alert.FailureThreshold)
+			}
+		})
+	}
+}
+
+func TestAlert_IsEnabled(t *testing.T) {
+	if !(Alert{Enabled: nil}).IsEnabled() {
+		t.Error("alert.IsEnabled() should've returned true, because Enabled was set to nil")
+	}
+	if value := false; (Alert{Enabled: &value}).IsEnabled() {
+		t.Error("alert.IsEnabled() should've returned false, because Enabled was set to false")
+	}
+	if value := true; !(Alert{Enabled: &value}).IsEnabled() {
+		t.Error("alert.IsEnabled() should've returned true, because Enabled was set to true")
+	}
+}
+
+func TestAlert_GetDescription(t *testing.T) {
+	if (Alert{Description: nil}).GetDescription() != "" {
+		t.Error("alert.GetDescription() should've returned an empty string, because Description was set to nil")
+	}
+	if value := "description"; (Alert{Description: &value}).GetDescription() != value {
+		t.Error("alert.GetDescription() should've returned false, because Description was set to 'description'")
+	}
+}
+
+func TestAlert_IsSendingOnResolved(t *testing.T) {
+	if (Alert{SendOnResolved: nil}).IsSendingOnResolved() {
+		t.Error("alert.IsSendingOnResolved() should've returned false, because SendOnResolved was set to nil")
+	}
+	if value := false; (Alert{SendOnResolved: &value}).IsSendingOnResolved() {
+		t.Error("alert.IsSendingOnResolved() should've returned false, because SendOnResolved was set to false")
+	}
+	if value := true; !(Alert{SendOnResolved: &value}).IsSendingOnResolved() {
+		t.Error("alert.IsSendingOnResolved() should've returned true, because SendOnResolved was set to true")
+	}
+}

alerting/alert/type.go

@@ -0,0 +1,55 @@
+package alert
+
+// Type is the type of the alert.
+// The value will generally be the name of the alert provider
+type Type string
+
+const (
+	// TypeCustom is the Type for the custom alerting provider
+	TypeCustom Type = "custom"
+
+	// TypeDiscord is the Type for the discord alerting provider
+	TypeDiscord Type = "discord"
+
+	// TypeEmail is the Type for the email alerting provider
+	TypeEmail Type = "email"
+
+	// TypeGitHub is the Type for the github alerting provider
+	TypeGitHub Type = "github"
+
+	// TypeGoogleChat is the Type for the googlechat alerting provider
+	TypeGoogleChat Type = "googlechat"
+
+	// TypeMatrix is the Type for the matrix alerting provider
+	TypeMatrix Type = "matrix"
+
+	// TypeMattermost is the Type for the mattermost alerting provider
+	TypeMattermost Type = "mattermost"
+
+	// TypeMessagebird is the Type for the messagebird alerting provider
+	TypeMessagebird Type = "messagebird"
+
+	// TypeNtfy is the Type for the ntfy alerting provider
+	TypeNtfy Type = "ntfy"
+
+	// TypeOpsgenie is the Type for the opsgenie alerting provider
+	TypeOpsgenie Type = "opsgenie"
+
+	// TypePagerDuty is the Type for the pagerduty alerting provider
+	TypePagerDuty Type = "pagerduty"
+
+	// TypePushover is the Type for the pushover alerting provider
+	TypePushover Type = "pushover"
+
+	// TypeSlack is the Type for the slack alerting provider
+	TypeSlack Type = "slack"
+
+	// TypeTeams is the Type for the teams alerting provider
+	TypeTeams Type = "teams"
+
+	// TypeTelegram is the Type for the telegram alerting provider
+	TypeTelegram Type = "telegram"
+
+	// TypeTwilio is the Type for the twilio alerting provider
+	TypeTwilio Type = "twilio"
+)

alerting/config.go

@@ -1,15 +1,106 @@
 package alerting
 
 import (
-	"github.com/TwinProduction/gatus/alerting/provider/custom"
-	"github.com/TwinProduction/gatus/alerting/provider/pagerduty"
-	"github.com/TwinProduction/gatus/alerting/provider/slack"
-	"github.com/TwinProduction/gatus/alerting/provider/twilio"
+	"log"
+	"reflect"
+	"strings"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/alerting/provider"
+	"github.com/TwiN/gatus/v5/alerting/provider/custom"
+	"github.com/TwiN/gatus/v5/alerting/provider/discord"
+	"github.com/TwiN/gatus/v5/alerting/provider/email"
+	"github.com/TwiN/gatus/v5/alerting/provider/github"
+	"github.com/TwiN/gatus/v5/alerting/provider/googlechat"
+	"github.com/TwiN/gatus/v5/alerting/provider/matrix"
+	"github.com/TwiN/gatus/v5/alerting/provider/mattermost"
+	"github.com/TwiN/gatus/v5/alerting/provider/messagebird"
+	"github.com/TwiN/gatus/v5/alerting/provider/ntfy"
+	"github.com/TwiN/gatus/v5/alerting/provider/opsgenie"
+	"github.com/TwiN/gatus/v5/alerting/provider/pagerduty"
+	"github.com/TwiN/gatus/v5/alerting/provider/pushover"
+	"github.com/TwiN/gatus/v5/alerting/provider/slack"
+	"github.com/TwiN/gatus/v5/alerting/provider/teams"
+	"github.com/TwiN/gatus/v5/alerting/provider/telegram"
+	"github.com/TwiN/gatus/v5/alerting/provider/twilio"
 )
 
+// Config is the configuration for alerting providers
 type Config struct {
-	Slack     *slack.AlertProvider     `yaml:"slack"`
-	PagerDuty *pagerduty.AlertProvider `yaml:"pagerduty"`
-	Twilio    *twilio.AlertProvider    `yaml:"twilio"`
-	Custom    *custom.AlertProvider    `yaml:"custom"`
+	// Custom is the configuration for the custom alerting provider
+	Custom *custom.AlertProvider `yaml:"custom,omitempty"`
+
+	// Discord is the configuration for the discord alerting provider
+	Discord *discord.AlertProvider `yaml:"discord,omitempty"`
+
+	// Email is the configuration for the email alerting provider
+	Email *email.AlertProvider `yaml:"email,omitempty"`
+
+	// GitHub is the configuration for the github alerting provider
+	GitHub *github.AlertProvider `yaml:"github,omitempty"`
+
+	// GoogleChat is the configuration for the googlechat alerting provider
+	GoogleChat *googlechat.AlertProvider `yaml:"googlechat,omitempty"`
+
+	// Matrix is the configuration for the matrix alerting provider
+	Matrix *matrix.AlertProvider `yaml:"matrix,omitempty"`
+
+	// Mattermost is the configuration for the mattermost alerting provider
+	Mattermost *mattermost.AlertProvider `yaml:"mattermost,omitempty"`
+
+	// Messagebird is the configuration for the messagebird alerting provider
+	Messagebird *messagebird.AlertProvider `yaml:"messagebird,omitempty"`
+
+	// Ntfy is the configuration for the ntfy alerting provider
+	Ntfy *ntfy.AlertProvider `yaml:"ntfy,omitempty"`
+
+	// Opsgenie is the configuration for the opsgenie alerting provider
+	Opsgenie *opsgenie.AlertProvider `yaml:"opsgenie,omitempty"`
+
+	// PagerDuty is the configuration for the pagerduty alerting provider
+	PagerDuty *pagerduty.AlertProvider `yaml:"pagerduty,omitempty"`
+
+	// Pushover is the configuration for the pushover alerting provider
+	Pushover *pushover.AlertProvider `yaml:"pushover,omitempty"`
+
+	// Slack is the configuration for the slack alerting provider
+	Slack *slack.AlertProvider `yaml:"slack,omitempty"`
+
+	// Teams is the configuration for the teams alerting provider
+	Teams *teams.AlertProvider `yaml:"teams,omitempty"`
+
+	// Telegram is the configuration for the telegram alerting provider
+	Telegram *telegram.AlertProvider `yaml:"telegram,omitempty"`
+
+	// Twilio is the configuration for the twilio alerting provider
+	Twilio *twilio.AlertProvider `yaml:"twilio,omitempty"`
+}
+
+// GetAlertingProviderByAlertType returns an provider.AlertProvider by its corresponding alert.Type
+func (config *Config) GetAlertingProviderByAlertType(alertType alert.Type) provider.AlertProvider {
+	entityType := reflect.TypeOf(config).Elem()
+	for i := 0; i < entityType.NumField(); i++ {
+		field := entityType.Field(i)
+		if strings.ToLower(field.Name) == string(alertType) {
+			fieldValue := reflect.ValueOf(config).Elem().Field(i)
+			if fieldValue.IsNil() {
+				return nil
+			}
+			return fieldValue.Interface().(provider.AlertProvider)
+		}
+	}
+	log.Printf("[alerting][GetAlertingProviderByAlertType] No alerting provider found for alert type %s", alertType)
+	return nil
+}
+
+// SetAlertingProviderToNil Sets an alerting provider to nil to avoid having to revalidate it every time an
+// alert of its corresponding type is sent.
+func (config *Config) SetAlertingProviderToNil(p provider.AlertProvider) {
+	entityType := reflect.TypeOf(config).Elem()
+	for i := 0; i < entityType.NumField(); i++ {
+		field := entityType.Field(i)
+		if field.Type == reflect.TypeOf(p) {
+			reflect.ValueOf(config).Elem().Field(i).Set(reflect.Zero(field.Type))
+		}
+	}
 }

alerting/provider/custom/custom.go

@@ -3,87 +3,96 @@ package custom
 import (
 	"bytes"
 	"fmt"
-	"github.com/TwinProduction/gatus/client"
-	"github.com/TwinProduction/gatus/core"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"strings"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
 )
 
 // AlertProvider is the configuration necessary for sending an alert using a custom HTTP request
 // Technically, all alert providers should be reachable using the custom alert provider
 type AlertProvider struct {
-	Url     string            `yaml:"url"`
-	Method  string            `yaml:"method,omitempty"`
-	Body    string            `yaml:"body,omitempty"`
-	Headers map[string]string `yaml:"headers,omitempty"`
+	URL          string                       `yaml:"url"`
+	Method       string                       `yaml:"method,omitempty"`
+	Body         string                       `yaml:"body,omitempty"`
+	Headers      map[string]string            `yaml:"headers,omitempty"`
+	Placeholders map[string]map[string]string `yaml:"placeholders,omitempty"`
+
+	// ClientConfig is the configuration of the client used to communicate with the provider's target
+	ClientConfig *client.Config `yaml:"client,omitempty"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
 }
 
 // IsValid returns whether the provider's configuration is valid
 func (provider *AlertProvider) IsValid() bool {
-	return len(provider.Url) > 0
+	if provider.ClientConfig == nil {
+		provider.ClientConfig = client.GetDefaultConfig()
+	}
+	return len(provider.URL) > 0 && provider.ClientConfig != nil
 }
 
-// ToCustomAlertProvider converts the provider into a custom.AlertProvider
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *AlertProvider {
-	return provider
+// GetAlertStatePlaceholderValue returns the Placeholder value for ALERT_TRIGGERED_OR_RESOLVED if configured
+func (provider *AlertProvider) GetAlertStatePlaceholderValue(resolved bool) string {
+	status := "TRIGGERED"
+	if resolved {
+		status = "RESOLVED"
+	}
+	if _, ok := provider.Placeholders["ALERT_TRIGGERED_OR_RESOLVED"]; ok {
+		if val, ok := provider.Placeholders["ALERT_TRIGGERED_OR_RESOLVED"][status]; ok {
+			return val
+		}
+	}
+	return status
 }
 
-func (provider *AlertProvider) buildRequest(serviceName, alertDescription string, resolved bool) *http.Request {
-	body := provider.Body
-	providerUrl := provider.Url
-	method := provider.Method
-	if strings.Contains(body, "[ALERT_DESCRIPTION]") {
-		body = strings.ReplaceAll(body, "[ALERT_DESCRIPTION]", alertDescription)
-	}
-	if strings.Contains(body, "[SERVICE_NAME]") {
-		body = strings.ReplaceAll(body, "[SERVICE_NAME]", serviceName)
-	}
-	if strings.Contains(body, "[ALERT_TRIGGERED_OR_RESOLVED]") {
-		if resolved {
-			body = strings.ReplaceAll(body, "[ALERT_TRIGGERED_OR_RESOLVED]", "RESOLVED")
-		} else {
-			body = strings.ReplaceAll(body, "[ALERT_TRIGGERED_OR_RESOLVED]", "TRIGGERED")
-		}
-	}
-	if strings.Contains(providerUrl, "[ALERT_DESCRIPTION]") {
-		providerUrl = strings.ReplaceAll(providerUrl, "[ALERT_DESCRIPTION]", alertDescription)
-	}
-	if strings.Contains(providerUrl, "[SERVICE_NAME]") {
-		providerUrl = strings.ReplaceAll(providerUrl, "[SERVICE_NAME]", serviceName)
-	}
-	if strings.Contains(providerUrl, "[ALERT_TRIGGERED_OR_RESOLVED]") {
-		if resolved {
-			providerUrl = strings.ReplaceAll(providerUrl, "[ALERT_TRIGGERED_OR_RESOLVED]", "RESOLVED")
-		} else {
-			providerUrl = strings.ReplaceAll(providerUrl, "[ALERT_TRIGGERED_OR_RESOLVED]", "TRIGGERED")
-		}
+func (provider *AlertProvider) buildHTTPRequest(endpoint *core.Endpoint, alert *alert.Alert, resolved bool) *http.Request {
+	body, url, method := provider.Body, provider.URL, provider.Method
+	body = strings.ReplaceAll(body, "[ALERT_DESCRIPTION]", alert.GetDescription())
+	url = strings.ReplaceAll(url, "[ALERT_DESCRIPTION]", alert.GetDescription())
+	body = strings.ReplaceAll(body, "[ENDPOINT_NAME]", endpoint.Name)
+	url = strings.ReplaceAll(url, "[ENDPOINT_NAME]", endpoint.Name)
+	body = strings.ReplaceAll(body, "[ENDPOINT_GROUP]", endpoint.Group)
+	url = strings.ReplaceAll(url, "[ENDPOINT_GROUP]", endpoint.Group)
+	body = strings.ReplaceAll(body, "[ENDPOINT_URL]", endpoint.URL)
+	url = strings.ReplaceAll(url, "[ENDPOINT_URL]", endpoint.URL)
+	if resolved {
+		body = strings.ReplaceAll(body, "[ALERT_TRIGGERED_OR_RESOLVED]", provider.GetAlertStatePlaceholderValue(true))
+		url = strings.ReplaceAll(url, "[ALERT_TRIGGERED_OR_RESOLVED]", provider.GetAlertStatePlaceholderValue(true))
+	} else {
+		body = strings.ReplaceAll(body, "[ALERT_TRIGGERED_OR_RESOLVED]", provider.GetAlertStatePlaceholderValue(false))
+		url = strings.ReplaceAll(url, "[ALERT_TRIGGERED_OR_RESOLVED]", provider.GetAlertStatePlaceholderValue(false))
 	}
 	if len(method) == 0 {
-		method = "GET"
+		method = http.MethodGet
 	}
 	bodyBuffer := bytes.NewBuffer([]byte(body))
-	request, _ := http.NewRequest(method, providerUrl, bodyBuffer)
+	request, _ := http.NewRequest(method, url, bodyBuffer)
 	for k, v := range provider.Headers {
 		request.Header.Set(k, v)
 	}
 	return request
 }
 
-// Send a request to the alert provider and return the body
-func (provider *AlertProvider) Send(serviceName, alertDescription string, resolved bool) ([]byte, error) {
-	request := provider.buildRequest(serviceName, alertDescription, resolved)
-	response, err := client.GetHttpClient().Do(request)
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	request := provider.buildHTTPRequest(endpoint, alert, resolved)
+	response, err := client.GetHTTPClient(provider.ClientConfig).Do(request)
 	if err != nil {
-		return nil, err
+		return err
 	}
+	defer response.Body.Close()
 	if response.StatusCode > 399 {
-		body, err := ioutil.ReadAll(response.Body)
-		if err != nil {
-			return nil, fmt.Errorf("call to provider alert returned status code %d", response.StatusCode)
-		} else {
-			return nil, fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
-		}
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
 	}
-	return ioutil.ReadAll(response.Body)
+	return err
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
 }

alerting/provider/custom/custom_test.go

@@ -1,59 +1,226 @@
 package custom
 
 import (
-	"io/ioutil"
+	"fmt"
+	"io"
+	"net/http"
 	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
 )
 
 func TestAlertProvider_IsValid(t *testing.T) {
-	invalidProvider := AlertProvider{Url: ""}
-	if invalidProvider.IsValid() {
-		t.Error("provider shouldn't have been valid")
+	t.Run("invalid-provider", func(t *testing.T) {
+		invalidProvider := AlertProvider{URL: ""}
+		if invalidProvider.IsValid() {
+			t.Error("provider shouldn't have been valid")
+		}
+	})
+	t.Run("valid-provider", func(t *testing.T) {
+		validProvider := AlertProvider{URL: "https://example.com"}
+		if validProvider.ClientConfig != nil {
+			t.Error("provider client config should have been nil prior to IsValid() being executed")
+		}
+		if !validProvider.IsValid() {
+			t.Error("provider should've been valid")
+		}
+		if validProvider.ClientConfig == nil {
+			t.Error("provider client config should have been set after IsValid() was executed")
+		}
+	})
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
 	}
-	validProvider := AlertProvider{Url: "http://example.com"}
-	if !validProvider.IsValid() {
-		t.Error("provider should've been valid")
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
 	}
 }
 
-func TestAlertProvider_buildRequestWhenResolved(t *testing.T) {
-	const (
-		ExpectedUrl  = "http://example.com/service-name"
-		ExpectedBody = "service-name,alert-description,RESOLVED"
-	)
+func TestAlertProvider_buildHTTPRequest(t *testing.T) {
 	customAlertProvider := &AlertProvider{
-		Url:     "http://example.com/[SERVICE_NAME]",
-		Method:  "GET",
-		Body:    "[SERVICE_NAME],[ALERT_DESCRIPTION],[ALERT_TRIGGERED_OR_RESOLVED]",
-		Headers: nil,
+		URL:  "https://example.com/[ENDPOINT_GROUP]/[ENDPOINT_NAME]?event=[ALERT_TRIGGERED_OR_RESOLVED]&description=[ALERT_DESCRIPTION]&url=[ENDPOINT_URL]",
+		Body: "[ENDPOINT_NAME],[ENDPOINT_GROUP],[ALERT_DESCRIPTION],[ENDPOINT_URL],[ALERT_TRIGGERED_OR_RESOLVED]",
 	}
-	request := customAlertProvider.buildRequest("service-name", "alert-description", true)
-	if request.URL.String() != ExpectedUrl {
-		t.Error("expected URL to be", ExpectedUrl, "was", request.URL.String())
+	alertDescription := "alert-description"
+	scenarios := []struct {
+		AlertProvider *AlertProvider
+		Resolved      bool
+		ExpectedURL   string
+		ExpectedBody  string
+	}{
+		{
+			AlertProvider: customAlertProvider,
+			Resolved:      true,
+			ExpectedURL:   "https://example.com/endpoint-group/endpoint-name?event=RESOLVED&description=alert-description&url=https://example.com",
+			ExpectedBody:  "endpoint-name,endpoint-group,alert-description,https://example.com,RESOLVED",
+		},
+		{
+			AlertProvider: customAlertProvider,
+			Resolved:      false,
+			ExpectedURL:   "https://example.com/endpoint-group/endpoint-name?event=TRIGGERED&description=alert-description&url=https://example.com",
+			ExpectedBody:  "endpoint-name,endpoint-group,alert-description,https://example.com,TRIGGERED",
+		},
 	}
-	body, _ := ioutil.ReadAll(request.Body)
-	if string(body) != ExpectedBody {
-		t.Error("expected body to be", ExpectedBody, "was", string(body))
+	for _, scenario := range scenarios {
+		t.Run(fmt.Sprintf("resolved-%v-with-default-placeholders", scenario.Resolved), func(t *testing.T) {
+			request := customAlertProvider.buildHTTPRequest(
+				&core.Endpoint{Name: "endpoint-name", Group: "endpoint-group", URL: "https://example.com"},
+				&alert.Alert{Description: &alertDescription},
+				scenario.Resolved,
+			)
+			if request.URL.String() != scenario.ExpectedURL {
+				t.Error("expected URL to be", scenario.ExpectedURL, "got", request.URL.String())
+			}
+			body, _ := io.ReadAll(request.Body)
+			if string(body) != scenario.ExpectedBody {
+				t.Error("expected body to be", scenario.ExpectedBody, "got", string(body))
+			}
+		})
 	}
 }
 
-func TestAlertProvider_buildRequestWhenTriggered(t *testing.T) {
-	const (
-		ExpectedUrl  = "http://example.com/service-name"
-		ExpectedBody = "service-name,alert-description,TRIGGERED"
-	)
+func TestAlertProvider_buildHTTPRequestWithCustomPlaceholder(t *testing.T) {
 	customAlertProvider := &AlertProvider{
-		Url:     "http://example.com/[SERVICE_NAME]",
-		Method:  "GET",
-		Body:    "[SERVICE_NAME],[ALERT_DESCRIPTION],[ALERT_TRIGGERED_OR_RESOLVED]",
+		URL:     "https://example.com/[ENDPOINT_GROUP]/[ENDPOINT_NAME]?event=[ALERT_TRIGGERED_OR_RESOLVED]&description=[ALERT_DESCRIPTION]",
+		Body:    "[ENDPOINT_NAME],[ENDPOINT_GROUP],[ALERT_DESCRIPTION],[ALERT_TRIGGERED_OR_RESOLVED]",
 		Headers: nil,
+		Placeholders: map[string]map[string]string{
+			"ALERT_TRIGGERED_OR_RESOLVED": {
+				"RESOLVED":  "fixed",
+				"TRIGGERED": "boom",
+			},
+		},
 	}
-	request := customAlertProvider.buildRequest("service-name", "alert-description", false)
-	if request.URL.String() != ExpectedUrl {
-		t.Error("expected URL to be", ExpectedUrl, "was", request.URL.String())
+	alertDescription := "alert-description"
+	scenarios := []struct {
+		AlertProvider *AlertProvider
+		Resolved      bool
+		ExpectedURL   string
+		ExpectedBody  string
+	}{
+		{
+			AlertProvider: customAlertProvider,
+			Resolved:      true,
+			ExpectedURL:   "https://example.com/endpoint-group/endpoint-name?event=fixed&description=alert-description",
+			ExpectedBody:  "endpoint-name,endpoint-group,alert-description,fixed",
+		},
+		{
+			AlertProvider: customAlertProvider,
+			Resolved:      false,
+			ExpectedURL:   "https://example.com/endpoint-group/endpoint-name?event=boom&description=alert-description",
+			ExpectedBody:  "endpoint-name,endpoint-group,alert-description,boom",
+		},
 	}
-	body, _ := ioutil.ReadAll(request.Body)
-	if string(body) != ExpectedBody {
-		t.Error("expected body to be", ExpectedBody, "was", string(body))
+	for _, scenario := range scenarios {
+		t.Run(fmt.Sprintf("resolved-%v-with-custom-placeholders", scenario.Resolved), func(t *testing.T) {
+			request := customAlertProvider.buildHTTPRequest(
+				&core.Endpoint{Name: "endpoint-name", Group: "endpoint-group"},
+				&alert.Alert{Description: &alertDescription},
+				scenario.Resolved,
+			)
+			if request.URL.String() != scenario.ExpectedURL {
+				t.Error("expected URL to be", scenario.ExpectedURL, "got", request.URL.String())
+			}
+			body, _ := io.ReadAll(request.Body)
+			if string(body) != scenario.ExpectedBody {
+				t.Error("expected body to be", scenario.ExpectedBody, "got", string(body))
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetAlertStatePlaceholderValueDefaults(t *testing.T) {
+	customAlertProvider := &AlertProvider{
+		URL:  "https://example.com/[ENDPOINT_NAME]?event=[ALERT_TRIGGERED_OR_RESOLVED]&description=[ALERT_DESCRIPTION]",
+		Body: "[ENDPOINT_NAME],[ENDPOINT_GROUP],[ALERT_DESCRIPTION],[ALERT_TRIGGERED_OR_RESOLVED]",
+	}
+	if customAlertProvider.GetAlertStatePlaceholderValue(true) != "RESOLVED" {
+		t.Error("expected RESOLVED, got", customAlertProvider.GetAlertStatePlaceholderValue(true))
+	}
+	if customAlertProvider.GetAlertStatePlaceholderValue(false) != "TRIGGERED" {
+		t.Error("expected TRIGGERED, got", customAlertProvider.GetAlertStatePlaceholderValue(false))
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
 	}
 }

alerting/provider/discord/discord.go

@@ -0,0 +1,143 @@
+package discord
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Discord
+type AlertProvider struct {
+	WebhookURL string `yaml:"webhook-url"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+
+	// Overrides is a list of Override that may be prioritized over the default configuration
+	Overrides []Override `yaml:"overrides,omitempty"`
+}
+
+// Override is a case under which the default integration is overridden
+type Override struct {
+	Group      string `yaml:"group"`
+	WebhookURL string `yaml:"webhook-url"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	registeredGroups := make(map[string]bool)
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if isAlreadyRegistered := registeredGroups[override.Group]; isAlreadyRegistered || override.Group == "" || len(override.WebhookURL) == 0 {
+				return false
+			}
+			registeredGroups[override.Group] = true
+		}
+	}
+	return len(provider.WebhookURL) > 0
+}
+
+// Send an alert using the provider
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer(provider.buildRequestBody(endpoint, alert, result, resolved))
+	request, err := http.NewRequest(http.MethodPost, provider.getWebhookURLForGroup(endpoint.Group), buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	response, err := client.GetHTTPClient(nil).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+type Body struct {
+	Content string  `json:"content"`
+	Embeds  []Embed `json:"embeds"`
+}
+
+type Embed struct {
+	Title       string  `json:"title"`
+	Description string  `json:"description"`
+	Color       int     `json:"color"`
+	Fields      []Field `json:"fields"`
+}
+
+type Field struct {
+	Name   string `json:"name"`
+	Value  string `json:"value"`
+	Inline bool   `json:"inline"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
+	var message, results string
+	var colorCode int
+	if resolved {
+		message = fmt.Sprintf("An alert for **%s** has been resolved after passing successfully %d time(s) in a row", endpoint.DisplayName(), alert.SuccessThreshold)
+		colorCode = 3066993
+	} else {
+		message = fmt.Sprintf("An alert for **%s** has been triggered due to having failed %d time(s) in a row", endpoint.DisplayName(), alert.FailureThreshold)
+		colorCode = 15158332
+	}
+	for _, conditionResult := range result.ConditionResults {
+		var prefix string
+		if conditionResult.Success {
+			prefix = ":white_check_mark:"
+		} else {
+			prefix = ":x:"
+		}
+		results += fmt.Sprintf("%s - `%s`\n", prefix, conditionResult.Condition)
+	}
+	var description string
+	if alertDescription := alert.GetDescription(); len(alertDescription) > 0 {
+		description = ":\n> " + alertDescription
+	}
+	body, _ := json.Marshal(Body{
+		Content: "",
+		Embeds: []Embed{
+			{
+				Title:       ":helmet_with_white_cross: Gatus",
+				Description: message + description,
+				Color:       colorCode,
+				Fields: []Field{
+					{
+						Name:   "Condition results",
+						Value:  results,
+						Inline: false,
+					},
+				},
+			},
+		},
+	})
+	return body
+}
+
+// getWebhookURLForGroup returns the appropriate Webhook URL integration to for a given group
+func (provider *AlertProvider) getWebhookURLForGroup(group string) string {
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if group == override.Group {
+				return override.WebhookURL
+			}
+		}
+	}
+	return provider.WebhookURL
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/discord/discord_test.go

@@ -0,0 +1,259 @@
+package discord
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestAlertProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{WebhookURL: ""}
+	if invalidProvider.IsValid() {
+		t.Error("provider shouldn't have been valid")
+	}
+	validProvider := AlertProvider{WebhookURL: "http://example.com"}
+	if !validProvider.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_IsValidWithOverride(t *testing.T) {
+	providerWithInvalidOverrideGroup := AlertProvider{
+		Overrides: []Override{
+			{
+				WebhookURL: "http://example.com",
+				Group:      "",
+			},
+		},
+	}
+	if providerWithInvalidOverrideGroup.IsValid() {
+		t.Error("provider Group shouldn't have been valid")
+	}
+	providerWithInvalidOverrideTo := AlertProvider{
+		Overrides: []Override{
+			{
+				WebhookURL: "",
+				Group:      "group",
+			},
+		},
+	}
+	if providerWithInvalidOverrideTo.IsValid() {
+		t.Error("provider integration key shouldn't have been valid")
+	}
+	providerWithValidOverride := AlertProvider{
+		WebhookURL: "http://example.com",
+		Overrides: []Override{
+			{
+				WebhookURL: "http://example.com",
+				Group:      "group",
+			},
+		},
+	}
+	if !providerWithValidOverride.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: "{\"content\":\"\",\"embeds\":[{\"title\":\":helmet_with_white_cross: Gatus\",\"description\":\"An alert for **endpoint-name** has been triggered due to having failed 3 time(s) in a row:\\n\\u003e description-1\",\"color\":15158332,\"fields\":[{\"name\":\"Condition results\",\"value\":\":x: - `[CONNECTED] == true`\\n:x: - `[STATUS] == 200`\\n:x: - `[BODY] != \\\"\\\"`\\n\",\"inline\":false}]}]}",
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"content\":\"\",\"embeds\":[{\"title\":\":helmet_with_white_cross: Gatus\",\"description\":\"An alert for **endpoint-name** has been resolved after passing successfully 5 time(s) in a row:\\n\\u003e description-2\",\"color\":3066993,\"fields\":[{\"name\":\"Condition results\",\"value\":\":white_check_mark: - `[CONNECTED] == true`\\n:white_check_mark: - `[STATUS] == 200`\\n:white_check_mark: - `[BODY] != \\\"\\\"`\\n\",\"inline\":false}]}]}",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+						{Condition: "[BODY] != \"\"", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal(body, &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}
+
+func TestAlertProvider_getWebhookURLForGroup(t *testing.T) {
+	tests := []struct {
+		Name           string
+		Provider       AlertProvider
+		InputGroup     string
+		ExpectedOutput string
+	}{
+		{
+			Name: "provider-no-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides:  nil,
+			},
+			InputGroup:     "",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-no-override-specify-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides:  nil,
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-with-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides: []Override{
+					{
+						Group:      "group",
+						WebhookURL: "http://example01.com",
+					},
+				},
+			},
+			InputGroup:     "",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-with-override-specify-group-should-override",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides: []Override{
+					{
+						Group:      "group",
+						WebhookURL: "http://example01.com",
+					},
+				},
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "http://example01.com",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			if got := tt.Provider.getWebhookURLForGroup(tt.InputGroup); got != tt.ExpectedOutput {
+				t.Errorf("AlertProvider.getWebhookURLForGroup() = %v, want %v", got, tt.ExpectedOutput)
+			}
+		})
+	}
+}

alerting/provider/email/email.go

@@ -0,0 +1,109 @@
+package email
+
+import (
+	"fmt"
+	"math"
+	"strings"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/core"
+	gomail "gopkg.in/mail.v2"
+)
+
+// AlertProvider is the configuration necessary for sending an alert using SMTP
+type AlertProvider struct {
+	From     string `yaml:"from"`
+	Username string `yaml:"username"`
+	Password string `yaml:"password"`
+	Host     string `yaml:"host"`
+	Port     int    `yaml:"port"`
+	To       string `yaml:"to"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+
+	// Overrides is a list of Override that may be prioritized over the default configuration
+	Overrides []Override `yaml:"overrides,omitempty"`
+}
+
+// Override is a case under which the default integration is overridden
+type Override struct {
+	Group string `yaml:"group"`
+	To    string `yaml:"to"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	registeredGroups := make(map[string]bool)
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if isAlreadyRegistered := registeredGroups[override.Group]; isAlreadyRegistered || override.Group == "" || len(override.To) == 0 {
+				return false
+			}
+			registeredGroups[override.Group] = true
+		}
+	}
+
+	return len(provider.From) > 0 && len(provider.Password) > 0 && len(provider.Host) > 0 && len(provider.To) > 0 && provider.Port > 0 && provider.Port < math.MaxUint16
+}
+
+// Send an alert using the provider
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	var username string
+	if len(provider.Username) > 0 {
+		username = provider.Username
+	} else {
+		username = provider.From
+	}
+	subject, body := provider.buildMessageSubjectAndBody(endpoint, alert, result, resolved)
+	m := gomail.NewMessage()
+	m.SetHeader("From", provider.From)
+	m.SetHeader("To", strings.Split(provider.getToForGroup(endpoint.Group), ",")...)
+	m.SetHeader("Subject", subject)
+	m.SetBody("text/plain", body)
+	d := gomail.NewDialer(provider.Host, provider.Port, username, provider.Password)
+	return d.DialAndSend(m)
+}
+
+// buildMessageSubjectAndBody builds the message subject and body
+func (provider *AlertProvider) buildMessageSubjectAndBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) (string, string) {
+	var subject, message, results string
+	if resolved {
+		subject = fmt.Sprintf("[%s] Alert resolved", endpoint.DisplayName())
+		message = fmt.Sprintf("An alert for %s has been resolved after passing successfully %d time(s) in a row", endpoint.DisplayName(), alert.SuccessThreshold)
+	} else {
+		subject = fmt.Sprintf("[%s] Alert triggered", endpoint.DisplayName())
+		message = fmt.Sprintf("An alert for %s has been triggered due to having failed %d time(s) in a row", endpoint.DisplayName(), alert.FailureThreshold)
+	}
+	for _, conditionResult := range result.ConditionResults {
+		var prefix string
+		if conditionResult.Success {
+			prefix = "✅"
+		} else {
+			prefix = "❌"
+		}
+		results += fmt.Sprintf("%s %s\n", prefix, conditionResult.Condition)
+	}
+	var description string
+	if alertDescription := alert.GetDescription(); len(alertDescription) > 0 {
+		description = "\n\nAlert description: " + alertDescription
+	}
+	return subject, message + description + "\n\nCondition results:\n" + results
+}
+
+// getToForGroup returns the appropriate email integration to for a given group
+func (provider *AlertProvider) getToForGroup(group string) string {
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if group == override.Group {
+				return override.To
+			}
+		}
+	}
+	return provider.To
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/email/email_test.go

@@ -0,0 +1,183 @@
+package email
+
+import (
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+func TestAlertDefaultProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{}
+	if invalidProvider.IsValid() {
+		t.Error("provider shouldn't have been valid")
+	}
+	validProvider := AlertProvider{From: "from@example.com", Password: "password", Host: "smtp.gmail.com", Port: 587, To: "to@example.com"}
+	if !validProvider.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_IsValidWithOverride(t *testing.T) {
+	providerWithInvalidOverrideGroup := AlertProvider{
+		Overrides: []Override{
+			{
+				To:    "to@example.com",
+				Group: "",
+			},
+		},
+	}
+	if providerWithInvalidOverrideGroup.IsValid() {
+		t.Error("provider Group shouldn't have been valid")
+	}
+	providerWithInvalidOverrideTo := AlertProvider{
+		Overrides: []Override{
+			{
+				To:    "",
+				Group: "group",
+			},
+		},
+	}
+	if providerWithInvalidOverrideTo.IsValid() {
+		t.Error("provider integration key shouldn't have been valid")
+	}
+	providerWithValidOverride := AlertProvider{
+		From:     "from@example.com",
+		Password: "password",
+		Host:     "smtp.gmail.com",
+		Port:     587,
+		To:       "to@example.com",
+		Overrides: []Override{
+			{
+				To:    "to@example.com",
+				Group: "group",
+			},
+		},
+	}
+	if !providerWithValidOverride.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name            string
+		Provider        AlertProvider
+		Alert           alert.Alert
+		Resolved        bool
+		ExpectedSubject string
+		ExpectedBody    string
+	}{
+		{
+			Name:            "triggered",
+			Provider:        AlertProvider{},
+			Alert:           alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:        false,
+			ExpectedSubject: "[endpoint-name] Alert triggered",
+			ExpectedBody:    "An alert for endpoint-name has been triggered due to having failed 3 time(s) in a row\n\nAlert description: description-1\n\nCondition results:\n❌ [CONNECTED] == true\n❌ [STATUS] == 200\n",
+		},
+		{
+			Name:            "resolved",
+			Provider:        AlertProvider{},
+			Alert:           alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:        true,
+			ExpectedSubject: "[endpoint-name] Alert resolved",
+			ExpectedBody:    "An alert for endpoint-name has been resolved after passing successfully 5 time(s) in a row\n\nAlert description: description-2\n\nCondition results:\n✅ [CONNECTED] == true\n✅ [STATUS] == 200\n",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			subject, body := scenario.Provider.buildMessageSubjectAndBody(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if subject != scenario.ExpectedSubject {
+				t.Errorf("expected subject to be %s, got %s", scenario.ExpectedSubject, subject)
+			}
+			if body != scenario.ExpectedBody {
+				t.Errorf("expected body to be %s, got %s", scenario.ExpectedBody, body)
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}
+
+func TestAlertProvider_getToForGroup(t *testing.T) {
+	tests := []struct {
+		Name           string
+		Provider       AlertProvider
+		InputGroup     string
+		ExpectedOutput string
+	}{
+		{
+			Name: "provider-no-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				To:        "to@example.com",
+				Overrides: nil,
+			},
+			InputGroup:     "",
+			ExpectedOutput: "to@example.com",
+		},
+		{
+			Name: "provider-no-override-specify-group-should-default",
+			Provider: AlertProvider{
+				To:        "to@example.com",
+				Overrides: nil,
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "to@example.com",
+		},
+		{
+			Name: "provider-with-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				To: "to@example.com",
+				Overrides: []Override{
+					{
+						Group: "group",
+						To:    "to01@example.com",
+					},
+				},
+			},
+			InputGroup:     "",
+			ExpectedOutput: "to@example.com",
+		},
+		{
+			Name: "provider-with-override-specify-group-should-override",
+			Provider: AlertProvider{
+				To: "to@example.com",
+				Overrides: []Override{
+					{
+						Group: "group",
+						To:    "to01@example.com",
+					},
+				},
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "to01@example.com",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			if got := tt.Provider.getToForGroup(tt.InputGroup); got != tt.ExpectedOutput {
+				t.Errorf("AlertProvider.getToForGroup() = %v, want %v", got, tt.ExpectedOutput)
+			}
+		})
+	}
+}

alerting/provider/github/github.go

@@ -0,0 +1,129 @@
+package github
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/google/go-github/v48/github"
+	"golang.org/x/oauth2"
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Discord
+type AlertProvider struct {
+	RepositoryURL string `yaml:"repository-url"` // The URL of the GitHub repository to create issues in
+	Token         string `yaml:"token"`          // Token requires at least RW on issues and RO on metadata
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+
+	username        string
+	repositoryOwner string
+	repositoryName  string
+	githubClient    *github.Client
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	if len(provider.Token) == 0 || len(provider.RepositoryURL) == 0 {
+		return false
+	}
+	// Validate format of the repository URL
+	repositoryURL, err := url.Parse(provider.RepositoryURL)
+	if err != nil {
+		return false
+	}
+	baseURL := repositoryURL.Scheme + "://" + repositoryURL.Host
+	pathParts := strings.Split(repositoryURL.Path, "/")
+	if len(pathParts) != 3 {
+		return false
+	}
+	provider.repositoryOwner = pathParts[1]
+	provider.repositoryName = pathParts[2]
+	// Create oauth2 HTTP client with GitHub token
+	httpClientWithStaticTokenSource := oauth2.NewClient(context.Background(), oauth2.StaticTokenSource(&oauth2.Token{
+		AccessToken: provider.Token,
+	}))
+	// Create GitHub client
+	if baseURL == "https://github.com" {
+		provider.githubClient = github.NewClient(httpClientWithStaticTokenSource)
+	} else {
+		provider.githubClient, err = github.NewEnterpriseClient(baseURL, baseURL, httpClientWithStaticTokenSource)
+		if err != nil {
+			return false
+		}
+	}
+	// Retrieve the username once to validate that the token is valid
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	user, _, err := provider.githubClient.Users.Get(ctx, "")
+	if err != nil {
+		return false
+	}
+	provider.username = *user.Login
+	return true
+}
+
+// Send creates an issue in the designed RepositoryURL if the resolved parameter passed is false,
+// or closes the relevant issue(s) if the resolved parameter passed is true.
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	title := "alert(gatus): " + endpoint.DisplayName()
+	if !resolved {
+		_, _, err := provider.githubClient.Issues.Create(context.Background(), provider.repositoryOwner, provider.repositoryName, &github.IssueRequest{
+			Title: github.String(title),
+			Body:  github.String(provider.buildIssueBody(endpoint, alert, result)),
+		})
+		if err != nil {
+			return fmt.Errorf("failed to create issue: %w", err)
+		}
+	} else {
+		issues, _, err := provider.githubClient.Issues.ListByRepo(context.Background(), provider.repositoryOwner, provider.repositoryName, &github.IssueListByRepoOptions{
+			State:       "open",
+			Creator:     provider.username,
+			ListOptions: github.ListOptions{PerPage: 100},
+		})
+		if err != nil {
+			return fmt.Errorf("failed to list issues: %w", err)
+		}
+		for _, issue := range issues {
+			if *issue.Title == title {
+				_, _, err = provider.githubClient.Issues.Edit(context.Background(), provider.repositoryOwner, provider.repositoryName, *issue.Number, &github.IssueRequest{
+					State: github.String("closed"),
+				})
+				if err != nil {
+					return fmt.Errorf("failed to close issue: %w", err)
+				}
+			}
+		}
+	}
+	return nil
+}
+
+// buildIssueBody builds the body of the issue
+func (provider *AlertProvider) buildIssueBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result) string {
+	var results string
+	for _, conditionResult := range result.ConditionResults {
+		var prefix string
+		if conditionResult.Success {
+			prefix = ":white_check_mark:"
+		} else {
+			prefix = ":x:"
+		}
+		results += fmt.Sprintf("- %s - `%s`\n", prefix, conditionResult.Condition)
+	}
+	var description string
+	if alertDescription := alert.GetDescription(); len(alertDescription) > 0 {
+		description = ":\n> " + alertDescription
+	}
+	message := fmt.Sprintf("An alert for **%s** has been triggered due to having failed %d time(s) in a row", endpoint.DisplayName(), alert.FailureThreshold)
+	return message + description + "\n\n## Condition results\n" + results
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/github/github_test.go

@@ -0,0 +1,158 @@
+package github
+
+import (
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+	"github.com/google/go-github/v48/github"
+)
+
+func TestAlertDefaultProvider_IsValid(t *testing.T) {
+	scenarios := []struct {
+		Name     string
+		Provider AlertProvider
+		Expected bool
+	}{
+		{
+			Name:     "invalid",
+			Provider: AlertProvider{RepositoryURL: "", Token: ""},
+			Expected: false,
+		},
+		{
+			Name:     "invalid-token",
+			Provider: AlertProvider{RepositoryURL: "https://github.com/TwiN/test", Token: "12345"},
+			Expected: false,
+		},
+		{
+			Name:     "missing-repository-name",
+			Provider: AlertProvider{RepositoryURL: "https://github.com/TwiN", Token: "12345"},
+			Expected: false,
+		},
+		{
+			Name:     "enterprise-client",
+			Provider: AlertProvider{RepositoryURL: "https://github.example.com/TwiN/test", Token: "12345"},
+			Expected: false,
+		},
+		{
+			Name:     "invalid-url",
+			Provider: AlertProvider{RepositoryURL: "github.com/TwiN/test", Token: "12345"},
+			Expected: false,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			if scenario.Provider.IsValid() != scenario.Expected {
+				t.Errorf("expected %t, got %t", scenario.Expected, scenario.Provider.IsValid())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:          "triggered-error",
+			Provider:      AlertProvider{RepositoryURL: "https://github.com/TwiN/test", Token: "12345"},
+			Alert:         alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:      false,
+			ExpectedError: true,
+		},
+		{
+			Name:          "resolved-error",
+			Provider:      AlertProvider{RepositoryURL: "https://github.com/TwiN/test", Token: "12345"},
+			Alert:         alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:      true,
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			scenario.Provider.githubClient = github.NewClient(nil)
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name", Group: "endpoint-group"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	scenarios := []struct {
+		Name         string
+		Endpoint     core.Endpoint
+		Provider     AlertProvider
+		Alert        alert.Alert
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Endpoint:     core.Endpoint{Name: "endpoint-name", URL: "https://example.org"},
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &firstDescription, FailureThreshold: 3},
+			ExpectedBody: "An alert for **endpoint-name** has been triggered due to having failed 3 time(s) in a row:\n> description-1\n\n## Condition results\n- :white_check_mark: - `[CONNECTED] == true`\n- :x: - `[STATUS] == 200`",
+		},
+		{
+			Name:         "no-description",
+			Endpoint:     core.Endpoint{Name: "endpoint-name", URL: "https://example.org"},
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{FailureThreshold: 10},
+			ExpectedBody: "An alert for **endpoint-name** has been triggered due to having failed 10 time(s) in a row\n\n## Condition results\n- :white_check_mark: - `[CONNECTED] == true`\n- :x: - `[STATUS] == 200`",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildIssueBody(
+				&scenario.Endpoint,
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: true},
+						{Condition: "[STATUS] == 200", Success: false},
+					},
+				},
+			)
+			if strings.TrimSpace(body) != strings.TrimSpace(scenario.ExpectedBody) {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}

alerting/provider/googlechat/googlechat.go

@@ -0,0 +1,201 @@
+package googlechat
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Google chat
+type AlertProvider struct {
+	WebhookURL string `yaml:"webhook-url"`
+
+	// ClientConfig is the configuration of the client used to communicate with the provider's target
+	ClientConfig *client.Config `yaml:"client,omitempty"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+
+	// Overrides is a list of Override that may be prioritized over the default configuration
+	Overrides []Override `yaml:"overrides,omitempty"`
+}
+
+// Override is a case under which the default integration is overridden
+type Override struct {
+	Group      string `yaml:"group"`
+	WebhookURL string `yaml:"webhook-url"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	if provider.ClientConfig == nil {
+		provider.ClientConfig = client.GetDefaultConfig()
+	}
+	registeredGroups := make(map[string]bool)
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if isAlreadyRegistered := registeredGroups[override.Group]; isAlreadyRegistered || override.Group == "" || len(override.WebhookURL) == 0 {
+				return false
+			}
+			registeredGroups[override.Group] = true
+		}
+	}
+	return len(provider.WebhookURL) > 0
+}
+
+// Send an alert using the provider
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer(provider.buildRequestBody(endpoint, alert, result, resolved))
+	request, err := http.NewRequest(http.MethodPost, provider.getWebhookURLForGroup(endpoint.Group), buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	response, err := client.GetHTTPClient(provider.ClientConfig).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+type Body struct {
+	Cards []Cards `json:"cards"`
+}
+
+type Cards struct {
+	Sections []Sections `json:"sections"`
+}
+
+type Sections struct {
+	Widgets []Widgets `json:"widgets"`
+}
+
+type Widgets struct {
+	KeyValue *KeyValue `json:"keyValue,omitempty"`
+	Buttons  []Buttons `json:"buttons,omitempty"`
+}
+
+type KeyValue struct {
+	TopLabel         string `json:"topLabel,omitempty"`
+	Content          string `json:"content,omitempty"`
+	ContentMultiline string `json:"contentMultiline,omitempty"`
+	BottomLabel      string `json:"bottomLabel,omitempty"`
+	Icon             string `json:"icon,omitempty"`
+}
+
+type Buttons struct {
+	TextButton TextButton `json:"textButton"`
+}
+
+type TextButton struct {
+	Text    string  `json:"text"`
+	OnClick OnClick `json:"onClick"`
+}
+
+type OnClick struct {
+	OpenLink OpenLink `json:"openLink"`
+}
+
+type OpenLink struct {
+	URL string `json:"url"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
+	var message, color string
+	if resolved {
+		color = "#36A64F"
+		message = fmt.Sprintf("<font color='%s'>An alert has been resolved after passing successfully %d time(s) in a row</font>", color, alert.SuccessThreshold)
+	} else {
+		color = "#DD0000"
+		message = fmt.Sprintf("<font color='%s'>An alert has been triggered due to having failed %d time(s) in a row</font>", color, alert.FailureThreshold)
+	}
+	var results string
+	for _, conditionResult := range result.ConditionResults {
+		var prefix string
+		if conditionResult.Success {
+			prefix = "✅"
+		} else {
+			prefix = "❌"
+		}
+		results += fmt.Sprintf("%s   %s<br>", prefix, conditionResult.Condition)
+	}
+	var description string
+	if alertDescription := alert.GetDescription(); len(alertDescription) > 0 {
+		description = ":: " + alertDescription
+	}
+	payload := Body{
+		Cards: []Cards{
+			{
+				Sections: []Sections{
+					{
+						Widgets: []Widgets{
+							{
+								KeyValue: &KeyValue{
+									TopLabel:         endpoint.DisplayName(),
+									Content:          message,
+									ContentMultiline: "true",
+									BottomLabel:      description,
+									Icon:             "BOOKMARK",
+								},
+							},
+							{
+								KeyValue: &KeyValue{
+									TopLabel:         "Condition results",
+									Content:          results,
+									ContentMultiline: "true",
+									Icon:             "DESCRIPTION",
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+	if endpoint.Type() == core.EndpointTypeHTTP {
+		// We only include a button targeting the URL if the endpoint is an HTTP endpoint
+		// If the URL isn't prefixed with https://, Google Chat will just display a blank message aynways.
+		// See https://github.com/TwiN/gatus/issues/362
+		payload.Cards[0].Sections[0].Widgets = append(payload.Cards[0].Sections[0].Widgets, Widgets{
+			Buttons: []Buttons{
+				{
+					TextButton: TextButton{
+						Text:    "URL",
+						OnClick: OnClick{OpenLink: OpenLink{URL: endpoint.URL}},
+					},
+				},
+			},
+		})
+	}
+	body, _ := json.Marshal(payload)
+	return body
+}
+
+// getWebhookURLForGroup returns the appropriate Webhook URL integration to for a given group
+func (provider *AlertProvider) getWebhookURLForGroup(group string) string {
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if group == override.Group {
+				return override.WebhookURL
+			}
+		}
+	}
+	return provider.WebhookURL
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/googlechat/googlechat_test.go

@@ -0,0 +1,277 @@
+package googlechat
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestAlertDefaultProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{WebhookURL: ""}
+	if invalidProvider.IsValid() {
+		t.Error("provider shouldn't have been valid")
+	}
+	validProvider := AlertProvider{WebhookURL: "http://example.com"}
+	if !validProvider.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_IsValidWithOverride(t *testing.T) {
+	providerWithInvalidOverrideGroup := AlertProvider{
+		Overrides: []Override{
+			{
+				WebhookURL: "http://example.com",
+				Group:      "",
+			},
+		},
+	}
+	if providerWithInvalidOverrideGroup.IsValid() {
+		t.Error("provider Group shouldn't have been valid")
+	}
+	providerWithInvalidOverrideTo := AlertProvider{
+		Overrides: []Override{
+			{
+				WebhookURL: "",
+				Group:      "group",
+			},
+		},
+	}
+	if providerWithInvalidOverrideTo.IsValid() {
+		t.Error("provider integration key shouldn't have been valid")
+	}
+	providerWithValidOverride := AlertProvider{
+		WebhookURL: "http://example.com",
+		Overrides: []Override{
+			{
+				WebhookURL: "http://example.com",
+				Group:      "group",
+			},
+		},
+	}
+	if !providerWithValidOverride.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name", Group: "endpoint-group"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Endpoint     core.Endpoint
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Endpoint:     core.Endpoint{Name: "endpoint-name", URL: "https://example.org"},
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: `{"cards":[{"sections":[{"widgets":[{"keyValue":{"topLabel":"endpoint-name","content":"\u003cfont color='#DD0000'\u003eAn alert has been triggered due to having failed 3 time(s) in a row\u003c/font\u003e","contentMultiline":"true","bottomLabel":":: description-1","icon":"BOOKMARK"}},{"keyValue":{"topLabel":"Condition results","content":"❌   [CONNECTED] == true\u003cbr\u003e❌   [STATUS] == 200\u003cbr\u003e","contentMultiline":"true","icon":"DESCRIPTION"}},{"buttons":[{"textButton":{"text":"URL","onClick":{"openLink":{"url":"https://example.org"}}}}]}]}]}]}`,
+		},
+		{
+			Name:         "resolved",
+			Endpoint:     core.Endpoint{Name: "endpoint-name", URL: "https://example.org"},
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: `{"cards":[{"sections":[{"widgets":[{"keyValue":{"topLabel":"endpoint-name","content":"\u003cfont color='#36A64F'\u003eAn alert has been resolved after passing successfully 5 time(s) in a row\u003c/font\u003e","contentMultiline":"true","bottomLabel":":: description-2","icon":"BOOKMARK"}},{"keyValue":{"topLabel":"Condition results","content":"✅   [CONNECTED] == true\u003cbr\u003e✅   [STATUS] == 200\u003cbr\u003e","contentMultiline":"true","icon":"DESCRIPTION"}},{"buttons":[{"textButton":{"text":"URL","onClick":{"openLink":{"url":"https://example.org"}}}}]}]}]}]}`,
+		},
+		{
+			Name:         "icmp-should-not-include-url", // See https://github.com/TwiN/gatus/issues/362
+			Endpoint:     core.Endpoint{Name: "endpoint-name", URL: "icmp://example.org"},
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: `{"cards":[{"sections":[{"widgets":[{"keyValue":{"topLabel":"endpoint-name","content":"\u003cfont color='#DD0000'\u003eAn alert has been triggered due to having failed 3 time(s) in a row\u003c/font\u003e","contentMultiline":"true","bottomLabel":":: description-1","icon":"BOOKMARK"}},{"keyValue":{"topLabel":"Condition results","content":"❌   [CONNECTED] == true\u003cbr\u003e❌   [STATUS] == 200\u003cbr\u003e","contentMultiline":"true","icon":"DESCRIPTION"}}]}]}]}`,
+		},
+		{
+			Name:         "tcp-should-not-include-url", // See https://github.com/TwiN/gatus/issues/362
+			Endpoint:     core.Endpoint{Name: "endpoint-name", URL: "tcp://example.org"},
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: `{"cards":[{"sections":[{"widgets":[{"keyValue":{"topLabel":"endpoint-name","content":"\u003cfont color='#DD0000'\u003eAn alert has been triggered due to having failed 3 time(s) in a row\u003c/font\u003e","contentMultiline":"true","bottomLabel":":: description-1","icon":"BOOKMARK"}},{"keyValue":{"topLabel":"Condition results","content":"❌   [CONNECTED] == true\u003cbr\u003e❌   [STATUS] == 200\u003cbr\u003e","contentMultiline":"true","icon":"DESCRIPTION"}}]}]}]}`,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&scenario.Endpoint,
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal(body, &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}
+
+func TestAlertProvider_getWebhookURLForGroup(t *testing.T) {
+	tests := []struct {
+		Name           string
+		Provider       AlertProvider
+		InputGroup     string
+		ExpectedOutput string
+	}{
+		{
+			Name: "provider-no-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides:  nil,
+			},
+			InputGroup:     "",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-no-override-specify-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides:  nil,
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-with-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides: []Override{
+					{
+						Group:      "group",
+						WebhookURL: "http://example01.com",
+					},
+				},
+			},
+			InputGroup:     "",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-with-override-specify-group-should-override",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides: []Override{
+					{
+						Group:      "group",
+						WebhookURL: "http://example01.com",
+					},
+				},
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "http://example01.com",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			if got := tt.Provider.getWebhookURLForGroup(tt.InputGroup); got != tt.ExpectedOutput {
+				t.Errorf("AlertProvider.getToForGroup() = %v, want %v", got, tt.ExpectedOutput)
+			}
+		})
+	}
+}

alerting/provider/matrix/matrix.go

@@ -0,0 +1,190 @@
+package matrix
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"math/rand"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Matrix
+type AlertProvider struct {
+	MatrixProviderConfig `yaml:",inline"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+
+	// Overrides is a list of Override that may be prioritized over the default configuration
+	Overrides []Override `yaml:"overrides,omitempty"`
+}
+
+// Override is a case under which the default integration is overridden
+type Override struct {
+	Group string `yaml:"group"`
+
+	MatrixProviderConfig `yaml:",inline"`
+}
+
+const defaultHomeserverURL = "https://matrix-client.matrix.org"
+
+type MatrixProviderConfig struct {
+	// ServerURL is the custom homeserver to use (optional)
+	ServerURL string `yaml:"server-url"`
+
+	// AccessToken is the bot user's access token to send messages
+	AccessToken string `yaml:"access-token"`
+
+	// InternalRoomID is the room that the bot user has permissions to send messages to
+	InternalRoomID string `yaml:"internal-room-id"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	registeredGroups := make(map[string]bool)
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if isAlreadyRegistered := registeredGroups[override.Group]; isAlreadyRegistered || override.Group == "" || len(override.AccessToken) == 0 || len(override.InternalRoomID) == 0 {
+				return false
+			}
+			registeredGroups[override.Group] = true
+		}
+	}
+	return len(provider.AccessToken) > 0 && len(provider.InternalRoomID) > 0
+}
+
+// Send an alert using the provider
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer(provider.buildRequestBody(endpoint, alert, result, resolved))
+	config := provider.getConfigForGroup(endpoint.Group)
+	if config.ServerURL == "" {
+		config.ServerURL = defaultHomeserverURL
+	}
+	// The Matrix endpoint requires a unique transaction ID for each event sent
+	txnId := randStringBytes(24)
+	request, err := http.NewRequest(
+		http.MethodPut,
+		fmt.Sprintf("%s/_matrix/client/v3/rooms/%s/send/m.room.message/%s?access_token=%s",
+			config.ServerURL,
+			url.PathEscape(config.InternalRoomID),
+			txnId,
+			url.QueryEscape(config.AccessToken),
+		),
+		buffer,
+	)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	response, err := client.GetHTTPClient(nil).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+type Body struct {
+	MsgType       string `json:"msgtype"`
+	Format        string `json:"format"`
+	Body          string `json:"body"`
+	FormattedBody string `json:"formatted_body"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
+	body, _ := json.Marshal(Body{
+		MsgType:       "m.text",
+		Format:        "org.matrix.custom.html",
+		Body:          buildPlaintextMessageBody(endpoint, alert, result, resolved),
+		FormattedBody: buildHTMLMessageBody(endpoint, alert, result, resolved),
+	})
+	return body
+}
+
+// buildPlaintextMessageBody builds the message body in plaintext to include in request
+func buildPlaintextMessageBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) string {
+	var message, results string
+	if resolved {
+		message = fmt.Sprintf("An alert for `%s` has been resolved after passing successfully %d time(s) in a row", endpoint.DisplayName(), alert.SuccessThreshold)
+	} else {
+		message = fmt.Sprintf("An alert for `%s` has been triggered due to having failed %d time(s) in a row", endpoint.DisplayName(), alert.FailureThreshold)
+	}
+	for _, conditionResult := range result.ConditionResults {
+		var prefix string
+		if conditionResult.Success {
+			prefix = "✓"
+		} else {
+			prefix = "✕"
+		}
+		results += fmt.Sprintf("\n%s - %s", prefix, conditionResult.Condition)
+	}
+	var description string
+	if alertDescription := alert.GetDescription(); len(alertDescription) > 0 {
+		description = "\n" + alertDescription
+	}
+	return fmt.Sprintf("%s%s\n%s", message, description, results)
+}
+
+// buildHTMLMessageBody builds the message body in HTML to include in request
+func buildHTMLMessageBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) string {
+	var message, results string
+	if resolved {
+		message = fmt.Sprintf("An alert for <code>%s</code> has been resolved after passing successfully %d time(s) in a row", endpoint.DisplayName(), alert.SuccessThreshold)
+	} else {
+		message = fmt.Sprintf("An alert for <code>%s</code> has been triggered due to having failed %d time(s) in a row", endpoint.DisplayName(), alert.FailureThreshold)
+	}
+	for _, conditionResult := range result.ConditionResults {
+		var prefix string
+		if conditionResult.Success {
+			prefix = "✅"
+		} else {
+			prefix = "❌"
+		}
+		results += fmt.Sprintf("<li>%s - <code>%s</code></li>", prefix, conditionResult.Condition)
+	}
+	var description string
+	if alertDescription := alert.GetDescription(); len(alertDescription) > 0 {
+		description = fmt.Sprintf("\n<blockquote>%s</blockquote>", alertDescription)
+	}
+	return fmt.Sprintf("<h3>%s</h3>%s\n<h5>Condition results</h5><ul>%s</ul>", message, description, results)
+}
+
+// getConfigForGroup returns the appropriate configuration for a given group
+func (provider *AlertProvider) getConfigForGroup(group string) MatrixProviderConfig {
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if group == override.Group {
+				return override.MatrixProviderConfig
+			}
+		}
+	}
+	return provider.MatrixProviderConfig
+}
+
+func randStringBytes(n int) string {
+	// All the compatible characters to use in a transaction ID
+	const availableCharacterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+	b := make([]byte, n)
+	rand.Seed(time.Now().UnixNano())
+	for i := range b {
+		b[i] = availableCharacterBytes[rand.Intn(len(availableCharacterBytes))]
+	}
+	return string(b)
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/matrix/matrix_test.go

@@ -0,0 +1,331 @@
+package matrix
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestAlertProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{
+		MatrixProviderConfig: MatrixProviderConfig{
+			AccessToken:    "",
+			InternalRoomID: "",
+		},
+	}
+	if invalidProvider.IsValid() {
+		t.Error("provider shouldn't have been valid")
+	}
+	validProvider := AlertProvider{
+		MatrixProviderConfig: MatrixProviderConfig{
+			AccessToken:    "1",
+			InternalRoomID: "!a:example.com",
+		},
+	}
+	if !validProvider.IsValid() {
+		t.Error("provider should've been valid")
+	}
+	validProviderWithHomeserver := AlertProvider{
+		MatrixProviderConfig: MatrixProviderConfig{
+			ServerURL:      "https://example.com",
+			AccessToken:    "1",
+			InternalRoomID: "!a:example.com",
+		},
+	}
+	if !validProviderWithHomeserver.IsValid() {
+		t.Error("provider with homeserver should've been valid")
+	}
+}
+
+func TestAlertProvider_IsValidWithOverride(t *testing.T) {
+	providerWithInvalidOverrideGroup := AlertProvider{
+		Overrides: []Override{
+			{
+				Group: "",
+				MatrixProviderConfig: MatrixProviderConfig{
+					AccessToken:    "",
+					InternalRoomID: "",
+				},
+			},
+		},
+	}
+	if providerWithInvalidOverrideGroup.IsValid() {
+		t.Error("provider Group shouldn't have been valid")
+	}
+	providerWithInvalidOverrideTo := AlertProvider{
+		Overrides: []Override{
+			{
+				Group: "group",
+				MatrixProviderConfig: MatrixProviderConfig{
+					AccessToken:    "",
+					InternalRoomID: "",
+				},
+			},
+		},
+	}
+	if providerWithInvalidOverrideTo.IsValid() {
+		t.Error("provider integration key shouldn't have been valid")
+	}
+	providerWithValidOverride := AlertProvider{
+		MatrixProviderConfig: MatrixProviderConfig{
+			AccessToken:    "1",
+			InternalRoomID: "!a:example.com",
+		},
+		Overrides: []Override{
+			{
+				Group: "group",
+				MatrixProviderConfig: MatrixProviderConfig{
+					ServerURL:      "https://example.com",
+					AccessToken:    "1",
+					InternalRoomID: "!a:example.com",
+				},
+			},
+		},
+	}
+	if !providerWithValidOverride.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: "{\"msgtype\":\"m.text\",\"format\":\"org.matrix.custom.html\",\"body\":\"An alert for `endpoint-name` has been triggered due to having failed 3 time(s) in a row\\ndescription-1\\n\\n✕ - [CONNECTED] == true\\n✕ - [STATUS] == 200\",\"formatted_body\":\"\\u003ch3\\u003eAn alert for \\u003ccode\\u003eendpoint-name\\u003c/code\\u003e has been triggered due to having failed 3 time(s) in a row\\u003c/h3\\u003e\\n\\u003cblockquote\\u003edescription-1\\u003c/blockquote\\u003e\\n\\u003ch5\\u003eCondition results\\u003c/h5\\u003e\\u003cul\\u003e\\u003cli\\u003e❌ - \\u003ccode\\u003e[CONNECTED] == true\\u003c/code\\u003e\\u003c/li\\u003e\\u003cli\\u003e❌ - \\u003ccode\\u003e[STATUS] == 200\\u003c/code\\u003e\\u003c/li\\u003e\\u003c/ul\\u003e\"}",
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"msgtype\":\"m.text\",\"format\":\"org.matrix.custom.html\",\"body\":\"An alert for `endpoint-name` has been resolved after passing successfully 5 time(s) in a row\\ndescription-2\\n\\n✓ - [CONNECTED] == true\\n✓ - [STATUS] == 200\",\"formatted_body\":\"\\u003ch3\\u003eAn alert for \\u003ccode\\u003eendpoint-name\\u003c/code\\u003e has been resolved after passing successfully 5 time(s) in a row\\u003c/h3\\u003e\\n\\u003cblockquote\\u003edescription-2\\u003c/blockquote\\u003e\\n\\u003ch5\\u003eCondition results\\u003c/h5\\u003e\\u003cul\\u003e\\u003cli\\u003e✅ - \\u003ccode\\u003e[CONNECTED] == true\\u003c/code\\u003e\\u003c/li\\u003e\\u003cli\\u003e✅ - \\u003ccode\\u003e[STATUS] == 200\\u003c/code\\u003e\\u003c/li\\u003e\\u003c/ul\\u003e\"}",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal(body, &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}
+
+func TestAlertProvider_getConfigForGroup(t *testing.T) {
+	tests := []struct {
+		Name           string
+		Provider       AlertProvider
+		InputGroup     string
+		ExpectedOutput MatrixProviderConfig
+	}{
+		{
+			Name: "provider-no-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				MatrixProviderConfig: MatrixProviderConfig{
+					ServerURL:      "https://example.com",
+					AccessToken:    "1",
+					InternalRoomID: "!a:example.com",
+				},
+				Overrides: nil,
+			},
+			InputGroup: "",
+			ExpectedOutput: MatrixProviderConfig{
+				ServerURL:      "https://example.com",
+				AccessToken:    "1",
+				InternalRoomID: "!a:example.com",
+			},
+		},
+		{
+			Name: "provider-no-override-specify-group-should-default",
+			Provider: AlertProvider{
+				MatrixProviderConfig: MatrixProviderConfig{
+					ServerURL:      "https://example.com",
+					AccessToken:    "1",
+					InternalRoomID: "!a:example.com",
+				},
+				Overrides: nil,
+			},
+			InputGroup: "group",
+			ExpectedOutput: MatrixProviderConfig{
+				ServerURL:      "https://example.com",
+				AccessToken:    "1",
+				InternalRoomID: "!a:example.com",
+			},
+		},
+		{
+			Name: "provider-with-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				MatrixProviderConfig: MatrixProviderConfig{
+					ServerURL:      "https://example.com",
+					AccessToken:    "1",
+					InternalRoomID: "!a:example.com",
+				},
+				Overrides: []Override{
+					{
+						Group: "group",
+						MatrixProviderConfig: MatrixProviderConfig{
+							ServerURL:      "https://example01.com",
+							AccessToken:    "12",
+							InternalRoomID: "!a:example01.com",
+						},
+					},
+				},
+			},
+			InputGroup: "",
+			ExpectedOutput: MatrixProviderConfig{
+				ServerURL:      "https://example.com",
+				AccessToken:    "1",
+				InternalRoomID: "!a:example.com",
+			},
+		},
+		{
+			Name: "provider-with-override-specify-group-should-override",
+			Provider: AlertProvider{
+				MatrixProviderConfig: MatrixProviderConfig{
+					ServerURL:      "https://example.com",
+					AccessToken:    "1",
+					InternalRoomID: "!a:example.com",
+				},
+				Overrides: []Override{
+					{
+						Group: "group",
+						MatrixProviderConfig: MatrixProviderConfig{
+							ServerURL:      "https://example01.com",
+							AccessToken:    "12",
+							InternalRoomID: "!a:example01.com",
+						},
+					},
+				},
+			},
+			InputGroup: "group",
+			ExpectedOutput: MatrixProviderConfig{
+				ServerURL:      "https://example01.com",
+				AccessToken:    "12",
+				InternalRoomID: "!a:example01.com",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			if got := tt.Provider.getConfigForGroup(tt.InputGroup); got != tt.ExpectedOutput {
+				t.Errorf("AlertProvider.getConfigForGroup() = %v, want %v", got, tt.ExpectedOutput)
+			}
+		})
+	}
+}

alerting/provider/mattermost/mattermost.go

@@ -0,0 +1,156 @@
+package mattermost
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Mattermost
+type AlertProvider struct {
+	WebhookURL string `yaml:"webhook-url"`
+
+	// ClientConfig is the configuration of the client used to communicate with the provider's target
+	ClientConfig *client.Config `yaml:"client,omitempty"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+
+	// Overrides is a list of Override that may be prioritized over the default configuration
+	Overrides []Override `yaml:"overrides,omitempty"`
+}
+
+// Override is a case under which the default integration is overridden
+type Override struct {
+	Group      string `yaml:"group"`
+	WebhookURL string `yaml:"webhook-url"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	if provider.ClientConfig == nil {
+		provider.ClientConfig = client.GetDefaultConfig()
+	}
+	if provider.Overrides != nil {
+		registeredGroups := make(map[string]bool)
+		for _, override := range provider.Overrides {
+			if isAlreadyRegistered := registeredGroups[override.Group]; isAlreadyRegistered || override.Group == "" || len(override.WebhookURL) == 0 {
+				return false
+			}
+			registeredGroups[override.Group] = true
+		}
+	}
+	return len(provider.WebhookURL) > 0
+}
+
+// Send an alert using the provider
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer([]byte(provider.buildRequestBody(endpoint, alert, result, resolved)))
+	request, err := http.NewRequest(http.MethodPost, provider.getWebhookURLForGroup(endpoint.Group), buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	response, err := client.GetHTTPClient(provider.ClientConfig).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+type Body struct {
+	Text        string       `json:"text"`
+	Username    string       `json:"username"`
+	IconURL     string       `json:"icon_url"`
+	Attachments []Attachment `json:"attachments"`
+}
+
+type Attachment struct {
+	Title    string  `json:"title"`
+	Fallback string  `json:"fallback"`
+	Text     string  `json:"text"`
+	Short    bool    `json:"short"`
+	Color    string  `json:"color"`
+	Fields   []Field `json:"fields"`
+}
+
+type Field struct {
+	Title string `json:"title"`
+	Value string `json:"value"`
+	Short bool   `json:"short"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
+	var message, color, results string
+	if resolved {
+		message = fmt.Sprintf("An alert for *%s* has been resolved after passing successfully %d time(s) in a row", endpoint.DisplayName(), alert.SuccessThreshold)
+		color = "#36A64F"
+	} else {
+		message = fmt.Sprintf("An alert for *%s* has been triggered due to having failed %d time(s) in a row", endpoint.DisplayName(), alert.FailureThreshold)
+		color = "#DD0000"
+	}
+	for _, conditionResult := range result.ConditionResults {
+		var prefix string
+		if conditionResult.Success {
+			prefix = ":white_check_mark:"
+		} else {
+			prefix = ":x:"
+		}
+		results += fmt.Sprintf("%s - `%s`\n", prefix, conditionResult.Condition)
+	}
+	var description string
+	if alertDescription := alert.GetDescription(); len(alertDescription) > 0 {
+		description = ":\n> " + alertDescription
+	}
+	body, _ := json.Marshal(Body{
+		Text:     "",
+		Username: "gatus",
+		IconURL:  "https://raw.githubusercontent.com/TwiN/gatus/master/.github/assets/logo.png",
+		Attachments: []Attachment{
+			{
+				Title:    ":helmet_with_white_cross: Gatus",
+				Fallback: "Gatus - " + message,
+				Text:     message + description,
+				Short:    false,
+				Color:    color,
+				Fields: []Field{
+					{
+						Title: "Condition results",
+						Value: results,
+						Short: false,
+					},
+				},
+			},
+		},
+	})
+	return body
+}
+
+// getWebhookURLForGroup returns the appropriate Webhook URL integration to for a given group
+func (provider *AlertProvider) getWebhookURLForGroup(group string) string {
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if group == override.Group {
+				return override.WebhookURL
+			}
+		}
+	}
+	return provider.WebhookURL
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/mattermost/mattermost_test.go

@@ -0,0 +1,262 @@
+package mattermost
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestAlertProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{WebhookURL: ""}
+	if invalidProvider.IsValid() {
+		t.Error("provider shouldn't have been valid")
+	}
+	validProvider := AlertProvider{WebhookURL: "http://example.com"}
+	if !validProvider.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_IsValidWithOverride(t *testing.T) {
+	providerWithInvalidOverrideGroup := AlertProvider{
+		Overrides: []Override{
+			{
+				WebhookURL: "http://example.com",
+				Group:      "",
+			},
+		},
+	}
+
+	if providerWithInvalidOverrideGroup.IsValid() {
+		t.Error("provider Group shouldn't have been valid")
+	}
+
+	providerWithInvalidOverrideWebHookUrl := AlertProvider{
+		Overrides: []Override{
+			{
+
+				WebhookURL: "",
+				Group:      "group",
+			},
+		},
+	}
+	if providerWithInvalidOverrideWebHookUrl.IsValid() {
+		t.Error("provider WebHookURL shoudn't have been valid")
+	}
+
+	providerWithValidOverride := AlertProvider{
+		WebhookURL: "http://example.com",
+		Overrides: []Override{
+			{
+				WebhookURL: "http://example.com",
+				Group:      "group",
+			},
+		},
+	}
+	if !providerWithValidOverride.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: "{\"text\":\"\",\"username\":\"gatus\",\"icon_url\":\"https://raw.githubusercontent.com/TwiN/gatus/master/.github/assets/logo.png\",\"attachments\":[{\"title\":\":helmet_with_white_cross: Gatus\",\"fallback\":\"Gatus - An alert for *endpoint-name* has been triggered due to having failed 3 time(s) in a row\",\"text\":\"An alert for *endpoint-name* has been triggered due to having failed 3 time(s) in a row:\\n\\u003e description-1\",\"short\":false,\"color\":\"#DD0000\",\"fields\":[{\"title\":\"Condition results\",\"value\":\":x: - `[CONNECTED] == true`\\n:x: - `[STATUS] == 200`\\n\",\"short\":false}]}]}",
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"text\":\"\",\"username\":\"gatus\",\"icon_url\":\"https://raw.githubusercontent.com/TwiN/gatus/master/.github/assets/logo.png\",\"attachments\":[{\"title\":\":helmet_with_white_cross: Gatus\",\"fallback\":\"Gatus - An alert for *endpoint-name* has been resolved after passing successfully 5 time(s) in a row\",\"text\":\"An alert for *endpoint-name* has been resolved after passing successfully 5 time(s) in a row:\\n\\u003e description-2\",\"short\":false,\"color\":\"#36A64F\",\"fields\":[{\"title\":\"Condition results\",\"value\":\":white_check_mark: - `[CONNECTED] == true`\\n:white_check_mark: - `[STATUS] == 200`\\n\",\"short\":false}]}]}",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal(body, &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}
+
+func TestAlertProvider_getWebhookURLForGroup(t *testing.T) {
+	tests := []struct {
+		Name           string
+		Provider       AlertProvider
+		InputGroup     string
+		ExpectedOutput string
+	}{
+		{
+			Name: "provider-no-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides:  nil,
+			},
+			InputGroup:     "",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-no-override-specify-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides:  nil,
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-with-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides: []Override{
+					{
+						Group:      "group",
+						WebhookURL: "http://example01.com",
+					},
+				},
+			},
+			InputGroup:     "",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-with-override-specify-group-should-override",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides: []Override{
+					{
+						Group:      "group",
+						WebhookURL: "http://example01.com",
+					},
+				},
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "http://example01.com",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			if got := tt.Provider.getWebhookURLForGroup(tt.InputGroup); got != tt.ExpectedOutput {
+				t.Errorf("AlertProvider.getToForGroup() = %v, want %v", got, tt.ExpectedOutput)
+			}
+		})
+	}
+}

alerting/provider/messagebird/messagebird.go

@@ -0,0 +1,81 @@
+package messagebird
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+const (
+	restAPIURL = "https://rest.messagebird.com/messages"
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Messagebird
+type AlertProvider struct {
+	AccessKey  string `yaml:"access-key"`
+	Originator string `yaml:"originator"`
+	Recipients string `yaml:"recipients"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	return len(provider.AccessKey) > 0 && len(provider.Originator) > 0 && len(provider.Recipients) > 0
+}
+
+// Send an alert using the provider
+// Reference doc for messagebird: https://developers.messagebird.com/api/sms-messaging/#send-outbound-sms
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer(provider.buildRequestBody(endpoint, alert, result, resolved))
+	request, err := http.NewRequest(http.MethodPost, restAPIURL, buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	request.Header.Set("Authorization", fmt.Sprintf("AccessKey %s", provider.AccessKey))
+	response, err := client.GetHTTPClient(nil).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+type Body struct {
+	Originator string `json:"originator"`
+	Recipients string `json:"recipients"`
+	Body       string `json:"body"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
+	var message string
+	if resolved {
+		message = fmt.Sprintf("RESOLVED: %s - %s", endpoint.DisplayName(), alert.GetDescription())
+	} else {
+		message = fmt.Sprintf("TRIGGERED: %s - %s", endpoint.DisplayName(), alert.GetDescription())
+	}
+	body, _ := json.Marshal(Body{
+		Originator: provider.Originator,
+		Recipients: provider.Recipients,
+		Body:       message,
+	})
+	return body
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/messagebird/messagebird_test.go

@@ -0,0 +1,162 @@
+package messagebird
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestMessagebirdAlertProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{}
+	if invalidProvider.IsValid() {
+		t.Error("provider shouldn't have been valid")
+	}
+	validProvider := AlertProvider{
+		AccessKey:  "1",
+		Originator: "1",
+		Recipients: "1",
+	}
+	if !validProvider.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{AccessKey: "1", Originator: "2", Recipients: "3"},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: "{\"originator\":\"2\",\"recipients\":\"3\",\"body\":\"TRIGGERED: endpoint-name - description-1\"}",
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{AccessKey: "4", Originator: "5", Recipients: "6"},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"originator\":\"5\",\"recipients\":\"6\",\"body\":\"RESOLVED: endpoint-name - description-2\"}",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal([]byte(body), &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}

alerting/provider/ntfy/ntfy.go

@@ -0,0 +1,96 @@
+package ntfy
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+const (
+	DefaultURL      = "https://ntfy.sh"
+	DefaultPriority = 3
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Slack
+type AlertProvider struct {
+	Topic    string `yaml:"topic"`
+	URL      string `yaml:"url,omitempty"`      // Defaults to DefaultURL
+	Priority int    `yaml:"priority,omitempty"` // Defaults to DefaultPriority
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	if len(provider.URL) == 0 {
+		provider.URL = DefaultURL
+	}
+	if provider.Priority == 0 {
+		provider.Priority = DefaultPriority
+	}
+	return len(provider.URL) > 0 && len(provider.Topic) > 0 && provider.Priority > 0 && provider.Priority < 6
+}
+
+// Send an alert using the provider
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer(provider.buildRequestBody(endpoint, alert, result, resolved))
+	request, err := http.NewRequest(http.MethodPost, provider.URL, buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	response, err := client.GetHTTPClient(nil).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+type Body struct {
+	Topic    string   `json:"topic"`
+	Title    string   `json:"title"`
+	Message  string   `json:"message"`
+	Tags     []string `json:"tags"`
+	Priority int      `json:"priority"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
+	var message, tag string
+	if resolved {
+		tag = "white_check_mark"
+		message = "An alert has been resolved after passing successfully " + strconv.Itoa(alert.SuccessThreshold) + " time(s) in a row"
+	} else {
+		tag = "x"
+		message = "An alert has been triggered due to having failed " + strconv.Itoa(alert.FailureThreshold) + " time(s) in a row"
+	}
+	if len(alert.GetDescription()) > 0 {
+		message += " with the following description: " + alert.GetDescription()
+	}
+	body, _ := json.Marshal(Body{
+		Topic:    provider.Topic,
+		Title:    "Gatus: " + endpoint.DisplayName(),
+		Message:  message,
+		Tags:     []string{tag},
+		Priority: provider.Priority,
+	})
+	return body
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/ntfy/ntfy_test.go

@@ -0,0 +1,104 @@
+package ntfy
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+func TestAlertDefaultProvider_IsValid(t *testing.T) {
+	scenarios := []struct {
+		name     string
+		provider AlertProvider
+		expected bool
+	}{
+		{
+			name:     "valid",
+			provider: AlertProvider{URL: "https://ntfy.sh", Topic: "example", Priority: 1},
+			expected: true,
+		},
+		{
+			name:     "no-url-should-use-default-value",
+			provider: AlertProvider{Topic: "example", Priority: 1},
+			expected: true,
+		},
+		{
+			name:     "invalid-topic",
+			provider: AlertProvider{URL: "https://ntfy.sh", Topic: "", Priority: 1},
+			expected: false,
+		},
+		{
+			name:     "invalid-priority-too-high",
+			provider: AlertProvider{URL: "https://ntfy.sh", Topic: "example", Priority: 6},
+			expected: false,
+		},
+		{
+			name:     "invalid-priority-too-low",
+			provider: AlertProvider{URL: "https://ntfy.sh", Topic: "example", Priority: -1},
+			expected: false,
+		},
+		{
+			name:     "no-priority-should-use-default-value",
+			provider: AlertProvider{URL: "https://ntfy.sh", Topic: "example"},
+			expected: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.name, func(t *testing.T) {
+			if scenario.provider.IsValid() != scenario.expected {
+				t.Errorf("expected %t, got %t", scenario.expected, scenario.provider.IsValid())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{URL: "https://ntfy.sh", Topic: "example", Priority: 1},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: `{"topic":"example","title":"Gatus: endpoint-name","message":"An alert has been triggered due to having failed 3 time(s) in a row with the following description: description-1","tags":["x"],"priority":1}`,
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{URL: "https://ntfy.sh", Topic: "example", Priority: 2},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: `{"topic":"example","title":"Gatus: endpoint-name","message":"An alert has been resolved after passing successfully 5 time(s) in a row with the following description: description-2","tags":["white_check_mark"],"priority":2}`,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal(body, &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}

alerting/provider/opsgenie/opsgenie.go

@@ -0,0 +1,239 @@
+package opsgenie
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+const (
+	restAPI = "https://api.opsgenie.com/v2/alerts"
+)
+
+type AlertProvider struct {
+	// APIKey to use for
+	APIKey string `yaml:"api-key"`
+
+	// Priority to be used in Opsgenie alert payload
+	//
+	// default: P1
+	Priority string `yaml:"priority"`
+
+	// Source define source to be used in Opsgenie alert payload
+	//
+	// default: gatus
+	Source string `yaml:"source"`
+
+	// EntityPrefix is a prefix to be used in entity argument in Opsgenie alert payload
+	//
+	// default: gatus-
+	EntityPrefix string `yaml:"entity-prefix"`
+
+	//AliasPrefix is a prefix to be used in alias argument in Opsgenie alert payload
+	//
+	// default: gatus-healthcheck-
+	AliasPrefix string `yaml:"alias-prefix"`
+
+	// Tags to be used in Opsgenie alert payload
+	//
+	// default: []
+	Tags []string `yaml:"tags"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	return len(provider.APIKey) > 0
+}
+
+// Send an alert using the provider
+//
+// Relevant: https://docs.opsgenie.com/docs/alert-api
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	err := provider.createAlert(endpoint, alert, result, resolved)
+	if err != nil {
+		return err
+	}
+	if resolved {
+		err = provider.closeAlert(endpoint, alert)
+		if err != nil {
+			return err
+		}
+	}
+	if alert.IsSendingOnResolved() {
+		if resolved {
+			// The alert has been resolved and there's no error, so we can clear the alert's ResolveKey
+			alert.ResolveKey = ""
+		} else {
+			alert.ResolveKey = provider.alias(buildKey(endpoint))
+		}
+	}
+	return nil
+}
+
+func (provider *AlertProvider) createAlert(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	payload := provider.buildCreateRequestBody(endpoint, alert, result, resolved)
+	return provider.sendRequest(restAPI, http.MethodPost, payload)
+}
+
+func (provider *AlertProvider) closeAlert(endpoint *core.Endpoint, alert *alert.Alert) error {
+	payload := provider.buildCloseRequestBody(endpoint, alert)
+	url := restAPI + "/" + provider.alias(buildKey(endpoint)) + "/close?identifierType=alias"
+	return provider.sendRequest(url, http.MethodPost, payload)
+}
+
+func (provider *AlertProvider) sendRequest(url, method string, payload interface{}) error {
+	body, err := json.Marshal(payload)
+	if err != nil {
+		return fmt.Errorf("error build alert with payload %v: %w", payload, err)
+	}
+	request, err := http.NewRequest(method, url, bytes.NewBuffer(body))
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	request.Header.Set("Authorization", "GenieKey "+provider.APIKey)
+	response, err := client.GetHTTPClient(nil).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		rBody, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(rBody))
+	}
+	return nil
+}
+
+func (provider *AlertProvider) buildCreateRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) alertCreateRequest {
+	var message, description, results string
+	if resolved {
+		message = fmt.Sprintf("RESOLVED: %s - %s", endpoint.Name, alert.GetDescription())
+		description = fmt.Sprintf("An alert for *%s* has been resolved after passing successfully %d time(s) in a row", endpoint.DisplayName(), alert.SuccessThreshold)
+	} else {
+		message = fmt.Sprintf("%s - %s", endpoint.Name, alert.GetDescription())
+		description = fmt.Sprintf("An alert for *%s* has been triggered due to having failed %d time(s) in a row", endpoint.DisplayName(), alert.FailureThreshold)
+	}
+	if endpoint.Group != "" {
+		message = fmt.Sprintf("[%s] %s", endpoint.Group, message)
+	}
+	for _, conditionResult := range result.ConditionResults {
+		var prefix string
+		if conditionResult.Success {
+			prefix = "▣"
+		} else {
+			prefix = "▢"
+		}
+		results += fmt.Sprintf("%s - `%s`\n", prefix, conditionResult.Condition)
+	}
+	description = description + "\n" + results
+	key := buildKey(endpoint)
+	details := map[string]string{
+		"endpoint:url":    endpoint.URL,
+		"endpoint:group":  endpoint.Group,
+		"result:hostname": result.Hostname,
+		"result:ip":       result.IP,
+		"result:dns_code": result.DNSRCode,
+		"result:errors":   strings.Join(result.Errors, ","),
+	}
+	for k, v := range details {
+		if v == "" {
+			delete(details, k)
+		}
+	}
+	if result.HTTPStatus > 0 {
+		details["result:http_status"] = strconv.Itoa(result.HTTPStatus)
+	}
+	return alertCreateRequest{
+		Message:     message,
+		Description: description,
+		Source:      provider.source(),
+		Priority:    provider.priority(),
+		Alias:       provider.alias(key),
+		Entity:      provider.entity(key),
+		Tags:        provider.Tags,
+		Details:     details,
+	}
+}
+
+func (provider *AlertProvider) buildCloseRequestBody(endpoint *core.Endpoint, alert *alert.Alert) alertCloseRequest {
+	return alertCloseRequest{
+		Source: buildKey(endpoint),
+		Note:   fmt.Sprintf("RESOLVED: %s - %s", endpoint.Name, alert.GetDescription()),
+	}
+}
+
+func (provider *AlertProvider) source() string {
+	source := provider.Source
+	if source == "" {
+		return "gatus"
+	}
+	return source
+}
+
+func (provider *AlertProvider) alias(key string) string {
+	alias := provider.AliasPrefix
+	if alias == "" {
+		alias = "gatus-healthcheck-"
+	}
+	return alias + key
+}
+
+func (provider *AlertProvider) entity(key string) string {
+	alias := provider.EntityPrefix
+	if alias == "" {
+		alias = "gatus-"
+	}
+	return alias + key
+}
+
+func (provider *AlertProvider) priority() string {
+	priority := provider.Priority
+	if priority == "" {
+		return "P1"
+	}
+	return priority
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}
+
+func buildKey(endpoint *core.Endpoint) string {
+	name := toKebabCase(endpoint.Name)
+	if endpoint.Group == "" {
+		return name
+	}
+	return toKebabCase(endpoint.Group) + "-" + name
+}
+
+func toKebabCase(val string) string {
+	return strings.ToLower(strings.ReplaceAll(val, " ", "-"))
+}
+
+type alertCreateRequest struct {
+	Message     string            `json:"message"`
+	Priority    string            `json:"priority"`
+	Source      string            `json:"source"`
+	Entity      string            `json:"entity"`
+	Alias       string            `json:"alias"`
+	Description string            `json:"description"`
+	Tags        []string          `json:"tags,omitempty"`
+	Details     map[string]string `json:"details"`
+}
+
+type alertCloseRequest struct {
+	Source string `json:"source"`
+	Note   string `json:"note"`
+}

alerting/provider/opsgenie/opsgenie_test.go

@@ -0,0 +1,319 @@
+package opsgenie
+
+import (
+	"net/http"
+	"reflect"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestAlertProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{APIKey: ""}
+	if invalidProvider.IsValid() {
+		t.Error("provider shouldn't have been valid")
+	}
+	validProvider := AlertProvider{APIKey: "00000000-0000-0000-0000-000000000000"}
+	if !validProvider.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	description := "my bad alert description"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:          "triggered",
+			Provider:      AlertProvider{},
+			Alert:         alert.Alert{Description: &description, SuccessThreshold: 1, FailureThreshold: 1},
+			Resolved:      false,
+			ExpectedError: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+		},
+		{
+			Name:          "triggered-error",
+			Provider:      AlertProvider{},
+			Alert:         alert.Alert{Description: &description, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:      false,
+			ExpectedError: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+		},
+		{
+			Name:          "resolved",
+			Provider:      AlertProvider{},
+			Alert:         alert.Alert{Description: &description, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:      true,
+			ExpectedError: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+		},
+		{
+			Name:          "resolved-error",
+			Provider:      AlertProvider{},
+			Alert:         alert.Alert{Description: &description, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:      true,
+			ExpectedError: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+		},
+	}
+
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildCreateRequestBody(t *testing.T) {
+	t.Parallel()
+	description := "alert description"
+	scenarios := []struct {
+		Name     string
+		Provider *AlertProvider
+		Alert    *alert.Alert
+		Endpoint *core.Endpoint
+		Result   *core.Result
+		Resolved bool
+		want     alertCreateRequest
+	}{
+		{
+			Name:     "missing all params (unresolved)",
+			Provider: &AlertProvider{},
+			Alert:    &alert.Alert{},
+			Endpoint: &core.Endpoint{},
+			Result:   &core.Result{},
+			Resolved: false,
+			want: alertCreateRequest{
+				Message:     " - ",
+				Priority:    "P1",
+				Source:      "gatus",
+				Entity:      "gatus-",
+				Alias:       "gatus-healthcheck-",
+				Description: "An alert for ** has been triggered due to having failed 0 time(s) in a row\n",
+				Tags:        nil,
+				Details:     map[string]string{},
+			},
+		},
+		{
+			Name:     "missing all params (resolved)",
+			Provider: &AlertProvider{},
+			Alert:    &alert.Alert{},
+			Endpoint: &core.Endpoint{},
+			Result:   &core.Result{},
+			Resolved: true,
+			want: alertCreateRequest{
+				Message:     "RESOLVED:  - ",
+				Priority:    "P1",
+				Source:      "gatus",
+				Entity:      "gatus-",
+				Alias:       "gatus-healthcheck-",
+				Description: "An alert for ** has been resolved after passing successfully 0 time(s) in a row\n",
+				Tags:        nil,
+				Details:     map[string]string{},
+			},
+		},
+		{
+			Name:     "with default options (unresolved)",
+			Provider: &AlertProvider{},
+			Alert: &alert.Alert{
+				Description:      &description,
+				FailureThreshold: 3,
+			},
+			Endpoint: &core.Endpoint{
+				Name: "my super app",
+			},
+			Result: &core.Result{
+				ConditionResults: []*core.ConditionResult{
+					{
+						Condition: "[STATUS] == 200",
+						Success:   true,
+					},
+					{
+						Condition: "[BODY] == OK",
+						Success:   false,
+					},
+				},
+			},
+			Resolved: false,
+			want: alertCreateRequest{
+				Message:     "my super app - " + description,
+				Priority:    "P1",
+				Source:      "gatus",
+				Entity:      "gatus-my-super-app",
+				Alias:       "gatus-healthcheck-my-super-app",
+				Description: "An alert for *my super app* has been triggered due to having failed 3 time(s) in a row\n▣ - `[STATUS] == 200`\n▢ - `[BODY] == OK`\n",
+				Tags:        nil,
+				Details:     map[string]string{},
+			},
+		},
+		{
+			Name: "with custom options (resolved)",
+			Provider: &AlertProvider{
+				Priority:     "P5",
+				EntityPrefix: "oompa-",
+				AliasPrefix:  "loompa-",
+				Source:       "gatus-hc",
+				Tags:         []string{"do-ba-dee-doo"},
+			},
+			Alert: &alert.Alert{
+				Description:      &description,
+				SuccessThreshold: 4,
+			},
+			Endpoint: &core.Endpoint{
+				Name: "my mega app",
+			},
+			Result: &core.Result{
+				ConditionResults: []*core.ConditionResult{
+					{
+						Condition: "[STATUS] == 200",
+						Success:   true,
+					},
+				},
+			},
+			Resolved: true,
+			want: alertCreateRequest{
+				Message:     "RESOLVED: my mega app - " + description,
+				Priority:    "P5",
+				Source:      "gatus-hc",
+				Entity:      "oompa-my-mega-app",
+				Alias:       "loompa-my-mega-app",
+				Description: "An alert for *my mega app* has been resolved after passing successfully 4 time(s) in a row\n▣ - `[STATUS] == 200`\n",
+				Tags:        []string{"do-ba-dee-doo"},
+				Details:     map[string]string{},
+			},
+		},
+		{
+			Name: "with default options and details (unresolved)",
+			Provider: &AlertProvider{
+				Tags: []string{"foo"},
+			},
+			Alert: &alert.Alert{
+				Description:      &description,
+				FailureThreshold: 6,
+			},
+			Endpoint: &core.Endpoint{
+				Name:  "my app",
+				Group: "end game",
+				URL:   "https://my.go/app",
+			},
+			Result: &core.Result{
+				HTTPStatus: 400,
+				Hostname:   "my.go",
+				Errors:     []string{"error 01", "error 02"},
+				Success:    false,
+				ConditionResults: []*core.ConditionResult{
+					{
+						Condition: "[STATUS] == 200",
+						Success:   false,
+					},
+				},
+			},
+			Resolved: false,
+			want: alertCreateRequest{
+				Message:     "[end game] my app - " + description,
+				Priority:    "P1",
+				Source:      "gatus",
+				Entity:      "gatus-end-game-my-app",
+				Alias:       "gatus-healthcheck-end-game-my-app",
+				Description: "An alert for *end game/my app* has been triggered due to having failed 6 time(s) in a row\n▢ - `[STATUS] == 200`\n",
+				Tags:        []string{"foo"},
+				Details: map[string]string{
+					"endpoint:url":       "https://my.go/app",
+					"endpoint:group":     "end game",
+					"result:hostname":    "my.go",
+					"result:errors":      "error 01,error 02",
+					"result:http_status": "400",
+				},
+			},
+		},
+	}
+	for _, scenario := range scenarios {
+		actual := scenario
+		t.Run(actual.Name, func(t *testing.T) {
+			if got := actual.Provider.buildCreateRequestBody(actual.Endpoint, actual.Alert, actual.Result, actual.Resolved); !reflect.DeepEqual(got, actual.want) {
+				t.Errorf("buildCreateRequestBody() = %v, want %v", got, actual.want)
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildCloseRequestBody(t *testing.T) {
+	t.Parallel()
+	description := "alert description"
+	scenarios := []struct {
+		Name     string
+		Provider *AlertProvider
+		Alert    *alert.Alert
+		Endpoint *core.Endpoint
+		want     alertCloseRequest
+	}{
+		{
+			Name:     "Missing all values",
+			Provider: &AlertProvider{},
+			Alert:    &alert.Alert{},
+			Endpoint: &core.Endpoint{},
+			want: alertCloseRequest{
+				Source: "",
+				Note:   "RESOLVED:  - ",
+			},
+		},
+		{
+			Name:     "Basic values",
+			Provider: &AlertProvider{},
+			Alert: &alert.Alert{
+				Description: &description,
+			},
+			Endpoint: &core.Endpoint{
+				Name: "endpoint name",
+			},
+			want: alertCloseRequest{
+				Source: "endpoint-name",
+				Note:   "RESOLVED: endpoint name - alert description",
+			},
+		},
+	}
+
+	for _, scenario := range scenarios {
+		actual := scenario
+		t.Run(actual.Name, func(t *testing.T) {
+			if got := actual.Provider.buildCloseRequestBody(actual.Endpoint, actual.Alert); !reflect.DeepEqual(got, actual.want) {
+				t.Errorf("buildCloseRequestBody() = %v, want %v", got, actual.want)
+			}
+		})
+	}
+}

alerting/provider/pagerduty/pagerduty.go

@@ -1,48 +1,149 @@
 package pagerduty
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
-	"github.com/TwinProduction/gatus/alerting/provider/custom"
-	"github.com/TwinProduction/gatus/core"
+	"io"
+	"log"
+	"net/http"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+const (
+	restAPIURL = "https://events.pagerduty.com/v2/enqueue"
 )
 
 // AlertProvider is the configuration necessary for sending an alert using PagerDuty
 type AlertProvider struct {
 	IntegrationKey string `yaml:"integration-key"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+
+	// Overrides is a list of Override that may be prioritized over the default configuration
+	Overrides []Override `yaml:"overrides,omitempty"`
+}
+
+// Override is a case under which the default integration is overridden
+type Override struct {
+	Group          string `yaml:"group"`
+	IntegrationKey string `yaml:"integration-key"`
 }
 
 // IsValid returns whether the provider's configuration is valid
 func (provider *AlertProvider) IsValid() bool {
-	return len(provider.IntegrationKey) == 32
+	registeredGroups := make(map[string]bool)
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if isAlreadyRegistered := registeredGroups[override.Group]; isAlreadyRegistered || override.Group == "" || len(override.IntegrationKey) != 32 {
+				return false
+			}
+			registeredGroups[override.Group] = true
+		}
+	}
+	// Either the default integration key has the right length, or there are overrides who are properly configured.
+	return len(provider.IntegrationKey) == 32 || len(provider.Overrides) != 0
 }
 
-// https://developer.pagerduty.com/docs/events-api-v2/trigger-events/
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+// Send an alert using the provider
+//
+// Relevant: https://developer.pagerduty.com/docs/events-api-v2/trigger-events/
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer(provider.buildRequestBody(endpoint, alert, result, resolved))
+	request, err := http.NewRequest(http.MethodPost, restAPIURL, buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	response, err := client.GetHTTPClient(nil).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	if alert.IsSendingOnResolved() {
+		if resolved {
+			// The alert has been resolved and there's no error, so we can clear the alert's ResolveKey
+			alert.ResolveKey = ""
+		} else {
+			// We need to retrieve the resolve key from the response
+			body, err := io.ReadAll(response.Body)
+			var payload pagerDutyResponsePayload
+			if err = json.Unmarshal(body, &payload); err != nil {
+				// Silently fail. We don't want to create tons of alerts just because we failed to parse the body.
+				log.Printf("[pagerduty][Send] Ran into error unmarshaling pagerduty response: %s", err.Error())
+			} else {
+				alert.ResolveKey = payload.DedupKey
+			}
+		}
+	}
+	return nil
+}
+
+type Body struct {
+	RoutingKey  string  `json:"routing_key"`
+	DedupKey    string  `json:"dedup_key"`
+	EventAction string  `json:"event_action"`
+	Payload     Payload `json:"payload"`
+}
+
+type Payload struct {
+	Summary  string `json:"summary"`
+	Source   string `json:"source"`
+	Severity string `json:"severity"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
 	var message, eventAction, resolveKey string
 	if resolved {
-		message = fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.Description)
+		message = fmt.Sprintf("RESOLVED: %s - %s", endpoint.DisplayName(), alert.GetDescription())
 		eventAction = "resolve"
 		resolveKey = alert.ResolveKey
 	} else {
-		message = fmt.Sprintf("TRIGGERED: %s - %s", service.Name, alert.Description)
+		message = fmt.Sprintf("TRIGGERED: %s - %s", endpoint.DisplayName(), alert.GetDescription())
 		eventAction = "trigger"
 		resolveKey = ""
 	}
-	return &custom.AlertProvider{
-		Url:    "https://events.pagerduty.com/v2/enqueue",
-		Method: "POST",
-		Body: fmt.Sprintf(`{
-  "routing_key": "%s",
-  "dedup_key": "%s",
-  "event_action": "%s",
-  "payload": {
-    "summary": "%s",
-    "source": "%s",
-    "severity": "critical"
-  }
-}`, provider.IntegrationKey, resolveKey, eventAction, message, service.Name),
-		Headers: map[string]string{
-			"Content-Type": "application/json",
+	body, _ := json.Marshal(Body{
+		RoutingKey:  provider.getIntegrationKeyForGroup(endpoint.Group),
+		DedupKey:    resolveKey,
+		EventAction: eventAction,
+		Payload: Payload{
+			Summary:  message,
+			Source:   "Gatus",
+			Severity: "critical",
 		},
-	}
+	})
+	return body
+}
+
+// getIntegrationKeyForGroup returns the appropriate pagerduty integration key for a given group
+func (provider *AlertProvider) getIntegrationKeyForGroup(group string) string {
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if group == override.Group {
+				return override.IntegrationKey
+			}
+		}
+	}
+	return provider.IntegrationKey
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}
+
+type pagerDutyResponsePayload struct {
+	Status   string `json:"status"`
+	Message  string `json:"message"`
+	DedupKey string `json:"dedup_key"`
 }

alerting/provider/pagerduty/pagerduty_test.go

@@ -1,6 +1,15 @@
 package pagerduty
 
-import "testing"
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
 
 func TestAlertProvider_IsValid(t *testing.T) {
 	invalidProvider := AlertProvider{IntegrationKey: ""}
@@ -12,3 +21,226 @@ func TestAlertProvider_IsValid(t *testing.T) {
 		t.Error("provider should've been valid")
 	}
 }
+
+func TestAlertProvider_IsValidWithOverride(t *testing.T) {
+	providerWithInvalidOverrideGroup := AlertProvider{
+		Overrides: []Override{
+			{
+				IntegrationKey: "00000000000000000000000000000000",
+				Group:          "",
+			},
+		},
+	}
+	if providerWithInvalidOverrideGroup.IsValid() {
+		t.Error("provider Group shouldn't have been valid")
+	}
+	providerWithInvalidOverrideIntegrationKey := AlertProvider{
+		Overrides: []Override{
+			{
+				IntegrationKey: "",
+				Group:          "group",
+			},
+		},
+	}
+	if providerWithInvalidOverrideIntegrationKey.IsValid() {
+		t.Error("provider integration key shouldn't have been valid")
+	}
+	providerWithValidOverride := AlertProvider{
+		Overrides: []Override{
+			{
+				IntegrationKey: "00000000000000000000000000000000",
+				Group:          "group",
+			},
+		},
+	}
+	if !providerWithValidOverride.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	description := "test"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{IntegrationKey: "00000000000000000000000000000000"},
+			Alert:        alert.Alert{Description: &description},
+			Resolved:     false,
+			ExpectedBody: "{\"routing_key\":\"00000000000000000000000000000000\",\"dedup_key\":\"\",\"event_action\":\"trigger\",\"payload\":{\"summary\":\"TRIGGERED: endpoint-name - test\",\"source\":\"Gatus\",\"severity\":\"critical\"}}",
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{IntegrationKey: "00000000000000000000000000000000"},
+			Alert:        alert.Alert{Description: &description, ResolveKey: "key"},
+			Resolved:     true,
+			ExpectedBody: "{\"routing_key\":\"00000000000000000000000000000000\",\"dedup_key\":\"key\",\"event_action\":\"resolve\",\"payload\":{\"summary\":\"RESOLVED: endpoint-name - test\",\"source\":\"Gatus\",\"severity\":\"critical\"}}",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(&core.Endpoint{Name: "endpoint-name"}, &scenario.Alert, &core.Result{}, scenario.Resolved)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal(body, &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_getIntegrationKeyForGroup(t *testing.T) {
+	scenarios := []struct {
+		Name           string
+		Provider       AlertProvider
+		InputGroup     string
+		ExpectedOutput string
+	}{
+		{
+			Name: "provider-no-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				IntegrationKey: "00000000000000000000000000000001",
+				Overrides:      nil,
+			},
+			InputGroup:     "",
+			ExpectedOutput: "00000000000000000000000000000001",
+		},
+		{
+			Name: "provider-no-override-specify-group-should-default",
+			Provider: AlertProvider{
+				IntegrationKey: "00000000000000000000000000000001",
+				Overrides:      nil,
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "00000000000000000000000000000001",
+		},
+		{
+			Name: "provider-with-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				IntegrationKey: "00000000000000000000000000000001",
+				Overrides: []Override{
+					{
+						Group:          "group",
+						IntegrationKey: "00000000000000000000000000000002",
+					},
+				},
+			},
+			InputGroup:     "",
+			ExpectedOutput: "00000000000000000000000000000001",
+		},
+		{
+			Name: "provider-with-override-specify-group-should-override",
+			Provider: AlertProvider{
+				IntegrationKey: "00000000000000000000000000000001",
+				Overrides: []Override{
+					{
+						Group:          "group",
+						IntegrationKey: "00000000000000000000000000000002",
+					},
+				},
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "00000000000000000000000000000002",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			if output := scenario.Provider.getIntegrationKeyForGroup(scenario.InputGroup); output != scenario.ExpectedOutput {
+				t.Errorf("expected %s, got %s", scenario.ExpectedOutput, output)
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}

alerting/provider/provider.go

@@ -1,8 +1,24 @@
 package provider
 
 import (
-	"github.com/TwinProduction/gatus/alerting/provider/custom"
-	"github.com/TwinProduction/gatus/core"
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/alerting/provider/custom"
+	"github.com/TwiN/gatus/v5/alerting/provider/discord"
+	"github.com/TwiN/gatus/v5/alerting/provider/email"
+	"github.com/TwiN/gatus/v5/alerting/provider/github"
+	"github.com/TwiN/gatus/v5/alerting/provider/googlechat"
+	"github.com/TwiN/gatus/v5/alerting/provider/matrix"
+	"github.com/TwiN/gatus/v5/alerting/provider/mattermost"
+	"github.com/TwiN/gatus/v5/alerting/provider/messagebird"
+	"github.com/TwiN/gatus/v5/alerting/provider/ntfy"
+	"github.com/TwiN/gatus/v5/alerting/provider/opsgenie"
+	"github.com/TwiN/gatus/v5/alerting/provider/pagerduty"
+	"github.com/TwiN/gatus/v5/alerting/provider/pushover"
+	"github.com/TwiN/gatus/v5/alerting/provider/slack"
+	"github.com/TwiN/gatus/v5/alerting/provider/teams"
+	"github.com/TwiN/gatus/v5/alerting/provider/telegram"
+	"github.com/TwiN/gatus/v5/alerting/provider/twilio"
+	"github.com/TwiN/gatus/v5/core"
 )
 
 // AlertProvider is the interface that each providers should implement
@@ -10,6 +26,51 @@ type AlertProvider interface {
 	// IsValid returns whether the provider's configuration is valid
 	IsValid() bool
 
-	// ToCustomAlertProvider converts the provider into a custom.AlertProvider
-	ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider
+	// GetDefaultAlert returns the provider's default alert configuration
+	GetDefaultAlert() *alert.Alert
+
+	// Send an alert using the provider
+	Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error
 }
+
+// ParseWithDefaultAlert parses an Endpoint alert by using the provider's default alert as a baseline
+func ParseWithDefaultAlert(providerDefaultAlert, endpointAlert *alert.Alert) {
+	if providerDefaultAlert == nil || endpointAlert == nil {
+		return
+	}
+	if endpointAlert.Enabled == nil {
+		endpointAlert.Enabled = providerDefaultAlert.Enabled
+	}
+	if endpointAlert.SendOnResolved == nil {
+		endpointAlert.SendOnResolved = providerDefaultAlert.SendOnResolved
+	}
+	if endpointAlert.Description == nil {
+		endpointAlert.Description = providerDefaultAlert.Description
+	}
+	if endpointAlert.FailureThreshold == 0 {
+		endpointAlert.FailureThreshold = providerDefaultAlert.FailureThreshold
+	}
+	if endpointAlert.SuccessThreshold == 0 {
+		endpointAlert.SuccessThreshold = providerDefaultAlert.SuccessThreshold
+	}
+}
+
+var (
+	// Validate interface implementation on compile
+	_ AlertProvider = (*custom.AlertProvider)(nil)
+	_ AlertProvider = (*discord.AlertProvider)(nil)
+	_ AlertProvider = (*email.AlertProvider)(nil)
+	_ AlertProvider = (*github.AlertProvider)(nil)
+	_ AlertProvider = (*googlechat.AlertProvider)(nil)
+	_ AlertProvider = (*matrix.AlertProvider)(nil)
+	_ AlertProvider = (*mattermost.AlertProvider)(nil)
+	_ AlertProvider = (*messagebird.AlertProvider)(nil)
+	_ AlertProvider = (*ntfy.AlertProvider)(nil)
+	_ AlertProvider = (*opsgenie.AlertProvider)(nil)
+	_ AlertProvider = (*pagerduty.AlertProvider)(nil)
+	_ AlertProvider = (*pushover.AlertProvider)(nil)
+	_ AlertProvider = (*slack.AlertProvider)(nil)
+	_ AlertProvider = (*teams.AlertProvider)(nil)
+	_ AlertProvider = (*telegram.AlertProvider)(nil)
+	_ AlertProvider = (*twilio.AlertProvider)(nil)
+)

alerting/provider/provider_test.go

@@ -0,0 +1,153 @@
+package provider
+
+import (
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+)
+
+func TestParseWithDefaultAlert(t *testing.T) {
+	type Scenario struct {
+		Name                                             string
+		DefaultAlert, EndpointAlert, ExpectedOutputAlert *alert.Alert
+	}
+	enabled := true
+	disabled := false
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []Scenario{
+		{
+			Name: "endpoint-alert-type-only",
+			DefaultAlert: &alert.Alert{
+				Enabled:          &enabled,
+				SendOnResolved:   &enabled,
+				Description:      &firstDescription,
+				FailureThreshold: 5,
+				SuccessThreshold: 10,
+			},
+			EndpointAlert: &alert.Alert{
+				Type: alert.TypeDiscord,
+			},
+			ExpectedOutputAlert: &alert.Alert{
+				Type:             alert.TypeDiscord,
+				Enabled:          &enabled,
+				SendOnResolved:   &enabled,
+				Description:      &firstDescription,
+				FailureThreshold: 5,
+				SuccessThreshold: 10,
+			},
+		},
+		{
+			Name: "endpoint-alert-overwrites-default-alert",
+			DefaultAlert: &alert.Alert{
+				Enabled:          &disabled,
+				SendOnResolved:   &disabled,
+				Description:      &firstDescription,
+				FailureThreshold: 5,
+				SuccessThreshold: 10,
+			},
+			EndpointAlert: &alert.Alert{
+				Type:             alert.TypeTelegram,
+				Enabled:          &enabled,
+				SendOnResolved:   &enabled,
+				Description:      &secondDescription,
+				FailureThreshold: 6,
+				SuccessThreshold: 11,
+			},
+			ExpectedOutputAlert: &alert.Alert{
+				Type:             alert.TypeTelegram,
+				Enabled:          &enabled,
+				SendOnResolved:   &enabled,
+				Description:      &secondDescription,
+				FailureThreshold: 6,
+				SuccessThreshold: 11,
+			},
+		},
+		{
+			Name: "endpoint-alert-partially-overwrites-default-alert",
+			DefaultAlert: &alert.Alert{
+				Enabled:          &enabled,
+				SendOnResolved:   &enabled,
+				Description:      &firstDescription,
+				FailureThreshold: 5,
+				SuccessThreshold: 10,
+			},
+			EndpointAlert: &alert.Alert{
+				Type:             alert.TypeDiscord,
+				Enabled:          nil,
+				SendOnResolved:   nil,
+				FailureThreshold: 6,
+				SuccessThreshold: 11,
+			},
+			ExpectedOutputAlert: &alert.Alert{
+				Type:             alert.TypeDiscord,
+				Enabled:          &enabled,
+				SendOnResolved:   &enabled,
+				Description:      &firstDescription,
+				FailureThreshold: 6,
+				SuccessThreshold: 11,
+			},
+		},
+		{
+			Name: "default-alert-type-should-be-ignored",
+			DefaultAlert: &alert.Alert{
+				Type:             alert.TypeTelegram,
+				Enabled:          &enabled,
+				SendOnResolved:   &enabled,
+				Description:      &firstDescription,
+				FailureThreshold: 5,
+				SuccessThreshold: 10,
+			},
+			EndpointAlert: &alert.Alert{
+				Type: alert.TypeDiscord,
+			},
+			ExpectedOutputAlert: &alert.Alert{
+				Type:             alert.TypeDiscord,
+				Enabled:          &enabled,
+				SendOnResolved:   &enabled,
+				Description:      &firstDescription,
+				FailureThreshold: 5,
+				SuccessThreshold: 10,
+			},
+		},
+		{
+			Name: "no-default-alert",
+			DefaultAlert: &alert.Alert{
+				Type:             alert.TypeDiscord,
+				Enabled:          nil,
+				SendOnResolved:   nil,
+				Description:      &firstDescription,
+				FailureThreshold: 2,
+				SuccessThreshold: 5,
+			},
+			EndpointAlert:       nil,
+			ExpectedOutputAlert: nil,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			ParseWithDefaultAlert(scenario.DefaultAlert, scenario.EndpointAlert)
+			if scenario.ExpectedOutputAlert == nil {
+				if scenario.EndpointAlert != nil {
+					t.Fail()
+				}
+				return
+			}
+			if scenario.EndpointAlert.IsEnabled() != scenario.ExpectedOutputAlert.IsEnabled() {
+				t.Errorf("expected EndpointAlert.IsEnabled() to be %v, got %v", scenario.ExpectedOutputAlert.IsEnabled(), scenario.EndpointAlert.IsEnabled())
+			}
+			if scenario.EndpointAlert.IsSendingOnResolved() != scenario.ExpectedOutputAlert.IsSendingOnResolved() {
+				t.Errorf("expected EndpointAlert.IsSendingOnResolved() to be %v, got %v", scenario.ExpectedOutputAlert.IsSendingOnResolved(), scenario.EndpointAlert.IsSendingOnResolved())
+			}
+			if scenario.EndpointAlert.GetDescription() != scenario.ExpectedOutputAlert.GetDescription() {
+				t.Errorf("expected EndpointAlert.GetDescription() to be %v, got %v", scenario.ExpectedOutputAlert.GetDescription(), scenario.EndpointAlert.GetDescription())
+			}
+			if scenario.EndpointAlert.FailureThreshold != scenario.ExpectedOutputAlert.FailureThreshold {
+				t.Errorf("expected EndpointAlert.FailureThreshold to be %v, got %v", scenario.ExpectedOutputAlert.FailureThreshold, scenario.EndpointAlert.FailureThreshold)
+			}
+			if scenario.EndpointAlert.SuccessThreshold != scenario.ExpectedOutputAlert.SuccessThreshold {
+				t.Errorf("expected EndpointAlert.SuccessThreshold to be %v, got %v", scenario.ExpectedOutputAlert.SuccessThreshold, scenario.EndpointAlert.SuccessThreshold)
+			}
+		})
+	}
+}

alerting/provider/pushover/pushover.go

@@ -0,0 +1,112 @@
+package pushover
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+const (
+	restAPIURL      = "https://api.pushover.net/1/messages.json"
+	defaultPriority = 0
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Pushover
+type AlertProvider struct {
+	// Key used to authenticate the application sending
+	// See "Your Applications" on the dashboard, or add a new one: https://pushover.net/apps/build
+	ApplicationToken string `yaml:"application-token"`
+
+	// Key of the user or group the messages should be sent to
+	UserKey string `yaml:"user-key"`
+
+	// The title of your message, likely the application name
+	// default: the name of your application in Pushover
+	Title string `yaml:"title,omitempty"`
+
+	// Priority of all messages, ranging from -2 (very low) to 2 (Emergency)
+	// default: 0
+	Priority int `yaml:"priority,omitempty"`
+
+	// Sound of the messages (see: https://pushover.net/api#sounds)
+	// default: "" (pushover)
+	Sound string `yaml:"sound,omitempty"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	if provider.Priority == 0 {
+		provider.Priority = defaultPriority
+	}
+	return len(provider.ApplicationToken) == 30 && len(provider.UserKey) == 30 && provider.Priority >= -2 && provider.Priority <= 2
+}
+
+// Send an alert using the provider
+// Reference doc for pushover: https://pushover.net/api
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer(provider.buildRequestBody(endpoint, alert, result, resolved))
+	request, err := http.NewRequest(http.MethodPost, restAPIURL, buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	response, err := client.GetHTTPClient(nil).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+type Body struct {
+	Token    string `json:"token"`
+	User     string `json:"user"`
+	Title    string `json:"title,omitempty"`
+	Message  string `json:"message"`
+	Priority int    `json:"priority"`
+	Sound    string `json:"sound,omitempty"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
+	var message string
+	if resolved {
+		message = fmt.Sprintf("RESOLVED: %s - %s", endpoint.DisplayName(), alert.GetDescription())
+	} else {
+		message = fmt.Sprintf("TRIGGERED: %s - %s", endpoint.DisplayName(), alert.GetDescription())
+	}
+	body, _ := json.Marshal(Body{
+		Token:    provider.ApplicationToken,
+		User:     provider.UserKey,
+		Title:    provider.Title,
+		Message:  message,
+		Priority: provider.priority(),
+		Sound:    provider.Sound,
+	})
+	return body
+}
+
+func (provider *AlertProvider) priority() int {
+	if provider.Priority == 0 {
+		return defaultPriority
+	}
+	return provider.Priority
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/pushover/pushover_test.go

@@ -0,0 +1,181 @@
+package pushover
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestPushoverAlertProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{}
+	if invalidProvider.IsValid() {
+		t.Error("provider shouldn't have been valid")
+	}
+	validProvider := AlertProvider{
+		ApplicationToken: "aTokenWithLengthOf30characters",
+		UserKey:          "aTokenWithLengthOf30characters",
+		Title:            "Gatus Notification",
+		Priority:         1,
+	}
+	if !validProvider.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestPushoverAlertProvider_IsInvalid(t *testing.T) {
+	invalidProvider := AlertProvider{
+		ApplicationToken: "aTokenWithLengthOfMoreThan30characters",
+		UserKey:          "aTokenWithLengthOfMoreThan30characters",
+		Priority:         5,
+	}
+	if invalidProvider.IsValid() {
+		t.Error("provider should've been invalid")
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{ApplicationToken: "TokenWithLengthOf30Characters1", UserKey: "TokenWithLengthOf30Characters4"},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: "{\"token\":\"TokenWithLengthOf30Characters1\",\"user\":\"TokenWithLengthOf30Characters4\",\"message\":\"TRIGGERED: endpoint-name - description-1\",\"priority\":0}",
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{ApplicationToken: "TokenWithLengthOf30Characters2", UserKey: "TokenWithLengthOf30Characters5", Title: "Gatus Notifications", Priority: 2},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"token\":\"TokenWithLengthOf30Characters2\",\"user\":\"TokenWithLengthOf30Characters5\",\"title\":\"Gatus Notifications\",\"message\":\"RESOLVED: endpoint-name - description-2\",\"priority\":2}",
+		},
+		{
+			Name:         "with-sound",
+			Provider:     AlertProvider{ApplicationToken: "TokenWithLengthOf30Characters2", UserKey: "TokenWithLengthOf30Characters5", Title: "Gatus Notifications", Priority: 2, Sound: "falling"},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"token\":\"TokenWithLengthOf30Characters2\",\"user\":\"TokenWithLengthOf30Characters5\",\"title\":\"Gatus Notifications\",\"message\":\"RESOLVED: endpoint-name - description-2\",\"priority\":2,\"sound\":\"falling\"}",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal(body, &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}

alerting/provider/slack/slack.go

@@ -1,63 +1,142 @@
 package slack
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
-	"github.com/TwinProduction/gatus/alerting/provider/custom"
-	"github.com/TwinProduction/gatus/core"
+	"io"
+	"net/http"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
 )
 
 // AlertProvider is the configuration necessary for sending an alert using Slack
 type AlertProvider struct {
-	WebhookUrl string `yaml:"webhook-url"`
+	WebhookURL string `yaml:"webhook-url"` // Slack webhook URL
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+	// Overrides is a list of Override that may be prioritized over the default configuration
+	Overrides []Override `yaml:"overrides,omitempty"`
+}
+
+// Override is a case under which the default integration is overridden
+type Override struct {
+	Group      string `yaml:"group"`
+	WebhookURL string `yaml:"webhook-url"`
 }
 
 // IsValid returns whether the provider's configuration is valid
 func (provider *AlertProvider) IsValid() bool {
-	return len(provider.WebhookUrl) > 0
+	registeredGroups := make(map[string]bool)
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if isAlreadyRegistered := registeredGroups[override.Group]; isAlreadyRegistered || override.Group == "" || len(override.WebhookURL) == 0 {
+				return false
+			}
+			registeredGroups[override.Group] = true
+		}
+	}
+	return len(provider.WebhookURL) > 0
 }
 
-// ToCustomAlertProvider converts the provider into a custom.AlertProvider
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
-	var message string
-	var color string
+// Send an alert using the provider
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer(provider.buildRequestBody(endpoint, alert, result, resolved))
+	request, err := http.NewRequest(http.MethodPost, provider.getWebhookURLForGroup(endpoint.Group), buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	response, err := client.GetHTTPClient(nil).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+type Body struct {
+	Text        string       `json:"text"`
+	Attachments []Attachment `json:"attachments"`
+}
+
+type Attachment struct {
+	Title  string  `json:"title"`
+	Text   string  `json:"text"`
+	Short  bool    `json:"short"`
+	Color  string  `json:"color"`
+	Fields []Field `json:"fields"`
+}
+
+type Field struct {
+	Title string `json:"title"`
+	Value string `json:"value"`
+	Short bool   `json:"short"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
+	var message, color, results string
 	if resolved {
-		message = fmt.Sprintf("An alert for *%s* has been resolved after passing successfully %d time(s) in a row", service.Name, alert.SuccessThreshold)
+		message = fmt.Sprintf("An alert for *%s* has been resolved after passing successfully %d time(s) in a row", endpoint.DisplayName(), alert.SuccessThreshold)
 		color = "#36A64F"
 	} else {
-		message = fmt.Sprintf("An alert for *%s* has been triggered due to having failed %d time(s) in a row", service.Name, alert.FailureThreshold)
+		message = fmt.Sprintf("An alert for *%s* has been triggered due to having failed %d time(s) in a row", endpoint.DisplayName(), alert.FailureThreshold)
 		color = "#DD0000"
 	}
-	var results string
 	for _, conditionResult := range result.ConditionResults {
 		var prefix string
 		if conditionResult.Success {
-			prefix = ":heavy_check_mark:"
+			prefix = ":white_check_mark:"
 		} else {
 			prefix = ":x:"
 		}
 		results += fmt.Sprintf("%s - `%s`\n", prefix, conditionResult.Condition)
 	}
-	return &custom.AlertProvider{
-		Url:    provider.WebhookUrl,
-		Method: "POST",
-		Body: fmt.Sprintf(`{
-  "text": "",
-  "attachments": [
-    {
-      "title": ":helmet_with_white_cross: Gatus",
-      "text": "%s:\n> %s",
-      "short": false,
-      "color": "%s",
-      "fields": [
-        {
-          "title": "Condition results",
-          "value": "%s",
-          "short": false
-        }
-      ]
-    },
-  ]
-}`, message, alert.Description, color, results),
-		Headers: map[string]string{"Content-Type": "application/json"},
+	var description string
+	if alertDescription := alert.GetDescription(); len(alertDescription) > 0 {
+		description = ":\n> " + alertDescription
 	}
+	body, _ := json.Marshal(Body{
+		Text: "",
+		Attachments: []Attachment{
+			{
+				Title: ":helmet_with_white_cross: Gatus",
+				Text:  message + description,
+				Short: false,
+				Color: color,
+				Fields: []Field{
+					{
+						Title: "Condition results",
+						Value: results,
+						Short: false,
+					},
+				},
+			},
+		},
+	})
+	return body
+}
+
+// getWebhookURLForGroup returns the appropriate Webhook URL integration to for a given group
+func (provider *AlertProvider) getWebhookURLForGroup(group string) string {
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if group == override.Group {
+				return override.WebhookURL
+			}
+		}
+	}
+	return provider.WebhookURL
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
 }

alerting/provider/slack/slack_test.go

@@ -1,14 +1,277 @@
 package slack
 
-import "testing"
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
 
-func TestAlertProvider_IsValid(t *testing.T) {
-	invalidProvider := AlertProvider{WebhookUrl: ""}
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestAlertDefaultProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{WebhookURL: ""}
 	if invalidProvider.IsValid() {
 		t.Error("provider shouldn't have been valid")
 	}
-	validProvider := AlertProvider{WebhookUrl: "http://example.com"}
+	validProvider := AlertProvider{WebhookURL: "https://example.com"}
 	if !validProvider.IsValid() {
 		t.Error("provider should've been valid")
 	}
 }
+
+func TestAlertProvider_IsValidWithOverride(t *testing.T) {
+	providerWithInvalidOverrideGroup := AlertProvider{
+		Overrides: []Override{
+			{
+				WebhookURL: "http://example.com",
+				Group:      "",
+			},
+		},
+	}
+	if providerWithInvalidOverrideGroup.IsValid() {
+		t.Error("provider Group shouldn't have been valid")
+	}
+	providerWithInvalidOverrideTo := AlertProvider{
+		Overrides: []Override{
+			{
+				WebhookURL: "",
+				Group:      "group",
+			},
+		},
+	}
+	if providerWithInvalidOverrideTo.IsValid() {
+		t.Error("provider integration key shouldn't have been valid")
+	}
+	providerWithValidOverride := AlertProvider{
+		WebhookURL: "http://example.com",
+		Overrides: []Override{
+			{
+				WebhookURL: "http://example.com",
+				Group:      "group",
+			},
+		},
+	}
+	if !providerWithValidOverride.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Endpoint     core.Endpoint
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{},
+			Endpoint:     core.Endpoint{Name: "name"},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: "{\"text\":\"\",\"attachments\":[{\"title\":\":helmet_with_white_cross: Gatus\",\"text\":\"An alert for *name* has been triggered due to having failed 3 time(s) in a row:\\n\\u003e description-1\",\"short\":false,\"color\":\"#DD0000\",\"fields\":[{\"title\":\"Condition results\",\"value\":\":x: - `[CONNECTED] == true`\\n:x: - `[STATUS] == 200`\\n\",\"short\":false}]}]}",
+		},
+		{
+			Name:         "triggered-with-group",
+			Provider:     AlertProvider{},
+			Endpoint:     core.Endpoint{Name: "name", Group: "group"},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: "{\"text\":\"\",\"attachments\":[{\"title\":\":helmet_with_white_cross: Gatus\",\"text\":\"An alert for *group/name* has been triggered due to having failed 3 time(s) in a row:\\n\\u003e description-1\",\"short\":false,\"color\":\"#DD0000\",\"fields\":[{\"title\":\"Condition results\",\"value\":\":x: - `[CONNECTED] == true`\\n:x: - `[STATUS] == 200`\\n\",\"short\":false}]}]}",
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{},
+			Endpoint:     core.Endpoint{Name: "name"},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"text\":\"\",\"attachments\":[{\"title\":\":helmet_with_white_cross: Gatus\",\"text\":\"An alert for *name* has been resolved after passing successfully 5 time(s) in a row:\\n\\u003e description-2\",\"short\":false,\"color\":\"#36A64F\",\"fields\":[{\"title\":\"Condition results\",\"value\":\":white_check_mark: - `[CONNECTED] == true`\\n:white_check_mark: - `[STATUS] == 200`\\n\",\"short\":false}]}]}",
+		},
+		{
+			Name:         "resolved-with-group",
+			Provider:     AlertProvider{},
+			Endpoint:     core.Endpoint{Name: "name", Group: "group"},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"text\":\"\",\"attachments\":[{\"title\":\":helmet_with_white_cross: Gatus\",\"text\":\"An alert for *group/name* has been resolved after passing successfully 5 time(s) in a row:\\n\\u003e description-2\",\"short\":false,\"color\":\"#36A64F\",\"fields\":[{\"title\":\"Condition results\",\"value\":\":white_check_mark: - `[CONNECTED] == true`\\n:white_check_mark: - `[STATUS] == 200`\\n\",\"short\":false}]}]}",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&scenario.Endpoint,
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal(body, &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}
+
+func TestAlertProvider_getWebhookURLForGroup(t *testing.T) {
+	tests := []struct {
+		Name           string
+		Provider       AlertProvider
+		InputGroup     string
+		ExpectedOutput string
+	}{
+		{
+			Name: "provider-no-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides:  nil,
+			},
+			InputGroup:     "",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-no-override-specify-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides:  nil,
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-with-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides: []Override{
+					{
+						Group:      "group",
+						WebhookURL: "http://example01.com",
+					},
+				},
+			},
+			InputGroup:     "",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-with-override-specify-group-should-override",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides: []Override{
+					{
+						Group:      "group",
+						WebhookURL: "http://example01.com",
+					},
+				},
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "http://example01.com",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			if got := tt.Provider.getWebhookURLForGroup(tt.InputGroup); got != tt.ExpectedOutput {
+				t.Errorf("AlertProvider.getWebhookURLForGroup() = %v, want %v", got, tt.ExpectedOutput)
+			}
+		})
+	}
+}

alerting/provider/teams/teams.go

@@ -0,0 +1,135 @@
+package teams
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Teams
+type AlertProvider struct {
+	WebhookURL string `yaml:"webhook-url"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+
+	// Overrides is a list of Override that may be prioritized over the default configuration
+	Overrides []Override `yaml:"overrides,omitempty"`
+}
+
+// Override is a case under which the default integration is overridden
+type Override struct {
+	Group      string `yaml:"group"`
+	WebhookURL string `yaml:"webhook-url"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	registeredGroups := make(map[string]bool)
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if isAlreadyRegistered := registeredGroups[override.Group]; isAlreadyRegistered || override.Group == "" || len(override.WebhookURL) == 0 {
+				return false
+			}
+			registeredGroups[override.Group] = true
+		}
+	}
+	return len(provider.WebhookURL) > 0
+}
+
+// Send an alert using the provider
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer(provider.buildRequestBody(endpoint, alert, result, resolved))
+	request, err := http.NewRequest(http.MethodPost, provider.getWebhookURLForGroup(endpoint.Group), buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	response, err := client.GetHTTPClient(nil).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+type Body struct {
+	Type       string    `json:"@type"`
+	Context    string    `json:"@context"`
+	ThemeColor string    `json:"themeColor"`
+	Title      string    `json:"title"`
+	Text       string    `json:"text"`
+	Sections   []Section `json:"sections"`
+}
+
+type Section struct {
+	ActivityTitle string `json:"activityTitle"`
+	Text          string `json:"text"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
+	var message, color string
+	if resolved {
+		message = fmt.Sprintf("An alert for *%s* has been resolved after passing successfully %d time(s) in a row", endpoint.DisplayName(), alert.SuccessThreshold)
+		color = "#36A64F"
+	} else {
+		message = fmt.Sprintf("An alert for *%s* has been triggered due to having failed %d time(s) in a row", endpoint.DisplayName(), alert.FailureThreshold)
+		color = "#DD0000"
+	}
+	var results string
+	for _, conditionResult := range result.ConditionResults {
+		var prefix string
+		if conditionResult.Success {
+			prefix = "✅"
+		} else {
+			prefix = "❌"
+		}
+		results += fmt.Sprintf("%s - `%s`<br/>", prefix, conditionResult.Condition)
+	}
+	var description string
+	if alertDescription := alert.GetDescription(); len(alertDescription) > 0 {
+		description = ": " + alertDescription
+	}
+	body, _ := json.Marshal(Body{
+		Type:       "MessageCard",
+		Context:    "http://schema.org/extensions",
+		ThemeColor: color,
+		Title:      "&#x1F6A8; Gatus",
+		Text:       message + description,
+		Sections: []Section{
+			{
+				ActivityTitle: "Condition results",
+				Text:          results,
+			},
+		},
+	})
+	return body
+}
+
+// getWebhookURLForGroup returns the appropriate Webhook URL integration to for a given group
+func (provider *AlertProvider) getWebhookURLForGroup(group string) string {
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if group == override.Group {
+				return override.WebhookURL
+			}
+		}
+	}
+	return provider.WebhookURL
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/teams/teams_test.go

@@ -0,0 +1,258 @@
+package teams
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestAlertDefaultProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{WebhookURL: ""}
+	if invalidProvider.IsValid() {
+		t.Error("provider shouldn't have been valid")
+	}
+	validProvider := AlertProvider{WebhookURL: "http://example.com"}
+	if !validProvider.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_IsValidWithOverride(t *testing.T) {
+	providerWithInvalidOverrideGroup := AlertProvider{
+		Overrides: []Override{
+			{
+				WebhookURL: "http://example.com",
+				Group:      "",
+			},
+		},
+	}
+	if providerWithInvalidOverrideGroup.IsValid() {
+		t.Error("provider Group shouldn't have been valid")
+	}
+	providerWithInvalidOverrideTo := AlertProvider{
+		Overrides: []Override{
+			{
+				WebhookURL: "",
+				Group:      "group",
+			},
+		},
+	}
+	if providerWithInvalidOverrideTo.IsValid() {
+		t.Error("provider integration key shouldn't have been valid")
+	}
+	providerWithValidOverride := AlertProvider{
+		WebhookURL: "http://example.com",
+		Overrides: []Override{
+			{
+				WebhookURL: "http://example.com",
+				Group:      "group",
+			},
+		},
+	}
+	if !providerWithValidOverride.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: "{\"@type\":\"MessageCard\",\"@context\":\"http://schema.org/extensions\",\"themeColor\":\"#DD0000\",\"title\":\"\\u0026#x1F6A8; Gatus\",\"text\":\"An alert for *endpoint-name* has been triggered due to having failed 3 time(s) in a row: description-1\",\"sections\":[{\"activityTitle\":\"Condition results\",\"text\":\"\\u0026#x274C; - `[CONNECTED] == true`\\u003cbr/\\u003e\\u0026#x274C; - `[STATUS] == 200`\\u003cbr/\\u003e\"}]}",
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"@type\":\"MessageCard\",\"@context\":\"http://schema.org/extensions\",\"themeColor\":\"#36A64F\",\"title\":\"\\u0026#x1F6A8; Gatus\",\"text\":\"An alert for *endpoint-name* has been resolved after passing successfully 5 time(s) in a row: description-2\",\"sections\":[{\"activityTitle\":\"Condition results\",\"text\":\"\\u0026#x2705; - `[CONNECTED] == true`\\u003cbr/\\u003e\\u0026#x2705; - `[STATUS] == 200`\\u003cbr/\\u003e\"}]}",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal(body, &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}
+
+func TestAlertProvider_getWebhookURLForGroup(t *testing.T) {
+	tests := []struct {
+		Name           string
+		Provider       AlertProvider
+		InputGroup     string
+		ExpectedOutput string
+	}{
+		{
+			Name: "provider-no-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides:  nil,
+			},
+			InputGroup:     "",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-no-override-specify-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides:  nil,
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-with-override-specify-no-group-should-default",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides: []Override{
+					{
+						Group:      "group",
+						WebhookURL: "http://example01.com",
+					},
+				},
+			},
+			InputGroup:     "",
+			ExpectedOutput: "http://example.com",
+		},
+		{
+			Name: "provider-with-override-specify-group-should-override",
+			Provider: AlertProvider{
+				WebhookURL: "http://example.com",
+				Overrides: []Override{
+					{
+						Group:      "group",
+						WebhookURL: "http://example01.com",
+					},
+				},
+			},
+			InputGroup:     "group",
+			ExpectedOutput: "http://example01.com",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.Name, func(t *testing.T) {
+			if got := tt.Provider.getWebhookURLForGroup(tt.InputGroup); got != tt.ExpectedOutput {
+				t.Errorf("AlertProvider.getToForGroup() = %v, want %v", got, tt.ExpectedOutput)
+			}
+		})
+	}
+}

alerting/provider/telegram/telegram.go

@@ -0,0 +1,102 @@
+package telegram
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+)
+
+const defaultAPIURL = "https://api.telegram.org"
+
+// AlertProvider is the configuration necessary for sending an alert using Telegram
+type AlertProvider struct {
+	Token  string `yaml:"token"`
+	ID     string `yaml:"id"`
+	APIURL string `yaml:"api-url"`
+
+	// ClientConfig is the configuration of the client used to communicate with the provider's target
+	ClientConfig *client.Config `yaml:"client,omitempty"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	if provider.ClientConfig == nil {
+		provider.ClientConfig = client.GetDefaultConfig()
+	}
+	return len(provider.Token) > 0 && len(provider.ID) > 0
+}
+
+// Send an alert using the provider
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer(provider.buildRequestBody(endpoint, alert, result, resolved))
+	apiURL := provider.APIURL
+	if apiURL == "" {
+		apiURL = defaultAPIURL
+	}
+	request, err := http.NewRequest(http.MethodPost, fmt.Sprintf("%s/bot%s/sendMessage", apiURL, provider.Token), buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/json")
+	response, err := client.GetHTTPClient(provider.ClientConfig).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+type Body struct {
+	ChatID    string `json:"chat_id"`
+	Text      string `json:"text"`
+	ParseMode string `json:"parse_mode"`
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) []byte {
+	var message, results string
+	if resolved {
+		message = fmt.Sprintf("An alert for *%s* has been resolved:\n—\n    _healthcheck passing successfully %d time(s) in a row_\n—  ", endpoint.DisplayName(), alert.FailureThreshold)
+	} else {
+		message = fmt.Sprintf("An alert for *%s* has been triggered:\n—\n    _healthcheck failed %d time(s) in a row_\n—  ", endpoint.DisplayName(), alert.FailureThreshold)
+	}
+	for _, conditionResult := range result.ConditionResults {
+		var prefix string
+		if conditionResult.Success {
+			prefix = "✅"
+		} else {
+			prefix = "❌"
+		}
+		results += fmt.Sprintf("%s - `%s`\n", prefix, conditionResult.Condition)
+	}
+	var text string
+	if len(alert.GetDescription()) > 0 {
+		text = fmt.Sprintf("⛑ *Gatus* \n%s \n*Description* \n_%s_  \n\n*Condition results*\n%s", message, alert.GetDescription(), results)
+	} else {
+		text = fmt.Sprintf("⛑ *Gatus* \n%s \n*Condition results*\n%s", message, results)
+	}
+	body, _ := json.Marshal(Body{
+		ChatID:    provider.ID,
+		Text:      text,
+		ParseMode: "MARKDOWN",
+	})
+	return body
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/telegram/telegram_test.go

@@ -0,0 +1,168 @@
+package telegram
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestAlertProvider_IsValid(t *testing.T) {
+	t.Run("invalid-provider", func(t *testing.T) {
+		invalidProvider := AlertProvider{Token: "", ID: ""}
+		if invalidProvider.IsValid() {
+			t.Error("provider shouldn't have been valid")
+		}
+	})
+	t.Run("valid-provider", func(t *testing.T) {
+		validProvider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "12345678"}
+		if validProvider.ClientConfig != nil {
+			t.Error("provider client config should have been nil prior to IsValid() being executed")
+		}
+		if !validProvider.IsValid() {
+			t.Error("provider should've been valid")
+		}
+		if validProvider.ClientConfig == nil {
+			t.Error("provider client config should have been set after IsValid() was executed")
+		}
+	})
+}
+
+func TestAlertProvider_Send(t *testing.T) {
+	defer client.InjectHTTPClient(nil)
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name             string
+		Provider         AlertProvider
+		Alert            alert.Alert
+		Resolved         bool
+		MockRoundTripper test.MockRoundTripper
+		ExpectedError    bool
+	}{
+		{
+			Name:     "triggered",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "triggered-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: false,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+		{
+			Name:     "resolved",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusOK, Body: http.NoBody}
+			}),
+			ExpectedError: false,
+		},
+		{
+			Name:     "resolved-error",
+			Provider: AlertProvider{},
+			Alert:    alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved: true,
+			MockRoundTripper: test.MockRoundTripper(func(r *http.Request) *http.Response {
+				return &http.Response{StatusCode: http.StatusInternalServerError, Body: http.NoBody}
+			}),
+			ExpectedError: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			client.InjectHTTPClient(&http.Client{Transport: scenario.MockRoundTripper})
+			err := scenario.Provider.Send(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if scenario.ExpectedError && err == nil {
+				t.Error("expected error, got none")
+			}
+			if !scenario.ExpectedError && err != nil {
+				t.Error("expected no error, got", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{ID: "123"},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: "{\"chat_id\":\"123\",\"text\":\"⛑ *Gatus* \\nAn alert for *endpoint-name* has been triggered:\\n—\\n    _healthcheck failed 3 time(s) in a row_\\n—   \\n*Description* \\n_description-1_  \\n\\n*Condition results*\\n❌ - `[CONNECTED] == true`\\n❌ - `[STATUS] == 200`\\n\",\"parse_mode\":\"MARKDOWN\"}",
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{ID: "123"},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"chat_id\":\"123\",\"text\":\"⛑ *Gatus* \\nAn alert for *endpoint-name* has been resolved:\\n—\\n    _healthcheck passing successfully 3 time(s) in a row_\\n—   \\n*Description* \\n_description-2_  \\n\\n*Condition results*\\n✅ - `[CONNECTED] == true`\\n✅ - `[STATUS] == 200`\\n\",\"parse_mode\":\"MARKDOWN\"}",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if string(body) != scenario.ExpectedBody {
+				t.Errorf("expected:\n%s\ngot:\n%s", scenario.ExpectedBody, body)
+			}
+			out := make(map[string]interface{})
+			if err := json.Unmarshal(body, &out); err != nil {
+				t.Error("expected body to be valid JSON, got error:", err.Error())
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}

alerting/provider/twilio/twilio.go

@@ -1,11 +1,16 @@
 package twilio
 
 import (
+	"bytes"
 	"encoding/base64"
 	"fmt"
-	"github.com/TwinProduction/gatus/alerting/provider/custom"
-	"github.com/TwinProduction/gatus/core"
+	"io"
+	"net/http"
 	"net/url"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/client"
+	"github.com/TwiN/gatus/v5/core"
 )
 
 // AlertProvider is the configuration necessary for sending an alert using Twilio
@@ -14,6 +19,9 @@ type AlertProvider struct {
 	Token string `yaml:"token"`
 	From  string `yaml:"from"`
 	To    string `yaml:"to"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
 }
 
 // IsValid returns whether the provider's configuration is valid
@@ -21,25 +29,43 @@ func (provider *AlertProvider) IsValid() bool {
 	return len(provider.Token) > 0 && len(provider.SID) > 0 && len(provider.From) > 0 && len(provider.To) > 0
 }
 
-// ToCustomAlertProvider converts the provider into a custom.AlertProvider
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+// Send an alert using the provider
+func (provider *AlertProvider) Send(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) error {
+	buffer := bytes.NewBuffer([]byte(provider.buildRequestBody(endpoint, alert, result, resolved)))
+	request, err := http.NewRequest(http.MethodPost, fmt.Sprintf("https://api.twilio.com/2010-04-01/Accounts/%s/Messages.json", provider.SID), buffer)
+	if err != nil {
+		return err
+	}
+	request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	request.Header.Set("Authorization", fmt.Sprintf("Basic %s", base64.StdEncoding.EncodeToString([]byte(provider.SID+":"+provider.Token))))
+	response, err := client.GetHTTPClient(nil).Do(request)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+	if response.StatusCode > 399 {
+		body, _ := io.ReadAll(response.Body)
+		return fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
+	}
+	return err
+}
+
+// buildRequestBody builds the request body for the provider
+func (provider *AlertProvider) buildRequestBody(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) string {
 	var message string
 	if resolved {
-		message = fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.Description)
+		message = fmt.Sprintf("RESOLVED: %s - %s", endpoint.DisplayName(), alert.GetDescription())
 	} else {
-		message = fmt.Sprintf("TRIGGERED: %s - %s", service.Name, alert.Description)
-	}
-	return &custom.AlertProvider{
-		Url:    fmt.Sprintf("https://api.twilio.com/2010-04-01/Accounts/%s/Messages.json", provider.SID),
-		Method: "POST",
-		Body: url.Values{
-			"To":   {provider.To},
-			"From": {provider.From},
-			"Body": {message},
-		}.Encode(),
-		Headers: map[string]string{
-			"Content-Type":  "application/x-www-form-urlencoded",
-			"Authorization": fmt.Sprintf("Basic %s", base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("%s:%s", provider.SID, provider.Token)))),
-		},
+		message = fmt.Sprintf("TRIGGERED: %s - %s", endpoint.DisplayName(), alert.GetDescription())
 	}
+	return url.Values{
+		"To":   {provider.To},
+		"From": {provider.From},
+		"Body": {message},
+	}.Encode()
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
 }

alerting/provider/twilio/twilio_test.go

@@ -1,6 +1,11 @@
 package twilio
 
-import "testing"
+import (
+	"testing"
+
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/core"
+)
 
 func TestTwilioAlertProvider_IsValid(t *testing.T) {
 	invalidProvider := AlertProvider{}
@@ -17,3 +22,57 @@ func TestTwilioAlertProvider_IsValid(t *testing.T) {
 		t.Error("provider should've been valid")
 	}
 }
+
+func TestAlertProvider_buildRequestBody(t *testing.T) {
+	firstDescription := "description-1"
+	secondDescription := "description-2"
+	scenarios := []struct {
+		Name         string
+		Provider     AlertProvider
+		Alert        alert.Alert
+		Resolved     bool
+		ExpectedBody string
+	}{
+		{
+			Name:         "triggered",
+			Provider:     AlertProvider{SID: "1", Token: "2", From: "3", To: "4"},
+			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     false,
+			ExpectedBody: "Body=TRIGGERED%3A+endpoint-name+-+description-1&From=3&To=4",
+		},
+		{
+			Name:         "resolved",
+			Provider:     AlertProvider{SID: "1", Token: "2", From: "3", To: "4"},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "Body=RESOLVED%3A+endpoint-name+-+description-2&From=3&To=4",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			body := scenario.Provider.buildRequestBody(
+				&core.Endpoint{Name: "endpoint-name"},
+				&scenario.Alert,
+				&core.Result{
+					ConditionResults: []*core.ConditionResult{
+						{Condition: "[CONNECTED] == true", Success: scenario.Resolved},
+						{Condition: "[STATUS] == 200", Success: scenario.Resolved},
+					},
+				},
+				scenario.Resolved,
+			)
+			if body != scenario.ExpectedBody {
+				t.Errorf("expected %s, got %s", scenario.ExpectedBody, body)
+			}
+		})
+	}
+}
+
+func TestAlertProvider_GetDefaultAlert(t *testing.T) {
+	if (AlertProvider{DefaultAlert: &alert.Alert{}}).GetDefaultAlert() == nil {
+		t.Error("expected default alert to be not nil")
+	}
+	if (AlertProvider{DefaultAlert: nil}).GetDefaultAlert() != nil {
+		t.Error("expected default alert to be nil")
+	}
+}

client/client.go

@@ -1,19 +1,190 @@
 package client
 
 import (
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"net"
 	"net/http"
+	"net/smtp"
+	"runtime"
+	"strings"
 	"time"
+
+	"github.com/TwiN/gocache/v2"
+	"github.com/TwiN/whois"
+	"github.com/ishidawataru/sctp"
+	ping "github.com/prometheus-community/pro-bing"
 )
 
 var (
-	client *http.Client
+	// injectedHTTPClient is used for testing purposes
+	injectedHTTPClient *http.Client
+
+	whoisClient              = whois.NewClient().WithReferralCache(true)
+	whoisExpirationDateCache = gocache.NewCache().WithMaxSize(10000).WithDefaultTTL(24 * time.Hour)
 )
 
-func GetHttpClient() *http.Client {
-	if client == nil {
-		client = &http.Client{
-			Timeout: time.Second * 10,
+// GetHTTPClient returns the shared HTTP client, or the client from the configuration passed
+func GetHTTPClient(config *Config) *http.Client {
+	if injectedHTTPClient != nil {
+		return injectedHTTPClient
+	}
+	if config == nil {
+		return defaultConfig.getHTTPClient()
+	}
+	return config.getHTTPClient()
+}
+
+// GetDomainExpiration retrieves the duration until the domain provided expires
+func GetDomainExpiration(hostname string) (domainExpiration time.Duration, err error) {
+	var retrievedCachedValue bool
+	if v, exists := whoisExpirationDateCache.Get(hostname); exists {
+		domainExpiration = time.Until(v.(time.Time))
+		retrievedCachedValue = true
+		// If the domain OR the TTL is not going to expire in less than 24 hours
+		// we don't have to refresh the cache. Otherwise, we'll refresh it.
+		cacheEntryTTL, _ := whoisExpirationDateCache.TTL(hostname)
+		if cacheEntryTTL > 24*time.Hour && domainExpiration > 24*time.Hour {
+			// No need to refresh, so we'll just return the cached values
+			return domainExpiration, nil
 		}
 	}
-	return client
+	if whoisResponse, err := whoisClient.QueryAndParse(hostname); err != nil {
+		if !retrievedCachedValue { // Add an error unless we already retrieved a cached value
+			return 0, fmt.Errorf("error querying and parsing hostname using whois client: %w", err)
+		}
+	} else {
+		domainExpiration = time.Until(whoisResponse.ExpirationDate)
+		if domainExpiration > 720*time.Hour {
+			whoisExpirationDateCache.SetWithTTL(hostname, whoisResponse.ExpirationDate, 240*time.Hour)
+		} else {
+			whoisExpirationDateCache.SetWithTTL(hostname, whoisResponse.ExpirationDate, 72*time.Hour)
+		}
+	}
+	return domainExpiration, nil
+}
+
+// CanCreateTCPConnection checks whether a connection can be established with a TCP endpoint
+func CanCreateTCPConnection(address string, config *Config) bool {
+	conn, err := net.DialTimeout("tcp", address, config.Timeout)
+	if err != nil {
+		return false
+	}
+	_ = conn.Close()
+	return true
+}
+
+// CanCreateUDPConnection checks whether a connection can be established with a UDP endpoint
+func CanCreateUDPConnection(address string, config *Config) bool {
+	conn, err := net.DialTimeout("udp", address, config.Timeout)
+	if err != nil {
+		return false
+	}
+	_ = conn.Close()
+	return true
+}
+
+// CanCreateSCTPConnection checks whether a connection can be established with a SCTP endpoint
+func CanCreateSCTPConnection(address string, config *Config) bool {
+	ch := make(chan bool)
+	go (func(res chan bool) {
+		addr, err := sctp.ResolveSCTPAddr("sctp", address)
+		if err != nil {
+			res <- false
+		}
+
+		conn, err := sctp.DialSCTP("sctp", nil, addr)
+		if err != nil {
+			res <- false
+		}
+		_ = conn.Close()
+		res <- true
+	})(ch)
+
+	select {
+	case result := <-ch:
+		return result
+	case <-time.After(config.Timeout):
+		return false
+	}
+}
+
+// CanPerformStartTLS checks whether a connection can be established to an address using the STARTTLS protocol
+func CanPerformStartTLS(address string, config *Config) (connected bool, certificate *x509.Certificate, err error) {
+	hostAndPort := strings.Split(address, ":")
+	if len(hostAndPort) != 2 {
+		return false, nil, errors.New("invalid address for starttls, format must be host:port")
+	}
+	connection, err := net.DialTimeout("tcp", address, config.Timeout)
+	if err != nil {
+		return
+	}
+	smtpClient, err := smtp.NewClient(connection, hostAndPort[0])
+	if err != nil {
+		return
+	}
+	err = smtpClient.StartTLS(&tls.Config{
+		InsecureSkipVerify: config.Insecure,
+		ServerName:         hostAndPort[0],
+	})
+	if err != nil {
+		return
+	}
+	if state, ok := smtpClient.TLSConnectionState(); ok {
+		certificate = state.PeerCertificates[0]
+	} else {
+		return false, nil, errors.New("could not get TLS connection state")
+	}
+	return true, certificate, nil
+}
+
+// CanPerformTLS checks whether a connection can be established to an address using the TLS protocol
+func CanPerformTLS(address string, config *Config) (connected bool, certificate *x509.Certificate, err error) {
+	connection, err := tls.DialWithDialer(&net.Dialer{Timeout: config.Timeout}, "tcp", address, nil)
+	if err != nil {
+		return
+	}
+	defer connection.Close()
+	verifiedChains := connection.ConnectionState().VerifiedChains
+	if len(verifiedChains) == 0 || len(verifiedChains[0]) == 0 {
+		return
+	}
+	return true, verifiedChains[0][0], nil
+}
+
+// Ping checks if an address can be pinged and returns the round-trip time if the address can be pinged
+//
+// Note that this function takes at least 100ms, even if the address is 127.0.0.1
+func Ping(address string, config *Config) (bool, time.Duration) {
+	pinger, err := ping.NewPinger(address)
+	if err != nil {
+		return false, 0
+	}
+	pinger.Count = 1
+	pinger.Timeout = config.Timeout
+	// Set the pinger's privileged mode to true for every GOOS except darwin
+	// See https://github.com/TwiN/gatus/issues/132
+	//
+	// Note that for this to work on Linux, Gatus must run with sudo privileges.
+	// See https://github.com/prometheus-community/pro-bing#linux
+	pinger.SetPrivileged(runtime.GOOS != "darwin")
+	err = pinger.Run()
+	if err != nil {
+		return false, 0
+	}
+	if pinger.Statistics() != nil {
+		// If the packet loss is 100, it means that the packet didn't reach the host
+		if pinger.Statistics().PacketLoss == 100 {
+			return false, pinger.Timeout
+		}
+		return true, pinger.Statistics().MaxRtt
+	}
+	return true, 0
+}
+
+// InjectHTTPClient is used to inject a custom HTTP client for testing purposes
+func InjectHTTPClient(httpClient *http.Client) {
+	injectedHTTPClient = httpClient
 }

client/client_test.go

@@ -1,13 +1,252 @@
 package client
 
-import "testing"
+import (
+	"bytes"
+	"io"
+	"net/http"
+	"testing"
+	"time"
 
-func TestGetHttpClient(t *testing.T) {
-	if client != nil {
-		t.Error("client should've been nil since it hasn't been called a single time yet")
+	"github.com/TwiN/gatus/v5/test"
+)
+
+func TestGetHTTPClient(t *testing.T) {
+	cfg := &Config{
+		Insecure:       false,
+		IgnoreRedirect: false,
+		Timeout:        0,
+		DNSResolver:    "tcp://1.1.1.1:53",
+		OAuth2Config: &OAuth2Config{
+			ClientID:     "00000000-0000-0000-0000-000000000000",
+			ClientSecret: "secretsauce",
+			TokenURL:     "https://token-server.local/token",
+			Scopes:       []string{"https://application.local/.default"},
+		},
 	}
-	_ = GetHttpClient()
-	if client == nil {
-		t.Error("client shouldn't have been nil, since it has been called once")
+	err := cfg.ValidateAndSetDefaults()
+	if err != nil {
+		t.Errorf("expected error to be nil, but got: `%s`", err)
+	}
+	if GetHTTPClient(cfg) == nil {
+		t.Error("expected client to not be nil")
+	}
+	if GetHTTPClient(nil) == nil {
+		t.Error("expected client to not be nil")
+	}
+}
+
+func TestGetDomainExpiration(t *testing.T) {
+	t.Parallel()
+	if domainExpiration, err := GetDomainExpiration("example.com"); err != nil {
+		t.Fatalf("expected error to be nil, but got: `%s`", err)
+	} else if domainExpiration <= 0 {
+		t.Error("expected domain expiration to be higher than 0")
+	}
+	if domainExpiration, err := GetDomainExpiration("example.com"); err != nil {
+		t.Errorf("expected error to be nil, but got: `%s`", err)
+	} else if domainExpiration <= 0 {
+		t.Error("expected domain expiration to be higher than 0")
+	}
+	// Hack to pretend like the domain is expiring in 1 hour, which should trigger a refresh
+	whoisExpirationDateCache.SetWithTTL("example.com", time.Now().Add(time.Hour), 25*time.Hour)
+	if domainExpiration, err := GetDomainExpiration("example.com"); err != nil {
+		t.Errorf("expected error to be nil, but got: `%s`", err)
+	} else if domainExpiration <= 0 {
+		t.Error("expected domain expiration to be higher than 0")
+	}
+	// Make sure the refresh works when the ttl is <24 hours
+	whoisExpirationDateCache.SetWithTTL("example.com", time.Now().Add(35*time.Hour), 23*time.Hour)
+	if domainExpiration, err := GetDomainExpiration("example.com"); err != nil {
+		t.Errorf("expected error to be nil, but got: `%s`", err)
+	} else if domainExpiration <= 0 {
+		t.Error("expected domain expiration to be higher than 0")
+	}
+}
+
+func TestPing(t *testing.T) {
+	t.Parallel()
+	if success, rtt := Ping("127.0.0.1", &Config{Timeout: 500 * time.Millisecond}); !success {
+		t.Error("expected true")
+		if rtt == 0 {
+			t.Error("Round-trip time returned on success should've higher than 0")
+		}
+	}
+	if success, rtt := Ping("256.256.256.256", &Config{Timeout: 500 * time.Millisecond}); success {
+		t.Error("expected false, because the IP is invalid")
+		if rtt != 0 {
+			t.Error("Round-trip time returned on failure should've been 0")
+		}
+	}
+	if success, rtt := Ping("192.168.152.153", &Config{Timeout: 500 * time.Millisecond}); success {
+		t.Error("expected false, because the IP is valid but the host should be unreachable")
+		if rtt != 0 {
+			t.Error("Round-trip time returned on failure should've been 0")
+		}
+	}
+}
+
+func TestCanPerformStartTLS(t *testing.T) {
+	type args struct {
+		address  string
+		insecure bool
+	}
+	tests := []struct {
+		name          string
+		args          args
+		wantConnected bool
+		wantErr       bool
+	}{
+		{
+			name: "invalid address",
+			args: args{
+				address: "test",
+			},
+			wantConnected: false,
+			wantErr:       true,
+		},
+		{
+			name: "error dial",
+			args: args{
+				address: "test:1234",
+			},
+			wantConnected: false,
+			wantErr:       true,
+		},
+		{
+			name: "valid starttls",
+			args: args{
+				address: "smtp.gmail.com:587",
+			},
+			wantConnected: true,
+			wantErr:       false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			connected, _, err := CanPerformStartTLS(tt.args.address, &Config{Insecure: tt.args.insecure, Timeout: 5 * time.Second})
+			if (err != nil) != tt.wantErr {
+				t.Errorf("CanPerformStartTLS() err=%v, wantErr=%v", err, tt.wantErr)
+				return
+			}
+			if connected != tt.wantConnected {
+				t.Errorf("CanPerformStartTLS() connected=%v, wantConnected=%v", connected, tt.wantConnected)
+			}
+		})
+	}
+}
+
+func TestCanPerformTLS(t *testing.T) {
+	type args struct {
+		address  string
+		insecure bool
+	}
+	tests := []struct {
+		name          string
+		args          args
+		wantConnected bool
+		wantErr       bool
+	}{
+		{
+			name: "invalid address",
+			args: args{
+				address: "test",
+			},
+			wantConnected: false,
+			wantErr:       true,
+		},
+		{
+			name: "error dial",
+			args: args{
+				address: "test:1234",
+			},
+			wantConnected: false,
+			wantErr:       true,
+		},
+		{
+			name: "valid tls",
+			args: args{
+				address: "smtp.gmail.com:465",
+			},
+			wantConnected: true,
+			wantErr:       false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			connected, _, err := CanPerformTLS(tt.args.address, &Config{Insecure: tt.args.insecure, Timeout: 5 * time.Second})
+			if (err != nil) != tt.wantErr {
+				t.Errorf("CanPerformTLS() err=%v, wantErr=%v", err, tt.wantErr)
+				return
+			}
+			if connected != tt.wantConnected {
+				t.Errorf("CanPerformTLS() connected=%v, wantConnected=%v", connected, tt.wantConnected)
+			}
+		})
+	}
+}
+
+func TestCanCreateTCPConnection(t *testing.T) {
+	if CanCreateTCPConnection("127.0.0.1", &Config{Timeout: 5 * time.Second}) {
+		t.Error("should've failed, because there's no port in the address")
+	}
+}
+
+// This test checks if a HTTP client configured with `configureOAuth2()` automatically
+// performs a Client Credentials OAuth2 flow and adds the obtained token as a `Authorization`
+// header to all outgoing HTTP calls.
+func TestHttpClientProvidesOAuth2BearerToken(t *testing.T) {
+	defer InjectHTTPClient(nil)
+	oAuth2Config := &OAuth2Config{
+		ClientID:     "00000000-0000-0000-0000-000000000000",
+		ClientSecret: "secretsauce",
+		TokenURL:     "https://token-server.local/token",
+		Scopes:       []string{"https://application.local/.default"},
+	}
+	mockHttpClient := &http.Client{
+		Transport: test.MockRoundTripper(func(r *http.Request) *http.Response {
+			// if the mock HTTP client tries to get a token from the `token-server`
+			// we provide the expected token response
+			if r.Host == "token-server.local" {
+				return &http.Response{
+					StatusCode: http.StatusOK,
+					Body: io.NopCloser(bytes.NewReader(
+						[]byte(
+							`{"token_type":"Bearer","expires_in":3599,"ext_expires_in":3599,"access_token":"secret-token"}`,
+						),
+					)),
+				}
+			}
+			// to verify the headers were sent as expected, we echo them back in the
+			// `X-Org-Authorization` header and check if the token value matches our
+			// mocked `token-server` response
+			return &http.Response{
+				StatusCode: http.StatusOK,
+				Header: map[string][]string{
+					"X-Org-Authorization": {r.Header.Get("Authorization")},
+				},
+				Body: http.NoBody,
+			}
+		}),
+	}
+	mockHttpClientWithOAuth := configureOAuth2(mockHttpClient, *oAuth2Config)
+	InjectHTTPClient(mockHttpClientWithOAuth)
+	request, err := http.NewRequest(http.MethodPost, "http://127.0.0.1:8282", http.NoBody)
+	if err != nil {
+		t.Error("expected no error, got", err.Error())
+	}
+	response, err := mockHttpClientWithOAuth.Do(request)
+	if err != nil {
+		t.Error("expected no error, got", err.Error())
+	}
+	if response.Header == nil {
+		t.Error("expected response headers, but got nil")
+	}
+	// the mock response echos the Authorization header used in the request back
+	// to us as `X-Org-Authorization` header, we check here if the value matches
+	// our expected token `secret-token`
+	if response.Header.Get("X-Org-Authorization") != "Bearer secret-token" {
+		t.Error("exptected `secret-token` as Bearer token in the mocked response header `X-Org-Authorization`, but got", response.Header.Get("X-Org-Authorization"))
 	}
 }

client/config.go

@@ -0,0 +1,199 @@
+package client
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"log"
+	"net"
+	"net/http"
+	"regexp"
+	"strconv"
+	"time"
+
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/clientcredentials"
+)
+
+const (
+	defaultHTTPTimeout = 10 * time.Second
+)
+
+var (
+	ErrInvalidDNSResolver        = errors.New("invalid DNS resolver specified. Required format is {proto}://{ip}:{port}")
+	ErrInvalidDNSResolverPort    = errors.New("invalid DNS resolver port")
+	ErrInvalidClientOAuth2Config = errors.New("invalid oauth2 configuration: must define all fields for client credentials flow (token-url, client-id, client-secret, scopes)")
+
+	defaultConfig = Config{
+		Insecure:       false,
+		IgnoreRedirect: false,
+		Timeout:        defaultHTTPTimeout,
+	}
+)
+
+// GetDefaultConfig returns a copy of the default configuration
+func GetDefaultConfig() *Config {
+	cfg := defaultConfig
+	return &cfg
+}
+
+// Config is the configuration for clients
+type Config struct {
+	// Insecure determines whether to skip verifying the server's certificate chain and host name
+	Insecure bool `yaml:"insecure,omitempty"`
+
+	// IgnoreRedirect determines whether to ignore redirects (true) or follow them (false, default)
+	IgnoreRedirect bool `yaml:"ignore-redirect,omitempty"`
+
+	// Timeout for the client
+	Timeout time.Duration `yaml:"timeout"`
+
+	// DNSResolver override for the HTTP client
+	// Expected format is {protocol}://{host}:{port}, e.g. tcp://8.8.8.8:53
+	DNSResolver string `yaml:"dns-resolver,omitempty"`
+
+	// OAuth2Config is the OAuth2 configuration used for the client.
+	//
+	// If non-nil, the http.Client returned by getHTTPClient will automatically retrieve a token if necessary.
+	// See configureOAuth2 for more details.
+	OAuth2Config *OAuth2Config `yaml:"oauth2,omitempty"`
+
+	httpClient *http.Client
+}
+
+// DNSResolverConfig is the parsed configuration from the DNSResolver config string.
+type DNSResolverConfig struct {
+	Protocol string
+	Host     string
+	Port     string
+}
+
+// OAuth2Config is the configuration for the OAuth2 client credentials flow
+type OAuth2Config struct {
+	TokenURL     string   `yaml:"token-url"` // e.g. https://dev-12345678.okta.com/token
+	ClientID     string   `yaml:"client-id"`
+	ClientSecret string   `yaml:"client-secret"`
+	Scopes       []string `yaml:"scopes"` // e.g. ["openid"]
+}
+
+// ValidateAndSetDefaults validates the client configuration and sets the default values if necessary
+func (c *Config) ValidateAndSetDefaults() error {
+	if c.Timeout < time.Millisecond {
+		c.Timeout = 10 * time.Second
+	}
+	if c.HasCustomDNSResolver() {
+		// Validate the DNS resolver now to make sure it will not return an error later.
+		if _, err := c.parseDNSResolver(); err != nil {
+			return err
+		}
+	}
+	if c.HasOAuth2Config() && !c.OAuth2Config.isValid() {
+		return ErrInvalidClientOAuth2Config
+	}
+	return nil
+}
+
+// HasCustomDNSResolver returns whether a custom DNSResolver is configured
+func (c *Config) HasCustomDNSResolver() bool {
+	return len(c.DNSResolver) > 0
+}
+
+// parseDNSResolver parses the DNS resolver into the DNSResolverConfig struct
+func (c *Config) parseDNSResolver() (*DNSResolverConfig, error) {
+	re := regexp.MustCompile(`^(?P<proto>(.*))://(?P<host>[A-Za-z0-9\-\.]+):(?P<port>[0-9]+)?(.*)$`)
+	matches := re.FindStringSubmatch(c.DNSResolver)
+	if len(matches) == 0 {
+		return nil, ErrInvalidDNSResolver
+	}
+	r := make(map[string]string)
+	for i, k := range re.SubexpNames() {
+		if i != 0 && k != "" {
+			r[k] = matches[i]
+		}
+	}
+	port, err := strconv.Atoi(r["port"])
+	if err != nil {
+		return nil, err
+	}
+	if port < 1 || port > 65535 {
+		return nil, ErrInvalidDNSResolverPort
+	}
+	return &DNSResolverConfig{
+		Protocol: r["proto"],
+		Host:     r["host"],
+		Port:     r["port"],
+	}, nil
+}
+
+// HasOAuth2Config returns true if the client has OAuth2 configuration parameters
+func (c *Config) HasOAuth2Config() bool {
+	return c.OAuth2Config != nil
+}
+
+// isValid() returns true if the OAuth2 configuration is valid
+func (c *OAuth2Config) isValid() bool {
+	return len(c.TokenURL) > 0 && len(c.ClientID) > 0 && len(c.ClientSecret) > 0 && len(c.Scopes) > 0
+}
+
+// GetHTTPClient return an HTTP client matching the Config's parameters.
+func (c *Config) getHTTPClient() *http.Client {
+	if c.httpClient == nil {
+		c.httpClient = &http.Client{
+			Timeout: c.Timeout,
+			Transport: &http.Transport{
+				MaxIdleConns:        100,
+				MaxIdleConnsPerHost: 20,
+				Proxy:               http.ProxyFromEnvironment,
+				TLSClientConfig: &tls.Config{
+					InsecureSkipVerify: c.Insecure,
+				},
+			},
+			CheckRedirect: func(req *http.Request, via []*http.Request) error {
+				if c.IgnoreRedirect {
+					// Don't follow redirects
+					return http.ErrUseLastResponse
+				}
+				// Follow redirects
+				return nil
+			},
+		}
+		if c.HasCustomDNSResolver() {
+			dnsResolver, err := c.parseDNSResolver()
+			if err != nil {
+				// We're ignoring the error, because it should have been validated on startup ValidateAndSetDefaults.
+				// It shouldn't happen, but if it does, we'll log it... Better safe than sorry ;)
+				log.Println("[client][getHTTPClient] THIS SHOULD NOT HAPPEN. Silently ignoring invalid DNS resolver due to error:", err.Error())
+			} else {
+				dialer := &net.Dialer{
+					Resolver: &net.Resolver{
+						PreferGo: true,
+						Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
+							d := net.Dialer{}
+							return d.DialContext(ctx, dnsResolver.Protocol, dnsResolver.Host+":"+dnsResolver.Port)
+						},
+					},
+				}
+				c.httpClient.Transport.(*http.Transport).DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
+					return dialer.DialContext(ctx, network, addr)
+				}
+			}
+		}
+		if c.HasOAuth2Config() {
+			c.httpClient = configureOAuth2(c.httpClient, *c.OAuth2Config)
+		}
+	}
+	return c.httpClient
+}
+
+// configureOAuth2 returns an HTTP client that will obtain and refresh tokens as necessary.
+// The returned Client and its Transport should not be modified.
+func configureOAuth2(httpClient *http.Client, c OAuth2Config) *http.Client {
+	oauth2cfg := clientcredentials.Config{
+		ClientID:     c.ClientID,
+		ClientSecret: c.ClientSecret,
+		Scopes:       c.Scopes,
+		TokenURL:     c.TokenURL,
+	}
+	ctx := context.WithValue(context.Background(), oauth2.HTTPClient, httpClient)
+	return oauth2cfg.Client(ctx)
+}

client/config_test.go

@@ -0,0 +1,81 @@
+package client
+
+import (
+	"net/http"
+	"testing"
+	"time"
+)
+
+func TestConfig_getHTTPClient(t *testing.T) {
+	insecureConfig := &Config{Insecure: true}
+	insecureConfig.ValidateAndSetDefaults()
+	insecureClient := insecureConfig.getHTTPClient()
+	if !(insecureClient.Transport).(*http.Transport).TLSClientConfig.InsecureSkipVerify {
+		t.Error("expected Config.Insecure set to true to cause the HTTP client to skip certificate verification")
+	}
+	if insecureClient.Timeout != defaultHTTPTimeout {
+		t.Error("expected Config.Timeout to default the HTTP client to a timeout of 10s")
+	}
+	request, _ := http.NewRequest("GET", "", nil)
+	if err := insecureClient.CheckRedirect(request, nil); err != nil {
+		t.Error("expected Config.IgnoreRedirect set to false to cause the HTTP client's CheckRedirect to return nil")
+	}
+
+	secureConfig := &Config{IgnoreRedirect: true, Timeout: 5 * time.Second}
+	secureConfig.ValidateAndSetDefaults()
+	secureClient := secureConfig.getHTTPClient()
+	if (secureClient.Transport).(*http.Transport).TLSClientConfig.InsecureSkipVerify {
+		t.Error("expected Config.Insecure set to false to cause the HTTP client to not skip certificate verification")
+	}
+	if secureClient.Timeout != 5*time.Second {
+		t.Error("expected Config.Timeout to cause the HTTP client to have a timeout of 5s")
+	}
+	request, _ = http.NewRequest("GET", "", nil)
+	if err := secureClient.CheckRedirect(request, nil); err != http.ErrUseLastResponse {
+		t.Error("expected Config.IgnoreRedirect set to true to cause the HTTP client's CheckRedirect to return http.ErrUseLastResponse")
+	}
+}
+
+func TestConfig_ValidateAndSetDefaults_withCustomDNSResolver(t *testing.T) {
+	type args struct {
+		dnsResolver string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		wantErr bool
+	}{
+		{
+			name: "with-valid-resolver",
+			args: args{
+				dnsResolver: "tcp://1.1.1.1:53",
+			},
+			wantErr: false,
+		},
+		{
+			name: "with-invalid-resolver-port",
+			args: args{
+				dnsResolver: "tcp://127.0.0.1:99999",
+			},
+			wantErr: true,
+		},
+		{
+			name: "with-invalid-resolver-format",
+			args: args{
+				dnsResolver: "foobar",
+			},
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cfg := &Config{
+				DNSResolver: tt.args.dnsResolver,
+			}
+			err := cfg.ValidateAndSetDefaults()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("ValidateAndSetDefaults() error=%v, wantErr=%v", err, tt.wantErr)
+			}
+		})
+	}
+}

config.yaml

@@ -1,16 +1,53 @@
-metrics: true
-services:
-  - name: twinnation
-    url: "https://twinnation.org/health"
-    interval: 30s
+endpoints:
+  - name: front-end
+    group: core
+    url: "https://twin.sh/health"
+    interval: 5m
     conditions:
       - "[STATUS] == 200"
       - "[BODY].status == UP"
-      - "[RESPONSE_TIME] < 1000"
-  - name: cat-fact
-    url: "https://cat-fact.herokuapp.com/facts/random"
-    interval: 1m
+      - "[RESPONSE_TIME] < 150"
+
+  - name: back-end
+    group: core
+    url: "https://example.org/"
+    interval: 5m
     conditions:
       - "[STATUS] == 200"
-      - "[BODY].deleted == false"
-      - "len([BODY].text) > 0"
+      - "[CERTIFICATE_EXPIRATION] > 48h"
+
+  - name: monitoring
+    group: internal
+    url: "https://example.org/"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+
+  - name: nas
+    group: internal
+    url: "https://example.org/"
+    interval: 5m
+    conditions:
+      - "[STATUS] == 200"
+
+  - name: example-dns-query
+    url: "8.8.8.8" # Address of the DNS server to use
+    interval: 5m
+    dns:
+      query-name: "example.com"
+      query-type: "A"
+    conditions:
+      - "[BODY] == 93.184.216.34"
+      - "[DNS_RCODE] == NOERROR"
+
+  - name: icmp-ping
+    url: "icmp://example.org"
+    interval: 1m
+    conditions:
+      - "[CONNECTED] == true"
+
+  - name: check-domain-expiration
+    url: "https://example.org/"
+    interval: 1h
+    conditions:
+      - "[DOMAIN_EXPIRATION] > 720h"

config/config.go

@@ -2,122 +2,391 @@ package config
 
 import (
 	"errors"
-	"github.com/TwinProduction/gatus/alerting"
-	"github.com/TwinProduction/gatus/alerting/provider"
-	"github.com/TwinProduction/gatus/core"
-	"gopkg.in/yaml.v2"
-	"io/ioutil"
+	"fmt"
+	"io/fs"
 	"log"
 	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/TwiN/deepmerge"
+	"github.com/TwiN/gatus/v5/alerting"
+	"github.com/TwiN/gatus/v5/alerting/alert"
+	"github.com/TwiN/gatus/v5/alerting/provider"
+	"github.com/TwiN/gatus/v5/config/maintenance"
+	"github.com/TwiN/gatus/v5/config/remote"
+	"github.com/TwiN/gatus/v5/config/ui"
+	"github.com/TwiN/gatus/v5/config/web"
+	"github.com/TwiN/gatus/v5/core"
+	"github.com/TwiN/gatus/v5/security"
+	"github.com/TwiN/gatus/v5/storage"
+	"github.com/TwiN/gatus/v5/util"
+	"gopkg.in/yaml.v3"
 )
 
 const (
 	// DefaultConfigurationFilePath is the default path that will be used to search for the configuration file
-	// if a custom path isn't configured through the GATUS_CONFIG_FILE environment variable
+	// if a custom path isn't configured through the GATUS_CONFIG_PATH environment variable
 	DefaultConfigurationFilePath = "config/config.yaml"
+
+	// DefaultFallbackConfigurationFilePath is the default fallback path that will be used to search for the
+	// configuration file if DefaultConfigurationFilePath didn't work
+	DefaultFallbackConfigurationFilePath = "config/config.yml"
 )
 
 var (
-	ErrNoServiceInConfig  = errors.New("configuration file should contain at least 1 service")
+	// ErrNoEndpointInConfig is an error returned when a configuration file or directory has no endpoints configured
+	ErrNoEndpointInConfig = errors.New("configuration should contain at least 1 endpoint")
+
+	// ErrConfigFileNotFound is an error returned when a configuration file could not be found
 	ErrConfigFileNotFound = errors.New("configuration file not found")
-	ErrConfigNotLoaded    = errors.New("configuration is nil")
-	config                *Config
+
+	// ErrInvalidSecurityConfig is an error returned when the security configuration is invalid
+	ErrInvalidSecurityConfig = errors.New("invalid security configuration")
+
+	// errEarlyReturn is returned to break out of a loop from a callback early
+	errEarlyReturn = errors.New("early escape")
 )
 
 // Config is the main configuration structure
 type Config struct {
-	Metrics  bool             `yaml:"metrics"`
-	Debug    bool             `yaml:"debug"`
-	Alerting *alerting.Config `yaml:"alerting"`
-	Services []*core.Service  `yaml:"services"`
+	// Debug Whether to enable debug logs
+	Debug bool `yaml:"debug,omitempty"`
+
+	// Metrics Whether to expose metrics at /metrics
+	Metrics bool `yaml:"metrics,omitempty"`
+
+	// SkipInvalidConfigUpdate Whether to make the application ignore invalid configuration
+	// if the configuration file is updated while the application is running
+	SkipInvalidConfigUpdate bool `yaml:"skip-invalid-config-update,omitempty"`
+
+	// DisableMonitoringLock Whether to disable the monitoring lock
+	// The monitoring lock is what prevents multiple endpoints from being processed at the same time.
+	// Disabling this may lead to inaccurate response times
+	DisableMonitoringLock bool `yaml:"disable-monitoring-lock,omitempty"`
+
+	// Security Configuration for securing access to Gatus
+	Security *security.Config `yaml:"security,omitempty"`
+
+	// Alerting Configuration for alerting
+	Alerting *alerting.Config `yaml:"alerting,omitempty"`
+
+	// Endpoints List of endpoints to monitor
+	Endpoints []*core.Endpoint `yaml:"endpoints,omitempty"`
+
+	// Storage is the configuration for how the data is stored
+	Storage *storage.Config `yaml:"storage,omitempty"`
+
+	// Web is the web configuration for the application
+	Web *web.Config `yaml:"web,omitempty"`
+
+	// UI is the configuration for the UI
+	UI *ui.Config `yaml:"ui,omitempty"`
+
+	// Maintenance is the configuration for creating a maintenance window in which no alerts are sent
+	Maintenance *maintenance.Config `yaml:"maintenance,omitempty"`
+
+	// Remote is the configuration for remote Gatus instances
+	// WARNING: This is in ALPHA and may change or be completely removed in the future
+	Remote *remote.Config `yaml:"remote,omitempty"`
+
+	configPath      string    // path to the file or directory from which config was loaded
+	lastFileModTime time.Time // last modification time
 }
 
-func Get() *Config {
-	if config == nil {
-		panic(ErrConfigNotLoaded)
+func (config *Config) GetEndpointByKey(key string) *core.Endpoint {
+	// TODO: Should probably add a mutex here to prevent concurrent access
+	for i := 0; i < len(config.Endpoints); i++ {
+		ep := config.Endpoints[i]
+		if util.ConvertGroupAndEndpointNameToKey(ep.Group, ep.Name) == key {
+			return ep
+		}
 	}
-	return config
+	return nil
 }
 
-func Load(configFile string) error {
-	log.Printf("[config][Load] Reading configuration from configFile=%s", configFile)
-	cfg, err := readConfigurationFile(configFile)
+// HasLoadedConfigurationBeenModified returns whether one of the file that the
+// configuration has been loaded from has been modified since it was last read
+func (config Config) HasLoadedConfigurationBeenModified() bool {
+	lastMod := config.lastFileModTime.Unix()
+	fileInfo, err := os.Stat(config.configPath)
 	if err != nil {
-		if os.IsNotExist(err) {
-			return ErrConfigFileNotFound
+		return false
+	}
+	if fileInfo.IsDir() {
+		err = walkConfigDir(config.configPath, func(path string, d fs.DirEntry, err error) error {
+			if info, err := d.Info(); err == nil && lastMod < info.ModTime().Unix() {
+				return errEarlyReturn
+			}
+			return nil
+		})
+		return err == errEarlyReturn
+	}
+	return !fileInfo.ModTime().IsZero() && config.lastFileModTime.Unix() < fileInfo.ModTime().Unix()
+}
+
+// UpdateLastFileModTime refreshes Config.lastFileModTime
+func (config *Config) UpdateLastFileModTime() {
+	config.lastFileModTime = time.Now()
+}
+
+// LoadConfiguration loads the full configuration composed from the main configuration file
+// and all composed configuration files
+func LoadConfiguration(configPath string) (*Config, error) {
+	var configBytes []byte
+	var fileInfo os.FileInfo
+	var usedConfigPath string
+	// Figure out what config path we'll use (either configPath or the default config path)
+	for _, configurationPath := range []string{configPath, DefaultConfigurationFilePath, DefaultFallbackConfigurationFilePath} {
+		if len(configurationPath) == 0 {
+			continue
+		}
+		var err error
+		fileInfo, err = os.Stat(configurationPath)
+		if err != nil {
+			continue
+		}
+		usedConfigPath = configurationPath
+		break
+	}
+	if len(usedConfigPath) == 0 {
+		return nil, ErrConfigFileNotFound
+	}
+	var config *Config
+	if fileInfo.IsDir() {
+		err := walkConfigDir(configPath, func(path string, d fs.DirEntry, err error) error {
+			if err != nil {
+				log.Printf("[config][LoadConfiguration] Error walking path=%s: %s", path, err)
+				return err
+			}
+			log.Printf("[config][LoadConfiguration] Reading configuration from %s", path)
+			data, err := os.ReadFile(path)
+			if err != nil {
+				log.Printf("[config][LoadConfiguration] Error reading configuration from %s: %s", path, err)
+				return fmt.Errorf("error reading configuration from file %s: %w", path, err)
+			}
+			configBytes, err = deepmerge.YAML(configBytes, data)
+			return err
+		})
+		if err != nil {
+			return nil, fmt.Errorf("error reading configuration from directory %s: %w", usedConfigPath, err)
+		}
+	} else {
+		log.Printf("[config][LoadConfiguration] Reading configuration from configFile=%s", configPath)
+		if data, err := os.ReadFile(usedConfigPath); err != nil {
+			return nil, err
 		} else {
+			configBytes = data
+		}
+	}
+	if len(configBytes) == 0 {
+		return nil, ErrConfigFileNotFound
+	}
+	config, err := parseAndValidateConfigBytes(configBytes)
+	if err != nil {
+		return nil, err
+	}
+	config.configPath = usedConfigPath
+	config.UpdateLastFileModTime()
+	return config, err
+}
+
+// walkConfigDir is a wrapper for filepath.WalkDir that strips directories and non-config files
+func walkConfigDir(path string, fn fs.WalkDirFunc) error {
+	if len(path) == 0 {
+		// If the user didn't provide a directory, we'll just use the default config file, so we can return nil now.
+		return nil
+	}
+	return filepath.WalkDir(path, func(path string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return nil
+		}
+		if d == nil || d.IsDir() {
+			return nil
+		}
+		ext := filepath.Ext(path)
+		if ext != ".yml" && ext != ".yaml" {
+			return nil
+		}
+		return fn(path, d, err)
+	})
+}
+
+// parseAndValidateConfigBytes parses a Gatus configuration file into a Config struct and validates its parameters
+func parseAndValidateConfigBytes(yamlBytes []byte) (config *Config, err error) {
+	// Replace $$ with __GATUS_LITERAL_DOLLAR_SIGN__ to prevent os.ExpandEnv from treating "$$" as if it was an
+	// environment variable. This allows Gatus to support literal "$" in the configuration file.
+	yamlBytes = []byte(strings.ReplaceAll(string(yamlBytes), "$$", "__GATUS_LITERAL_DOLLAR_SIGN__"))
+	// Expand environment variables
+	yamlBytes = []byte(os.ExpandEnv(string(yamlBytes)))
+	// Replace __GATUS_LITERAL_DOLLAR_SIGN__ with "$" to restore the literal "$" in the configuration file
+	yamlBytes = []byte(strings.ReplaceAll(string(yamlBytes), "__GATUS_LITERAL_DOLLAR_SIGN__", "$"))
+	// Parse configuration file
+	if err = yaml.Unmarshal(yamlBytes, &config); err != nil {
+		return
+	}
+	// Check if the configuration file at least has endpoints configured
+	if config == nil || config.Endpoints == nil || len(config.Endpoints) == 0 {
+		err = ErrNoEndpointInConfig
+	} else {
+		validateAlertingConfig(config.Alerting, config.Endpoints, config.Debug)
+		if err := validateSecurityConfig(config); err != nil {
+			return nil, err
+		}
+		if err := validateEndpointsConfig(config); err != nil {
+			return nil, err
+		}
+		if err := validateWebConfig(config); err != nil {
+			return nil, err
+		}
+		if err := validateUIConfig(config); err != nil {
+			return nil, err
+		}
+		if err := validateMaintenanceConfig(config); err != nil {
+			return nil, err
+		}
+		if err := validateStorageConfig(config); err != nil {
+			return nil, err
+		}
+		if err := validateRemoteConfig(config); err != nil {
+			return nil, err
+		}
+	}
+	return
+}
+
+func validateRemoteConfig(config *Config) error {
+	if config.Remote != nil {
+		if err := config.Remote.ValidateAndSetDefaults(); err != nil {
 			return err
 		}
 	}
-	config = cfg
 	return nil
 }
 
-func LoadDefaultConfiguration() error {
-	err := Load(DefaultConfigurationFilePath)
-	if err != nil {
-		if err == ErrConfigFileNotFound {
-			return Load("config/config.yml")
+func validateStorageConfig(config *Config) error {
+	if config.Storage == nil {
+		config.Storage = &storage.Config{
+			Type: storage.TypeMemory,
 		}
-		return err
-	}
-	return nil
-}
-
-func readConfigurationFile(fileName string) (config *Config, err error) {
-	var bytes []byte
-	if bytes, err = ioutil.ReadFile(fileName); err == nil {
-		// file exists, so we'll parse it and return it
-		return parseAndValidateConfigBytes(bytes)
-	}
-	return
-}
-
-func parseAndValidateConfigBytes(yamlBytes []byte) (config *Config, err error) {
-	// Expand environment variables
-	yamlBytes = []byte(os.ExpandEnv(string(yamlBytes)))
-	// Parse configuration file
-	err = yaml.Unmarshal(yamlBytes, &config)
-	// Check if the configuration file at least has services.
-	if config == nil || config.Services == nil || len(config.Services) == 0 {
-		err = ErrNoServiceInConfig
 	} else {
-		validateAlertingConfig(config)
-		validateServicesConfig(config)
-	}
-	return
-}
-
-func validateServicesConfig(config *Config) {
-	for _, service := range config.Services {
-		if config.Debug {
-			log.Printf("[config][validateServicesConfig] Validating service '%s'", service.Name)
+		if err := config.Storage.ValidateAndSetDefaults(); err != nil {
+			return err
 		}
-		service.ValidateAndSetDefaults()
 	}
-	log.Printf("[config][validateServicesConfig] Validated %d services", len(config.Services))
+	return nil
 }
 
-func validateAlertingConfig(config *Config) {
-	if config.Alerting == nil {
+func validateMaintenanceConfig(config *Config) error {
+	if config.Maintenance == nil {
+		config.Maintenance = maintenance.GetDefaultConfig()
+	} else {
+		if err := config.Maintenance.ValidateAndSetDefaults(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func validateUIConfig(config *Config) error {
+	if config.UI == nil {
+		config.UI = ui.GetDefaultConfig()
+	} else {
+		if err := config.UI.ValidateAndSetDefaults(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func validateWebConfig(config *Config) error {
+	if config.Web == nil {
+		config.Web = web.GetDefaultConfig()
+	} else {
+		return config.Web.ValidateAndSetDefaults()
+	}
+	return nil
+}
+
+func validateEndpointsConfig(config *Config) error {
+	for _, endpoint := range config.Endpoints {
+		if config.Debug {
+			log.Printf("[config][validateEndpointsConfig] Validating endpoint '%s'", endpoint.Name)
+		}
+		if err := endpoint.ValidateAndSetDefaults(); err != nil {
+			return fmt.Errorf("invalid endpoint %s: %w", endpoint.DisplayName(), err)
+		}
+	}
+	log.Printf("[config][validateEndpointsConfig] Validated %d endpoints", len(config.Endpoints))
+	return nil
+}
+
+func validateSecurityConfig(config *Config) error {
+	if config.Security != nil {
+		if config.Security.IsValid() {
+			if config.Debug {
+				log.Printf("[config][validateSecurityConfig] Basic security configuration has been validated")
+			}
+		} else {
+			// If there was an attempt to configure security, then it must mean that some confidential or private
+			// data are exposed. As a result, we'll force a panic because it's better to be safe than sorry.
+			return ErrInvalidSecurityConfig
+		}
+	}
+	return nil
+}
+
+// validateAlertingConfig validates the alerting configuration
+// Note that the alerting configuration has to be validated before the endpoint configuration, because the default alert
+// returned by provider.AlertProvider.GetDefaultAlert() must be parsed before core.Endpoint.ValidateAndSetDefaults()
+// sets the default alert values when none are set.
+func validateAlertingConfig(alertingConfig *alerting.Config, endpoints []*core.Endpoint, debug bool) {
+	if alertingConfig == nil {
 		log.Printf("[config][validateAlertingConfig] Alerting is not configured")
 		return
 	}
-	alertTypes := []core.AlertType{
-		core.SlackAlert,
-		core.TwilioAlert,
-		core.PagerDutyAlert,
-		core.CustomAlert,
+	alertTypes := []alert.Type{
+		alert.TypeCustom,
+		alert.TypeDiscord,
+		alert.TypeGitHub,
+		alert.TypeGoogleChat,
+		alert.TypeEmail,
+		alert.TypeMatrix,
+		alert.TypeMattermost,
+		alert.TypeMessagebird,
+		alert.TypeNtfy,
+		alert.TypeOpsgenie,
+		alert.TypePagerDuty,
+		alert.TypePushover,
+		alert.TypeSlack,
+		alert.TypeTeams,
+		alert.TypeTelegram,
+		alert.TypeTwilio,
 	}
-	var validProviders, invalidProviders []core.AlertType
+	var validProviders, invalidProviders []alert.Type
 	for _, alertType := range alertTypes {
-		alertProvider := GetAlertingProviderByAlertType(config, alertType)
+		alertProvider := alertingConfig.GetAlertingProviderByAlertType(alertType)
 		if alertProvider != nil {
 			if alertProvider.IsValid() {
+				// Parse alerts with the provider's default alert
+				if alertProvider.GetDefaultAlert() != nil {
+					for _, endpoint := range endpoints {
+						for alertIndex, endpointAlert := range endpoint.Alerts {
+							if alertType == endpointAlert.Type {
+								if debug {
+									log.Printf("[config][validateAlertingConfig] Parsing alert %d with provider's default alert for provider=%s in endpoint=%s", alertIndex, alertType, endpoint.Name)
+								}
+								provider.ParseWithDefaultAlert(alertProvider.GetDefaultAlert(), endpointAlert)
+							}
+						}
+					}
+				}
 				validProviders = append(validProviders, alertType)
 			} else {
 				log.Printf("[config][validateAlertingConfig] Ignoring provider=%s because configuration is invalid", alertType)
 				invalidProviders = append(invalidProviders, alertType)
+				alertingConfig.SetAlertingProviderToNil(alertProvider)
 			}
 		} else {
 			invalidProviders = append(invalidProviders, alertType)
@@ -125,33 +394,3 @@ func validateAlertingConfig(config *Config) {
 	}
 	log.Printf("[config][validateAlertingConfig] configuredProviders=%s; ignoredProviders=%s", validProviders, invalidProviders)
 }
-
-func GetAlertingProviderByAlertType(config *Config, alertType core.AlertType) provider.AlertProvider {
-	switch alertType {
-	case core.SlackAlert:
-		if config.Alerting.Slack == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.Slack
-	case core.TwilioAlert:
-		if config.Alerting.Twilio == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.Twilio
-	case core.PagerDutyAlert:
-		if config.Alerting.PagerDuty == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.PagerDuty
-	case core.CustomAlert:
-		if config.Alerting.Custom == nil {
-			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
-			return nil
-		}
-		return config.Alerting.Custom
-	}
-	return nil
-}