#191: Handle memory issue caused by migration from Service to Endpoint

* Add clarifications in comments

* #191: Rename Service to Endpoint

.dockerignore

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

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

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

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

@@ -1,12 +1,11 @@
-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
     networks:
@@ -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/main.json

@@ -58,9 +58,9 @@
       "steppedLine": false,
       "targets": [
         {
-          "expr": "sum(rate(gatus_tasks[30s])) by (service)",
+          "expr": "sum(rate(gatus_tasks[30s])) by (endpoint)",
           "interval": "30s",
-          "legendFormat": "{{service}}",
+          "legendFormat": "{{endpoint}}",
           "refId": "A"
         }
       ],
@@ -145,9 +145,9 @@
       "steppedLine": false,
       "targets": [
         {
-          "expr": "sum(rate(gatus_tasks{success=\"false\"}[30s])) by (service)",
+          "expr": "sum(rate(gatus_tasks{success=\"false\"}[30s])) by (endpoint)",
           "interval": "30s",
-          "legendFormat": "{{service}}",
+          "legendFormat": "{{endpoint}}",
           "refId": "A"
         }
       ],
@@ -232,10 +232,10 @@
       "steppedLine": false,
       "targets": [
         {
-          "expr": "sum(rate(gatus_tasks{success=\"true\"}[30s])) by (service)",
+          "expr": "sum(rate(gatus_tasks{success=\"true\"}[30s])) by (endpoint)",
           "instant": false,
           "interval": "30s",
-          "legendFormat": "{{service}}",
+          "legendFormat": "{{endpoint}}",
           "refId": "A"
         }
       ],

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

@@ -0,0 +1,16 @@
+alerting:
+  mattermost:
+    webhook-url: "http://mattermost:8065/hooks/tokengoeshere"
+    insecure: true
+
+endpoints:
+  - name: example
+    url: https://example.org
+    interval: 1m
+    alerts:
+      - type: mattermost
+        enabled: true
+        description: "health check failed 3 times in a row"
+        send-on-resolved: true
+    conditions:
+      - "[STATUS] == 200"

.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.yaml:/config/config.yaml
+    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-postgres-storage/config.yaml

@@ -0,0 +1,42 @@
+storage:
+  type: postgres
+  file: "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.yaml:/config/config.yaml
+    networks:
+      - web
+    depends_on:
+      - postgres
+
+networks:
+  web:

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

@@ -0,0 +1,42 @@
+storage:
+  type: sqlite
+  file: /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.yaml:/config/config.yaml
+      - ./data:/data/

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

.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
+        app: gatus
       name: gatus
       namespace: kube-system
     spec:
+      serviceAccountName: gatus
+      terminationGracePeriodSeconds: 5
       containers:
         - image: twinproduction/gatus
           imagePullPolicy: IfNotPresent
@@ -49,11 +71,11 @@ spec:
               protocol: TCP
           resources:
             limits:
-              cpu: 200m
-              memory: 50M
+              cpu: 250m
+              memory: 100M
             requests:
               cpu: 50m
-              memory: 20M
+              memory: 30M
           volumeMounts:
             - mountPath: /config
               name: gatus-config
@@ -74,4 +96,4 @@ 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="2021-09-12T22:49:28.336Z" agent="5.0 (Windows)" etag="r9FJ6Bphqwq-LaTO-jp3" version="15.0.6" type="device"><diagram id="FBbfVOMCjf6Z2LK8Yagy" name="Page-1">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</diagram></mxfile>

.github/codecov.yml

@@ -0,0 +1,7 @@
+ignore:
+  - "watchdog/watchdog.go"
+  - "storage/store/sql/specific_postgres.go" # Can't test for postgres
+
+coverage:
+  status:
+    patch: off

.github/workflows/build.yml

@@ -14,14 +14,20 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - name: Set up Go 1.14
-        uses: actions/setup-go@v1
+      - name: Set up Go
+        uses: actions/setup-go@v2
         with:
-          go-version: 1.14
-        id: go
+          go-version: 1.16
       - name: Check out code into the Go module directory
-        uses: actions/checkout@v1
+        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 ./...
+        # 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 1.15" step (otherwise, it'd use sudo's "go" executable)
+        run: sudo env "PATH=$PATH" "GOROOT=$GOROOT" go test -mod vendor ./... -race -coverprofile=coverage.txt -covermode=atomic
+      - name: Codecov
+        uses: codecov/codecov-action@v1.5.2
+        with:
+          file: ./coverage.txt

.github/workflows/publish-latest.yml

@@ -0,0 +1,34 @@
+name: publish-latest
+on:
+  workflow_run:
+    workflows: ["build"]
+    branches: [master]
+    types: [completed]
+jobs:
+  publish-latest:
+    name: Publish latest
+    runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'success' }}
+    timeout-minutes: 30
+    steps:
+      - name: Check out code
+        uses: actions/checkout@v2
+      - name: Get image repository
+        run: echo IMAGE_REPOSITORY=$(echo ${{ secrets.DOCKER_USERNAME }}/${{ github.event.repository.name }} | tr '[:upper:]' '[:lower:]') >> $GITHUB_ENV
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      - name: Login to Docker Registry
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+      - name: Build and push docker image
+        uses: docker/build-push-action@v2
+        with:
+          platforms: linux/amd64
+          pull: true
+          push: true
+          tags: |
+            ${{ env.IMAGE_REPOSITORY }}:latest

.github/workflows/publish-release.yml

@@ -0,0 +1,33 @@
+name: publish-release
+on:
+  release:
+    types: [published]
+jobs:
+  publish-release:
+    name: Publish release
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - name: Check out code
+        uses: actions/checkout@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: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      - name: Login to Docker Registry
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+      - name: Build and push docker image
+        uses: docker/build-push-action@v2
+        with:
+          platforms: linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64
+          pull: true
+          push: true
+          tags: |
+            ${{ env.IMAGE_REPOSITORY }}:${{ env.RELEASE }}

.gitignore

@@ -1,2 +1,8 @@
-bin
-.idea
+.idea
+.vscode
+gatus
+db.db
+config/config.yml
+db.db-shm
+db.db-wal
+memory.db

Dockerfile

@@ -1,16 +1,20 @@
 # 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 -mod vendor -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 /app/web/static ./web/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.md

@@ -1,201 +1,9 @@
-                                 Apache License
-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
+MIT License
 
-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+Copyright (c) 2021 TwiN
 
-   1. Definitions.
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
-      "License" shall mean the terms and conditions for use, reproduction,
-      and distribution as defined by Sections 1 through 9 of this document.
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 
-      "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,
-      "control" means (i) the power, direct or indirect, to cause the
-      direction or management of such entity, whether by contract or
-      otherwise, or (ii) ownership of fifty percent (50%) or more of the
-      outstanding shares, or (iii) beneficial ownership of such entity.
-
-      "You" (or "Your") shall mean an individual or Legal Entity
-      exercising permissions granted by this License.
-
-      "Source" form shall mean the preferred form for making modifications,
-      including but not limited to software source code, documentation
-      source, and configuration files.
-
-      "Object" form shall mean any form resulting from mechanical
-      transformation or translation of a Source form, including but
-      not limited to compiled object code, generated documentation,
-      and conversions to other media types.
-
-      "Work" shall mean the work of authorship, whether in Source or
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-      with the Work to which such Contribution(s) was submitted. If You
-      institute patent litigation against any entity (including a
-      cross-claim or counterclaim in a lawsuit) alleging that the Work
-      or a Contribution incorporated within the Work constitutes direct
-      or contributory patent infringement, then any patent licenses
-      granted to You under this License for that Work shall terminate
-      as of the date such litigation is filed.
-
-   4. Redistribution. You may reproduce and distribute copies of the
-      Work or Derivative Works thereof in any medium, with or without
-      modifications, and in Source or Object form, provided that You
-      meet the following conditions:
-
-      (a) You must give any other recipients of the Work or
-          Derivative Works a copy of this License; and
-
-      (b) You must cause any modified files to carry prominent notices
-          stating that You changed the files; and
-
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-          that You distribute, all copyright, patent, trademark, and
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-          the Derivative Works; and
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-      (d) If the Work includes a "NOTICE" text file as part of its
-          distribution, then any Derivative Works that You distribute must
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-          pertain to any part of the Derivative Works, in at least one
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-          of the NOTICE file are for informational purposes only and
-          do not modify the License. You may add Your own attribution
-          notices within Derivative Works that You distribute, alongside
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-          that such additional attribution notices cannot be construed
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-      for any such Derivative Works as a whole, provided Your use,
-      reproduction, and distribution of the Work otherwise complies with
-      the conditions stated in this License.
-
-   5. Submission of Contributions. Unless You explicitly state otherwise,
-      any Contribution intentionally submitted for inclusion in the Work
-      by You to the Licensor shall be under the terms and conditions of
-      this License, without any additional terms or conditions.
-      Notwithstanding the above, nothing herein shall supersede or modify
-      the terms of any separate license agreement you may have executed
-      with Licensor regarding such Contributions.
-
-   6. Trademarks. This License does not grant permission to use the trade
-      names, trademarks, service marks, or product names of the Licensor,
-      except as required for reasonable and customary use in describing the
-      origin of the Work and reproducing the content of the NOTICE file.
-
-   7. Disclaimer of Warranty. Unless required by applicable law or
-      agreed to in writing, Licensor provides the Work (and each
-      Contributor provides its Contributions) on an "AS IS" BASIS,
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-      PARTICULAR PURPOSE. You are solely responsible for determining the
-      appropriateness of using or redistributing the Work and assume any
-      risks associated with Your exercise of permissions under this License.
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-   8. Limitation of Liability. In no event and under no legal theory,
-      whether in tort (including negligence), contract, or otherwise,
-      unless required by applicable law (such as deliberate and grossly
-      negligent acts) or agreed to in writing, shall any Contributor be
-      liable to You for damages, including any direct, indirect, special,
-      incidental, or consequential damages of any character arising as a
-      result of this License or out of the use or inability to use the
-      Work (including but not limited to damages for loss of goodwill,
-      work stoppage, computer failure or malfunction, or any and all
-      other commercial damages or losses), even if such Contributor
-      has been advised of the possibility of such damages.
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-   9. Accepting Warranty or Additional Liability. While redistributing
-      the Work or Derivative Works thereof, You may choose to offer,
-      and charge a fee for, acceptance of support, warranty, indemnity,
-      or other liability obligations and/or rights consistent with this
-      License. However, in accepting such obligations, You may act only
-      on Your own behalf and on Your sole responsibility, not on behalf
-      of any other Contributor, and only if You agree to indemnify,
-      defend, and hold each Contributor harmless for any liability
-      incurred by, or claims asserted against, such Contributor by reason
-      of your accepting any such warranty or additional liability.
-
-   END OF TERMS AND CONDITIONS
-
-   APPENDIX: How to apply the Apache License to your work.
-
-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
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-
-   Copyright 2020 TwinProduction
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   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.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Makefile

@@ -0,0 +1,37 @@
+BINARY=gatus
+
+install:
+	go build -mod vendor -o $(BINARY) .
+
+run:
+	GATUS_CONFIG_FILE=./config.yaml ./$(BINARY)
+
+clean:
+	rm $(BINARY)
+
+test:
+	sudo go test ./alerting/... ./client/... ./config/... ./controller/... ./core/... ./jsonpath/... ./pattern/... ./security/... ./storage/... ./util/... ./watchdog/... -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 +1,69 @@
+package alert
+
+// 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
+	//
+	// 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"`
+
+	// 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
+
+	// 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
+}
+
+// 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
+func (alert Alert) IsEnabled() bool {
+	if alert.Enabled == nil {
+		return false
+	}
+	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 +1,36 @@
+package alert
+
+import "testing"
+
+func TestAlert_IsEnabled(t *testing.T) {
+	if (Alert{Enabled: nil}).IsEnabled() {
+		t.Error("alert.IsEnabled() should've returned false, 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 +1,34 @@
+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"
+
+	// TypeMattermost is the Type for the mattermost alerting provider
+	TypeMattermost Type = "mattermost"
+
+	// TypeMessagebird is the Type for the messagebird alerting provider
+	TypeMessagebird Type = "messagebird"
+
+	// TypePagerDuty is the Type for the pagerduty alerting provider
+	TypePagerDuty Type = "pagerduty"
+
+	// 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"
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider"
+	"github.com/TwiN/gatus/v3/alerting/provider/custom"
+	"github.com/TwiN/gatus/v3/alerting/provider/discord"
+	"github.com/TwiN/gatus/v3/alerting/provider/mattermost"
+	"github.com/TwiN/gatus/v3/alerting/provider/messagebird"
+	"github.com/TwiN/gatus/v3/alerting/provider/pagerduty"
+	"github.com/TwiN/gatus/v3/alerting/provider/slack"
+	"github.com/TwiN/gatus/v3/alerting/provider/teams"
+	"github.com/TwiN/gatus/v3/alerting/provider/telegram"
+	"github.com/TwiN/gatus/v3/alerting/provider/twilio"
 )
 
+// Config is the configuration for alerting providers
 type Config struct {
-	Slack     *slack.AlertProvider     `yaml:"slack"`
+	// Custom is the configuration for the custom alerting provider
+	Custom *custom.AlertProvider `yaml:"custom"`
+
+	// Discord is the configuration for the discord alerting provider
+	Discord *discord.AlertProvider `yaml:"discord"`
+
+	// Mattermost is the configuration for the mattermost alerting provider
+	Mattermost *mattermost.AlertProvider `yaml:"mattermost"`
+
+	// Messagebird is the configuration for the messagebird alerting provider
+	Messagebird *messagebird.AlertProvider `yaml:"messagebird"`
+
+	// PagerDuty is the configuration for the pagerduty alerting provider
 	PagerDuty *pagerduty.AlertProvider `yaml:"pagerduty"`
-	Twilio    *twilio.AlertProvider    `yaml:"twilio"`
-	Custom    *custom.AlertProvider    `yaml:"custom"`
+
+	// Slack is the configuration for the slack alerting provider
+	Slack *slack.AlertProvider `yaml:"slack"`
+
+	// Teams is the configuration for the teams alerting provider
+	Teams *teams.AlertProvider `yaml:"teams"`
+
+	// Telegram is the configuration for the telegram alerting provider
+	Telegram *telegram.AlertProvider `yaml:"telegram"`
+
+	// Twilio is the configuration for the twilio alerting provider
+	Twilio *twilio.AlertProvider `yaml:"twilio"`
+}
+
+// GetAlertingProviderByAlertType returns an provider.AlertProvider by its corresponding alert.Type
+func (config Config) GetAlertingProviderByAlertType(alertType alert.Type) provider.AlertProvider {
+	switch alertType {
+	case alert.TypeCustom:
+		if config.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.Custom
+	case alert.TypeDiscord:
+		if config.Discord == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Discord
+	case alert.TypeMattermost:
+		if config.Mattermost == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Mattermost
+	case alert.TypeMessagebird:
+		if config.Messagebird == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Messagebird
+	case alert.TypePagerDuty:
+		if config.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.PagerDuty
+	case alert.TypeSlack:
+		if config.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.Slack
+	case alert.TypeTeams:
+		if config.Teams == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Teams
+	case alert.TypeTelegram:
+		if config.Telegram == nil {
+			// Since we're returning an interface, we need to explicitly return nil, even if the provider itself is nil
+			return nil
+		}
+		return config.Telegram
+	case alert.TypeTwilio:
+		if config.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.Twilio
+	}
+	return nil
 }

alerting/provider/custom/custom.go

@@ -2,64 +2,103 @@ package custom
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
-	"github.com/TwinProduction/gatus/client"
-	"github.com/TwinProduction/gatus/core"
 	"io/ioutil"
 	"net/http"
+	"os"
 	"strings"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/client"
+	"github.com/TwiN/gatus/v3/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"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
 }
 
+// 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
 }
 
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *AlertProvider {
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+func (provider *AlertProvider) ToCustomAlertProvider(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) *AlertProvider {
 	return provider
 }
 
-func (provider *AlertProvider) buildRequest(serviceName, alertDescription string, resolved bool) *http.Request {
+// 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) buildHTTPRequest(endpointName, alertDescription string, resolved bool) *http.Request {
 	body := provider.Body
-	providerUrl := provider.Url
+	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, "[SERVICE_NAME]") { // XXX: Remove this in v4.0.0
+		body = strings.ReplaceAll(body, "[SERVICE_NAME]", endpointName)
+	}
+	if strings.Contains(body, "[ENDPOINT_NAME]") {
+		body = strings.ReplaceAll(body, "[ENDPOINT_NAME]", endpointName)
 	}
 	if strings.Contains(body, "[ALERT_TRIGGERED_OR_RESOLVED]") {
 		if resolved {
-			body = strings.ReplaceAll(body, "[ALERT_TRIGGERED_OR_RESOLVED]", "RESOLVED")
+			body = strings.ReplaceAll(body, "[ALERT_TRIGGERED_OR_RESOLVED]", provider.GetAlertStatePlaceholderValue(true))
 		} else {
-			body = strings.ReplaceAll(body, "[ALERT_TRIGGERED_OR_RESOLVED]", "TRIGGERED")
+			body = strings.ReplaceAll(body, "[ALERT_TRIGGERED_OR_RESOLVED]", provider.GetAlertStatePlaceholderValue(false))
 		}
 	}
-	if strings.Contains(providerUrl, "[ALERT_DESCRIPTION]") {
-		providerUrl = strings.ReplaceAll(providerUrl, "[ALERT_DESCRIPTION]", alertDescription)
+	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, "[SERVICE_NAME]") { // XXX: Remove this in v4.0.0
+		providerURL = strings.ReplaceAll(providerURL, "[SERVICE_NAME]", endpointName)
 	}
-	if strings.Contains(providerUrl, "[ALERT_TRIGGERED_OR_RESOLVED]") {
+	if strings.Contains(providerURL, "[ENDPOINT_NAME]") {
+		providerURL = strings.ReplaceAll(providerURL, "[ENDPOINT_NAME]", endpointName)
+	}
+	if strings.Contains(providerURL, "[ALERT_TRIGGERED_OR_RESOLVED]") {
 		if resolved {
-			providerUrl = strings.ReplaceAll(providerUrl, "[ALERT_TRIGGERED_OR_RESOLVED]", "RESOLVED")
+			providerURL = strings.ReplaceAll(providerURL, "[ALERT_TRIGGERED_OR_RESOLVED]", provider.GetAlertStatePlaceholderValue(true))
 		} else {
-			providerUrl = strings.ReplaceAll(providerUrl, "[ALERT_TRIGGERED_OR_RESOLVED]", "TRIGGERED")
+			providerURL = strings.ReplaceAll(providerURL, "[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, providerURL, bodyBuffer)
 	for k, v := range provider.Headers {
 		request.Header.Set(k, v)
 	}
@@ -67,9 +106,15 @@ func (provider *AlertProvider) buildRequest(serviceName, alertDescription string
 }
 
 // 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(endpointName, alertDescription string, resolved bool) ([]byte, error) {
+	if os.Getenv("MOCK_ALERT_PROVIDER") == "true" {
+		if os.Getenv("MOCK_ALERT_PROVIDER_ERROR") == "true" {
+			return nil, errors.New("error")
+		}
+		return []byte("{}"), nil
+	}
+	request := provider.buildHTTPRequest(endpointName, alertDescription, resolved)
+	response, err := client.GetHTTPClient(provider.ClientConfig).Do(request)
 	if err != nil {
 		return nil, err
 	}
@@ -77,9 +122,13 @@ func (provider *AlertProvider) Send(serviceName, alertDescription string, resolv
 		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))
 		}
+		return nil, fmt.Errorf("call to provider alert returned status code %d: %s", response.StatusCode, string(body))
 	}
 	return ioutil.ReadAll(response.Body)
 }
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/custom/custom_test.go

@@ -3,33 +3,35 @@ package custom
 import (
 	"io/ioutil"
 	"testing"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/core"
 )
 
 func TestAlertProvider_IsValid(t *testing.T) {
-	invalidProvider := AlertProvider{Url: ""}
+	invalidProvider := AlertProvider{URL: ""}
 	if invalidProvider.IsValid() {
 		t.Error("provider shouldn't have been valid")
 	}
-	validProvider := AlertProvider{Url: "http://example.com"}
+	validProvider := AlertProvider{URL: "https://example.com"}
 	if !validProvider.IsValid() {
 		t.Error("provider should've been valid")
 	}
 }
 
-func TestAlertProvider_buildRequestWhenResolved(t *testing.T) {
+func TestAlertProvider_buildHTTPRequestWhenResolved(t *testing.T) {
 	const (
-		ExpectedUrl  = "http://example.com/service-name"
-		ExpectedBody = "service-name,alert-description,RESOLVED"
+		ExpectedURL  = "https://example.com/endpoint-name?event=RESOLVED&description=alert-description"
+		ExpectedBody = "endpoint-name,alert-description,RESOLVED"
 	)
 	customAlertProvider := &AlertProvider{
-		Url:     "http://example.com/[SERVICE_NAME]",
-		Method:  "GET",
-		Body:    "[SERVICE_NAME],[ALERT_DESCRIPTION],[ALERT_TRIGGERED_OR_RESOLVED]",
+		URL:     "https://example.com/[ENDPOINT_NAME]?event=[ALERT_TRIGGERED_OR_RESOLVED]&description=[ALERT_DESCRIPTION]",
+		Body:    "[ENDPOINT_NAME],[ALERT_DESCRIPTION],[ALERT_TRIGGERED_OR_RESOLVED]",
 		Headers: nil,
 	}
-	request := customAlertProvider.buildRequest("service-name", "alert-description", true)
-	if request.URL.String() != ExpectedUrl {
-		t.Error("expected URL to be", ExpectedUrl, "was", request.URL.String())
+	request := customAlertProvider.buildHTTPRequest("endpoint-name", "alert-description", true)
+	if request.URL.String() != ExpectedURL {
+		t.Error("expected URL to be", ExpectedURL, "was", request.URL.String())
 	}
 	body, _ := ioutil.ReadAll(request.Body)
 	if string(body) != ExpectedBody {
@@ -37,20 +39,93 @@ func TestAlertProvider_buildRequestWhenResolved(t *testing.T) {
 	}
 }
 
-func TestAlertProvider_buildRequestWhenTriggered(t *testing.T) {
+func TestAlertProvider_buildHTTPRequestWhenTriggered(t *testing.T) {
 	const (
-		ExpectedUrl  = "http://example.com/service-name"
-		ExpectedBody = "service-name,alert-description,TRIGGERED"
+		ExpectedURL  = "https://example.com/endpoint-name?event=TRIGGERED&description=alert-description"
+		ExpectedBody = "endpoint-name,alert-description,TRIGGERED"
 	)
 	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_NAME]?event=[ALERT_TRIGGERED_OR_RESOLVED]&description=[ALERT_DESCRIPTION]",
+		Body:    "[ENDPOINT_NAME],[ALERT_DESCRIPTION],[ALERT_TRIGGERED_OR_RESOLVED]",
+		Headers: map[string]string{"Authorization": "Basic hunter2"},
 	}
-	request := customAlertProvider.buildRequest("service-name", "alert-description", false)
-	if request.URL.String() != ExpectedUrl {
-		t.Error("expected URL to be", ExpectedUrl, "was", request.URL.String())
+	request := customAlertProvider.buildHTTPRequest("endpoint-name", "alert-description", false)
+	if request.URL.String() != ExpectedURL {
+		t.Error("expected URL to be", ExpectedURL, "was", request.URL.String())
+	}
+	body, _ := ioutil.ReadAll(request.Body)
+	if string(body) != ExpectedBody {
+		t.Error("expected body to be", ExpectedBody, "was", string(body))
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProvider(t *testing.T) {
+	provider := AlertProvider{URL: "https://example.com"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{}, true)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if customAlertProvider.URL != "https://example.com" {
+		t.Error("expected URL to be https://example.com, got", customAlertProvider.URL)
+	}
+}
+
+func TestAlertProvider_buildHTTPRequestWithCustomPlaceholder(t *testing.T) {
+	const (
+		ExpectedURL  = "https://example.com/endpoint-name?event=test&description=alert-description"
+		ExpectedBody = "endpoint-name,alert-description,test"
+	)
+	customAlertProvider := &AlertProvider{
+		URL:     "https://example.com/[ENDPOINT_NAME]?event=[ALERT_TRIGGERED_OR_RESOLVED]&description=[ALERT_DESCRIPTION]",
+		Body:    "[ENDPOINT_NAME],[ALERT_DESCRIPTION],[ALERT_TRIGGERED_OR_RESOLVED]",
+		Headers: nil,
+		Placeholders: map[string]map[string]string{
+			"ALERT_TRIGGERED_OR_RESOLVED": {
+				"RESOLVED": "test",
+			},
+		},
+	}
+	request := customAlertProvider.buildHTTPRequest("endpoint-name", "alert-description", true)
+	if request.URL.String() != ExpectedURL {
+		t.Error("expected URL to be", ExpectedURL, "was", request.URL.String())
+	}
+	body, _ := ioutil.ReadAll(request.Body)
+	if string(body) != ExpectedBody {
+		t.Error("expected body to be", ExpectedBody, "was", 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],[ALERT_DESCRIPTION],[ALERT_TRIGGERED_OR_RESOLVED]",
+		Headers:      nil,
+		Placeholders: nil,
+	}
+	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))
+	}
+}
+
+// TestAlertProvider_isBackwardCompatibleWithServiceRename checks if the custom alerting provider still supports
+// service placeholders after the migration from "service" to "endpoint"
+//
+// XXX: Remove this in v4.0.0
+func TestAlertProvider_isBackwardCompatibleWithServiceRename(t *testing.T) {
+	const (
+		ExpectedURL  = "https://example.com/endpoint-name?event=TRIGGERED&description=alert-description"
+		ExpectedBody = "endpoint-name,alert-description,TRIGGERED"
+	)
+	customAlertProvider := &AlertProvider{
+		URL:  "https://example.com/[SERVICE_NAME]?event=[ALERT_TRIGGERED_OR_RESOLVED]&description=[ALERT_DESCRIPTION]",
+		Body: "[SERVICE_NAME],[ALERT_DESCRIPTION],[ALERT_TRIGGERED_OR_RESOLVED]",
+	}
+	request := customAlertProvider.buildHTTPRequest("endpoint-name", "alert-description", false)
+	if request.URL.String() != ExpectedURL {
+		t.Error("expected URL to be", ExpectedURL, "was", request.URL.String())
 	}
 	body, _ := ioutil.ReadAll(request.Body)
 	if string(body) != ExpectedBody {

alerting/provider/discord/discord.go

@@ -0,0 +1,76 @@
+package discord
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider/custom"
+	"github.com/TwiN/gatus/v3/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"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	return len(provider.WebhookURL) > 0
+}
+
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+func (provider *AlertProvider) ToCustomAlertProvider(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+	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.Name, 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.Name, 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
+	}
+	return &custom.AlertProvider{
+		URL:    provider.WebhookURL,
+		Method: http.MethodPost,
+		Body: fmt.Sprintf(`{
+  "content": "",
+  "embeds": [
+    {
+      "title": ":helmet_with_white_cross: Gatus",
+      "description": "%s%s",
+      "color": %d,
+      "fields": [
+        {
+          "name": "Condition results",
+          "value": "%s",
+          "inline": false
+        }
+      ]
+    }
+  ]
+}`, message, description, colorCode, results),
+		Headers: map[string]string{"Content-Type": "application/json"},
+	}
+}
+
+// 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 +1,70 @@
+package discord
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/core"
+)
+
+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_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
+	provider := AlertProvider{WebhookURL: "http://example.com"}
+	alertDescription := "test"
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{Name: "svc"}, &alert.Alert{Description: &alertDescription}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "resolved") {
+		t.Error("customAlertProvider.Body should've contained the substring resolved")
+	}
+	if customAlertProvider.URL != "http://example.com" {
+		t.Errorf("expected URL to be %s, got %s", "http://example.com", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+	if expected := "An alert for **svc** has been resolved after passing successfully 0 time(s) in a row:\n> test"; expected != body["embeds"].([]interface{})[0].(map[string]interface{})["description"] {
+		t.Errorf("expected $.embeds[0].description to be %s, got %s", expected, body["embeds"].([]interface{})[0].(map[string]interface{})["description"])
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
+	provider := AlertProvider{WebhookURL: "http://example.com"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "triggered") {
+		t.Error("customAlertProvider.Body should've contained the substring triggered")
+	}
+	if customAlertProvider.URL != "http://example.com" {
+		t.Errorf("expected URL to be %s, got %s", "http://example.com", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}

alerting/provider/mattermost/mattermost.go

@@ -0,0 +1,94 @@
+package mattermost
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider/custom"
+	"github.com/TwiN/gatus/v3/client"
+	"github.com/TwiN/gatus/v3/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"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
+}
+
+// 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.WebhookURL) > 0
+}
+
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+func (provider *AlertProvider) ToCustomAlertProvider(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+	var message string
+	var color string
+	if resolved {
+		message = fmt.Sprintf("An alert for *%s* has been resolved after passing successfully %d time(s) in a row", endpoint.Name, 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.Name, alert.FailureThreshold)
+		color = "#DD0000"
+	}
+	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
+	}
+	return &custom.AlertProvider{
+		URL:          provider.WebhookURL,
+		Method:       http.MethodPost,
+		ClientConfig: provider.ClientConfig,
+		Body: fmt.Sprintf(`{
+  "text": "",
+  "username": "gatus",
+  "icon_url": "https://raw.githubusercontent.com/TwiN/gatus/master/static/logo.png",
+  "attachments": [
+    {
+      "title": ":rescue_worker_helmet: Gatus",
+      "fallback": "Gatus - %s",
+      "text": "%s%s",
+      "short": false,
+      "color": "%s",
+      "fields": [
+        {
+          "title": "URL",
+          "value": "%s",
+          "short": false
+        },
+        {
+          "title": "Condition results",
+          "value": "%s",
+          "short": false
+        }
+      ]
+    }
+  ]
+}`, message, message, description, color, endpoint.URL, results),
+		Headers: map[string]string{"Content-Type": "application/json"},
+	}
+}
+
+// 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 +1,70 @@
+package mattermost
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/core"
+)
+
+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_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
+	provider := AlertProvider{WebhookURL: "http://example.org"}
+	alertDescription := "test"
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{Name: "svc"}, &alert.Alert{Description: &alertDescription}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "resolved") {
+		t.Error("customAlertProvider.Body should've contained the substring resolved")
+	}
+	if customAlertProvider.URL != "http://example.org" {
+		t.Errorf("expected URL to be %s, got %s", "http://example.org", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+	if expected := "An alert for *svc* has been resolved after passing successfully 0 time(s) in a row:\n> test"; expected != body["attachments"].([]interface{})[0].(map[string]interface{})["text"] {
+		t.Errorf("expected $.attachments[0].description to be %s, got %s", expected, body["attachments"].([]interface{})[0].(map[string]interface{})["text"])
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
+	provider := AlertProvider{WebhookURL: "http://example.org"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "triggered") {
+		t.Error("customAlertProvider.Body should've contained the substring triggered")
+	}
+	if customAlertProvider.URL != "http://example.org" {
+		t.Errorf("expected URL to be %s, got %s", "http://example.org", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}

alerting/provider/messagebird/messagebird.go

@@ -0,0 +1,58 @@
+package messagebird
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider/custom"
+	"github.com/TwiN/gatus/v3/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"`
+}
+
+// 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
+}
+
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+// Reference doc for messagebird https://developers.messagebird.com/api/sms-messaging/#send-outbound-sms
+func (provider *AlertProvider) ToCustomAlertProvider(endpoint *core.Endpoint, alert *alert.Alert, _ *core.Result, resolved bool) *custom.AlertProvider {
+	var message string
+	if resolved {
+		message = fmt.Sprintf("RESOLVED: %s - %s", endpoint.Name, alert.GetDescription())
+	} else {
+		message = fmt.Sprintf("TRIGGERED: %s - %s", endpoint.Name, alert.GetDescription())
+	}
+	return &custom.AlertProvider{
+		URL:    restAPIURL,
+		Method: http.MethodPost,
+		Body: fmt.Sprintf(`{
+  "originator": "%s",
+  "recipients": "%s",
+  "body": "%s"
+}`, provider.Originator, provider.Recipients, message),
+		Headers: map[string]string{
+			"Content-Type":  "application/json",
+			"Authorization": fmt.Sprintf("AccessKey %s", provider.AccessKey),
+		},
+	}
+}
+
+// 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 +1,78 @@
+package messagebird
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/core"
+)
+
+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_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
+	provider := AlertProvider{
+		AccessKey:  "1",
+		Originator: "1",
+		Recipients: "1",
+	}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{}, true)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "RESOLVED") {
+		t.Error("customAlertProvider.Body should've contained the substring RESOLVED")
+	}
+	if customAlertProvider.URL != "https://rest.messagebird.com/messages" {
+		t.Errorf("expected URL to be %s, got %s", "https://rest.messagebird.com/messages", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
+	provider := AlertProvider{
+		AccessKey:  "1",
+		Originator: "1",
+		Recipients: "1",
+	}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{}, false)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "TRIGGERED") {
+		t.Error("customAlertProvider.Body should've contained the substring TRIGGERED")
+	}
+	if customAlertProvider.URL != "https://rest.messagebird.com/messages" {
+		t.Errorf("expected URL to be %s, got %s", "https://rest.messagebird.com/messages", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}

alerting/provider/pagerduty/pagerduty.go

@@ -2,33 +2,66 @@ package pagerduty
 
 import (
 	"fmt"
-	"github.com/TwinProduction/gatus/alerting/provider/custom"
-	"github.com/TwinProduction/gatus/core"
+	"net/http"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider/custom"
+	"github.com/TwiN/gatus/v3/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"`
+
+	// Overrides is a list of Override that may be prioritized over the default configuration
+	Overrides []Override `yaml:"overrides"`
+}
+
+// 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 {
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+//
+// relevant: https://developer.pagerduty.com/docs/events-api-v2/trigger-events/
+func (provider *AlertProvider) ToCustomAlertProvider(endpoint *core.Endpoint, alert *alert.Alert, _ *core.Result, resolved bool) *custom.AlertProvider {
 	var message, eventAction, resolveKey string
 	if resolved {
-		message = fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.Description)
+		message = fmt.Sprintf("RESOLVED: %s - %s", endpoint.Name, 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.Name, alert.GetDescription())
 		eventAction = "trigger"
 		resolveKey = ""
 	}
 	return &custom.AlertProvider{
-		Url:    "https://events.pagerduty.com/v2/enqueue",
-		Method: "POST",
+		URL:    restAPIURL,
+		Method: http.MethodPost,
 		Body: fmt.Sprintf(`{
   "routing_key": "%s",
   "dedup_key": "%s",
@@ -38,9 +71,29 @@ func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, aler
     "source": "%s",
     "severity": "critical"
   }
-}`, provider.IntegrationKey, resolveKey, eventAction, message, service.Name),
+}`, provider.getPagerDutyIntegrationKeyForGroup(endpoint.Group), resolveKey, eventAction, message, endpoint.Name),
 		Headers: map[string]string{
 			"Content-Type": "application/json",
 		},
 	}
 }
+
+// getPagerDutyIntegrationKeyForGroup returns the appropriate pagerduty integration key for a given group
+func (provider *AlertProvider) getPagerDutyIntegrationKeyForGroup(group string) string {
+	if provider.Overrides != nil {
+		for _, override := range provider.Overrides {
+			if group == override.Group {
+				return override.IntegrationKey
+			}
+		}
+	}
+	if provider.IntegrationKey != "" {
+		return provider.IntegrationKey
+	}
+	return ""
+}
+
+// GetDefaultAlert returns the provider's default alert configuration
+func (provider AlertProvider) GetDefaultAlert() *alert.Alert {
+	return provider.DefaultAlert
+}

alerting/provider/pagerduty/pagerduty_test.go

@@ -1,6 +1,14 @@
 package pagerduty
 
-import "testing"
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/core"
+)
 
 func TestAlertProvider_IsValid(t *testing.T) {
 	invalidProvider := AlertProvider{IntegrationKey: ""}
@@ -12,3 +20,206 @@ 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_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
+	provider := AlertProvider{IntegrationKey: "00000000000000000000000000000000"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{}, true)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "RESOLVED") {
+		t.Error("customAlertProvider.Body should've contained the substring RESOLVED")
+	}
+	if customAlertProvider.URL != "https://events.pagerduty.com/v2/enqueue" {
+		t.Errorf("expected URL to be %s, got %s", "https://events.pagerduty.com/v2/enqueue", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithResolvedAlertAndOverride(t *testing.T) {
+	provider := AlertProvider{
+		IntegrationKey: "",
+		Overrides: []Override{
+			{
+				IntegrationKey: "00000000000000000000000000000000",
+				Group:          "group",
+			},
+		},
+	}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{}, true)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "RESOLVED") {
+		t.Error("customAlertProvider.Body should've contained the substring RESOLVED")
+	}
+	if customAlertProvider.URL != "https://events.pagerduty.com/v2/enqueue" {
+		t.Errorf("expected URL to be %s, got %s", "https://events.pagerduty.com/v2/enqueue", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
+	provider := AlertProvider{IntegrationKey: "00000000000000000000000000000000"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{}, false)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "TRIGGERED") {
+		t.Error("customAlertProvider.Body should've contained the substring TRIGGERED")
+	}
+	if customAlertProvider.URL != "https://events.pagerduty.com/v2/enqueue" {
+		t.Errorf("expected URL to be %s, got %s", "https://events.pagerduty.com/v2/enqueue", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlertAndOverride(t *testing.T) {
+	provider := AlertProvider{
+		IntegrationKey: "",
+		Overrides: []Override{
+			{
+				IntegrationKey: "00000000000000000000000000000000",
+				Group:          "group",
+			},
+		},
+	}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{}, false)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "TRIGGERED") {
+		t.Error("customAlertProvider.Body should've contained the substring TRIGGERED")
+	}
+	if customAlertProvider.URL != "https://events.pagerduty.com/v2/enqueue" {
+		t.Errorf("expected URL to be %s, got %s", "https://events.pagerduty.com/v2/enqueue", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}
+
+func TestAlertProvider_getPagerDutyIntegrationKey(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.getPagerDutyIntegrationKeyForGroup(scenario.InputGroup); output != scenario.ExpectedOutput {
+				t.Errorf("expected %s, got %s", scenario.ExpectedOutput, output)
+			}
+		})
+	}
+}

alerting/provider/provider.go

@@ -1,11 +1,62 @@
 package provider
 
 import (
-	"github.com/TwinProduction/gatus/alerting/provider/custom"
-	"github.com/TwinProduction/gatus/core"
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider/custom"
+	"github.com/TwiN/gatus/v3/alerting/provider/discord"
+	"github.com/TwiN/gatus/v3/alerting/provider/mattermost"
+	"github.com/TwiN/gatus/v3/alerting/provider/messagebird"
+	"github.com/TwiN/gatus/v3/alerting/provider/pagerduty"
+	"github.com/TwiN/gatus/v3/alerting/provider/slack"
+	"github.com/TwiN/gatus/v3/alerting/provider/teams"
+	"github.com/TwiN/gatus/v3/alerting/provider/telegram"
+	"github.com/TwiN/gatus/v3/alerting/provider/twilio"
+	"github.com/TwiN/gatus/v3/core"
 )
 
+// AlertProvider is the interface that each providers should implement
 type AlertProvider interface {
+	// IsValid returns whether the provider's configuration is valid
 	IsValid() bool
-	ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider
+
+	// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+	ToCustomAlertProvider(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider
+
+	// GetDefaultAlert returns the provider's default alert configuration
+	GetDefaultAlert() *alert.Alert
 }
+
+// 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 = (*mattermost.AlertProvider)(nil)
+	_ AlertProvider = (*messagebird.AlertProvider)(nil)
+	_ AlertProvider = (*pagerduty.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/v3/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/slack/slack.go

@@ -2,47 +2,58 @@ package slack
 
 import (
 	"fmt"
-	"github.com/TwinProduction/gatus/alerting/provider/custom"
-	"github.com/TwinProduction/gatus/core"
+	"net/http"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider/custom"
+	"github.com/TwiN/gatus/v3/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"`
 }
 
+// IsValid returns whether the provider's configuration is valid
 func (provider *AlertProvider) IsValid() bool {
-	return len(provider.WebhookUrl) > 0
+	return len(provider.WebhookURL) > 0
 }
 
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
-	var message string
-	var color string
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+func (provider *AlertProvider) ToCustomAlertProvider(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+	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.Name, 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.Name, 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)
+		results += fmt.Sprintf("%s - `%s`\\n", prefix, conditionResult.Condition)
+	}
+	var description string
+	if alertDescription := alert.GetDescription(); len(alertDescription) > 0 {
+		description = ":\\n> " + alertDescription
 	}
 	return &custom.AlertProvider{
-		Url:    provider.WebhookUrl,
-		Method: "POST",
+		URL:    provider.WebhookURL,
+		Method: http.MethodPost,
 		Body: fmt.Sprintf(`{
   "text": "",
   "attachments": [
     {
       "title": ":helmet_with_white_cross: Gatus",
-      "text": "%s:\n> %s",
+      "text": "%s%s",
       "short": false,
       "color": "%s",
       "fields": [
@@ -52,9 +63,14 @@ func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, aler
           "short": false
         }
       ]
-    },
+    }
   ]
-}`, message, alert.Description, color, results),
+}`, message, description, color, results),
 		Headers: map[string]string{"Content-Type": "application/json"},
 	}
 }
+
+// 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 +1,70 @@
 package slack
 
-import "testing"
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/core"
+)
 
 func TestAlertProvider_IsValid(t *testing.T) {
-	invalidProvider := AlertProvider{WebhookUrl: ""}
+	invalidProvider := AlertProvider{WebhookURL: ""}
 	if invalidProvider.IsValid() {
 		t.Error("provider shouldn't have been valid")
 	}
-	validProvider := AlertProvider{WebhookUrl: "http://example.com"}
+	validProvider := AlertProvider{WebhookURL: "http://example.com"}
 	if !validProvider.IsValid() {
 		t.Error("provider should've been valid")
 	}
 }
+
+func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
+	provider := AlertProvider{WebhookURL: "http://example.com"}
+	alertDescription := "test"
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{Name: "svc"}, &alert.Alert{Description: &alertDescription}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "resolved") {
+		t.Error("customAlertProvider.Body should've contained the substring resolved")
+	}
+	if customAlertProvider.URL != "http://example.com" {
+		t.Errorf("expected URL to be %s, got %s", "http://example.com", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+	if expected := "An alert for *svc* has been resolved after passing successfully 0 time(s) in a row:\n> test"; expected != body["attachments"].([]interface{})[0].(map[string]interface{})["text"] {
+		t.Errorf("expected $.attachments[0].description to be %s, got %s", expected, body["attachments"].([]interface{})[0].(map[string]interface{})["text"])
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
+	provider := AlertProvider{WebhookURL: "http://example.com"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "triggered") {
+		t.Error("customAlertProvider.Body should've contained the substring triggered")
+	}
+	if customAlertProvider.URL != "http://example.com" {
+		t.Errorf("expected URL to be %s, got %s", "http://example.com", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}

alerting/provider/teams/teams.go

@@ -0,0 +1,77 @@
+package teams
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider/custom"
+	"github.com/TwiN/gatus/v3/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"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	return len(provider.WebhookURL) > 0
+}
+
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+func (provider *AlertProvider) ToCustomAlertProvider(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+	var message string
+	var color string
+	if resolved {
+		message = fmt.Sprintf("An alert for *%s* has been resolved after passing successfully %d time(s) in a row", endpoint.Name, 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.Name, 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 = ":\\n> " + alertDescription
+	}
+	return &custom.AlertProvider{
+		URL:    provider.WebhookURL,
+		Method: http.MethodPost,
+		Body: fmt.Sprintf(`{
+  "@type": "MessageCard",
+  "@context": "http://schema.org/extensions",
+  "themeColor": "%s",
+  "title": "&#x1F6A8; Gatus",
+  "text": "%s%s",
+  "sections": [
+    {
+      "activityTitle": "URL",
+      "text": "%s"
+    },
+    {
+      "activityTitle": "Condition results",
+      "text": "%s"
+    }
+  ]
+}`, color, message, description, endpoint.URL, results),
+		Headers: map[string]string{"Content-Type": "application/json"},
+	}
+}
+
+// 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 +1,70 @@
+package teams
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/core"
+)
+
+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_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
+	provider := AlertProvider{WebhookURL: "http://example.org"}
+	alertDescription := "test"
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{Name: "svc"}, &alert.Alert{Description: &alertDescription}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "resolved") {
+		t.Error("customAlertProvider.Body should've contained the substring resolved")
+	}
+	if customAlertProvider.URL != "http://example.org" {
+		t.Errorf("expected URL to be %s, got %s", "http://example.org", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+	if expected := "An alert for *svc* has been resolved after passing successfully 0 time(s) in a row:\n> test"; expected != body["text"] {
+		t.Errorf("expected $.text to be %s, got %s", expected, body["text"])
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
+	provider := AlertProvider{WebhookURL: "http://example.org"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "triggered") {
+		t.Error("customAlertProvider.Body should've contained the substring triggered")
+	}
+	if customAlertProvider.URL != "http://example.org" {
+		t.Errorf("expected URL to be %s, got %s", "http://example.org", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}

alerting/provider/telegram/telegram.go

@@ -0,0 +1,60 @@
+package telegram
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider/custom"
+	"github.com/TwiN/gatus/v3/core"
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Telegram
+type AlertProvider struct {
+	Token string `yaml:"token"`
+	ID    string `yaml:"id"`
+
+	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
+	DefaultAlert *alert.Alert `yaml:"default-alert"`
+}
+
+// IsValid returns whether the provider's configuration is valid
+func (provider *AlertProvider) IsValid() bool {
+	return len(provider.Token) > 0 && len(provider.ID) > 0
+}
+
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+func (provider *AlertProvider) ToCustomAlertProvider(endpoint *core.Endpoint, alert *alert.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+	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.Name, 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.Name, 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)
+	}
+	return &custom.AlertProvider{
+		URL:     fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", provider.Token),
+		Method:  http.MethodPost,
+		Body:    fmt.Sprintf(`{"chat_id": "%s", "text": "%s", "parse_mode": "MARKDOWN"}`, provider.ID, text),
+		Headers: map[string]string{"Content-Type": "application/json"},
+	}
+}
+
+// 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 +1,91 @@
+package telegram
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/core"
+)
+
+func TestAlertProvider_IsValid(t *testing.T) {
+	invalidProvider := AlertProvider{Token: "", ID: ""}
+	if invalidProvider.IsValid() {
+		t.Error("provider shouldn't have been valid")
+	}
+	validProvider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "12345678"}
+	if !validProvider.IsValid() {
+		t.Error("provider should've been valid")
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
+	provider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "12345678"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "SUCCESSFUL_CONDITION", Success: true}}}, true)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "resolved") {
+		t.Error("customAlertProvider.Body should've contained the substring resolved")
+	}
+	if customAlertProvider.URL != fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", provider.Token) {
+		t.Errorf("expected URL to be %s, got %s", fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", provider.Token), customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	//_, err := json.Marshal(customAlertProvider.Body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
+	provider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "0123456789"}
+	description := "Healthcheck Successful"
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{Description: &description}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "triggered") {
+		t.Error("customAlertProvider.Body should've contained the substring triggered")
+	}
+	if customAlertProvider.URL != fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", provider.Token) {
+		t.Errorf("expected URL to be %s, got %s", fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", provider.Token), customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithDescription(t *testing.T) {
+	provider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "0123456789"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{}, &alert.Alert{}, &core.Result{ConditionResults: []*core.ConditionResult{{Condition: "UNSUCCESSFUL_CONDITION", Success: false}}}, false)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "triggered") {
+		t.Error("customAlertProvider.Body should've contained the substring triggered")
+	}
+	if customAlertProvider.URL != fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", provider.Token) {
+		t.Errorf("expected URL to be %s, got %s", fmt.Sprintf("https://api.telegram.org/bot%s/sendMessage", provider.Token), customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	body := make(map[string]interface{})
+	err := json.Unmarshal([]byte(customAlertProvider.Body), &body)
+	if err != nil {
+		t.Error("expected body to be valid JSON, got error:", err.Error())
+	}
+}

alerting/provider/twilio/twilio.go

@@ -3,32 +3,41 @@ package twilio
 import (
 	"encoding/base64"
 	"fmt"
-	"github.com/TwinProduction/gatus/alerting/provider/custom"
-	"github.com/TwinProduction/gatus/core"
+	"net/http"
 	"net/url"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider/custom"
+	"github.com/TwiN/gatus/v3/core"
 )
 
+// AlertProvider is the configuration necessary for sending an alert using Twilio
 type AlertProvider struct {
 	SID   string `yaml:"sid"`
 	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"`
 }
 
+// IsValid returns whether the provider's configuration is valid
 func (provider *AlertProvider) IsValid() bool {
 	return len(provider.Token) > 0 && len(provider.SID) > 0 && len(provider.From) > 0 && len(provider.To) > 0
 }
 
-func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+func (provider *AlertProvider) ToCustomAlertProvider(endpoint *core.Endpoint, alert *alert.Alert, _ *core.Result, resolved bool) *custom.AlertProvider {
 	var message string
 	if resolved {
-		message = fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.Description)
+		message = fmt.Sprintf("RESOLVED: %s - %s", endpoint.Name, alert.GetDescription())
 	} else {
-		message = fmt.Sprintf("TRIGGERED: %s - %s", service.Name, alert.Description)
+		message = fmt.Sprintf("TRIGGERED: %s - %s", endpoint.Name, alert.GetDescription())
 	}
 	return &custom.AlertProvider{
-		Url:    fmt.Sprintf("https://api.twilio.com/2010-04-01/Accounts/%s/Messages.json", provider.SID),
-		Method: "POST",
+		URL:    fmt.Sprintf("https://api.twilio.com/2010-04-01/Accounts/%s/Messages.json", provider.SID),
+		Method: http.MethodPost,
 		Body: url.Values{
 			"To":   {provider.To},
 			"From": {provider.From},
@@ -40,3 +49,8 @@ func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, aler
 		},
 	}
 }
+
+// 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 +1,13 @@
 package twilio
 
-import "testing"
+import (
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/core"
+)
 
 func TestTwilioAlertProvider_IsValid(t *testing.T) {
 	invalidProvider := AlertProvider{}
@@ -17,3 +24,55 @@ func TestTwilioAlertProvider_IsValid(t *testing.T) {
 		t.Error("provider should've been valid")
 	}
 }
+
+func TestAlertProvider_ToCustomAlertProviderWithResolvedAlert(t *testing.T) {
+	provider := AlertProvider{
+		SID:   "1",
+		Token: "2",
+		From:  "3",
+		To:    "4",
+	}
+	description := "alert-description"
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{Name: "endpoint-name"}, &alert.Alert{Description: &description}, &core.Result{}, true)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "RESOLVED") {
+		t.Error("customAlertProvider.Body should've contained the substring RESOLVED")
+	}
+	if customAlertProvider.URL != "https://api.twilio.com/2010-04-01/Accounts/1/Messages.json" {
+		t.Errorf("expected URL to be %s, got %s", "https://api.twilio.com/2010-04-01/Accounts/1/Messages.json", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	if customAlertProvider.Body != "Body=RESOLVED%3A+endpoint-name+-+alert-description&From=3&To=4" {
+		t.Errorf("expected body to be %s, got %s", "Body=RESOLVED%3A+endpoint-name+-+alert-description&From=3&To=4", customAlertProvider.Body)
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
+	provider := AlertProvider{
+		SID:   "4",
+		Token: "3",
+		From:  "2",
+		To:    "1",
+	}
+	description := "alert-description"
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Endpoint{Name: "endpoint-name"}, &alert.Alert{Description: &description}, &core.Result{}, false)
+	if customAlertProvider == nil {
+		t.Fatal("customAlertProvider shouldn't have been nil")
+	}
+	if !strings.Contains(customAlertProvider.Body, "TRIGGERED") {
+		t.Error("customAlertProvider.Body should've contained the substring TRIGGERED")
+	}
+	if customAlertProvider.URL != "https://api.twilio.com/2010-04-01/Accounts/4/Messages.json" {
+		t.Errorf("expected URL to be %s, got %s", "https://api.twilio.com/2010-04-01/Accounts/4/Messages.json", customAlertProvider.URL)
+	}
+	if customAlertProvider.Method != http.MethodPost {
+		t.Errorf("expected method to be %s, got %s", http.MethodPost, customAlertProvider.Method)
+	}
+	if customAlertProvider.Body != "Body=TRIGGERED%3A+endpoint-name+-+alert-description&From=2&To=1" {
+		t.Errorf("expected body to be %s, got %s", "Body=TRIGGERED%3A+endpoint-name+-+alert-description&From=2&To=1", customAlertProvider.Body)
+	}
+}

client/client.go

@@ -1,19 +1,106 @@
 package client
 
 import (
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"net"
 	"net/http"
+	"net/smtp"
+	"runtime"
+	"strings"
 	"time"
+
+	"github.com/go-ping/ping"
 )
 
-var (
-	client *http.Client
-)
-
-func GetHttpClient() *http.Client {
-	if client == nil {
-		client = &http.Client{
-			Timeout: time.Second * 10,
-		}
+// GetHTTPClient returns the shared HTTP client
+func GetHTTPClient(config *Config) *http.Client {
+	if config == nil {
+		return defaultConfig.getHTTPClient()
 	}
-	return client
+	return config.getHTTPClient()
+}
+
+// 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
+}
+
+// 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/go-ping/ping#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
 }

client/client_test.go

@@ -1,13 +1,148 @@
 package client
 
-import "testing"
+import (
+	"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")
+func TestGetHTTPClient(t *testing.T) {
+	cfg := &Config{
+		Insecure:       false,
+		IgnoreRedirect: false,
+		Timeout:        0,
 	}
-	_ = GetHttpClient()
-	if client == nil {
-		t.Error("client shouldn't have been nil, since it has been called once")
+	cfg.ValidateAndSetDefaults()
+	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 TestPing(t *testing.T) {
+	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) {
+			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) {
+			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")
 	}
 }

client/config.go

@@ -0,0 +1,73 @@
+package client
+
+import (
+	"crypto/tls"
+	"net/http"
+	"time"
+)
+
+const (
+	defaultHTTPTimeout = 10 * time.Second
+)
+
+var (
+	// DefaultConfig is the default client configuration
+	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"`
+
+	// IgnoreRedirect determines whether to ignore redirects (true) or follow them (false, default)
+	IgnoreRedirect bool `yaml:"ignore-redirect"`
+
+	// Timeout for the client
+	Timeout time.Duration `yaml:"timeout"`
+
+	httpClient *http.Client
+}
+
+// ValidateAndSetDefaults validates the client configuration and sets the default values if necessary
+func (c *Config) ValidateAndSetDefaults() {
+	if c.Timeout < time.Millisecond {
+		c.Timeout = 10 * time.Second
+	}
+}
+
+// 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
+			},
+		}
+	}
+	return c.httpClient
+}

client/config_test.go

@@ -0,0 +1,37 @@
+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")
+	}
+}

config.yaml

@@ -1,16 +1,47 @@
-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"

config/config.go

@@ -2,63 +2,142 @@ 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"
 	"log"
 	"os"
+	"time"
+
+	"github.com/TwiN/gatus/v3/alerting"
+	"github.com/TwiN/gatus/v3/alerting/alert"
+	"github.com/TwiN/gatus/v3/alerting/provider"
+	"github.com/TwiN/gatus/v3/config/maintenance"
+	"github.com/TwiN/gatus/v3/config/ui"
+	"github.com/TwiN/gatus/v3/config/web"
+	"github.com/TwiN/gatus/v3/core"
+	"github.com/TwiN/gatus/v3/security"
+	"github.com/TwiN/gatus/v3/storage"
+	"gopkg.in/yaml.v2"
 )
 
 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
 	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 has no endpoints configured
+	ErrNoEndpointInConfig = errors.New("configuration file should contain at least 1 endpoint")
+
+	// ErrConfigFileNotFound is an error returned when the 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")
 )
 
+// 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"`
+
+	// Services List of endpoints to monitor
+	//
+	// XXX: Remove this in v5.0.0
+	// XXX: This is not a typo -- not v4.0.0, but v5.0.0 -- I want to give enough time for people to migrate
+	//
+	// Deprecated in favor of Endpoints
+	Services []*core.Endpoint `yaml:"services,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"`
+
+	filePath        string    // path to the file from which config was loaded from
+	lastFileModTime time.Time // last modification time
 }
 
-func Get() *Config {
-	if config == nil {
-		panic(ErrConfigNotLoaded)
+// HasLoadedConfigurationFileBeenModified returns whether the file that the
+// configuration has been loaded from has been modified since it was last read
+func (config Config) HasLoadedConfigurationFileBeenModified() bool {
+	if fileInfo, err := os.Stat(config.filePath); err == nil {
+		if !fileInfo.ModTime().IsZero() {
+			return config.lastFileModTime.Unix() != fileInfo.ModTime().Unix()
+		}
 	}
-	return config
+	return false
 }
 
-func Load(configFile string) error {
+// UpdateLastFileModTime refreshes Config.lastFileModTime
+func (config *Config) UpdateLastFileModTime() {
+	if fileInfo, err := os.Stat(config.filePath); err == nil {
+		if !fileInfo.ModTime().IsZero() {
+			config.lastFileModTime = fileInfo.ModTime()
+		}
+	} else {
+		log.Println("[config][UpdateLastFileModTime] Ran into error updating lastFileModTime:", err.Error())
+	}
+}
+
+// Load loads a custom configuration file
+// Note that the misconfiguration of some fields may lead to panics. This is on purpose.
+func Load(configFile string) (*Config, error) {
 	log.Printf("[config][Load] Reading configuration from configFile=%s", configFile)
 	cfg, err := readConfigurationFile(configFile)
 	if err != nil {
 		if os.IsNotExist(err) {
-			return ErrConfigFileNotFound
-		} else {
-			return err
+			return nil, ErrConfigFileNotFound
 		}
+		return nil, err
 	}
-	config = cfg
-	return nil
+	cfg.filePath = configFile
+	cfg.UpdateLastFileModTime()
+	return cfg, nil
 }
 
-func LoadDefaultConfiguration() error {
-	err := Load(DefaultConfigurationFilePath)
+// LoadDefaultConfiguration loads the default configuration file
+func LoadDefaultConfiguration() (*Config, error) {
+	cfg, err := Load(DefaultConfigurationFilePath)
 	if err != nil {
 		if err == ErrConfigFileNotFound {
-			return Load("config/config.yml")
+			return Load(DefaultFallbackConfigurationFilePath)
 		}
-		return err
+		return nil, err
 	}
-	return nil
+	return cfg, nil
 }
 
 func readConfigurationFile(fileName string) (config *Config, err error) {
@@ -70,47 +149,166 @@ func readConfigurationFile(fileName string) (config *Config, err error) {
 	return
 }
 
+// parseAndValidateConfigBytes parses a Gatus configuration file into a Config struct and validates its parameters
 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
+	if err = yaml.Unmarshal(yamlBytes, &config); err != nil {
+		return
+	}
+	if config != nil && len(config.Services) > 0 { // XXX: Remove this in v5.0.0
+		log.Println("WARNING: Your configuration is using 'services:', which is deprecated in favor of 'endpoints:'.")
+		log.Println("WARNING: See https://github.com/TwiN/gatus/issues/191 for more information")
+		config.Endpoints = append(config.Endpoints, config.Services...)
+		config.Services = nil
+	}
+	// 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)
-		validateServicesConfig(config)
+		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
+		}
 	}
 	return
 }
 
-func validateServicesConfig(config *Config) {
-	for _, service := range config.Services {
-		if config.Debug {
-			log.Printf("[config][validateServicesConfig] Validating service '%s'", service.Name)
+func validateStorageConfig(config *Config) error {
+	if config.Storage == nil {
+		config.Storage = &storage.Config{
+			Type: storage.TypeMemory,
 		}
-		service.ValidateAndSetDefaults()
 	}
-	log.Printf("[config][validateServicesConfig] Validated %d services", len(config.Services))
+	err := storage.Initialize(config.Storage)
+	if err != nil {
+		return err
+	}
+	// Remove all EndpointStatus that represent endpoints which no longer exist in the configuration
+	var keys []string
+	for _, endpoint := range config.Endpoints {
+		keys = append(keys, endpoint.Key())
+	}
+	numberOfEndpointStatusesDeleted := storage.Get().DeleteAllEndpointStatusesNotInKeys(keys)
+	if numberOfEndpointStatusesDeleted > 0 {
+		log.Printf("[config][validateStorageConfig] Deleted %d endpoint statuses because their matching endpoints no longer existed", numberOfEndpointStatusesDeleted)
+	}
+	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 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.TypeMattermost,
+		alert.TypeMessagebird,
+		alert.TypePagerDuty,
+		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)
@@ -122,33 +320,3 @@ 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
-}

config/maintenance/maintenance.go

@@ -0,0 +1,146 @@
+package maintenance
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var (
+	errInvalidMaintenanceStartFormat = errors.New("invalid maintenance start format: must be hh:mm, between 00:00 and 23:59 inclusively (e.g. 23:00)")
+	errInvalidMaintenanceDuration    = errors.New("invalid maintenance duration: must be bigger than 0 (e.g. 30m)")
+	errInvalidDayName                = fmt.Errorf("invalid value specified for 'on'. supported values are %s", longDayNames)
+
+	longDayNames = []string{
+		"Sunday",
+		"Monday",
+		"Tuesday",
+		"Wednesday",
+		"Thursday",
+		"Friday",
+		"Saturday",
+	}
+)
+
+// Config allows for the configuration of a maintenance period.
+// During this maintenance period, no alerts will be sent.
+//
+// Uses UTC.
+type Config struct {
+	Enabled  *bool         `yaml:"enabled"`  // Whether the maintenance period is enabled. Enabled by default if nil.
+	Start    string        `yaml:"start"`    // Time at which the maintenance period starts (e.g. 23:00)
+	Duration time.Duration `yaml:"duration"` // Duration of the maintenance period (e.g. 4h)
+
+	// Every is a list of days of the week during which maintenance period applies.
+	// See longDayNames for list of valid values.
+	// Every day if empty.
+	Every []string `yaml:"every"`
+
+	durationToStartFromMidnight time.Duration
+	timeLocation                *time.Location
+}
+
+func GetDefaultConfig() *Config {
+	defaultValue := false
+	return &Config{
+		Enabled: &defaultValue,
+	}
+}
+
+// IsEnabled returns whether maintenance is enabled or not
+func (c Config) IsEnabled() bool {
+	if c.Enabled == nil {
+		return true
+	}
+	return *c.Enabled
+}
+
+// ValidateAndSetDefaults validates the maintenance configuration and sets the default values if necessary.
+//
+// Must be called once in the application's lifecycle before IsUnderMaintenance is called, since it
+// also sets durationToStartFromMidnight.
+func (c *Config) ValidateAndSetDefaults() error {
+	if c == nil || !c.IsEnabled() {
+		// Don't waste time validating if maintenance is not enabled.
+		return nil
+	}
+	for _, day := range c.Every {
+		isDayValid := false
+		for _, longDayName := range longDayNames {
+			if day == longDayName {
+				isDayValid = true
+				break
+			}
+		}
+		if !isDayValid {
+			return errInvalidDayName
+		}
+	}
+	var err error
+	c.durationToStartFromMidnight, err = hhmmToDuration(c.Start)
+	if err != nil {
+		return err
+	}
+	if c.Duration <= 0 || c.Duration >= 24*time.Hour {
+		return errInvalidMaintenanceDuration
+	}
+	return nil
+}
+
+// IsUnderMaintenance checks whether the endpoints that Gatus monitors are within the configured maintenance window
+func (c Config) IsUnderMaintenance() bool {
+	if !c.IsEnabled() {
+		return false
+	}
+	now := time.Now().UTC()
+	var dayWhereMaintenancePeriodWouldStart time.Time
+	if now.Hour() >= int(c.durationToStartFromMidnight.Hours()) {
+		dayWhereMaintenancePeriodWouldStart = now.Truncate(24 * time.Hour)
+	} else {
+		dayWhereMaintenancePeriodWouldStart = now.Add(-c.Duration).Truncate(24 * time.Hour)
+	}
+	hasMaintenanceEveryDay := len(c.Every) == 0
+	hasMaintenancePeriodScheduledToStartOnThatWeekday := c.hasDay(dayWhereMaintenancePeriodWouldStart.Weekday().String())
+	if !hasMaintenanceEveryDay && !hasMaintenancePeriodScheduledToStartOnThatWeekday {
+		// The day when the maintenance period would start is not scheduled
+		// to have any maintenance, so we can just return false.
+		return false
+	}
+	startOfMaintenancePeriod := dayWhereMaintenancePeriodWouldStart.Add(c.durationToStartFromMidnight)
+	endOfMaintenancePeriod := startOfMaintenancePeriod.Add(c.Duration)
+	return now.After(startOfMaintenancePeriod) && now.Before(endOfMaintenancePeriod)
+}
+
+func (c Config) hasDay(day string) bool {
+	for _, d := range c.Every {
+		if d == day {
+			return true
+		}
+	}
+	return false
+}
+
+func hhmmToDuration(s string) (time.Duration, error) {
+	if len(s) != 5 {
+		return 0, errInvalidMaintenanceStartFormat
+	}
+	var hours, minutes int
+	var err error
+	if hours, err = extractNumericalValueFromPotentiallyZeroPaddedString(s[:2]); err != nil {
+		return 0, err
+	}
+	if minutes, err = extractNumericalValueFromPotentiallyZeroPaddedString(s[3:5]); err != nil {
+		return 0, err
+	}
+	duration := (time.Duration(hours) * time.Hour) + (time.Duration(minutes) * time.Minute)
+	if hours < 0 || hours > 23 || minutes < 0 || minutes > 59 || duration < 0 || duration >= 24*time.Hour {
+		return 0, errInvalidMaintenanceStartFormat
+	}
+	return duration, nil
+}
+
+func extractNumericalValueFromPotentiallyZeroPaddedString(s string) (int, error) {
+	return strconv.Atoi(strings.TrimPrefix(s, "0"))
+}

config/maintenance/maintenance_test.go

@@ -0,0 +1,226 @@
+package maintenance
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"testing"
+	"time"
+)
+
+func TestGetDefaultConfig(t *testing.T) {
+	if *GetDefaultConfig().Enabled {
+		t.Fatal("expected default config to be disabled by default")
+	}
+}
+
+func TestConfig_ValidateAndSetDefaults(t *testing.T) {
+	yes, no := true, false
+	scenarios := []struct {
+		name          string
+		cfg           *Config
+		expectedError error
+	}{
+		{
+			name:          "nil",
+			cfg:           nil,
+			expectedError: nil,
+		},
+		{
+			name: "disabled",
+			cfg: &Config{
+				Enabled: &no,
+			},
+			expectedError: nil,
+		},
+		{
+			name: "invalid-day",
+			cfg: &Config{
+				Every: []string{"invalid-day"},
+			},
+			expectedError: errInvalidDayName,
+		},
+		{
+			name: "invalid-day",
+			cfg: &Config{
+				Every: []string{"invalid-day"},
+			},
+			expectedError: errInvalidDayName,
+		},
+		{
+			name: "invalid-start-format",
+			cfg: &Config{
+				Start: "0000",
+			},
+			expectedError: errInvalidMaintenanceStartFormat,
+		},
+		{
+			name: "invalid-start-hours",
+			cfg: &Config{
+				Start: "25:00",
+			},
+			expectedError: errInvalidMaintenanceStartFormat,
+		},
+		{
+			name: "invalid-start-minutes",
+			cfg: &Config{
+				Start: "0:61",
+			},
+			expectedError: errInvalidMaintenanceStartFormat,
+		},
+		{
+			name: "invalid-start-minutes-non-numerical",
+			cfg: &Config{
+				Start: "00:zz",
+			},
+			expectedError: strconv.ErrSyntax,
+		},
+		{
+			name: "invalid-start-hours-non-numerical",
+			cfg: &Config{
+				Start: "zz:00",
+			},
+			expectedError: strconv.ErrSyntax,
+		},
+		{
+			name: "invalid-duration",
+			cfg: &Config{
+				Start:    "23:00",
+				Duration: 0,
+			},
+			expectedError: errInvalidMaintenanceDuration,
+		},
+		{
+			name: "every-day-at-2300",
+			cfg: &Config{
+				Start:    "23:00",
+				Duration: time.Hour,
+			},
+			expectedError: nil,
+		},
+		{
+			name: "every-monday-at-0000",
+			cfg: &Config{
+				Start:    "00:00",
+				Duration: 30 * time.Minute,
+				Every:    []string{"Monday"},
+			},
+			expectedError: nil,
+		},
+		{
+			name: "every-friday-and-sunday-at-0000-explicitly-enabled",
+			cfg: &Config{
+				Enabled:  &yes,
+				Start:    "08:00",
+				Duration: 8 * time.Hour,
+				Every:    []string{"Friday", "Sunday"},
+			},
+			expectedError: nil,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.name, func(t *testing.T) {
+			err := scenario.cfg.ValidateAndSetDefaults()
+			if !errors.Is(err, scenario.expectedError) {
+				t.Errorf("expected %v, got %v", scenario.expectedError, err)
+			}
+		})
+	}
+}
+
+func TestConfig_IsUnderMaintenance(t *testing.T) {
+	yes, no := true, false
+	now := time.Now().UTC()
+	scenarios := []struct {
+		name     string
+		cfg      *Config
+		expected bool
+	}{
+		{
+			name: "disabled",
+			cfg: &Config{
+				Enabled: &no,
+			},
+			expected: false,
+		},
+		{
+			name: "under-maintenance-explicitly-enabled",
+			cfg: &Config{
+				Enabled:  &yes,
+				Start:    fmt.Sprintf("%02d:00", now.Hour()),
+				Duration: 2 * time.Hour,
+			},
+			expected: true,
+		},
+		{
+			name: "under-maintenance-starting-now-for-2h",
+			cfg: &Config{
+				Start:    fmt.Sprintf("%02d:00", now.Hour()),
+				Duration: 2 * time.Hour,
+			},
+			expected: true,
+		},
+		{
+			name: "under-maintenance-starting-now-for-8h",
+			cfg: &Config{
+				Start:    fmt.Sprintf("%02d:00", now.Hour()),
+				Duration: 8 * time.Hour,
+			},
+			expected: true,
+		},
+		{
+			name: "under-maintenance-starting-4h-ago-for-8h",
+			cfg: &Config{
+				Start:    fmt.Sprintf("%02d:00", normalizeHour(now.Hour()-4)),
+				Duration: 8 * time.Hour,
+			},
+			expected: true,
+		},
+		{
+			name: "under-maintenance-starting-4h-ago-for-3h",
+			cfg: &Config{
+				Start:    fmt.Sprintf("%02d:00", normalizeHour(now.Hour()-4)),
+				Duration: 3 * time.Hour,
+			},
+			expected: false,
+		},
+		{
+			name: "under-maintenance-starting-5h-ago-for-1h",
+			cfg: &Config{
+				Start:    fmt.Sprintf("%02d:00", normalizeHour(now.Hour()-5)),
+				Duration: time.Hour,
+			},
+			expected: false,
+		},
+		{
+			name: "not-under-maintenance-today",
+			cfg: &Config{
+				Start:    fmt.Sprintf("%02d:00", now.Hour()),
+				Duration: time.Hour,
+				Every:    []string{now.Add(48 * time.Hour).Weekday().String()},
+			},
+			expected: false,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.name, func(t *testing.T) {
+			t.Log(scenario.cfg.Start)
+			t.Log(now)
+			if err := scenario.cfg.ValidateAndSetDefaults(); err != nil {
+				t.Fatal("validation shouldn't have returned an error, got", err)
+			}
+			isUnderMaintenance := scenario.cfg.IsUnderMaintenance()
+			if isUnderMaintenance != scenario.expected {
+				t.Errorf("expected %v, got %v", scenario.expected, isUnderMaintenance)
+				t.Logf("start=%v; duration=%v; now=%v", scenario.cfg.Start, scenario.cfg.Duration, time.Now().UTC())
+			}
+		})
+	}
+}
+
+func normalizeHour(hour int) int {
+	if hour < 0 {
+		return hour + 24
+	}
+	return hour
+}

config/ui/ui.go

@@ -0,0 +1,48 @@
+package ui
+
+import (
+	"bytes"
+	"html/template"
+)
+
+const (
+	defaultTitle = "Health Dashboard | Gatus"
+	defaultLogo  = ""
+)
+
+var (
+	// StaticFolder is the path to the location of the static folder from the root path of the project
+	// The only reason this is exposed is to allow running tests from a different path than the root path of the project
+	StaticFolder = "./web/static"
+)
+
+// Config is the configuration for the UI of Gatus
+type Config struct {
+	Title string `yaml:"title"` // Title of the page
+	Logo  string `yaml:"logo"`  // Logo to display on the page
+}
+
+// GetDefaultConfig returns a Config struct with the default values
+func GetDefaultConfig() *Config {
+	return &Config{
+		Title: defaultTitle,
+		Logo:  defaultLogo,
+	}
+}
+
+// ValidateAndSetDefaults validates the UI configuration and sets the default values if necessary.
+func (cfg *Config) ValidateAndSetDefaults() error {
+	if len(cfg.Title) == 0 {
+		cfg.Title = defaultTitle
+	}
+	t, err := template.ParseFiles(StaticFolder + "/index.html")
+	if err != nil {
+		return err
+	}
+	var buffer bytes.Buffer
+	err = t.Execute(&buffer, cfg)
+	if err != nil {
+		return err
+	}
+	return nil
+}

config/ui/ui_test.go

@@ -0,0 +1,26 @@
+package ui
+
+import (
+	"testing"
+)
+
+func TestConfig_ValidateAndSetDefaults(t *testing.T) {
+	StaticFolder = "../../web/static"
+	defer func() {
+		StaticFolder = "./web/static"
+	}()
+	cfg := &Config{Title: ""}
+	if err := cfg.ValidateAndSetDefaults(); err != nil {
+		t.Error("expected no error, got", err.Error())
+	}
+}
+
+func TestGetDefaultConfig(t *testing.T) {
+	defaultConfig := GetDefaultConfig()
+	if defaultConfig.Title != defaultTitle {
+		t.Error("expected GetDefaultConfig() to return defaultTitle, got", defaultConfig.Title)
+	}
+	if defaultConfig.Logo != defaultLogo {
+		t.Error("expected GetDefaultConfig() to return defaultLogo, got", defaultConfig.Logo)
+	}
+}

config/web/web.go

@@ -0,0 +1,49 @@
+package web
+
+import (
+	"fmt"
+	"math"
+)
+
+const (
+	// DefaultAddress is the default address the application will bind to
+	DefaultAddress = "0.0.0.0"
+
+	// DefaultPort is the default port the application will listen on
+	DefaultPort = 8080
+)
+
+// Config is the structure which supports the configuration of the endpoint
+// which provides access to the web frontend
+type Config struct {
+	// Address to listen on (defaults to 0.0.0.0 specified by DefaultAddress)
+	Address string `yaml:"address"`
+
+	// Port to listen on (default to 8080 specified by DefaultPort)
+	Port int `yaml:"port"`
+}
+
+// GetDefaultConfig returns a Config struct with the default values
+func GetDefaultConfig() *Config {
+	return &Config{Address: DefaultAddress, Port: DefaultPort}
+}
+
+// ValidateAndSetDefaults validates the web configuration and sets the default values if necessary.
+func (web *Config) ValidateAndSetDefaults() error {
+	// Validate the Address
+	if len(web.Address) == 0 {
+		web.Address = DefaultAddress
+	}
+	// Validate the Port
+	if web.Port == 0 {
+		web.Port = DefaultPort
+	} else if web.Port < 0 || web.Port > math.MaxUint16 {
+		return fmt.Errorf("invalid port: value should be between %d and %d", 0, math.MaxUint16)
+	}
+	return nil
+}
+
+// SocketAddress returns the combination of the Address and the Port
+func (web *Config) SocketAddress() string {
+	return fmt.Sprintf("%s:%d", web.Address, web.Port)
+}

config/web/web_test.go

@@ -0,0 +1,65 @@
+package web
+
+import (
+	"testing"
+)
+
+func TestGetDefaultConfig(t *testing.T) {
+	defaultConfig := GetDefaultConfig()
+	if defaultConfig.Port != DefaultPort {
+		t.Error("expected default config to have the default port")
+	}
+	if defaultConfig.Address != DefaultAddress {
+		t.Error("expected default config to have the default address")
+	}
+}
+
+func TestConfig_ValidateAndSetDefaults(t *testing.T) {
+	scenarios := []struct {
+		name            string
+		cfg             *Config
+		expectedAddress string
+		expectedPort    int
+		expectedErr     bool
+	}{
+		{
+			name:            "no-explicit-config",
+			cfg:             &Config{},
+			expectedAddress: "0.0.0.0",
+			expectedPort:    8080,
+			expectedErr:     false,
+		},
+		{
+			name:        "invalid-port",
+			cfg:         &Config{Port: 100000000},
+			expectedErr: true,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.name, func(t *testing.T) {
+			err := scenario.cfg.ValidateAndSetDefaults()
+			if (err != nil) != scenario.expectedErr {
+				t.Errorf("expected the existence of an error to be %v, got %v", scenario.expectedErr, err)
+				return
+			}
+			if !scenario.expectedErr {
+				if scenario.cfg.Port != scenario.expectedPort {
+					t.Errorf("expected port to be %d, got %d", scenario.expectedPort, scenario.cfg.Port)
+				}
+				if scenario.cfg.Address != scenario.expectedAddress {
+					t.Errorf("expected address to be %s, got %s", scenario.expectedAddress, scenario.cfg.Address)
+				}
+			}
+		})
+	}
+}
+
+func TestConfig_SocketAddress(t *testing.T) {
+	web := &Config{
+		Address: "0.0.0.0",
+		Port:    8081,
+	}
+	if web.SocketAddress() != "0.0.0.0:8081" {
+		t.Errorf("expected %s, got %s", "0.0.0.0:8081", web.SocketAddress())
+	}
+}

controller/controller.go

@@ -0,0 +1,49 @@
+package controller
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/TwiN/gatus/v3/config/ui"
+	"github.com/TwiN/gatus/v3/config/web"
+	"github.com/TwiN/gatus/v3/controller/handler"
+	"github.com/TwiN/gatus/v3/security"
+)
+
+var (
+	// server is the http.Server created by Handle.
+	// The only reason it exists is for testing purposes.
+	server *http.Server
+)
+
+// Handle creates the router and starts the server
+func Handle(securityConfig *security.Config, webConfig *web.Config, uiConfig *ui.Config, enableMetrics bool) {
+	var router http.Handler = handler.CreateRouter(ui.StaticFolder, securityConfig, uiConfig, enableMetrics)
+	if os.Getenv("ENVIRONMENT") == "dev" {
+		router = handler.DevelopmentCORS(router)
+	}
+	server = &http.Server{
+		Addr:         fmt.Sprintf("%s:%d", webConfig.Address, webConfig.Port),
+		Handler:      router,
+		ReadTimeout:  15 * time.Second,
+		WriteTimeout: 15 * time.Second,
+		IdleTimeout:  15 * time.Second,
+	}
+	log.Println("[controller][Handle] Listening on " + webConfig.SocketAddress())
+	if os.Getenv("ROUTER_TEST") == "true" {
+		return
+	}
+	log.Println("[controller][Handle]", server.ListenAndServe())
+}
+
+// Shutdown stops the server
+func Shutdown() {
+	if server != nil {
+		_ = server.Shutdown(context.TODO())
+		server = nil
+	}
+}

controller/controller_test.go

@@ -0,0 +1,55 @@
+package controller
+
+import (
+	"math/rand"
+	"net/http"
+	"net/http/httptest"
+	"os"
+	"testing"
+
+	"github.com/TwiN/gatus/v3/config"
+	"github.com/TwiN/gatus/v3/config/web"
+	"github.com/TwiN/gatus/v3/core"
+)
+
+func TestHandle(t *testing.T) {
+	cfg := &config.Config{
+		Web: &web.Config{
+			Address: "0.0.0.0",
+			Port:    rand.Intn(65534),
+		},
+		Endpoints: []*core.Endpoint{
+			{
+				Name:  "frontend",
+				Group: "core",
+			},
+			{
+				Name:  "backend",
+				Group: "core",
+			},
+		},
+	}
+	_ = os.Setenv("ROUTER_TEST", "true")
+	_ = os.Setenv("ENVIRONMENT", "dev")
+	defer os.Clearenv()
+	Handle(cfg.Security, cfg.Web, cfg.UI, cfg.Metrics)
+	defer Shutdown()
+	request, _ := http.NewRequest("GET", "/health", nil)
+	responseRecorder := httptest.NewRecorder()
+	server.Handler.ServeHTTP(responseRecorder, request)
+	if responseRecorder.Code != http.StatusOK {
+		t.Error("expected GET /health to return status code 200")
+	}
+	if server == nil {
+		t.Fatal("server should've been set (but because we set ROUTER_TEST, it shouldn't have been started)")
+	}
+}
+
+func TestShutdown(t *testing.T) {
+	// Pretend that we called controller.Handle(), which initializes the server variable
+	server = &http.Server{}
+	Shutdown()
+	if server != nil {
+		t.Error("server should've been shut down")
+	}
+}

controller/handler/badge.go

@@ -0,0 +1,229 @@
+package handler
+
+import (
+	"fmt"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/TwiN/gatus/v3/storage"
+	"github.com/TwiN/gatus/v3/storage/store/common"
+	"github.com/gorilla/mux"
+)
+
+const (
+	badgeColorHexAwesome  = "#40cc11"
+	badgeColorHexGreat    = "#94cc11"
+	badgeColorHexGood     = "#ccd311"
+	badgeColorHexPassable = "#ccb311"
+	badgeColorHexBad      = "#cc8111"
+	badgeColorHexVeryBad  = "#c7130a"
+)
+
+// UptimeBadge handles the automatic generation of badge based on the group name and endpoint name passed.
+//
+// Valid values for {duration}: 7d, 24h, 1h
+func UptimeBadge(writer http.ResponseWriter, request *http.Request) {
+	variables := mux.Vars(request)
+	duration := variables["duration"]
+	var from time.Time
+	switch duration {
+	case "7d":
+		from = time.Now().Add(-7 * 24 * time.Hour)
+	case "24h":
+		from = time.Now().Add(-24 * time.Hour)
+	case "1h":
+		from = time.Now().Add(-2 * time.Hour) // Because uptime metrics are stored by hour, we have to cheat a little
+	default:
+		http.Error(writer, "Durations supported: 7d, 24h, 1h", http.StatusBadRequest)
+		return
+	}
+	key := variables["key"]
+	uptime, err := storage.Get().GetUptimeByKey(key, from, time.Now())
+	if err != nil {
+		if err == common.ErrEndpointNotFound {
+			writer.WriteHeader(http.StatusNotFound)
+		} else if err == common.ErrInvalidTimeRange {
+			writer.WriteHeader(http.StatusBadRequest)
+		} else {
+			writer.WriteHeader(http.StatusInternalServerError)
+		}
+		_, _ = writer.Write([]byte(err.Error()))
+		return
+	}
+	formattedDate := time.Now().Format(http.TimeFormat)
+	writer.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	writer.Header().Set("Date", formattedDate)
+	writer.Header().Set("Expires", formattedDate)
+	writer.Header().Set("Content-Type", "image/svg+xml")
+	_, _ = writer.Write(generateUptimeBadgeSVG(duration, uptime))
+}
+
+// ResponseTimeBadge handles the automatic generation of badge based on the group name and endpoint name passed.
+//
+// Valid values for {duration}: 7d, 24h, 1h
+func ResponseTimeBadge(writer http.ResponseWriter, request *http.Request) {
+	variables := mux.Vars(request)
+	duration := variables["duration"]
+	var from time.Time
+	switch duration {
+	case "7d":
+		from = time.Now().Add(-7 * 24 * time.Hour)
+	case "24h":
+		from = time.Now().Add(-24 * time.Hour)
+	case "1h":
+		from = time.Now().Add(-2 * time.Hour) // Because response time metrics are stored by hour, we have to cheat a little
+	default:
+		http.Error(writer, "Durations supported: 7d, 24h, 1h", http.StatusBadRequest)
+		return
+	}
+	key := variables["key"]
+	averageResponseTime, err := storage.Get().GetAverageResponseTimeByKey(key, from, time.Now())
+	if err != nil {
+		if err == common.ErrEndpointNotFound {
+			writer.WriteHeader(http.StatusNotFound)
+		} else if err == common.ErrInvalidTimeRange {
+			writer.WriteHeader(http.StatusBadRequest)
+		} else {
+			writer.WriteHeader(http.StatusInternalServerError)
+		}
+		_, _ = writer.Write([]byte(err.Error()))
+		return
+	}
+	formattedDate := time.Now().Format(http.TimeFormat)
+	writer.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+	writer.Header().Set("Date", formattedDate)
+	writer.Header().Set("Expires", formattedDate)
+	writer.Header().Set("Content-Type", "image/svg+xml")
+	_, _ = writer.Write(generateResponseTimeBadgeSVG(duration, averageResponseTime))
+}
+
+func generateUptimeBadgeSVG(duration string, uptime float64) []byte {
+	var labelWidth, valueWidth, valueWidthAdjustment int
+	switch duration {
+	case "7d":
+		labelWidth = 65
+	case "24h":
+		labelWidth = 70
+	case "1h":
+		labelWidth = 65
+	default:
+	}
+	color := getBadgeColorFromUptime(uptime)
+	sanitizedValue := strings.TrimRight(strings.TrimRight(fmt.Sprintf("%.2f", uptime*100), "0"), ".") + "%"
+	if strings.Contains(sanitizedValue, ".") {
+		valueWidthAdjustment = -10
+	}
+	valueWidth = (len(sanitizedValue) * 11) + valueWidthAdjustment
+	width := labelWidth + valueWidth
+	labelX := labelWidth / 2
+	valueX := labelWidth + (valueWidth / 2)
+	svg := []byte(fmt.Sprintf(`<svg xmlns="http://www.w3.org/2000/svg" width="%d" height="20">
+  <linearGradient id="b" x2="0" y2="100%%">
+    <stop offset="0" stop-color="#bbb" stop-opacity=".1"/>
+    <stop offset="1" stop-opacity=".1"/>
+  </linearGradient>
+  <mask id="a">
+    <rect width="%d" height="20" rx="3" fill="#fff"/>
+  </mask>
+  <g mask="url(#a)">
+    <path fill="#555" d="M0 0h%dv20H0z"/>
+    <path fill="%s" d="M%d 0h%dv20H%dz"/>
+    <path fill="url(#b)" d="M0 0h%dv20H0z"/>
+  </g>
+  <g fill="#fff" text-anchor="middle" font-family="DejaVu Sans,Verdana,Geneva,sans-serif" font-size="11">
+    <text x="%d" y="15" fill="#010101" fill-opacity=".3">
+      uptime %s
+    </text>
+    <text x="%d" y="14">
+      uptime %s
+    </text>
+    <text x="%d" y="15" fill="#010101" fill-opacity=".3">
+      %s
+    </text>
+    <text x="%d" y="14">
+      %s
+    </text>
+  </g>
+</svg>`, width, width, labelWidth, color, labelWidth, valueWidth, labelWidth, width, labelX, duration, labelX, duration, valueX, sanitizedValue, valueX, sanitizedValue))
+	return svg
+}
+
+func getBadgeColorFromUptime(uptime float64) string {
+	if uptime >= 0.975 {
+		return badgeColorHexAwesome
+	} else if uptime >= 0.95 {
+		return badgeColorHexGreat
+	} else if uptime >= 0.9 {
+		return badgeColorHexGood
+	} else if uptime >= 0.8 {
+		return badgeColorHexPassable
+	} else if uptime >= 0.65 {
+		return badgeColorHexBad
+	}
+	return badgeColorHexVeryBad
+}
+
+func generateResponseTimeBadgeSVG(duration string, averageResponseTime int) []byte {
+	var labelWidth, valueWidth int
+	switch duration {
+	case "7d":
+		labelWidth = 105
+	case "24h":
+		labelWidth = 110
+	case "1h":
+		labelWidth = 105
+	default:
+	}
+	color := getBadgeColorFromResponseTime(averageResponseTime)
+	sanitizedValue := strconv.Itoa(averageResponseTime) + "ms"
+	valueWidth = len(sanitizedValue) * 11
+	width := labelWidth + valueWidth
+	labelX := labelWidth / 2
+	valueX := labelWidth + (valueWidth / 2)
+	svg := []byte(fmt.Sprintf(`<svg xmlns="http://www.w3.org/2000/svg" width="%d" height="20">
+  <linearGradient id="b" x2="0" y2="100%%">
+    <stop offset="0" stop-color="#bbb" stop-opacity=".1"/>
+    <stop offset="1" stop-opacity=".1"/>
+  </linearGradient>
+  <mask id="a">
+    <rect width="%d" height="20" rx="3" fill="#fff"/>
+  </mask>
+  <g mask="url(#a)">
+    <path fill="#555" d="M0 0h%dv20H0z"/>
+    <path fill="%s" d="M%d 0h%dv20H%dz"/>
+    <path fill="url(#b)" d="M0 0h%dv20H0z"/>
+  </g>
+  <g fill="#fff" text-anchor="middle" font-family="DejaVu Sans,Verdana,Geneva,sans-serif" font-size="11">
+    <text x="%d" y="15" fill="#010101" fill-opacity=".3">
+      response time %s
+    </text>
+    <text x="%d" y="14">
+      response time %s
+    </text>
+    <text x="%d" y="15" fill="#010101" fill-opacity=".3">
+      %s
+    </text>
+    <text x="%d" y="14">
+      %s
+    </text>
+  </g>
+</svg>`, width, width, labelWidth, color, labelWidth, valueWidth, labelWidth, width, labelX, duration, labelX, duration, valueX, sanitizedValue, valueX, sanitizedValue))
+	return svg
+}
+
+func getBadgeColorFromResponseTime(responseTime int) string {
+	if responseTime <= 50 {
+		return badgeColorHexAwesome
+	} else if responseTime <= 200 {
+		return badgeColorHexGreat
+	} else if responseTime <= 300 {
+		return badgeColorHexGood
+	} else if responseTime <= 500 {
+		return badgeColorHexPassable
+	} else if responseTime <= 750 {
+		return badgeColorHexBad
+	}
+	return badgeColorHexVeryBad
+}

controller/handler/badge_test.go

@@ -0,0 +1,231 @@
+package handler
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strconv"
+	"testing"
+	"time"
+
+	"github.com/TwiN/gatus/v3/config"
+	"github.com/TwiN/gatus/v3/core"
+	"github.com/TwiN/gatus/v3/storage"
+	"github.com/TwiN/gatus/v3/watchdog"
+)
+
+func TestUptimeBadge(t *testing.T) {
+	defer storage.Get().Clear()
+	defer cache.Clear()
+	cfg := &config.Config{
+		Metrics: true,
+		Endpoints: []*core.Endpoint{
+			{
+				Name:  "frontend",
+				Group: "core",
+			},
+			{
+				Name:  "backend",
+				Group: "core",
+			},
+		},
+	}
+	watchdog.UpdateEndpointStatuses(cfg.Endpoints[0], &core.Result{Success: true, Duration: time.Millisecond, Timestamp: time.Now()})
+	watchdog.UpdateEndpointStatuses(cfg.Endpoints[1], &core.Result{Success: false, Duration: time.Second, Timestamp: time.Now()})
+	router := CreateRouter("../../web/static", cfg.Security, nil, cfg.Metrics)
+	type Scenario struct {
+		Name         string
+		Path         string
+		ExpectedCode int
+		Gzip         bool
+	}
+	scenarios := []Scenario{
+		{
+			Name:         "badge-uptime-1h",
+			Path:         "/api/v1/endpoints/core_frontend/uptimes/1h/badge.svg",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "badge-uptime-24h",
+			Path:         "/api/v1/endpoints/core_backend/uptimes/24h/badge.svg",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "badge-uptime-7d",
+			Path:         "/api/v1/endpoints/core_frontend/uptimes/7d/badge.svg",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "badge-uptime-with-invalid-duration",
+			Path:         "/api/v1/endpoints/core_backend/uptimes/3d/badge.svg",
+			ExpectedCode: http.StatusBadRequest,
+		},
+		{
+			Name:         "badge-uptime-for-invalid-key",
+			Path:         "/api/v1/endpoints/invalid_key/uptimes/7d/badge.svg",
+			ExpectedCode: http.StatusNotFound,
+		},
+		{
+			Name:         "badge-response-time-1h",
+			Path:         "/api/v1/endpoints/core_frontend/response-times/1h/badge.svg",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "badge-response-time-24h",
+			Path:         "/api/v1/endpoints/core_backend/response-times/24h/badge.svg",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "badge-response-time-7d",
+			Path:         "/api/v1/endpoints/core_frontend/response-times/7d/badge.svg",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "badge-response-time-with-invalid-duration",
+			Path:         "/api/v1/endpoints/core_backend/response-times/3d/badge.svg",
+			ExpectedCode: http.StatusBadRequest,
+		},
+		{
+			Name:         "badge-response-time-for-invalid-key",
+			Path:         "/api/v1/endpoints/invalid_key/response-times/7d/badge.svg",
+			ExpectedCode: http.StatusNotFound,
+		},
+		{
+			Name:         "chart-response-time-24h",
+			Path:         "/api/v1/endpoints/core_backend/response-times/24h/chart.svg",
+			ExpectedCode: http.StatusOK,
+		},
+		{ // XXX: Remove this in v4.0.0
+			Name:         "backward-compatible-services-badge-uptime-1h",
+			Path:         "/api/v1/services/core_frontend/uptimes/1h/badge.svg",
+			ExpectedCode: http.StatusOK,
+		},
+		{ // XXX: Remove this in v4.0.0
+			Name:         "backward-compatible-services-chart-response-time-24h",
+			Path:         "/api/v1/services/core_backend/response-times/24h/chart.svg",
+			ExpectedCode: http.StatusOK,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			request, _ := http.NewRequest("GET", scenario.Path, nil)
+			if scenario.Gzip {
+				request.Header.Set("Accept-Encoding", "gzip")
+			}
+			responseRecorder := httptest.NewRecorder()
+			router.ServeHTTP(responseRecorder, request)
+			if responseRecorder.Code != scenario.ExpectedCode {
+				t.Errorf("%s %s should have returned %d, but returned %d instead", request.Method, request.URL, scenario.ExpectedCode, responseRecorder.Code)
+			}
+		})
+	}
+}
+
+func TestGetBadgeColorFromUptime(t *testing.T) {
+	scenarios := []struct {
+		Uptime        float64
+		ExpectedColor string
+	}{
+		{
+			Uptime:        1,
+			ExpectedColor: badgeColorHexAwesome,
+		},
+		{
+			Uptime:        0.99,
+			ExpectedColor: badgeColorHexAwesome,
+		},
+		{
+			Uptime:        0.97,
+			ExpectedColor: badgeColorHexGreat,
+		},
+		{
+			Uptime:        0.95,
+			ExpectedColor: badgeColorHexGreat,
+		},
+		{
+			Uptime:        0.93,
+			ExpectedColor: badgeColorHexGood,
+		},
+		{
+			Uptime:        0.9,
+			ExpectedColor: badgeColorHexGood,
+		},
+		{
+			Uptime:        0.85,
+			ExpectedColor: badgeColorHexPassable,
+		},
+		{
+			Uptime:        0.7,
+			ExpectedColor: badgeColorHexBad,
+		},
+		{
+			Uptime:        0.65,
+			ExpectedColor: badgeColorHexBad,
+		},
+		{
+			Uptime:        0.6,
+			ExpectedColor: badgeColorHexVeryBad,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run("uptime-"+strconv.Itoa(int(scenario.Uptime*100)), func(t *testing.T) {
+			if getBadgeColorFromUptime(scenario.Uptime) != scenario.ExpectedColor {
+				t.Errorf("expected %s from %f, got %v", scenario.ExpectedColor, scenario.Uptime, getBadgeColorFromUptime(scenario.Uptime))
+			}
+		})
+	}
+}
+
+func TestGetBadgeColorFromResponseTime(t *testing.T) {
+	scenarios := []struct {
+		ResponseTime  int
+		ExpectedColor string
+	}{
+		{
+			ResponseTime:  10,
+			ExpectedColor: badgeColorHexAwesome,
+		},
+		{
+			ResponseTime:  50,
+			ExpectedColor: badgeColorHexAwesome,
+		},
+		{
+			ResponseTime:  75,
+			ExpectedColor: badgeColorHexGreat,
+		},
+		{
+			ResponseTime:  150,
+			ExpectedColor: badgeColorHexGreat,
+		},
+		{
+			ResponseTime:  201,
+			ExpectedColor: badgeColorHexGood,
+		},
+		{
+			ResponseTime:  300,
+			ExpectedColor: badgeColorHexGood,
+		},
+		{
+			ResponseTime:  301,
+			ExpectedColor: badgeColorHexPassable,
+		},
+		{
+			ResponseTime:  450,
+			ExpectedColor: badgeColorHexPassable,
+		},
+		{
+			ResponseTime:  700,
+			ExpectedColor: badgeColorHexBad,
+		},
+		{
+			ResponseTime:  1500,
+			ExpectedColor: badgeColorHexVeryBad,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run("response-time-"+strconv.Itoa(scenario.ResponseTime), func(t *testing.T) {
+			if getBadgeColorFromResponseTime(scenario.ResponseTime) != scenario.ExpectedColor {
+				t.Errorf("expected %s from %d, got %v", scenario.ExpectedColor, scenario.ResponseTime, getBadgeColorFromResponseTime(scenario.ResponseTime))
+			}
+		})
+	}
+}

controller/handler/chart.go

@@ -0,0 +1,121 @@
+package handler
+
+import (
+	"log"
+	"math"
+	"net/http"
+	"sort"
+	"time"
+
+	"github.com/TwiN/gatus/v3/storage"
+	"github.com/TwiN/gatus/v3/storage/store/common"
+	"github.com/gorilla/mux"
+	"github.com/wcharczuk/go-chart/v2"
+	"github.com/wcharczuk/go-chart/v2/drawing"
+)
+
+const timeFormat = "3:04PM"
+
+var (
+	gridStyle = chart.Style{
+		StrokeColor: drawing.Color{R: 119, G: 119, B: 119, A: 40},
+		StrokeWidth: 1.0,
+	}
+	axisStyle = chart.Style{
+		FontColor: drawing.Color{R: 119, G: 119, B: 119, A: 255},
+	}
+	transparentStyle = chart.Style{
+		FillColor: drawing.Color{R: 255, G: 255, B: 255, A: 0},
+	}
+)
+
+func ResponseTimeChart(writer http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	duration := vars["duration"]
+	var from time.Time
+	switch duration {
+	case "7d":
+		from = time.Now().Truncate(time.Hour).Add(-24 * 7 * time.Hour)
+	case "24h":
+		from = time.Now().Truncate(time.Hour).Add(-24 * time.Hour)
+	default:
+		http.Error(writer, "Durations supported: 7d, 24h", http.StatusBadRequest)
+		return
+	}
+	hourlyAverageResponseTime, err := storage.Get().GetHourlyAverageResponseTimeByKey(vars["key"], from, time.Now())
+	if err != nil {
+		if err == common.ErrEndpointNotFound {
+			writer.WriteHeader(http.StatusNotFound)
+		} else if err == common.ErrInvalidTimeRange {
+			writer.WriteHeader(http.StatusBadRequest)
+		} else {
+			writer.WriteHeader(http.StatusInternalServerError)
+		}
+		_, _ = writer.Write([]byte(err.Error()))
+		return
+	}
+	if len(hourlyAverageResponseTime) == 0 {
+		writer.WriteHeader(http.StatusNoContent)
+		_, _ = writer.Write(nil)
+		return
+	}
+	series := chart.TimeSeries{
+		Name: "Average response time per hour",
+		Style: chart.Style{
+			StrokeWidth: 1.5,
+			DotWidth:    2.0,
+		},
+	}
+	keys := make([]int, 0, len(hourlyAverageResponseTime))
+	earliestTimestamp := int64(0)
+	for hourlyTimestamp := range hourlyAverageResponseTime {
+		keys = append(keys, int(hourlyTimestamp))
+		if earliestTimestamp == 0 || hourlyTimestamp < earliestTimestamp {
+			earliestTimestamp = hourlyTimestamp
+		}
+	}
+	for earliestTimestamp > from.Unix() {
+		earliestTimestamp -= int64(time.Hour.Seconds())
+		keys = append(keys, int(earliestTimestamp))
+	}
+	sort.Ints(keys)
+	var maxAverageResponseTime float64
+	for _, key := range keys {
+		averageResponseTime := float64(hourlyAverageResponseTime[int64(key)])
+		if maxAverageResponseTime < averageResponseTime {
+			maxAverageResponseTime = averageResponseTime
+		}
+		series.XValues = append(series.XValues, time.Unix(int64(key), 0))
+		series.YValues = append(series.YValues, averageResponseTime)
+	}
+	graph := chart.Chart{
+		Canvas:     transparentStyle,
+		Background: transparentStyle,
+		Width:      1280,
+		Height:     300,
+		XAxis: chart.XAxis{
+			ValueFormatter: chart.TimeValueFormatterWithFormat(timeFormat),
+			GridMajorStyle: gridStyle,
+			GridMinorStyle: gridStyle,
+			Style:          axisStyle,
+			NameStyle:      axisStyle,
+		},
+		YAxis: chart.YAxis{
+			Name:           "Average response time",
+			GridMajorStyle: gridStyle,
+			GridMinorStyle: gridStyle,
+			Style:          axisStyle,
+			NameStyle:      axisStyle,
+			Range: &chart.ContinuousRange{
+				Min: 0,
+				Max: math.Ceil(maxAverageResponseTime * 1.25),
+			},
+		},
+		Series: []chart.Series{series},
+	}
+	writer.Header().Set("Content-Type", "image/svg+xml")
+	if err := graph.Render(chart.SVG, writer); err != nil {
+		log.Println("[handler][ResponseTimeChart] Failed to render response time chart:", err.Error())
+		return
+	}
+}

controller/handler/chart_test.go

@@ -0,0 +1,80 @@
+package handler
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/TwiN/gatus/v3/config"
+	"github.com/TwiN/gatus/v3/core"
+	"github.com/TwiN/gatus/v3/storage"
+	"github.com/TwiN/gatus/v3/watchdog"
+)
+
+func TestResponseTimeChart(t *testing.T) {
+	defer storage.Get().Clear()
+	defer cache.Clear()
+	cfg := &config.Config{
+		Metrics: true,
+		Endpoints: []*core.Endpoint{
+			{
+				Name:  "frontend",
+				Group: "core",
+			},
+			{
+				Name:  "backend",
+				Group: "core",
+			},
+		},
+	}
+	watchdog.UpdateEndpointStatuses(cfg.Endpoints[0], &core.Result{Success: true, Duration: time.Millisecond, Timestamp: time.Now()})
+	watchdog.UpdateEndpointStatuses(cfg.Endpoints[1], &core.Result{Success: false, Duration: time.Second, Timestamp: time.Now()})
+	router := CreateRouter("../../web/static", cfg.Security, nil, cfg.Metrics)
+	type Scenario struct {
+		Name         string
+		Path         string
+		ExpectedCode int
+		Gzip         bool
+	}
+	scenarios := []Scenario{
+		{
+			Name:         "chart-response-time-24h",
+			Path:         "/api/v1/endpoints/core_backend/response-times/24h/chart.svg",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "chart-response-time-7d",
+			Path:         "/api/v1/endpoints/core_frontend/response-times/7d/chart.svg",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "chart-response-time-with-invalid-duration",
+			Path:         "/api/v1/endpoints/core_backend/response-times/3d/chart.svg",
+			ExpectedCode: http.StatusBadRequest,
+		},
+		{
+			Name:         "chart-response-time-for-invalid-key",
+			Path:         "/api/v1/endpoints/invalid_key/response-times/7d/chart.svg",
+			ExpectedCode: http.StatusNotFound,
+		},
+		{ // XXX: Remove this in v4.0.0
+			Name:         "backward-compatible-services-chart-response-time-24h",
+			Path:         "/api/v1/services/core_backend/response-times/24h/chart.svg",
+			ExpectedCode: http.StatusOK,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			request, _ := http.NewRequest("GET", scenario.Path, nil)
+			if scenario.Gzip {
+				request.Header.Set("Accept-Encoding", "gzip")
+			}
+			responseRecorder := httptest.NewRecorder()
+			router.ServeHTTP(responseRecorder, request)
+			if responseRecorder.Code != scenario.ExpectedCode {
+				t.Errorf("%s %s should have returned %d, but returned %d instead", request.Method, request.URL, scenario.ExpectedCode, responseRecorder.Code)
+			}
+		})
+	}
+}

controller/handler/cors.go

@@ -0,0 +1,10 @@
+package handler
+
+import "net/http"
+
+func DevelopmentCORS(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Origin", "http://localhost:8081")
+		next.ServeHTTP(w, r)
+	})
+}

controller/handler/endpoint_status.go

@@ -0,0 +1,103 @@
+package handler
+
+import (
+	"bytes"
+	"compress/gzip"
+	"encoding/json"
+	"fmt"
+	"log"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/TwiN/gatus/v3/storage"
+	"github.com/TwiN/gatus/v3/storage/store/common"
+	"github.com/TwiN/gatus/v3/storage/store/common/paging"
+	"github.com/TwiN/gocache"
+	"github.com/gorilla/mux"
+)
+
+const (
+	cacheTTL = 10 * time.Second
+)
+
+var (
+	cache = gocache.NewCache().WithMaxSize(100).WithEvictionPolicy(gocache.FirstInFirstOut)
+)
+
+// EndpointStatuses handles requests to retrieve all EndpointStatus
+// Due to the size of the response, this function leverages a cache.
+// Must not be wrapped by GzipHandler
+func EndpointStatuses(writer http.ResponseWriter, r *http.Request) {
+	page, pageSize := extractPageAndPageSizeFromRequest(r)
+	gzipped := strings.Contains(r.Header.Get("Accept-Encoding"), "gzip")
+	var exists bool
+	var value interface{}
+	if gzipped {
+		writer.Header().Set("Content-Encoding", "gzip")
+		value, exists = cache.Get(fmt.Sprintf("endpoint-status-%d-%d-gzipped", page, pageSize))
+	} else {
+		value, exists = cache.Get(fmt.Sprintf("endpoint-status-%d-%d", page, pageSize))
+	}
+	var data []byte
+	if !exists {
+		var err error
+		buffer := &bytes.Buffer{}
+		gzipWriter := gzip.NewWriter(buffer)
+		endpointStatuses, err := storage.Get().GetAllEndpointStatuses(paging.NewEndpointStatusParams().WithResults(page, pageSize))
+		if err != nil {
+			log.Printf("[handler][EndpointStatuses] Failed to retrieve endpoint statuses: %s", err.Error())
+			http.Error(writer, err.Error(), http.StatusInternalServerError)
+			return
+		}
+		data, err = json.Marshal(endpointStatuses)
+		if err != nil {
+			log.Printf("[handler][EndpointStatuses] Unable to marshal object to JSON: %s", err.Error())
+			http.Error(writer, "unable to marshal object to JSON", http.StatusInternalServerError)
+			return
+		}
+		_, _ = gzipWriter.Write(data)
+		_ = gzipWriter.Close()
+		gzippedData := buffer.Bytes()
+		cache.SetWithTTL(fmt.Sprintf("endpoint-status-%d-%d", page, pageSize), data, cacheTTL)
+		cache.SetWithTTL(fmt.Sprintf("endpoint-status-%d-%d-gzipped", page, pageSize), gzippedData, cacheTTL)
+		if gzipped {
+			data = gzippedData
+		}
+	} else {
+		data = value.([]byte)
+	}
+	writer.Header().Add("Content-Type", "application/json")
+	writer.WriteHeader(http.StatusOK)
+	_, _ = writer.Write(data)
+}
+
+// EndpointStatus retrieves a single core.EndpointStatus by group and endpoint name
+func EndpointStatus(writer http.ResponseWriter, r *http.Request) {
+	page, pageSize := extractPageAndPageSizeFromRequest(r)
+	vars := mux.Vars(r)
+	endpointStatus, err := storage.Get().GetEndpointStatusByKey(vars["key"], paging.NewEndpointStatusParams().WithResults(page, pageSize).WithEvents(1, common.MaximumNumberOfEvents))
+	if err != nil {
+		if err == common.ErrEndpointNotFound {
+			http.Error(writer, err.Error(), http.StatusNotFound)
+			return
+		}
+		log.Printf("[handler][EndpointStatus] Failed to retrieve endpoint status: %s", err.Error())
+		http.Error(writer, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	if endpointStatus == nil {
+		log.Printf("[handler][EndpointStatus] Endpoint with key=%s not found", vars["key"])
+		http.Error(writer, "not found", http.StatusNotFound)
+		return
+	}
+	output, err := json.Marshal(endpointStatus)
+	if err != nil {
+		log.Printf("[handler][EndpointStatus] Unable to marshal object to JSON: %s", err.Error())
+		http.Error(writer, "unable to marshal object to JSON", http.StatusInternalServerError)
+		return
+	}
+	writer.Header().Add("Content-Type", "application/json")
+	writer.WriteHeader(http.StatusOK)
+	_, _ = writer.Write(output)
+}

controller/handler/endpoint_status_test.go

@@ -0,0 +1,226 @@
+package handler
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/TwiN/gatus/v3/config"
+	"github.com/TwiN/gatus/v3/core"
+	"github.com/TwiN/gatus/v3/storage"
+	"github.com/TwiN/gatus/v3/watchdog"
+)
+
+var (
+	firstCondition  = core.Condition("[STATUS] == 200")
+	secondCondition = core.Condition("[RESPONSE_TIME] < 500")
+	thirdCondition  = core.Condition("[CERTIFICATE_EXPIRATION] < 72h")
+
+	timestamp = time.Now()
+
+	testEndpoint = core.Endpoint{
+		Name:                    "name",
+		Group:                   "group",
+		URL:                     "https://example.org/what/ever",
+		Method:                  "GET",
+		Body:                    "body",
+		Interval:                30 * time.Second,
+		Conditions:              []*core.Condition{&firstCondition, &secondCondition, &thirdCondition},
+		Alerts:                  nil,
+		NumberOfFailuresInARow:  0,
+		NumberOfSuccessesInARow: 0,
+	}
+	testSuccessfulResult = core.Result{
+		Hostname:              "example.org",
+		IP:                    "127.0.0.1",
+		HTTPStatus:            200,
+		Errors:                nil,
+		Connected:             true,
+		Success:               true,
+		Timestamp:             timestamp,
+		Duration:              150 * time.Millisecond,
+		CertificateExpiration: 10 * time.Hour,
+		ConditionResults: []*core.ConditionResult{
+			{
+				Condition: "[STATUS] == 200",
+				Success:   true,
+			},
+			{
+				Condition: "[RESPONSE_TIME] < 500",
+				Success:   true,
+			},
+			{
+				Condition: "[CERTIFICATE_EXPIRATION] < 72h",
+				Success:   true,
+			},
+		},
+	}
+	testUnsuccessfulResult = core.Result{
+		Hostname:              "example.org",
+		IP:                    "127.0.0.1",
+		HTTPStatus:            200,
+		Errors:                []string{"error-1", "error-2"},
+		Connected:             true,
+		Success:               false,
+		Timestamp:             timestamp,
+		Duration:              750 * time.Millisecond,
+		CertificateExpiration: 10 * time.Hour,
+		ConditionResults: []*core.ConditionResult{
+			{
+				Condition: "[STATUS] == 200",
+				Success:   true,
+			},
+			{
+				Condition: "[RESPONSE_TIME] < 500",
+				Success:   false,
+			},
+			{
+				Condition: "[CERTIFICATE_EXPIRATION] < 72h",
+				Success:   false,
+			},
+		},
+	}
+)
+
+func TestEndpointStatus(t *testing.T) {
+	defer storage.Get().Clear()
+	defer cache.Clear()
+	cfg := &config.Config{
+		Metrics: true,
+		Endpoints: []*core.Endpoint{
+			{
+				Name:  "frontend",
+				Group: "core",
+			},
+			{
+				Name:  "backend",
+				Group: "core",
+			},
+		},
+	}
+	watchdog.UpdateEndpointStatuses(cfg.Endpoints[0], &core.Result{Success: true, Duration: time.Millisecond, Timestamp: time.Now()})
+	watchdog.UpdateEndpointStatuses(cfg.Endpoints[1], &core.Result{Success: false, Duration: time.Second, Timestamp: time.Now()})
+	router := CreateRouter("../../web/static", cfg.Security, nil, cfg.Metrics)
+
+	type Scenario struct {
+		Name         string
+		Path         string
+		ExpectedCode int
+		Gzip         bool
+	}
+	scenarios := []Scenario{
+		{
+			Name:         "endpoint-status",
+			Path:         "/api/v1/endpoints/core_frontend/statuses",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "endpoint-status-gzip",
+			Path:         "/api/v1/endpoints/core_frontend/statuses",
+			ExpectedCode: http.StatusOK,
+			Gzip:         true,
+		},
+		{
+			Name:         "endpoint-status-pagination",
+			Path:         "/api/v1/endpoints/core_frontend/statuses?page=1&pageSize=20",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "endpoint-status-for-invalid-key",
+			Path:         "/api/v1/endpoints/invalid_key/statuses",
+			ExpectedCode: http.StatusNotFound,
+		},
+		{ // XXX: Remove this in v4.0.0
+			Name:         "backward-compatible-service-status",
+			Path:         "/api/v1/services/core_frontend/statuses",
+			ExpectedCode: http.StatusOK,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			request, _ := http.NewRequest("GET", scenario.Path, nil)
+			if scenario.Gzip {
+				request.Header.Set("Accept-Encoding", "gzip")
+			}
+			responseRecorder := httptest.NewRecorder()
+			router.ServeHTTP(responseRecorder, request)
+			if responseRecorder.Code != scenario.ExpectedCode {
+				t.Errorf("%s %s should have returned %d, but returned %d instead", request.Method, request.URL, scenario.ExpectedCode, responseRecorder.Code)
+			}
+		})
+	}
+}
+
+func TestEndpointStatuses(t *testing.T) {
+	defer storage.Get().Clear()
+	defer cache.Clear()
+	firstResult := &testSuccessfulResult
+	secondResult := &testUnsuccessfulResult
+	storage.Get().Insert(&testEndpoint, firstResult)
+	storage.Get().Insert(&testEndpoint, secondResult)
+	// Can't be bothered dealing with timezone issues on the worker that runs the automated tests
+	firstResult.Timestamp = time.Time{}
+	secondResult.Timestamp = time.Time{}
+	router := CreateRouter("../../web/static", nil, nil, false)
+
+	type Scenario struct {
+		Name         string
+		Path         string
+		ExpectedCode int
+		ExpectedBody string
+	}
+	scenarios := []Scenario{
+		{
+			Name:         "no-pagination",
+			Path:         "/api/v1/endpoints/statuses",
+			ExpectedCode: http.StatusOK,
+			ExpectedBody: `[{"name":"name","group":"group","key":"group_name","results":[{"status":200,"hostname":"example.org","duration":150000000,"errors":null,"conditionResults":[{"condition":"[STATUS] == 200","success":true},{"condition":"[RESPONSE_TIME] \u003c 500","success":true},{"condition":"[CERTIFICATE_EXPIRATION] \u003c 72h","success":true}],"success":true,"timestamp":"0001-01-01T00:00:00Z"},{"status":200,"hostname":"example.org","duration":750000000,"errors":["error-1","error-2"],"conditionResults":[{"condition":"[STATUS] == 200","success":true},{"condition":"[RESPONSE_TIME] \u003c 500","success":false},{"condition":"[CERTIFICATE_EXPIRATION] \u003c 72h","success":false}],"success":false,"timestamp":"0001-01-01T00:00:00Z"}],"events":[]}]`,
+		},
+		{
+			Name:         "pagination-first-result",
+			Path:         "/api/v1/endpoints/statuses?page=1&pageSize=1",
+			ExpectedCode: http.StatusOK,
+			ExpectedBody: `[{"name":"name","group":"group","key":"group_name","results":[{"status":200,"hostname":"example.org","duration":750000000,"errors":["error-1","error-2"],"conditionResults":[{"condition":"[STATUS] == 200","success":true},{"condition":"[RESPONSE_TIME] \u003c 500","success":false},{"condition":"[CERTIFICATE_EXPIRATION] \u003c 72h","success":false}],"success":false,"timestamp":"0001-01-01T00:00:00Z"}],"events":[]}]`,
+		},
+		{
+			Name:         "pagination-second-result",
+			Path:         "/api/v1/endpoints/statuses?page=2&pageSize=1",
+			ExpectedCode: http.StatusOK,
+			ExpectedBody: `[{"name":"name","group":"group","key":"group_name","results":[{"status":200,"hostname":"example.org","duration":150000000,"errors":null,"conditionResults":[{"condition":"[STATUS] == 200","success":true},{"condition":"[RESPONSE_TIME] \u003c 500","success":true},{"condition":"[CERTIFICATE_EXPIRATION] \u003c 72h","success":true}],"success":true,"timestamp":"0001-01-01T00:00:00Z"}],"events":[]}]`,
+		},
+		{
+			Name:         "pagination-no-results",
+			Path:         "/api/v1/endpoints/statuses?page=5&pageSize=20",
+			ExpectedCode: http.StatusOK,
+			ExpectedBody: `[{"name":"name","group":"group","key":"group_name","results":[],"events":[]}]`,
+		},
+		{
+			Name:         "invalid-pagination-should-fall-back-to-default",
+			Path:         "/api/v1/endpoints/statuses?page=INVALID&pageSize=INVALID",
+			ExpectedCode: http.StatusOK,
+			ExpectedBody: `[{"name":"name","group":"group","key":"group_name","results":[{"status":200,"hostname":"example.org","duration":150000000,"errors":null,"conditionResults":[{"condition":"[STATUS] == 200","success":true},{"condition":"[RESPONSE_TIME] \u003c 500","success":true},{"condition":"[CERTIFICATE_EXPIRATION] \u003c 72h","success":true}],"success":true,"timestamp":"0001-01-01T00:00:00Z"},{"status":200,"hostname":"example.org","duration":750000000,"errors":["error-1","error-2"],"conditionResults":[{"condition":"[STATUS] == 200","success":true},{"condition":"[RESPONSE_TIME] \u003c 500","success":false},{"condition":"[CERTIFICATE_EXPIRATION] \u003c 72h","success":false}],"success":false,"timestamp":"0001-01-01T00:00:00Z"}],"events":[]}]`,
+		},
+		{ // XXX: Remove this in v4.0.0
+			Name:         "backward-compatible-service-status",
+			Path:         "/api/v1/services/statuses",
+			ExpectedCode: http.StatusOK,
+			ExpectedBody: `[{"name":"name","group":"group","key":"group_name","results":[{"status":200,"hostname":"example.org","duration":150000000,"errors":null,"conditionResults":[{"condition":"[STATUS] == 200","success":true},{"condition":"[RESPONSE_TIME] \u003c 500","success":true},{"condition":"[CERTIFICATE_EXPIRATION] \u003c 72h","success":true}],"success":true,"timestamp":"0001-01-01T00:00:00Z"},{"status":200,"hostname":"example.org","duration":750000000,"errors":["error-1","error-2"],"conditionResults":[{"condition":"[STATUS] == 200","success":true},{"condition":"[RESPONSE_TIME] \u003c 500","success":false},{"condition":"[CERTIFICATE_EXPIRATION] \u003c 72h","success":false}],"success":false,"timestamp":"0001-01-01T00:00:00Z"}],"events":[]}]`,
+		},
+	}
+
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			request, _ := http.NewRequest("GET", scenario.Path, nil)
+			responseRecorder := httptest.NewRecorder()
+			router.ServeHTTP(responseRecorder, request)
+			if responseRecorder.Code != scenario.ExpectedCode {
+				t.Errorf("%s %s should have returned %d, but returned %d instead", request.Method, request.URL, scenario.ExpectedCode, responseRecorder.Code)
+			}
+			output := responseRecorder.Body.String()
+			if output != scenario.ExpectedBody {
+				t.Errorf("expected:\n %s\n\ngot:\n %s", scenario.ExpectedBody, output)
+			}
+		})
+	}
+}

controller/handler/favicon.go

@@ -0,0 +1,12 @@
+package handler
+
+import (
+	"net/http"
+)
+
+// FavIcon handles requests for /favicon.ico
+func FavIcon(staticFolder string) http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		http.ServeFile(writer, request, staticFolder+"/favicon.ico")
+	}
+}

controller/handler/favicon_test.go

@@ -0,0 +1,33 @@
+package handler
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestFavIcon(t *testing.T) {
+	router := CreateRouter("../../web/static", nil, nil, false)
+	type Scenario struct {
+		Name         string
+		Path         string
+		ExpectedCode int
+	}
+	scenarios := []Scenario{
+		{
+			Name:         "favicon",
+			Path:         "/favicon.ico",
+			ExpectedCode: http.StatusOK,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			request, _ := http.NewRequest("GET", scenario.Path, nil)
+			responseRecorder := httptest.NewRecorder()
+			router.ServeHTTP(responseRecorder, request)
+			if responseRecorder.Code != scenario.ExpectedCode {
+				t.Errorf("%s %s should have returned %d, but returned %d instead", request.Method, request.URL, scenario.ExpectedCode, responseRecorder.Code)
+			}
+		})
+	}
+}

controller/handler/gzip.go

@@ -1,4 +1,4 @@
-package main
+package handler
 
 import (
 	"compress/gzip"
@@ -20,17 +20,30 @@ type gzipResponseWriter struct {
 	http.ResponseWriter
 }
 
+// WriteHeader sends an HTTP response header with the provided status code.
+// It also deletes the Content-Length header, since the GZIP compression may modify the size of the payload
 func (w *gzipResponseWriter) WriteHeader(status int) {
 	w.Header().Del("Content-Length")
 	w.ResponseWriter.WriteHeader(status)
 }
 
+// Write writes len(b) bytes from b to the underlying data stream.
 func (w *gzipResponseWriter) Write(b []byte) (int, error) {
 	return w.Writer.Write(b)
 }
 
+// GzipHandler compresses the response of a given http.Handler if the request's headers specify that the client
+// supports gzip encoding
 func GzipHandler(next http.Handler) http.Handler {
-	return http.HandlerFunc(func(writer http.ResponseWriter, r *http.Request) {
+	return GzipHandlerFunc(func(writer http.ResponseWriter, r *http.Request) {
+		next.ServeHTTP(writer, r)
+	})
+}
+
+// GzipHandlerFunc compresses the response of a given http.HandlerFunc if the request's headers specify that the client
+// supports gzip encoding
+func GzipHandlerFunc(next http.HandlerFunc) http.HandlerFunc {
+	return func(writer http.ResponseWriter, r *http.Request) {
 		// If the request doesn't specify that it supports gzip, then don't compress it
 		if !strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
 			next.ServeHTTP(writer, r)
@@ -42,5 +55,5 @@ func GzipHandler(next http.Handler) http.Handler {
 		gz.Reset(writer)
 		defer gz.Close()
 		next.ServeHTTP(&gzipResponseWriter{ResponseWriter: writer, Writer: gz}, r)
-	})
+	}
 }

controller/handler/handler.go

@@ -0,0 +1,47 @@
+package handler
+
+import (
+	"net/http"
+
+	"github.com/TwiN/gatus/v3/config/ui"
+	"github.com/TwiN/gatus/v3/security"
+	"github.com/TwiN/health"
+	"github.com/gorilla/mux"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+func CreateRouter(staticFolder string, securityConfig *security.Config, uiConfig *ui.Config, enabledMetrics bool) *mux.Router {
+	router := mux.NewRouter()
+	if enabledMetrics {
+		router.Handle("/metrics", promhttp.Handler()).Methods("GET")
+	}
+	router.Handle("/health", health.Handler().WithJSON(true)).Methods("GET")
+	router.HandleFunc("/favicon.ico", FavIcon(staticFolder)).Methods("GET")
+	// Endpoints
+	router.HandleFunc("/api/v1/endpoints/statuses", secureIfNecessary(securityConfig, EndpointStatuses)).Methods("GET") // No GzipHandler for this one, because we cache the content as Gzipped already
+	router.HandleFunc("/api/v1/endpoints/{key}/statuses", secureIfNecessary(securityConfig, GzipHandlerFunc(EndpointStatus))).Methods("GET")
+	router.HandleFunc("/api/v1/endpoints/{key}/uptimes/{duration}/badge.svg", UptimeBadge).Methods("GET")
+	router.HandleFunc("/api/v1/endpoints/{key}/response-times/{duration}/badge.svg", ResponseTimeBadge).Methods("GET")
+	router.HandleFunc("/api/v1/endpoints/{key}/response-times/{duration}/chart.svg", ResponseTimeChart).Methods("GET")
+	// XXX: Remove the lines between this and the next XXX comment in v4.0.0
+	router.HandleFunc("/api/v1/services/statuses", secureIfNecessary(securityConfig, EndpointStatuses)).Methods("GET") // No GzipHandler for this one, because we cache the content as Gzipped already
+	router.HandleFunc("/api/v1/services/{key}/statuses", secureIfNecessary(securityConfig, GzipHandlerFunc(EndpointStatus))).Methods("GET")
+	router.HandleFunc("/api/v1/services/{key}/uptimes/{duration}/badge.svg", UptimeBadge).Methods("GET")
+	router.HandleFunc("/api/v1/services/{key}/response-times/{duration}/badge.svg", ResponseTimeBadge).Methods("GET")
+	router.HandleFunc("/api/v1/services/{key}/response-times/{duration}/chart.svg", ResponseTimeChart).Methods("GET")
+	// XXX: Remove the lines between this and the previous XXX comment in v4.0.0
+	// SPA
+	router.HandleFunc("/services/{name}", SinglePageApplication(staticFolder, uiConfig)).Methods("GET") // XXX: Remove this in v4.0.0
+	router.HandleFunc("/endpoints/{name}", SinglePageApplication(staticFolder, uiConfig)).Methods("GET")
+	router.HandleFunc("/", SinglePageApplication(staticFolder, uiConfig)).Methods("GET")
+	// Everything else falls back on static content
+	router.PathPrefix("/").Handler(GzipHandler(http.FileServer(http.Dir(staticFolder))))
+	return router
+}
+
+func secureIfNecessary(securityConfig *security.Config, handler http.HandlerFunc) http.HandlerFunc {
+	if securityConfig != nil && securityConfig.IsValid() {
+		return security.Handler(handler, securityConfig)
+	}
+	return handler
+}

controller/handler/handler_test.go

@@ -0,0 +1,58 @@
+package handler
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestCreateRouter(t *testing.T) {
+	router := CreateRouter("../../web/static", nil, nil, true)
+	type Scenario struct {
+		Name         string
+		Path         string
+		ExpectedCode int
+		Gzip         bool
+	}
+	scenarios := []Scenario{
+		{
+			Name:         "health",
+			Path:         "/health",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "metrics",
+			Path:         "/metrics",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "scripts",
+			Path:         "/js/app.js",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "scripts-gzipped",
+			Path:         "/js/app.js",
+			ExpectedCode: http.StatusOK,
+			Gzip:         true,
+		},
+		{
+			Name:         "index-redirect",
+			Path:         "/index.html",
+			ExpectedCode: http.StatusMovedPermanently,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			request, _ := http.NewRequest("GET", scenario.Path, nil)
+			if scenario.Gzip {
+				request.Header.Set("Accept-Encoding", "gzip")
+			}
+			responseRecorder := httptest.NewRecorder()
+			router.ServeHTTP(responseRecorder, request)
+			if responseRecorder.Code != scenario.ExpectedCode {
+				t.Errorf("%s %s should have returned %d, but returned %d instead", request.Method, request.URL, scenario.ExpectedCode, responseRecorder.Code)
+			}
+		})
+	}
+}

controller/handler/spa.go

@@ -0,0 +1,27 @@
+package handler
+
+import (
+	"html/template"
+	"log"
+	"net/http"
+
+	"github.com/TwiN/gatus/v3/config/ui"
+)
+
+func SinglePageApplication(staticFolder string, ui *ui.Config) http.HandlerFunc {
+	return func(writer http.ResponseWriter, request *http.Request) {
+		t, err := template.ParseFiles(staticFolder + "/index.html")
+		if err != nil {
+			log.Println("[handler][SinglePageApplication] Failed to parse template:", err.Error())
+			http.ServeFile(writer, request, staticFolder+"/index.html")
+			return
+		}
+		writer.Header().Set("Content-Type", "text/html")
+		err = t.Execute(writer, ui)
+		if err != nil {
+			log.Println("[handler][SinglePageApplication] Failed to parse template:", err.Error())
+			http.ServeFile(writer, request, staticFolder+"/index.html")
+			return
+		}
+	}
+}

controller/handler/spa_test.go

@@ -0,0 +1,70 @@
+package handler
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+	"time"
+
+	"github.com/TwiN/gatus/v3/config"
+	"github.com/TwiN/gatus/v3/core"
+	"github.com/TwiN/gatus/v3/storage"
+	"github.com/TwiN/gatus/v3/watchdog"
+)
+
+func TestSinglePageApplication(t *testing.T) {
+	defer storage.Get().Clear()
+	defer cache.Clear()
+	cfg := &config.Config{
+		Metrics: true,
+		Endpoints: []*core.Endpoint{
+			{
+				Name:  "frontend",
+				Group: "core",
+			},
+			{
+				Name:  "backend",
+				Group: "core",
+			},
+		},
+	}
+	watchdog.UpdateEndpointStatuses(cfg.Endpoints[0], &core.Result{Success: true, Duration: time.Millisecond, Timestamp: time.Now()})
+	watchdog.UpdateEndpointStatuses(cfg.Endpoints[1], &core.Result{Success: false, Duration: time.Second, Timestamp: time.Now()})
+	router := CreateRouter("../../web/static", cfg.Security, nil, cfg.Metrics)
+	type Scenario struct {
+		Name         string
+		Path         string
+		ExpectedCode int
+		Gzip         bool
+	}
+	scenarios := []Scenario{
+		{
+			Name:         "frontend-home",
+			Path:         "/",
+			ExpectedCode: http.StatusOK,
+		},
+		{
+			Name:         "frontend-endpoint",
+			Path:         "/endpoints/core_frontend",
+			ExpectedCode: http.StatusOK,
+		},
+		{ // XXX: Remove this in v4.0.0
+			Name:         "frontend-service",
+			Path:         "/services/core_frontend",
+			ExpectedCode: http.StatusOK,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			request, _ := http.NewRequest("GET", scenario.Path, nil)
+			if scenario.Gzip {
+				request.Header.Set("Accept-Encoding", "gzip")
+			}
+			responseRecorder := httptest.NewRecorder()
+			router.ServeHTTP(responseRecorder, request)
+			if responseRecorder.Code != scenario.ExpectedCode {
+				t.Errorf("%s %s should have returned %d, but returned %d instead", request.Method, request.URL, scenario.ExpectedCode, responseRecorder.Code)
+			}
+		})
+	}
+}

controller/handler/util.go

@@ -0,0 +1,48 @@
+package handler
+
+import (
+	"net/http"
+	"strconv"
+
+	"github.com/TwiN/gatus/v3/storage/store/common"
+)
+
+const (
+	// DefaultPage is the default page to use if none is specified or an invalid value is provided
+	DefaultPage = 1
+
+	// DefaultPageSize is the default page siZE to use if none is specified or an invalid value is provided
+	DefaultPageSize = 20
+
+	// MaximumPageSize is the maximum page size allowed
+	MaximumPageSize = common.MaximumNumberOfResults
+)
+
+func extractPageAndPageSizeFromRequest(r *http.Request) (page int, pageSize int) {
+	var err error
+	if pageParameter := r.URL.Query().Get("page"); len(pageParameter) == 0 {
+		page = DefaultPage
+	} else {
+		page, err = strconv.Atoi(pageParameter)
+		if err != nil {
+			page = DefaultPage
+		}
+		if page < 1 {
+			page = DefaultPage
+		}
+	}
+	if pageSizeParameter := r.URL.Query().Get("pageSize"); len(pageSizeParameter) == 0 {
+		pageSize = DefaultPageSize
+	} else {
+		pageSize, err = strconv.Atoi(pageSizeParameter)
+		if err != nil {
+			pageSize = DefaultPageSize
+		}
+		if pageSize > MaximumPageSize {
+			pageSize = MaximumPageSize
+		} else if pageSize < 1 {
+			pageSize = DefaultPageSize
+		}
+	}
+	return
+}

controller/handler/util_test.go

@@ -0,0 +1,67 @@
+package handler
+
+import (
+	"fmt"
+	"net/http"
+	"testing"
+)
+
+func TestExtractPageAndPageSizeFromRequest(t *testing.T) {
+	type Scenario struct {
+		Name             string
+		Page             string
+		PageSize         string
+		ExpectedPage     int
+		ExpectedPageSize int
+	}
+	scenarios := []Scenario{
+		{
+			Page:             "1",
+			PageSize:         "20",
+			ExpectedPage:     1,
+			ExpectedPageSize: 20,
+		},
+		{
+			Page:             "2",
+			PageSize:         "10",
+			ExpectedPage:     2,
+			ExpectedPageSize: 10,
+		},
+		{
+			Page:             "2",
+			PageSize:         "10",
+			ExpectedPage:     2,
+			ExpectedPageSize: 10,
+		},
+		{
+			Page:             "1",
+			PageSize:         "999999",
+			ExpectedPage:     1,
+			ExpectedPageSize: MaximumPageSize,
+		},
+		{
+			Page:             "-1",
+			PageSize:         "-1",
+			ExpectedPage:     DefaultPage,
+			ExpectedPageSize: DefaultPageSize,
+		},
+		{
+			Page:             "invalid",
+			PageSize:         "invalid",
+			ExpectedPage:     DefaultPage,
+			ExpectedPageSize: DefaultPageSize,
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run("page-"+scenario.Page+"-pageSize-"+scenario.PageSize, func(t *testing.T) {
+			request, _ := http.NewRequest("GET", fmt.Sprintf("/api/v1/statuses?page=%s&pageSize=%s", scenario.Page, scenario.PageSize), nil)
+			actualPage, actualPageSize := extractPageAndPageSizeFromRequest(request)
+			if actualPage != scenario.ExpectedPage {
+				t.Errorf("expected %d, got %d", scenario.ExpectedPage, actualPage)
+			}
+			if actualPageSize != scenario.ExpectedPageSize {
+				t.Errorf("expected %d, got %d", scenario.ExpectedPageSize, actualPageSize)
+			}
+		})
+	}
+}

core/alert.go

@@ -1,39 +0,0 @@
-package core
-
-// Alert is the service's alert configuration
-type Alert struct {
-	// Type of alert
-	Type AlertType `yaml:"type"`
-
-	// Enabled defines whether or not the alert is enabled
-	Enabled bool `yaml:"enabled"`
-
-	// 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.
-	Description string `yaml:"description"`
-
-	// SendOnResolved defines whether to send a second notification when the issue has been resolved
-	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
-
-	// 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.
-	Triggered bool
-}
-
-type AlertType string
-
-const (
-	SlackAlert     AlertType = "slack"
-	PagerDutyAlert AlertType = "pagerduty"
-	TwilioAlert    AlertType = "twilio"
-	CustomAlert    AlertType = "custom"
-)

core/condition.go

@@ -2,50 +2,313 @@ package core
 
 import (
 	"fmt"
-	"log"
+	"strconv"
 	"strings"
+	"time"
+
+	"github.com/TwiN/gatus/v3/jsonpath"
+	"github.com/TwiN/gatus/v3/pattern"
 )
 
+const (
+	// StatusPlaceholder is a placeholder for a HTTP status.
+	//
+	// Values that could replace the placeholder: 200, 404, 500, ...
+	StatusPlaceholder = "[STATUS]"
+
+	// IPPlaceholder is a placeholder for an IP.
+	//
+	// Values that could replace the placeholder: 127.0.0.1, 10.0.0.1, ...
+	IPPlaceholder = "[IP]"
+
+	// DNSRCodePlaceholder is a place holder for DNS_RCODE
+	//
+	// Values that could replace the placeholder: NOERROR, FORMERR, SERVFAIL, NXDOMAIN, NOTIMP, REFUSED
+	DNSRCodePlaceholder = "[DNS_RCODE]"
+
+	// ResponseTimePlaceholder is a placeholder for the request response time, in milliseconds.
+	//
+	// Values that could replace the placeholder: 1, 500, 1000, ...
+	ResponseTimePlaceholder = "[RESPONSE_TIME]"
+
+	// BodyPlaceholder is a placeholder for the body of the response
+	//
+	// Values that could replace the placeholder: {}, {"data":{"name":"john"}}, ...
+	BodyPlaceholder = "[BODY]"
+
+	// ConnectedPlaceholder is a placeholder for whether a connection was successfully established.
+	//
+	// Values that could replace the placeholder: true, false
+	ConnectedPlaceholder = "[CONNECTED]"
+
+	// CertificateExpirationPlaceholder is a placeholder for the duration before certificate expiration, in milliseconds.
+	//
+	// Values that could replace the placeholder: 4461677039 (~52 days)
+	CertificateExpirationPlaceholder = "[CERTIFICATE_EXPIRATION]"
+
+	// LengthFunctionPrefix is the prefix for the length function
+	//
+	// Usage: len([BODY].articles) == 10, len([BODY].name) > 5
+	LengthFunctionPrefix = "len("
+
+	// HasFunctionPrefix is the prefix for the has function
+	//
+	// Usage: has([BODY].errors) == true
+	HasFunctionPrefix = "has("
+
+	// PatternFunctionPrefix is the prefix for the pattern function
+	//
+	// Usage: [IP] == pat(192.168.*.*)
+	PatternFunctionPrefix = "pat("
+
+	// AnyFunctionPrefix is the prefix for the any function
+	//
+	// Usage: [IP] == any(1.1.1.1, 1.0.0.1)
+	AnyFunctionPrefix = "any("
+
+	// FunctionSuffix is the suffix for all functions
+	FunctionSuffix = ")"
+
+	// InvalidConditionElementSuffix is the suffix that will be appended to an invalid condition
+	InvalidConditionElementSuffix = "(INVALID)"
+
+	// maximumLengthBeforeTruncatingWhenComparedWithPattern is the maximum length an element being compared to a
+	// pattern can have.
+	//
+	// This is only used for aesthetic purposes; it does not influence whether the condition evaluation results in a
+	// success or a failure
+	maximumLengthBeforeTruncatingWhenComparedWithPattern = 25
+)
+
+// Condition is a condition that needs to be met in order for a Endpoint to be considered healthy.
 type Condition string
 
-func (c *Condition) evaluate(result *Result) bool {
-	condition := string(*c)
+// evaluate the Condition with the Result of the health check
+// TODO: Add a mandatory space between each operators (e.g. " == " instead of "==") (BREAKING CHANGE)
+func (c Condition) evaluate(result *Result, dontResolveFailedConditions bool) bool {
+	condition := string(c)
 	success := false
-	var resolvedCondition string
+	conditionToDisplay := condition
 	if strings.Contains(condition, "==") {
-		parts := sanitizeAndResolve(strings.Split(condition, "=="), result)
-		success = parts[0] == parts[1]
-		resolvedCondition = fmt.Sprintf("%v == %v", parts[0], parts[1])
+		parameters, resolvedParameters := sanitizeAndResolve(strings.Split(condition, "=="), result)
+		success = isEqual(resolvedParameters[0], resolvedParameters[1])
+		if !success && !dontResolveFailedConditions {
+			conditionToDisplay = prettify(parameters, resolvedParameters, "==")
+		}
 	} else if strings.Contains(condition, "!=") {
-		parts := sanitizeAndResolve(strings.Split(condition, "!="), result)
-		success = parts[0] != parts[1]
-		resolvedCondition = fmt.Sprintf("%v != %v", parts[0], parts[1])
+		parameters, resolvedParameters := sanitizeAndResolve(strings.Split(condition, "!="), result)
+		success = !isEqual(resolvedParameters[0], resolvedParameters[1])
+		if !success && !dontResolveFailedConditions {
+			conditionToDisplay = prettify(parameters, resolvedParameters, "!=")
+		}
 	} else if strings.Contains(condition, "<=") {
-		parts := sanitizeAndResolveNumerical(strings.Split(condition, "<="), result)
-		success = parts[0] <= parts[1]
-		resolvedCondition = fmt.Sprintf("%v <= %v", parts[0], parts[1])
+		parameters, resolvedParameters := sanitizeAndResolveNumerical(strings.Split(condition, "<="), result)
+		success = resolvedParameters[0] <= resolvedParameters[1]
+		if !success && !dontResolveFailedConditions {
+			conditionToDisplay = prettifyNumericalParameters(parameters, resolvedParameters, "<=")
+		}
 	} else if strings.Contains(condition, ">=") {
-		parts := sanitizeAndResolveNumerical(strings.Split(condition, ">="), result)
-		success = parts[0] >= parts[1]
-		resolvedCondition = fmt.Sprintf("%v >= %v", parts[0], parts[1])
+		parameters, resolvedParameters := sanitizeAndResolveNumerical(strings.Split(condition, ">="), result)
+		success = resolvedParameters[0] >= resolvedParameters[1]
+		if !success && !dontResolveFailedConditions {
+			conditionToDisplay = prettifyNumericalParameters(parameters, resolvedParameters, ">=")
+		}
 	} else if strings.Contains(condition, ">") {
-		parts := sanitizeAndResolveNumerical(strings.Split(condition, ">"), result)
-		success = parts[0] > parts[1]
-		resolvedCondition = fmt.Sprintf("%v > %v", parts[0], parts[1])
+		parameters, resolvedParameters := sanitizeAndResolveNumerical(strings.Split(condition, ">"), result)
+		success = resolvedParameters[0] > resolvedParameters[1]
+		if !success && !dontResolveFailedConditions {
+			conditionToDisplay = prettifyNumericalParameters(parameters, resolvedParameters, ">")
+		}
 	} else if strings.Contains(condition, "<") {
-		parts := sanitizeAndResolveNumerical(strings.Split(condition, "<"), result)
-		success = parts[0] < parts[1]
-		resolvedCondition = fmt.Sprintf("%v < %v", parts[0], parts[1])
+		parameters, resolvedParameters := sanitizeAndResolveNumerical(strings.Split(condition, "<"), result)
+		success = resolvedParameters[0] < resolvedParameters[1]
+		if !success && !dontResolveFailedConditions {
+			conditionToDisplay = prettifyNumericalParameters(parameters, resolvedParameters, "<")
+		}
 	} else {
-		result.Errors = append(result.Errors, fmt.Sprintf("invalid condition '%s' has been provided", condition))
+		result.AddError(fmt.Sprintf("invalid condition '%s' has been provided", condition))
 		return false
 	}
-	conditionToDisplay := condition
-	// If the condition isn't a success, return what the resolved condition was too
 	if !success {
-		log.Printf("[Condition][evaluate] Condition '%s' did not succeed because '%s' is false", condition, resolvedCondition)
-		conditionToDisplay = fmt.Sprintf("%s (%s)", condition, resolvedCondition)
+		//log.Printf("[Condition][evaluate] Condition '%s' did not succeed because '%s' is false", condition, condition)
 	}
 	result.ConditionResults = append(result.ConditionResults, &ConditionResult{Condition: conditionToDisplay, Success: success})
 	return success
 }
+
+// hasBodyPlaceholder checks whether the condition has a BodyPlaceholder
+// Used for determining whether the response body should be read or not
+func (c Condition) hasBodyPlaceholder() bool {
+	return strings.Contains(string(c), BodyPlaceholder)
+}
+
+// isEqual compares two strings.
+//
+// Supports the pattern and the any functions.
+// i.e. if one of the parameters starts with PatternFunctionPrefix and ends with FunctionSuffix, it will be treated like
+// a pattern.
+func isEqual(first, second string) bool {
+	firstHasFunctionSuffix := strings.HasSuffix(first, FunctionSuffix)
+	secondHasFunctionSuffix := strings.HasSuffix(second, FunctionSuffix)
+	if firstHasFunctionSuffix || secondHasFunctionSuffix {
+		var isFirstPattern, isSecondPattern bool
+		if strings.HasPrefix(first, PatternFunctionPrefix) && firstHasFunctionSuffix {
+			isFirstPattern = true
+			first = strings.TrimSuffix(strings.TrimPrefix(first, PatternFunctionPrefix), FunctionSuffix)
+		}
+		if strings.HasPrefix(second, PatternFunctionPrefix) && secondHasFunctionSuffix {
+			isSecondPattern = true
+			second = strings.TrimSuffix(strings.TrimPrefix(second, PatternFunctionPrefix), FunctionSuffix)
+		}
+		if isFirstPattern && !isSecondPattern {
+			return pattern.Match(first, second)
+		} else if !isFirstPattern && isSecondPattern {
+			return pattern.Match(second, first)
+		}
+		var isFirstAny, isSecondAny bool
+		if strings.HasPrefix(first, AnyFunctionPrefix) && firstHasFunctionSuffix {
+			isFirstAny = true
+			first = strings.TrimSuffix(strings.TrimPrefix(first, AnyFunctionPrefix), FunctionSuffix)
+		}
+		if strings.HasPrefix(second, AnyFunctionPrefix) && secondHasFunctionSuffix {
+			isSecondAny = true
+			second = strings.TrimSuffix(strings.TrimPrefix(second, AnyFunctionPrefix), FunctionSuffix)
+		}
+		if isFirstAny && !isSecondAny {
+			options := strings.Split(first, ",")
+			for _, option := range options {
+				if strings.TrimSpace(option) == second {
+					return true
+				}
+			}
+			return false
+		} else if !isFirstAny && isSecondAny {
+			options := strings.Split(second, ",")
+			for _, option := range options {
+				if strings.TrimSpace(option) == first {
+					return true
+				}
+			}
+			return false
+		}
+	}
+	return first == second
+}
+
+// sanitizeAndResolve sanitizes and resolves a list of elements and returns the list of parameters as well as a list
+// of resolved parameters
+func sanitizeAndResolve(elements []string, result *Result) ([]string, []string) {
+	parameters := make([]string, len(elements))
+	resolvedParameters := make([]string, len(elements))
+	body := strings.TrimSpace(string(result.body))
+	for i, element := range elements {
+		element = strings.TrimSpace(element)
+		parameters[i] = element
+		switch strings.ToUpper(element) {
+		case StatusPlaceholder:
+			element = strconv.Itoa(result.HTTPStatus)
+		case IPPlaceholder:
+			element = result.IP
+		case ResponseTimePlaceholder:
+			element = strconv.Itoa(int(result.Duration.Milliseconds()))
+		case BodyPlaceholder:
+			element = body
+		case DNSRCodePlaceholder:
+			element = result.DNSRCode
+		case ConnectedPlaceholder:
+			element = strconv.FormatBool(result.Connected)
+		case CertificateExpirationPlaceholder:
+			element = strconv.FormatInt(result.CertificateExpiration.Milliseconds(), 10)
+		default:
+			// if contains the BodyPlaceholder, then evaluate json path
+			if strings.Contains(element, BodyPlaceholder) {
+				checkingForLength := false
+				checkingForExistence := false
+				if strings.HasPrefix(element, LengthFunctionPrefix) && strings.HasSuffix(element, FunctionSuffix) {
+					checkingForLength = true
+					element = strings.TrimSuffix(strings.TrimPrefix(element, LengthFunctionPrefix), FunctionSuffix)
+				}
+				if strings.HasPrefix(element, HasFunctionPrefix) && strings.HasSuffix(element, FunctionSuffix) {
+					checkingForExistence = true
+					element = strings.TrimSuffix(strings.TrimPrefix(element, HasFunctionPrefix), FunctionSuffix)
+				}
+				resolvedElement, resolvedElementLength, err := jsonpath.Eval(strings.TrimPrefix(strings.TrimPrefix(element, BodyPlaceholder), "."), result.body)
+				if checkingForExistence {
+					if err != nil {
+						element = "false"
+					} else {
+						element = "true"
+					}
+				} else {
+					if err != nil {
+						if err.Error() != "unexpected end of JSON input" {
+							result.AddError(err.Error())
+						}
+						if checkingForLength {
+							element = LengthFunctionPrefix + element + FunctionSuffix + " " + InvalidConditionElementSuffix
+						} else {
+							element = element + " " + InvalidConditionElementSuffix
+						}
+					} else {
+						if checkingForLength {
+							element = strconv.Itoa(resolvedElementLength)
+						} else {
+							element = resolvedElement
+						}
+					}
+				}
+			}
+		}
+		resolvedParameters[i] = element
+	}
+	return parameters, resolvedParameters
+}
+
+func sanitizeAndResolveNumerical(list []string, result *Result) (parameters []string, resolvedNumericalParameters []int64) {
+	parameters, resolvedParameters := sanitizeAndResolve(list, result)
+	for _, element := range resolvedParameters {
+		if duration, err := time.ParseDuration(element); duration != 0 && err == nil {
+			resolvedNumericalParameters = append(resolvedNumericalParameters, duration.Milliseconds())
+		} else if number, err := strconv.ParseInt(element, 10, 64); err != nil {
+			// Default to 0 if the string couldn't be converted to an integer
+			resolvedNumericalParameters = append(resolvedNumericalParameters, 0)
+		} else {
+			resolvedNumericalParameters = append(resolvedNumericalParameters, number)
+		}
+	}
+	return parameters, resolvedNumericalParameters
+}
+
+func prettifyNumericalParameters(parameters []string, resolvedParameters []int64, operator string) string {
+	return prettify(parameters, []string{strconv.Itoa(int(resolvedParameters[0])), strconv.Itoa(int(resolvedParameters[1]))}, operator)
+}
+
+// XXX: make this configurable? i.e. show-resolved-conditions-on-failure
+func prettify(parameters []string, resolvedParameters []string, operator string) string {
+	// Since, in the event of an invalid path, the resolvedParameters also contain the condition itself,
+	// we'll return the resolvedParameters as-is.
+	if strings.HasSuffix(resolvedParameters[0], InvalidConditionElementSuffix) || strings.HasSuffix(resolvedParameters[1], InvalidConditionElementSuffix) {
+		return resolvedParameters[0] + " " + operator + " " + resolvedParameters[1]
+	}
+	// If using the pattern function, truncate the parameter it's being compared to if said parameter is long enough
+	if strings.HasPrefix(parameters[0], PatternFunctionPrefix) && strings.HasSuffix(parameters[0], FunctionSuffix) && len(resolvedParameters[1]) > maximumLengthBeforeTruncatingWhenComparedWithPattern {
+		resolvedParameters[1] = fmt.Sprintf("%.25s...(truncated)", resolvedParameters[1])
+	}
+	if strings.HasPrefix(parameters[1], PatternFunctionPrefix) && strings.HasSuffix(parameters[1], FunctionSuffix) && len(resolvedParameters[0]) > maximumLengthBeforeTruncatingWhenComparedWithPattern {
+		resolvedParameters[0] = fmt.Sprintf("%.25s...(truncated)", resolvedParameters[0])
+	}
+	// First element is a placeholder
+	if parameters[0] != resolvedParameters[0] && parameters[1] == resolvedParameters[1] {
+		return parameters[0] + " (" + resolvedParameters[0] + ") " + operator + " " + parameters[1]
+	}
+	// Second element is a placeholder
+	if parameters[0] == resolvedParameters[0] && parameters[1] != resolvedParameters[1] {
+		return parameters[0] + " " + operator + " " + parameters[1] + " (" + resolvedParameters[1] + ")"
+	}
+	// Both elements are placeholders...?
+	if parameters[0] != resolvedParameters[0] && parameters[1] != resolvedParameters[1] {
+		return parameters[0] + " (" + resolvedParameters[0] + ") " + operator + " " + parameters[1] + " (" + resolvedParameters[1] + ")"
+	}
+	// Neither elements are placeholders
+	return parameters[0] + " " + operator + " " + parameters[1]
+}

core/condition_bench_test.go

@@ -0,0 +1,84 @@
+package core
+
+import "testing"
+
+func BenchmarkCondition_evaluateWithBodyStringAny(b *testing.B) {
+	condition := Condition("[BODY].name == any(john.doe, jane.doe)")
+	for n := 0; n < b.N; n++ {
+		result := &Result{body: []byte("{\"name\": \"john.doe\"}")}
+		condition.evaluate(result, false)
+	}
+	b.ReportAllocs()
+}
+
+func BenchmarkCondition_evaluateWithBodyStringAnyFailure(b *testing.B) {
+	condition := Condition("[BODY].name == any(john.doe, jane.doe)")
+	for n := 0; n < b.N; n++ {
+		result := &Result{body: []byte("{\"name\": \"bob.doe\"}")}
+		condition.evaluate(result, false)
+	}
+	b.ReportAllocs()
+}
+
+func BenchmarkCondition_evaluateWithBodyString(b *testing.B) {
+	condition := Condition("[BODY].name == john.doe")
+	for n := 0; n < b.N; n++ {
+		result := &Result{body: []byte("{\"name\": \"john.doe\"}")}
+		condition.evaluate(result, false)
+	}
+	b.ReportAllocs()
+}
+
+func BenchmarkCondition_evaluateWithBodyStringFailure(b *testing.B) {
+	condition := Condition("[BODY].name == john.doe")
+	for n := 0; n < b.N; n++ {
+		result := &Result{body: []byte("{\"name\": \"bob.doe\"}")}
+		condition.evaluate(result, false)
+	}
+	b.ReportAllocs()
+}
+
+func BenchmarkCondition_evaluateWithBodyStringFailureInvalidPath(b *testing.B) {
+	condition := Condition("[BODY].user.name == bob.doe")
+	for n := 0; n < b.N; n++ {
+		result := &Result{body: []byte("{\"name\": \"bob.doe\"}")}
+		condition.evaluate(result, false)
+	}
+	b.ReportAllocs()
+}
+
+func BenchmarkCondition_evaluateWithBodyStringLen(b *testing.B) {
+	condition := Condition("len([BODY].name) == 8")
+	for n := 0; n < b.N; n++ {
+		result := &Result{body: []byte("{\"name\": \"john.doe\"}")}
+		condition.evaluate(result, false)
+	}
+	b.ReportAllocs()
+}
+
+func BenchmarkCondition_evaluateWithBodyStringLenFailure(b *testing.B) {
+	condition := Condition("len([BODY].name) == 8")
+	for n := 0; n < b.N; n++ {
+		result := &Result{body: []byte("{\"name\": \"bob.doe\"}")}
+		condition.evaluate(result, false)
+	}
+	b.ReportAllocs()
+}
+
+func BenchmarkCondition_evaluateWithStatus(b *testing.B) {
+	condition := Condition("[STATUS] == 200")
+	for n := 0; n < b.N; n++ {
+		result := &Result{HTTPStatus: 200}
+		condition.evaluate(result, false)
+	}
+	b.ReportAllocs()
+}
+
+func BenchmarkCondition_evaluateWithStatusFailure(b *testing.B) {
+	condition := Condition("[STATUS] == 200")
+	for n := 0; n < b.N; n++ {
+		result := &Result{HTTPStatus: 400}
+		condition.evaluate(result, false)
+	}
+	b.ReportAllocs()
+}

core/condition_result.go

@@ -0,0 +1,10 @@
+package core
+
+// ConditionResult result of a Condition
+type ConditionResult struct {
+	// Condition that was evaluated
+	Condition string `json:"condition"`
+
+	// Success whether the condition was met (successful) or not (failed)
+	Success bool `json:"success"`
+}

core/condition_test.go

@@ -1,186 +1,485 @@
 package core
 
 import (
+	"strconv"
 	"testing"
 	"time"
 )
 
-func TestCondition_evaluateWithIp(t *testing.T) {
-	condition := Condition("[IP] == 127.0.0.1")
-	result := &Result{Ip: "127.0.0.1"}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
+func TestCondition_evaluate(t *testing.T) {
+	scenarios := []struct {
+		Name                        string
+		Condition                   Condition
+		Result                      *Result
+		DontResolveFailedConditions bool
+		ExpectedSuccess             bool
+		ExpectedOutput              string
+	}{
+		{
+			Name:            "ip",
+			Condition:       Condition("[IP] == 127.0.0.1"),
+			Result:          &Result{IP: "127.0.0.1"},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[IP] == 127.0.0.1",
+		},
+		{
+			Name:            "status",
+			Condition:       Condition("[STATUS] == 200"),
+			Result:          &Result{HTTPStatus: 200},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[STATUS] == 200",
+		},
+		{
+			Name:            "status-failure",
+			Condition:       Condition("[STATUS] == 200"),
+			Result:          &Result{HTTPStatus: 500},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[STATUS] (500) == 200",
+		},
+		{
+			Name:            "status-using-less-than",
+			Condition:       Condition("[STATUS] < 300"),
+			Result:          &Result{HTTPStatus: 201},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[STATUS] < 300",
+		},
+		{
+			Name:            "status-using-less-than-failure",
+			Condition:       Condition("[STATUS] < 300"),
+			Result:          &Result{HTTPStatus: 404},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[STATUS] (404) < 300",
+		},
+		{
+			Name:            "response-time-using-less-than",
+			Condition:       Condition("[RESPONSE_TIME] < 500"),
+			Result:          &Result{Duration: 50 * time.Millisecond},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[RESPONSE_TIME] < 500",
+		},
+		{
+			Name:            "response-time-using-less-than-with-duration",
+			Condition:       Condition("[RESPONSE_TIME] < 1s"),
+			Result:          &Result{Duration: 50 * time.Millisecond},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[RESPONSE_TIME] < 1s",
+		},
+		{
+			Name:            "response-time-using-less-than-invalid",
+			Condition:       Condition("[RESPONSE_TIME] < potato"),
+			Result:          &Result{Duration: 50 * time.Millisecond},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[RESPONSE_TIME] (50) < potato (0)", // Non-numerical values automatically resolve to 0
+		},
+		{
+			Name:            "response-time-using-greater-than",
+			Condition:       Condition("[RESPONSE_TIME] > 500"),
+			Result:          &Result{Duration: 750 * time.Millisecond},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[RESPONSE_TIME] > 500",
+		},
+		{
+			Name:            "response-time-using-greater-than-with-duration",
+			Condition:       Condition("[RESPONSE_TIME] > 1s"),
+			Result:          &Result{Duration: 2 * time.Second},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[RESPONSE_TIME] > 1s",
+		},
+		{
+			Name:            "response-time-using-greater-than-or-equal-to-equal",
+			Condition:       Condition("[RESPONSE_TIME] >= 500"),
+			Result:          &Result{Duration: 500 * time.Millisecond},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[RESPONSE_TIME] >= 500",
+		},
+		{
+			Name:            "response-time-using-greater-than-or-equal-to-greater",
+			Condition:       Condition("[RESPONSE_TIME] >= 500"),
+			Result:          &Result{Duration: 499 * time.Millisecond},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[RESPONSE_TIME] (499) >= 500",
+		},
+		{
+			Name:            "response-time-using-greater-than-or-equal-to-failure",
+			Condition:       Condition("[RESPONSE_TIME] >= 500"),
+			Result:          &Result{Duration: 499 * time.Millisecond},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[RESPONSE_TIME] (499) >= 500",
+		},
+		{
+			Name:            "response-time-using-less-than-or-equal-to-equal",
+			Condition:       Condition("[RESPONSE_TIME] <= 500"),
+			Result:          &Result{Duration: 500 * time.Millisecond},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[RESPONSE_TIME] <= 500",
+		},
+		{
+			Name:            "response-time-using-less-than-or-equal-to-less",
+			Condition:       Condition("[RESPONSE_TIME] <= 500"),
+			Result:          &Result{Duration: 25 * time.Millisecond},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[RESPONSE_TIME] <= 500",
+		},
+		{
+			Name:            "response-time-using-less-than-or-equal-to-failure",
+			Condition:       Condition("[RESPONSE_TIME] <= 500"),
+			Result:          &Result{Duration: 750 * time.Millisecond},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[RESPONSE_TIME] (750) <= 500",
+		},
+		{
+			Name:            "body",
+			Condition:       Condition("[BODY] == test"),
+			Result:          &Result{body: []byte("test")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY] == test",
+		},
+		{
+			Name:            "body-jsonpath",
+			Condition:       Condition("[BODY].status == UP"),
+			Result:          &Result{body: []byte("{\"status\":\"UP\"}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY].status == UP",
+		},
+		{
+			Name:            "body-jsonpath-complex",
+			Condition:       Condition("[BODY].data.name == john"),
+			Result:          &Result{body: []byte("{\"data\": {\"id\": 1, \"name\": \"john\"}}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY].data.name == john",
+		},
+		{
+			Name:            "body-jsonpath-complex-invalid",
+			Condition:       Condition("[BODY].data.name == john"),
+			Result:          &Result{body: []byte("{\"data\": {\"id\": 1}}")},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[BODY].data.name (INVALID) == john",
+		},
+		{
+			Name:            "body-jsonpath-complex-len",
+			Condition:       Condition("len([BODY].data.name) == 4"),
+			Result:          &Result{body: []byte("{\"data\": {\"name\": \"john\"}}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "len([BODY].data.name) == 4",
+		},
+		{
+			Name:            "body-jsonpath-complex-len-invalid",
+			Condition:       Condition("len([BODY].data.name) == john"),
+			Result:          &Result{body: []byte("{\"data\": {\"id\": 1}}")},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "len([BODY].data.name) (INVALID) == john",
+		},
+		{
+			Name:            "body-jsonpath-double-placeholder",
+			Condition:       Condition("[BODY].user.firstName != [BODY].user.lastName"),
+			Result:          &Result{body: []byte("{\"user\": {\"firstName\": \"john\", \"lastName\": \"doe\"}}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY].user.firstName != [BODY].user.lastName",
+		},
+		{
+			Name:            "body-jsonpath-double-placeholder-failure",
+			Condition:       Condition("[BODY].user.firstName == [BODY].user.lastName"),
+			Result:          &Result{body: []byte("{\"user\": {\"firstName\": \"john\", \"lastName\": \"doe\"}}")},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[BODY].user.firstName (john) == [BODY].user.lastName (doe)",
+		},
+		{
+			Name:            "body-jsonpath-when-body-is-array",
+			Condition:       Condition("[BODY][0].id == 1"),
+			Result:          &Result{body: []byte("[{\"id\": 1}, {\"id\": 2}]")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY][0].id == 1",
+		},
+		{
+			Name:            "body-jsonpath-complex-int",
+			Condition:       Condition("[BODY].data.id == 1"),
+			Result:          &Result{body: []byte("{\"data\": {\"id\": 1}}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY].data.id == 1",
+		},
+		{
+			Name:            "body-jsonpath-complex-array-int",
+			Condition:       Condition("[BODY].data[1].id == 2"),
+			Result:          &Result{body: []byte("{\"data\": [{\"id\": 1}, {\"id\": 2}, {\"id\": 3}]}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY].data[1].id == 2",
+		},
+		{
+			Name:            "body-jsonpath-complex-int-using-greater-than",
+			Condition:       Condition("[BODY].data.id > 0"),
+			Result:          &Result{body: []byte("{\"data\": {\"id\": 1}}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY].data.id > 0",
+		},
+		{
+			Name:            "body-jsonpath-complex-int-using-greater-than-failure",
+			Condition:       Condition("[BODY].data.id > 5"),
+			Result:          &Result{body: []byte("{\"data\": {\"id\": 1}}")},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[BODY].data.id (1) > 5",
+		},
+		{
+			Name:            "body-jsonpath-complex-int-using-less-than",
+			Condition:       Condition("[BODY].data.id < 5"),
+			Result:          &Result{body: []byte("{\"data\": {\"id\": 2}}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY].data.id < 5",
+		},
+		{
+			Name:            "body-jsonpath-complex-int-using-less-than-failure",
+			Condition:       Condition("[BODY].data.id < 5"),
+			Result:          &Result{body: []byte("{\"data\": {\"id\": 10}}")},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[BODY].data.id (10) < 5",
+		},
+		{
+			Name:            "body-len-array",
+			Condition:       Condition("len([BODY].data) == 3"),
+			Result:          &Result{body: []byte("{\"data\": [{\"id\": 1}, {\"id\": 2}, {\"id\": 3}]}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "len([BODY].data) == 3",
+		},
+		{
+			Name:            "body-len-array-invalid",
+			Condition:       Condition("len([BODY].data) == 8"),
+			Result:          &Result{body: []byte("{\"name\": \"john.doe\"}")},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "len([BODY].data) (INVALID) == 8",
+		},
+		{
+			Name:            "body-len-string",
+			Condition:       Condition("len([BODY].name) == 8"),
+			Result:          &Result{body: []byte("{\"name\": \"john.doe\"}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "len([BODY].name) == 8",
+		},
+		{
+			Name:            "body-pattern",
+			Condition:       Condition("[BODY] == pat(*john*)"),
+			Result:          &Result{body: []byte("{\"name\": \"john.doe\"}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY] == pat(*john*)",
+		},
+		{
+			Name:            "body-pattern-2",
+			Condition:       Condition("[BODY].name == pat(john*)"),
+			Result:          &Result{body: []byte("{\"name\": \"john.doe\"}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY].name == pat(john*)",
+		},
+		{
+			Name:            "body-pattern-failure",
+			Condition:       Condition("[BODY].name == pat(bob*)"),
+			Result:          &Result{body: []byte("{\"name\": \"john.doe\"}")},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[BODY].name (john.doe) == pat(bob*)",
+		},
+		{
+			Name:            "body-pattern-html",
+			Condition:       Condition("[BODY] == pat(*<div id=\"user\">john.doe</div>*)"),
+			Result:          &Result{body: []byte(`<!DOCTYPE html><html lang="en"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /></head><body><div id="user">john.doe</div></body></html>`)},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY] == pat(*<div id=\"user\">john.doe</div>*)",
+		},
+		{
+			Name:            "body-pattern-html-failure",
+			Condition:       Condition("[BODY] == pat(*<div id=\"user\">john.doe</div>*)"),
+			Result:          &Result{body: []byte(`<!DOCTYPE html><html lang="en"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /></head><body><div id="user">jane.doe</div></body></html>`)},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[BODY] (<!DOCTYPE html><html lang...(truncated)) == pat(*<div id=\"user\">john.doe</div>*)",
+		},
+		{
+			Name:            "body-pattern-html-failure-alt",
+			Condition:       Condition("pat(*<div id=\"user\">john.doe</div>*) == [BODY]"),
+			Result:          &Result{body: []byte(`<!DOCTYPE html><html lang="en"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /></head><body><div id="user">jane.doe</div></body></html>`)},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "pat(*<div id=\"user\">john.doe</div>*) == [BODY] (<!DOCTYPE html><html lang...(truncated))",
+		},
+		{
+			Name:            "ip-pattern",
+			Condition:       Condition("[IP] == pat(10.*)"),
+			Result:          &Result{IP: "10.0.0.0"},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[IP] == pat(10.*)",
+		},
+		{
+			Name:            "ip-pattern-failure",
+			Condition:       Condition("[IP] == pat(10.*)"),
+			Result:          &Result{IP: "255.255.255.255"},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[IP] (255.255.255.255) == pat(10.*)",
+		},
+		{
+			Name:            "status-pattern",
+			Condition:       Condition("[STATUS] == pat(4*)"),
+			Result:          &Result{HTTPStatus: 404},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[STATUS] == pat(4*)",
+		},
+		{
+			Name:            "status-pattern-failure",
+			Condition:       Condition("[STATUS] == pat(4*)"),
+			Result:          &Result{HTTPStatus: 200},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[STATUS] (200) == pat(4*)",
+		},
+		{
+			Name:            "body-any",
+			Condition:       Condition("[BODY].name == any(john.doe, jane.doe)"),
+			Result:          &Result{body: []byte("{\"name\": \"john.doe\"}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY].name == any(john.doe, jane.doe)",
+		},
+		{
+			Name:            "body-any-2",
+			Condition:       Condition("[BODY].name == any(john.doe, jane.doe)"),
+			Result:          &Result{body: []byte("{\"name\": \"jane.doe\"}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[BODY].name == any(john.doe, jane.doe)",
+		},
+		{
+			Name:            "body-any-failure",
+			Condition:       Condition("[BODY].name == any(john.doe, jane.doe)"),
+			Result:          &Result{body: []byte("{\"name\": \"bob\"}")},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[BODY].name (bob) == any(john.doe, jane.doe)",
+		},
+		{
+			Name:            "status-any",
+			Condition:       Condition("[STATUS] == any(200, 429)"),
+			Result:          &Result{HTTPStatus: 200},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[STATUS] == any(200, 429)",
+		},
+		{
+			Name:            "status-any-2",
+			Condition:       Condition("[STATUS] == any(200, 429)"),
+			Result:          &Result{HTTPStatus: 429},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[STATUS] == any(200, 429)",
+		},
+		{
+			Name:            "status-any-reverse",
+			Condition:       Condition("any(200, 429) == [STATUS]"),
+			Result:          &Result{HTTPStatus: 429},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "any(200, 429) == [STATUS]",
+		},
+		{
+			Name:            "status-any-failure",
+			Condition:       Condition("[STATUS] == any(200, 429)"),
+			Result:          &Result{HTTPStatus: 404},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[STATUS] (404) == any(200, 429)",
+		},
+		{
+			Name:                        "status-any-failure-but-dont-resolve",
+			Condition:                   Condition("[STATUS] == any(200, 429)"),
+			Result:                      &Result{HTTPStatus: 404},
+			DontResolveFailedConditions: true,
+			ExpectedSuccess:             false,
+			ExpectedOutput:              "[STATUS] == any(200, 429)",
+		},
+		{
+			Name:            "connected",
+			Condition:       Condition("[CONNECTED] == true"),
+			Result:          &Result{Connected: true},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[CONNECTED] == true",
+		},
+		{
+			Name:            "connected-failure",
+			Condition:       Condition("[CONNECTED] == true"),
+			Result:          &Result{Connected: false},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[CONNECTED] (false) == true",
+		},
+		{
+			Name:            "certificate-expiration-not-set",
+			Condition:       Condition("[CERTIFICATE_EXPIRATION] == 0"),
+			Result:          &Result{},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[CERTIFICATE_EXPIRATION] == 0",
+		},
+		{
+			Name:            "certificate-expiration-greater-than-numerical",
+			Condition:       Condition("[CERTIFICATE_EXPIRATION] > " + strconv.FormatInt((time.Hour*24*28).Milliseconds(), 10)),
+			Result:          &Result{CertificateExpiration: time.Hour * 24 * 60},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[CERTIFICATE_EXPIRATION] > 2419200000",
+		},
+		{
+			Name:            "certificate-expiration-greater-than-numerical-failure",
+			Condition:       Condition("[CERTIFICATE_EXPIRATION] > " + strconv.FormatInt((time.Hour*24*28).Milliseconds(), 10)),
+			Result:          &Result{CertificateExpiration: time.Hour * 24 * 14},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[CERTIFICATE_EXPIRATION] (1209600000) > 2419200000",
+		},
+		{
+			Name:            "certificate-expiration-greater-than-duration",
+			Condition:       Condition("[CERTIFICATE_EXPIRATION] > 12h"),
+			Result:          &Result{CertificateExpiration: 24 * time.Hour},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "[CERTIFICATE_EXPIRATION] > 12h",
+		},
+		{
+			Name:            "certificate-expiration-greater-than-duration",
+			Condition:       Condition("[CERTIFICATE_EXPIRATION] > 48h"),
+			Result:          &Result{CertificateExpiration: 24 * time.Hour},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "[CERTIFICATE_EXPIRATION] (86400000) > 48h (172800000)",
+		},
+		{
+			Name:            "has",
+			Condition:       Condition("has([BODY].errors) == false"),
+			Result:          &Result{body: []byte("{}")},
+			ExpectedSuccess: true,
+			ExpectedOutput:  "has([BODY].errors) == false",
+		},
+		{
+			Name:            "has-failure",
+			Condition:       Condition("has([BODY].errors) == false"),
+			Result:          &Result{body: []byte("{\"errors\": [\"1\"]}")},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "has([BODY].errors) (true) == false",
+		},
+		{
+			Name:                        "has-failure-but-dont-resolve",
+			Condition:                   Condition("has([BODY].errors) == false"),
+			Result:                      &Result{body: []byte("{\"errors\": [\"1\"]}")},
+			DontResolveFailedConditions: true,
+			ExpectedSuccess:             false,
+			ExpectedOutput:              "has([BODY].errors) == false",
+		},
+		{
+			Name:            "no-placeholders",
+			Condition:       Condition("1 == 2"),
+			Result:          &Result{},
+			ExpectedSuccess: false,
+			ExpectedOutput:  "1 == 2",
+		},
+	}
+	for _, scenario := range scenarios {
+		t.Run(scenario.Name, func(t *testing.T) {
+			scenario.Condition.evaluate(scenario.Result, scenario.DontResolveFailedConditions)
+			if scenario.Result.ConditionResults[0].Success != scenario.ExpectedSuccess {
+				t.Errorf("Condition '%s' should have been success=%v", scenario.Condition, scenario.ExpectedSuccess)
+			}
+			if scenario.Result.ConditionResults[0].Condition != scenario.ExpectedOutput {
+				t.Errorf("Condition '%s' should have resolved to '%s', got '%s'", scenario.Condition, scenario.ExpectedOutput, scenario.Result.ConditionResults[0].Condition)
+			}
+		})
 	}
 }
 
-func TestCondition_evaluateWithStatus(t *testing.T) {
-	condition := Condition("[STATUS] == 201")
-	result := &Result{HttpStatus: 201}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithStatusFailure(t *testing.T) {
-	condition := Condition("[STATUS] == 200")
-	result := &Result{HttpStatus: 500}
-	condition.evaluate(result)
-	if result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a failure", condition)
-	}
-}
-
-func TestCondition_evaluateWithStatusUsingLessThan(t *testing.T) {
-	condition := Condition("[STATUS] < 300")
-	result := &Result{HttpStatus: 201}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithStatusFailureUsingLessThan(t *testing.T) {
-	condition := Condition("[STATUS] < 300")
-	result := &Result{HttpStatus: 404}
-	condition.evaluate(result)
-	if result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a failure", condition)
-	}
-}
-
-func TestCondition_evaluateWithResponseTimeUsingLessThan(t *testing.T) {
-	condition := Condition("[RESPONSE_TIME] < 500")
-	result := &Result{Duration: time.Millisecond * 50}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithResponseTimeUsingGreaterThan(t *testing.T) {
-	condition := Condition("[RESPONSE_TIME] > 500")
-	result := &Result{Duration: time.Millisecond * 750}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithResponseTimeUsingGreaterThanOrEqualTo(t *testing.T) {
-	condition := Condition("[RESPONSE_TIME] >= 500")
-	result := &Result{Duration: time.Millisecond * 500}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithResponseTimeUsingLessThanOrEqualTo(t *testing.T) {
-	condition := Condition("[RESPONSE_TIME] <= 500")
-	result := &Result{Duration: time.Millisecond * 500}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithBody(t *testing.T) {
-	condition := Condition("[BODY] == test")
-	result := &Result{Body: []byte("test")}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithBodyJsonPath(t *testing.T) {
-	condition := Condition("[BODY].status == UP")
-	result := &Result{Body: []byte("{\"status\":\"UP\"}")}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithBodyJsonPathComplex(t *testing.T) {
-	condition := Condition("[BODY].data.name == john")
-	result := &Result{Body: []byte("{\"data\": {\"id\": 1, \"name\": \"john\"}}")}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithBodyJsonPathLongInt(t *testing.T) {
-	condition := Condition("[BODY].data.id == 1")
-	result := &Result{Body: []byte("{\"data\": {\"id\": 1}}")}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithBodyJsonPathComplexInt(t *testing.T) {
-	condition := Condition("[BODY].data[1].id == 2")
-	result := &Result{Body: []byte("{\"data\": [{\"id\": 1}, {\"id\": 2}, {\"id\": 3}]}")}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithBodyJsonPathComplexIntUsingGreaterThan(t *testing.T) {
-	condition := Condition("[BODY].data.id > 0")
-	result := &Result{Body: []byte("{\"data\": {\"id\": 1}}")}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithBodyJsonPathComplexIntFailureUsingGreaterThan(t *testing.T) {
-	condition := Condition("[BODY].data.id > 5")
-	result := &Result{Body: []byte("{\"data\": {\"id\": 1}}")}
-	condition.evaluate(result)
-	if result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a failure", condition)
-	}
-}
-
-func TestCondition_evaluateWithBodyJsonPathComplexIntUsingLessThan(t *testing.T) {
-	condition := Condition("[BODY].data.id < 5")
-	result := &Result{Body: []byte("{\"data\": {\"id\": 2}}")}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithBodyJsonPathComplexIntFailureUsingLessThan(t *testing.T) {
-	condition := Condition("[BODY].data.id < 5")
-	result := &Result{Body: []byte("{\"data\": {\"id\": 10}}")}
-	condition.evaluate(result)
-	if result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a failure", condition)
-	}
-}
-
-func TestCondition_evaluateWithBodySliceLength(t *testing.T) {
-	condition := Condition("len([BODY].data) == 3")
-	result := &Result{Body: []byte("{\"data\": [{\"id\": 1}, {\"id\": 2}, {\"id\": 3}]}")}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
-	}
-}
-
-func TestCondition_evaluateWithBodyStringLength(t *testing.T) {
-	condition := Condition("len([BODY].name) == 8")
-	result := &Result{Body: []byte("{\"name\": \"john.doe\"}")}
-	condition.evaluate(result)
-	if !result.ConditionResults[0].Success {
-		t.Errorf("Condition '%s' should have been a success", condition)
+func TestCondition_evaluateWithInvalidOperator(t *testing.T) {
+	condition := Condition("[STATUS] ? 201")
+	result := &Result{HTTPStatus: 201}
+	condition.evaluate(result, false)
+	if result.Success {
+		t.Error("condition was invalid, result should've been a failure")
+	}
+	if len(result.Errors) != 1 {
+		t.Error("condition was invalid, result should've had an error")
 	}
 }

core/dns.go

@@ -0,0 +1,86 @@
+package core
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/miekg/dns"
+)
+
+var (
+	// ErrDNSWithNoQueryName is the error with which gatus will panic if a dns is configured without query name
+	ErrDNSWithNoQueryName = errors.New("you must specify a query name for DNS")
+
+	// ErrDNSWithInvalidQueryType is the error with which gatus will panic if a dns is configured with invalid query type
+	ErrDNSWithInvalidQueryType = errors.New("invalid query type")
+)
+
+const (
+	dnsPort = 53
+)
+
+// DNS is the configuration for a Endpoint of type DNS
+type DNS struct {
+	// QueryType is the type for the DNS records like A, AAAA, CNAME...
+	QueryType string `yaml:"query-type"`
+
+	// QueryName is the query for DNS
+	QueryName string `yaml:"query-name"`
+}
+
+func (d *DNS) validateAndSetDefault() error {
+	if len(d.QueryName) == 0 {
+		return ErrDNSWithNoQueryName
+	}
+	if !strings.HasSuffix(d.QueryName, ".") {
+		d.QueryName += "."
+	}
+	if _, ok := dns.StringToType[d.QueryType]; !ok {
+		return ErrDNSWithInvalidQueryType
+	}
+	return nil
+}
+
+func (d *DNS) query(url string, result *Result) {
+	if !strings.Contains(url, ":") {
+		url = fmt.Sprintf("%s:%d", url, dnsPort)
+	}
+	queryType := dns.StringToType[d.QueryType]
+	c := new(dns.Client)
+	m := new(dns.Msg)
+	m.SetQuestion(d.QueryName, queryType)
+	r, _, err := c.Exchange(m, url)
+	if err != nil {
+		result.AddError(err.Error())
+		return
+	}
+	result.Connected = true
+	result.DNSRCode = dns.RcodeToString[r.Rcode]
+	for _, rr := range r.Answer {
+		switch rr.Header().Rrtype {
+		case dns.TypeA:
+			if a, ok := rr.(*dns.A); ok {
+				result.body = []byte(a.A.String())
+			}
+		case dns.TypeAAAA:
+			if aaaa, ok := rr.(*dns.AAAA); ok {
+				result.body = []byte(aaaa.AAAA.String())
+			}
+		case dns.TypeCNAME:
+			if cname, ok := rr.(*dns.CNAME); ok {
+				result.body = []byte(cname.Target)
+			}
+		case dns.TypeMX:
+			if mx, ok := rr.(*dns.MX); ok {
+				result.body = []byte(mx.Mx)
+			}
+		case dns.TypeNS:
+			if ns, ok := rr.(*dns.NS); ok {
+				result.body = []byte(ns.Ns)
+			}
+		default:
+			result.body = []byte("query type is not supported yet")
+		}
+	}
+}