Merge util.go into condition.go

Close #1: Add support for refresh interval

.github/workflows/build.yml

@@ -14,13 +14,13 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 5
     steps:
-      - name: Set up Go 1.14
+      - name: Set up Go 1.15
         uses: actions/setup-go@v1
         with:
-          go-version: 1.14
+          go-version: 1.15
         id: go
       - 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

README.md

@@ -1,13 +1,13 @@
 ![Gatus](static/logo-with-name.png)
 
 ![build](https://github.com/TwinProduction/gatus/workflows/build/badge.svg?branch=master)
-[![Go Report Card](https://goreportcard.com/badge/github.com/TwinProduction/gatus)](https://goreportcard.com/report/github.com/TwinProduction/gatus)
+[![Go Report Card](https://goreportcard.com/badge/github.com/TwinProduction/gatus?)](https://goreportcard.com/report/github.com/TwinProduction/gatus)
 [![Docker pulls](https://img.shields.io/docker/pulls/twinproduction/gatus.svg)](https://cloud.docker.com/repository/docker/twinproduction/gatus)
 
 A service health dashboard in Go that is meant to be used as a docker 
 image with a custom configuration file.
 
-I personally deploy it in my Kubernetes cluster and have it monitor the status of my
+I personally deploy it in my Kubernetes cluster and let it monitor the status of my
 core applications: https://status.twinnation.org/
 
 
@@ -17,6 +17,8 @@ core applications: https://status.twinnation.org/
 - [Usage](#usage)
   - [Configuration](#configuration)
   - [Conditions](#conditions)
+    - [Placeholders](#placeholders)
+    - [Functions](#functions)
   - [Alerting](#alerting)
     - [Configuring Slack alerts](#configuring-slack-alerts)
     - [Configuring PagerDuty alerts](#configuring-pagerduty-alerts)
@@ -27,6 +29,9 @@ core applications: https://status.twinnation.org/
 - [Using in Production](#using-in-production)
 - [FAQ](#faq)
   - [Sending a GraphQL request](#sending-a-graphql-request)
+  - [Recommended interval](#recommended-interval)
+  - [Default timeouts](#default-timeouts)
+  - [Monitoring a TCP service](#monitoring-a-tcp-service)
 
 
 ## Features
@@ -75,13 +80,14 @@ Note that you can also add environment variables in the configuration file (i.e.
 ### Configuration
 
 | Parameter                                | Description                                                                   | Default        |
-| ---------------------------------------- | ----------------------------------------------------------------------------- | -------------- |
+|:---------------------------------------- |:----------------------------------------------------------------------------- |:-------------- |
 | `debug`                                  | Whether to enable debug logs                                                  | `false`        |
 | `metrics`                                | Whether to expose metrics at /metrics                                         | `false`        |
 | `services`                               | List of services to monitor                                                   | Required `[]`  |
 | `services[].name`                        | Name of the service. Can be anything.                                         | Required `""`  |
 | `services[].url`                         | URL to send the request to                                                    | Required `""`  |
 | `services[].conditions`                  | Conditions used to determine the health of the service                        | `[]`           |
+| `services[].insecure`                    | Whether to skip verifying the server's certificate chain and host name        | `false`        |
 | `services[].interval`                    | Duration to wait between every status check                                   | `60s`          |
 | `services[].method`                      | Request method                                                                | `GET`          |
 | `services[].graphql`                     | Whether to wrap the body in a query param (`{"query":"$body"}`)               | `false`        |
@@ -114,23 +120,48 @@ Note that you can also add environment variables in the configuration file (i.e.
 Here are some examples of conditions you can use:
 
 | Condition                    | Description                                             | Passing values             | Failing values |
-| -----------------------------| ------------------------------------------------------- | -------------------------- | -------------- |
+|:-----------------------------|:------------------------------------------------------- |:-------------------------- | -------------- |
 | `[STATUS] == 200`            | Status must be equal to 200                             | 200                        | 201, 404, ...  |
 | `[STATUS] < 300`             | Status must lower than 300                              | 200, 201, 299              | 301, 302, ...  |
 | `[STATUS] <= 299`            | Status must be less than or equal to 299                | 200, 201, 299              | 301, 302, ...  |
 | `[STATUS] > 400`             | Status must be greater than 400                         | 401, 402, 403, 404         | 400, 200, ...  |
+| `[CONNECTED] == true`        | Connection to host must've been successful              | true, false                |  |
 | `[RESPONSE_TIME] < 500`      | Response time must be below 500ms                       | 100ms, 200ms, 300ms        | 500ms, 501ms   |
-| `[BODY] == 1`                | The body must be equal to 1                             | 1                          | Anything else  |
+| `[IP] == 127.0.0.1`          | Target IP must be 127.0.0.1                             | 127.0.0.1                  | 0.0.0.0        |
+| `[BODY] == 1`                | The body must be equal to 1                             | 1                          | `{}`, `2`, ... |
 | `[BODY].user.name == john`   | JSONPath value of `$.user.name` is equal to `john`      | `{"user":{"name":"john"}}` |  |
 | `[BODY].data[0].id == 1`     | JSONPath value of `$.data[0].id` is equal to 1          | `{"data":[{"id":1}]}`      |  |
+| `[BODY].age == [BODY].id`    | JSONPath value of `$.age` is equal JSONPath `$.id`      | `{"age":1,"id":1}`         |  |
 | `len([BODY].data) < 5`       | Array at JSONPath `$.data` has less than 5 elements     | `{"data":[{"id":1}]}`      |  |
 | `len([BODY].name) == 8`      | String at JSONPath `$.name` has a length of 8           | `{"name":"john.doe"}`      | `{"name":"bob"}` |
+| `[BODY].name == pat(john*)`  | String at JSONPath `$.name` matches pattern `john*`     | `{"name":"john.doe"}`      | `{"name":"bob"}` |
+
+
+#### Placeholders
+
+| Placeholder             | Description                                             | Example of resolved value |
+|:----------------------- |:------------------------------------------------------- |:------------------------- |
+| `[STATUS]`              | Resolves into the HTTP status of the request            | 404
+| `[RESPONSE_TIME]`       | Resolves into the response time the request took, in ms | 10
+| `[IP]`                  | Resolves into the IP of the target host                 | 192.168.0.232
+| `[BODY]`                | Resolves into the response body. Supports JSONPath.     | `{"name":"john.doe"}`
+| `[CONNECTED]`           | Resolves into whether a connection could be established | `true`
+
+
+#### Functions
+
+| Function   | Description                                                                                                      | Example                    |
+|:-----------|:---------------------------------------------------------------------------------------------------------------- |:-------------------------- |
+| `len`      | Returns the length of the object/slice. Works only with the `[BODY]` placeholder.                                | `len([BODY].username) > 8`
+| `pat`      | Specifies that the string passed as parameter should be evaluated as a pattern. Works only with `==` and `!=`.   | `[IP] == pat(192.168.*)`
+
+**NOTE**: Use `pat` only when you need to. `[STATUS] == pat(2*)` is a lot more expensive than `[STATUS] < 300`.
+
 
 
 ### Alerting
 
 
-
 #### Configuring Slack alerts
 
 ```yaml
@@ -139,8 +170,8 @@ alerting:
     webhook-url: "https://hooks.slack.com/services/**********/**********/**********"
 services:
   - name: twinnation
-    interval: 30s
     url: "https://twinnation.org/health"
+    interval: 30s
     alerts:
       - type: slack
         enabled: true
@@ -175,15 +206,15 @@ alerting:
     integration-key: "********************************"
 services:
   - name: twinnation
-    interval: 30s
     url: "https://twinnation.org/health"
+    interval: 30s
     alerts:
       - type: pagerduty
         enabled: true
         failure-threshold: 3
         success-threshold: 5
-        description: "healthcheck failed 3 times in a row"
         send-on-resolved: true
+        description: "healthcheck failed 3 times in a row"
     conditions:
       - "[STATUS] == 200"
       - "[BODY].status == UP"
@@ -208,8 +239,8 @@ services:
       - type: twilio
         enabled: true
         failure-threshold: 5
-        description: "healthcheck failed 5 times in a row"
         send-on-resolved: true
+        description: "healthcheck failed 5 times in a row"
     conditions:
       - "[STATUS] == 200"
       - "[BODY].status == UP"
@@ -245,8 +276,8 @@ alerting:
       }
 services:
   - name: twinnation
-    interval: 30s
     url: "https://twinnation.org/health"
+    interval: 30s
     alerts:
       - type: custom
         enabled: true
@@ -267,12 +298,12 @@ Other than using one of the examples provided in the `examples` folder, you can
 creating a configuration file - we'll call it `config.yaml` for this example - and running the following 
 command:
 ```
-docker run -p 8080:8080 --mount type=bind,source="$(pwd)"/test.yaml,target=/config/config.yaml --name gatus twinproduction/gatus
+docker run -p 8080:8080 --mount type=bind,source="$(pwd)"/config.yaml,target=/config/config.yaml --name gatus twinproduction/gatus
 ```
 
 If you're on Windows, replace `"$(pwd)"` by the absolute path to your current directory, e.g.:
 ```
-docker run -p 8080:8080 --mount type=bind,source=E:/Go/src/github.com/TwinProduction/gatus/test.yaml,target=/config/config.yaml --name gatus twinproduction/gatus
+docker run -p 8080:8080 --mount type=bind,source=C:/Users/Chris/Desktop/config.yaml,target=/config/config.yaml --name gatus twinproduction/gatus
 ```
 
 ## Running the tests
@@ -320,3 +351,60 @@ will send a `POST` request to `http://localhost:8080/playground` with the follow
 ```json
 {"query":"      {\n        user(gender: \"female\") {\n          id\n          name\n          gender\n          avatar\n        }\n      }"}
 ```
+
+
+### Recommended interval
+
+To ensure that Gatus provides reliable and accurate results (i.e. response time), Gatus only evaluates one service at a time. 
+In other words, even if you have multiple services with the exact same interval, they will not execute at the same time.
+
+You can test this yourself by running Gatus with several services configured with a very short, unrealistic interval, 
+such as 1ms. You'll notice that the response time does not fluctuate - that is because while services are evaluated on
+different goroutines, there's a global lock that prevents multiple services from running at the same time.
+
+Unfortunately, there is a drawback. If you have a lot of services, including some that are very slow or prone to time out (the default
+time out is 10s for HTTP and 5s for TCP), then it means that for the entire duration of the request, no other services can be evaluated.
+
+**This does mean that Gatus will be unable to evaluate the health of other services**. 
+The interval does not include the duration of the request itself, which means that if a service has an interval of 30s 
+and the request takes 2s to complete, the timestamp between two evaluations will be 32s, not 30s. 
+
+While this does not prevent Gatus' from performing health checks on all other services, it may cause Gatus to be unable 
+to respect the configured interval, for instance:
+- Service A has an interval of 5s, and times out after 10s to complete 
+- Service B has an interval of 5s, and takes 1ms to complete
+- Service B will be unable to run every 5s, because service A's health evaluation takes longer than its interval
+
+To sum it up, while Gatus can really handle any interval you throw at it, you're better off having slow requests with 
+higher interval.
+
+As a rule of the thumb, I personally set interval for more complex health checks to `5m` (5 minutes) and 
+simple health checks used for alerting (PagerDuty/Twilio) to `30s`.
+
+
+### Default timeouts
+
+| Protocol | Timeout |
+|:-------- |:------- |
+| HTTP     | 10s
+| TCP      | 5s
+
+
+### Monitoring a TCP service
+
+By prefixing `services[].url` with `tcp:\\`, you can monitor TCP services at a very basic level:
+
+```yaml
+  - name: redis
+    url: "tcp://127.0.0.1:6379"
+    interval: 30s
+    conditions:
+      - "[CONNECTED] == true"
+```
+
+Placeholders `[STATUS]` and `[BODY]` as well as the fields `services[].body`, `services[].insecure`, 
+`services[].headers`, `services[].method` and `services[].graphql` are not supported for TCP services.
+
+**NOTE**: `[CONNECTED] == true` does not guarantee that the service itself is healthy - it only guarantees that there's 
+something at the given address listening to the given port, and that a connection to that address was successfully 
+established.

alerting/provider/custom/custom.go

@@ -4,11 +4,14 @@ import (
 	"bytes"
 	"fmt"
 	"github.com/TwinProduction/gatus/client"
+	"github.com/TwinProduction/gatus/core"
 	"io/ioutil"
 	"net/http"
 	"strings"
 )
 
+// 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"`
@@ -16,10 +19,16 @@ type AlertProvider struct {
 	Headers map[string]string `yaml:"headers,omitempty"`
 }
 
+// IsValid returns whether the provider's configuration is valid
 func (provider *AlertProvider) IsValid() bool {
 	return len(provider.Url) > 0
 }
 
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *AlertProvider {
+	return provider
+}
+
 func (provider *AlertProvider) buildRequest(serviceName, alertDescription string, resolved bool) *http.Request {
 	body := provider.Body
 	providerUrl := provider.Url
@@ -64,7 +73,7 @@ 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)
+	response, err := client.GetHttpClient(false).Do(request)
 	if err != nil {
 		return nil, err
 	}

alerting/provider/pagerduty/pagerduty.go

@@ -6,16 +6,28 @@ import (
 	"github.com/TwinProduction/gatus/core"
 )
 
+// AlertProvider is the configuration necessary for sending an alert using PagerDuty
 type AlertProvider struct {
 	IntegrationKey string `yaml:"integration-key"`
 }
 
+// IsValid returns whether the provider's configuration is valid
 func (provider *AlertProvider) IsValid() bool {
 	return len(provider.IntegrationKey) == 32
 }
 
 // https://developer.pagerduty.com/docs/events-api-v2/trigger-events/
-func (provider *AlertProvider) ToCustomAlertProvider(eventAction, resolveKey string, service *core.Service, message string) *custom.AlertProvider {
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+	var message, eventAction, resolveKey string
+	if resolved {
+		message = fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.Description)
+		eventAction = "resolve"
+		resolveKey = alert.ResolveKey
+	} else {
+		message = fmt.Sprintf("TRIGGERED: %s - %s", service.Name, alert.Description)
+		eventAction = "trigger"
+		resolveKey = ""
+	}
 	return &custom.AlertProvider{
 		Url:    "https://events.pagerduty.com/v2/enqueue",
 		Method: "POST",

alerting/provider/provider.go

@@ -0,0 +1,15 @@
+package provider
+
+import (
+	"github.com/TwinProduction/gatus/alerting/provider/custom"
+	"github.com/TwinProduction/gatus/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 converts the provider into a custom.AlertProvider
+	ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider
+}

alerting/provider/slack/slack.go

@@ -6,14 +6,17 @@ import (
 	"github.com/TwinProduction/gatus/core"
 )
 
+// AlertProvider is the configuration necessary for sending an alert using Slack
 type AlertProvider struct {
 	WebhookUrl string `yaml:"webhook-url"`
 }
 
+// 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(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
 	var message string
 	var color string

alerting/provider/twilio/twilio.go

@@ -4,9 +4,11 @@ import (
 	"encoding/base64"
 	"fmt"
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
+	"github.com/TwinProduction/gatus/core"
 	"net/url"
 )
 
+// AlertProvider is the configuration necessary for sending an alert using Twilio
 type AlertProvider struct {
 	SID   string `yaml:"sid"`
 	Token string `yaml:"token"`
@@ -14,11 +16,19 @@ type AlertProvider struct {
 	To    string `yaml:"to"`
 }
 
+// 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(message string) *custom.AlertProvider {
+// ToCustomAlertProvider converts the provider into a custom.AlertProvider
+func (provider *AlertProvider) ToCustomAlertProvider(service *core.Service, alert *core.Alert, result *core.Result, resolved bool) *custom.AlertProvider {
+	var message string
+	if resolved {
+		message = fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.Description)
+	} else {
+		message = fmt.Sprintf("TRIGGERED: %s - %s", service.Name, alert.Description)
+	}
 	return &custom.AlertProvider{
 		Url:    fmt.Sprintf("https://api.twilio.com/2010-04-01/Accounts/%s/Messages.json", provider.SID),
 		Method: "POST",

client/client.go

@@ -1,19 +1,45 @@
 package client
 
 import (
+	"crypto/tls"
+	"net"
 	"net/http"
 	"time"
 )
 
 var (
-	client *http.Client
+	secureHttpClient   *http.Client
+	insecureHttpClient *http.Client
 )
 
-func GetHttpClient() *http.Client {
-	if client == nil {
-		client = &http.Client{
-			Timeout: time.Second * 10,
+func GetHttpClient(insecure bool) *http.Client {
+	if insecure {
+		if insecureHttpClient == nil {
+			insecureHttpClient = &http.Client{
+				Timeout: time.Second * 10,
+				Transport: &http.Transport{
+					TLSClientConfig: &tls.Config{
+						InsecureSkipVerify: true,
+					},
+				},
+			}
 		}
+		return insecureHttpClient
+	} else {
+		if secureHttpClient == nil {
+			secureHttpClient = &http.Client{
+				Timeout: time.Second * 10,
+			}
+		}
+		return secureHttpClient
 	}
-	return client
+}
+
+func CanCreateConnectionToTcpService(address string) bool {
+	conn, err := net.DialTimeout("tcp", address, 5*time.Second)
+	if err != nil {
+		return false
+	}
+	_ = conn.Close()
+	return true
 }

client/client_test.go

@@ -0,0 +1,28 @@
+package client
+
+import (
+	"testing"
+)
+
+func TestGetHttpClient(t *testing.T) {
+	if secureHttpClient != nil {
+		t.Error("secureHttpClient should've been nil since it hasn't been called a single time yet")
+	}
+	if insecureHttpClient != nil {
+		t.Error("insecureHttpClient should've been nil since it hasn't been called a single time yet")
+	}
+	_ = GetHttpClient(false)
+	if secureHttpClient == nil {
+		t.Error("secureHttpClient shouldn't have been nil, since it has been called once")
+	}
+	if insecureHttpClient != nil {
+		t.Error("insecureHttpClient should've been nil since it hasn't been called a single time yet")
+	}
+	_ = GetHttpClient(true)
+	if secureHttpClient == nil {
+		t.Error("secureHttpClient shouldn't have been nil, since it has been called once")
+	}
+	if insecureHttpClient == nil {
+		t.Error("insecureHttpClient shouldn't have been nil, since it has been called once")
+	}
+}

config.yaml

@@ -1,15 +1,15 @@
 metrics: true
 services:
   - name: twinnation
+    url: "https://twinnation.org/health"
     interval: 30s
-    url: https://twinnation.org/health
     conditions:
       - "[STATUS] == 200"
       - "[BODY].status == UP"
       - "[RESPONSE_TIME] < 1000"
   - name: cat-fact
-    interval: 1m
     url: "https://cat-fact.herokuapp.com/facts/random"
+    interval: 1m
     conditions:
       - "[STATUS] == 200"
       - "[BODY].deleted == false"

config/config.go

@@ -3,6 +3,7 @@ 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"
@@ -11,6 +12,8 @@ import (
 )
 
 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"
 )
 
@@ -21,6 +24,7 @@ var (
 	config                *Config
 )
 
+// Config is the main configuration structure
 type Config struct {
 	Metrics  bool             `yaml:"metrics"`
 	Debug    bool             `yaml:"debug"`
@@ -36,7 +40,7 @@ func Get() *Config {
 }
 
 func Load(configFile string) error {
-	log.Printf("[config][Load] Attempting to load config from configFile=%s", configFile)
+	log.Printf("[config][Load] Reading configuration from configFile=%s", configFile)
 	cfg, err := readConfigurationFile(configFile)
 	if err != nil {
 		if os.IsNotExist(err) {
@@ -75,13 +79,79 @@ func parseAndValidateConfigBytes(yamlBytes []byte) (config *Config, err error) {
 	// Parse configuration file
 	err = yaml.Unmarshal(yamlBytes, &config)
 	// Check if the configuration file at least has services.
-	if config == nil || len(config.Services) == 0 {
+	if config == nil || config.Services == nil || len(config.Services) == 0 {
 		err = ErrNoServiceInConfig
 	} else {
-		// Set the default values if they aren't set
-		for _, service := range config.Services {
-			service.Validate()
-		}
+		validateAlertingConfig(config)
+		validateServicesConfig(config)
 	}
 	return
 }
+
+func validateServicesConfig(config *Config) {
+	for _, service := range config.Services {
+		if config.Debug {
+			log.Printf("[config][validateServicesConfig] Validating service '%s'", service.Name)
+		}
+		service.ValidateAndSetDefaults()
+	}
+	log.Printf("[config][validateServicesConfig] Validated %d services", len(config.Services))
+}
+
+func validateAlertingConfig(config *Config) {
+	if config.Alerting == nil {
+		log.Printf("[config][validateAlertingConfig] Alerting is not configured")
+		return
+	}
+	alertTypes := []core.AlertType{
+		core.SlackAlert,
+		core.TwilioAlert,
+		core.PagerDutyAlert,
+		core.CustomAlert,
+	}
+	var validProviders, invalidProviders []core.AlertType
+	for _, alertType := range alertTypes {
+		alertProvider := GetAlertingProviderByAlertType(config, alertType)
+		if alertProvider != nil {
+			if alertProvider.IsValid() {
+				validProviders = append(validProviders, alertType)
+			} else {
+				log.Printf("[config][validateAlertingConfig] Ignoring provider=%s because configuration is invalid", alertType)
+				invalidProviders = append(invalidProviders, alertType)
+			}
+		} else {
+			invalidProviders = append(invalidProviders, alertType)
+		}
+	}
+	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/config_test.go

@@ -1,7 +1,6 @@
 package config
 
 import (
-	"fmt"
 	"github.com/TwinProduction/gatus/core"
 	"testing"
 	"time"
@@ -36,7 +35,6 @@ services:
 	if config.Services[1].Url != "https://api.github.com/healthz" {
 		t.Errorf("URL should have been %s", "https://api.github.com/healthz")
 	}
-	fmt.Println(config.Services[0].Interval)
 	if config.Services[0].Interval != 15*time.Second {
 		t.Errorf("Interval should have been %s", 15*time.Second)
 	}
@@ -123,6 +121,8 @@ func TestParseAndValidateConfigBytesWithAlerting(t *testing.T) {
 alerting:
   slack:
     webhook-url: "http://example.com"
+  pagerduty:
+    integration-key: "00000000000000000000000000000000"
 services:
   - name: twinnation
     url: https://twinnation.org/actuator/health
@@ -144,10 +144,19 @@ services:
 		t.Error("Metrics should've been false by default")
 	}
 	if config.Alerting == nil {
-		t.Fatal("config.AlertingConfig shouldn't have been nil")
+		t.Fatal("config.Alerting shouldn't have been nil")
+	}
+	if config.Alerting.Slack == nil || !config.Alerting.Slack.IsValid() {
+		t.Fatal("Slack alerting config should've been valid")
 	}
 	if config.Alerting.Slack.WebhookUrl != "http://example.com" {
-		t.Errorf("Slack webhook should've been %s, but was %s", "http://example.com", config.Alerting.Slack)
+		t.Errorf("Slack webhook should've been %s, but was %s", "http://example.com", config.Alerting.Slack.WebhookUrl)
+	}
+	if config.Alerting.PagerDuty == nil || !config.Alerting.PagerDuty.IsValid() {
+		t.Fatal("PagerDuty alerting config should've been valid")
+	}
+	if config.Alerting.PagerDuty.IntegrationKey != "00000000000000000000000000000000" {
+		t.Errorf("PagerDuty integration key should've been %s, but was %s", "00000000000000000000000000000000", config.Alerting.PagerDuty.IntegrationKey)
 	}
 	if len(config.Services) != 1 {
 		t.Error("There should've been 1 service")
@@ -180,3 +189,31 @@ services:
 		t.Errorf("The type of the alert should've been %s, but it was %s", "Healthcheck failed 7 times in a row", config.Services[0].Alerts[0].Description)
 	}
 }
+
+func TestParseAndValidateConfigBytesWithInvalidPagerDutyAlertingConfig(t *testing.T) {
+	config, err := parseAndValidateConfigBytes([]byte(`
+alerting:
+  pagerduty:
+    integration-key: "INVALID_KEY"
+services:
+  - name: twinnation
+    url: https://twinnation.org/actuator/health
+    conditions:
+      - "[STATUS] == 200"
+`))
+	if err != nil {
+		t.Error("No error should've been returned")
+	}
+	if config == nil {
+		t.Fatal("Config shouldn't have been nil")
+	}
+	if config.Alerting == nil {
+		t.Fatal("config.Alerting shouldn't have been nil")
+	}
+	if config.Alerting.PagerDuty == nil {
+		t.Fatal("PagerDuty alerting config shouldn't have been nil")
+	}
+	if config.Alerting.PagerDuty.IsValid() {
+		t.Fatal("PagerDuty alerting config should've been invalid")
+	}
+}

core/condition.go

@@ -2,23 +2,41 @@ package core
 
 import (
 	"fmt"
+	"github.com/TwinProduction/gatus/jsonpath"
+	"github.com/TwinProduction/gatus/pattern"
 	"log"
+	"strconv"
 	"strings"
 )
 
+const (
+	StatusPlaceholder       = "[STATUS]"
+	IPPlaceHolder           = "[IP]"
+	ResponseTimePlaceHolder = "[RESPONSE_TIME]"
+	BodyPlaceHolder         = "[BODY]"
+	ConnectedPlaceHolder    = "[CONNECTED]"
+
+	LengthFunctionPrefix  = "len("
+	PatternFunctionPrefix = "pat("
+	FunctionSuffix        = ")"
+
+	InvalidConditionElementSuffix = "(INVALID)"
+)
+
 type Condition string
 
+// evaluate the Condition with the Result of the health check
 func (c *Condition) evaluate(result *Result) bool {
 	condition := string(*c)
 	success := false
 	var resolvedCondition string
 	if strings.Contains(condition, "==") {
 		parts := sanitizeAndResolve(strings.Split(condition, "=="), result)
-		success = parts[0] == parts[1]
+		success = isEqual(parts[0], parts[1])
 		resolvedCondition = fmt.Sprintf("%v == %v", parts[0], parts[1])
 	} else if strings.Contains(condition, "!=") {
 		parts := sanitizeAndResolve(strings.Split(condition, "!="), result)
-		success = parts[0] != parts[1]
+		success = !isEqual(parts[0], parts[1])
 		resolvedCondition = fmt.Sprintf("%v != %v", parts[0], parts[1])
 	} else if strings.Contains(condition, "<=") {
 		parts := sanitizeAndResolveNumerical(strings.Split(condition, "<="), result)
@@ -49,3 +67,83 @@ func (c *Condition) evaluate(result *Result) bool {
 	result.ConditionResults = append(result.ConditionResults, &ConditionResult{Condition: conditionToDisplay, Success: success})
 	return success
 }
+
+// isEqual compares two strings.
+//
+// It also supports the pattern function. That is to say, if one of the strings starts with PatternFunctionPrefix
+// and ends with FunctionSuffix, it will be treated like a pattern.
+func isEqual(first, second string) bool {
+	var isFirstPattern, isSecondPattern bool
+	if strings.HasPrefix(first, PatternFunctionPrefix) && strings.HasSuffix(first, FunctionSuffix) {
+		isFirstPattern = true
+		first = strings.TrimSuffix(strings.TrimPrefix(first, PatternFunctionPrefix), FunctionSuffix)
+	}
+	if strings.HasPrefix(second, PatternFunctionPrefix) && strings.HasSuffix(second, FunctionSuffix) {
+		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)
+	} else {
+		return first == second
+	}
+}
+
+// sanitizeAndResolve sanitizes and resolves a list of element and returns the list of resolved elements
+func sanitizeAndResolve(list []string, result *Result) []string {
+	var sanitizedList []string
+	body := strings.TrimSpace(string(result.Body))
+	for _, element := range list {
+		element = strings.TrimSpace(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 ConnectedPlaceHolder:
+			element = strconv.FormatBool(result.Connected)
+		default:
+			// if contains the BodyPlaceHolder, then evaluate json path
+			if strings.Contains(element, BodyPlaceHolder) {
+				wantLength := false
+				if strings.HasPrefix(element, LengthFunctionPrefix) && strings.HasSuffix(element, FunctionSuffix) {
+					wantLength = true
+					element = strings.TrimSuffix(strings.TrimPrefix(element, LengthFunctionPrefix), FunctionSuffix)
+				}
+				resolvedElement, resolvedElementLength, err := jsonpath.Eval(strings.Replace(element, fmt.Sprintf("%s.", BodyPlaceHolder), "", 1), result.Body)
+				if err != nil {
+					result.Errors = append(result.Errors, err.Error())
+					element = fmt.Sprintf("%s %s", element, InvalidConditionElementSuffix)
+				} else {
+					if wantLength {
+						element = fmt.Sprintf("%d", resolvedElementLength)
+					} else {
+						element = resolvedElement
+					}
+				}
+			}
+		}
+		sanitizedList = append(sanitizedList, element)
+	}
+	return sanitizedList
+}
+
+func sanitizeAndResolveNumerical(list []string, result *Result) []int {
+	var sanitizedNumbers []int
+	sanitizedList := sanitizeAndResolve(list, result)
+	for _, element := range sanitizedList {
+		if number, err := strconv.Atoi(element); err != nil {
+			// Default to 0 if the string couldn't be converted to an integer
+			sanitizedNumbers = append(sanitizedNumbers, 0)
+		} else {
+			sanitizedNumbers = append(sanitizedNumbers, number)
+		}
+	}
+	return sanitizedNumbers
+}

core/condition_test.go

@@ -113,6 +113,24 @@ func TestCondition_evaluateWithBodyJsonPathComplex(t *testing.T) {
 	}
 }
 
+func TestCondition_evaluateWithBodyJsonPathDoublePlaceholders(t *testing.T) {
+	condition := Condition("[BODY].user.firstName != [BODY].user.lastName")
+	result := &Result{Body: []byte("{\"user\": {\"firstName\": \"john\", \"lastName\": \"doe\"}}")}
+	condition.evaluate(result)
+	if !result.ConditionResults[0].Success {
+		t.Errorf("Condition '%s' should have been a success", condition)
+	}
+}
+
+func TestCondition_evaluateWithBodyJsonPathDoublePlaceholdersFailure(t *testing.T) {
+	condition := Condition("[BODY].user.firstName == [BODY].user.lastName")
+	result := &Result{Body: []byte("{\"user\": {\"firstName\": \"john\", \"lastName\": \"doe\"}}")}
+	condition.evaluate(result)
+	if result.ConditionResults[0].Success {
+		t.Errorf("Condition '%s' should have been a failure", condition)
+	}
+}
+
 func TestCondition_evaluateWithBodyJsonPathLongInt(t *testing.T) {
 	condition := Condition("[BODY].data.id == 1")
 	result := &Result{Body: []byte("{\"data\": {\"id\": 1}}")}
@@ -184,3 +202,84 @@ func TestCondition_evaluateWithBodyStringLength(t *testing.T) {
 		t.Errorf("Condition '%s' should have been a success", condition)
 	}
 }
+
+func TestCondition_evaluateWithBodyStringPattern(t *testing.T) {
+	condition := Condition("[BODY].name == pat(*ohn*)")
+	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_evaluateWithBodyStringPatternFailure(t *testing.T) {
+	condition := Condition("[BODY].name == pat(bob*)")
+	result := &Result{Body: []byte("{\"name\": \"john.doe\"}")}
+	condition.evaluate(result)
+	if result.ConditionResults[0].Success {
+		t.Errorf("Condition '%s' should have been a failure", condition)
+	}
+}
+
+func TestCondition_evaluateWithBodyPatternFailure(t *testing.T) {
+	condition := Condition("[BODY] == pat(*john*)")
+	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_evaluateWithIPPattern(t *testing.T) {
+	condition := Condition("[IP] == pat(10.*)")
+	result := &Result{Ip: "10.0.0.0"}
+	condition.evaluate(result)
+	if !result.ConditionResults[0].Success {
+		t.Errorf("Condition '%s' should have been a success", condition)
+	}
+}
+
+func TestCondition_evaluateWithIPPatternFailure(t *testing.T) {
+	condition := Condition("[IP] == pat(10.*)")
+	result := &Result{Ip: "255.255.255.255"}
+	condition.evaluate(result)
+	if result.ConditionResults[0].Success {
+		t.Errorf("Condition '%s' should have been a failure", condition)
+	}
+}
+
+func TestCondition_evaluateWithStatusPattern(t *testing.T) {
+	condition := Condition("[STATUS] == pat(4*)")
+	result := &Result{HttpStatus: 404}
+	condition.evaluate(result)
+	if !result.ConditionResults[0].Success {
+		t.Errorf("Condition '%s' should have been a success", condition)
+	}
+}
+
+func TestCondition_evaluateWithStatusPatternFailure(t *testing.T) {
+	condition := Condition("[STATUS] != pat(4*)")
+	result := &Result{HttpStatus: 404}
+	condition.evaluate(result)
+	if result.ConditionResults[0].Success {
+		t.Errorf("Condition '%s' should have been a failure", condition)
+	}
+}
+
+func TestCondition_evaluateWithConnected(t *testing.T) {
+	condition := Condition("[CONNECTED] == true")
+	result := &Result{Connected: true}
+	condition.evaluate(result)
+	if !result.ConditionResults[0].Success {
+		t.Errorf("Condition '%s' should have been a success", condition)
+	}
+}
+
+func TestCondition_evaluateWithConnectedFailure(t *testing.T) {
+	condition := Condition("[CONNECTED] == true")
+	result := &Result{Connected: false}
+	condition.evaluate(result)
+	if result.ConditionResults[0].Success {
+		t.Errorf("Condition '%s' should have been a failure", condition)
+	}
+}

core/service.go

@@ -9,6 +9,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"strings"
 	"time"
 )
 
@@ -46,11 +47,15 @@ type Service struct {
 	// Alerts is the alerting configuration for the service in case of failure
 	Alerts []*Alert `yaml:"alerts"`
 
+	// Insecure is whether to skip verifying the server's certificate chain and host name
+	Insecure bool `yaml:"insecure,omitempty"`
+
 	NumberOfFailuresInARow  int
 	NumberOfSuccessesInARow int
 }
 
-func (service *Service) Validate() {
+// ValidateAndSetDefaults validates the service's configuration and sets the default value of fields that have one
+func (service *Service) ValidateAndSetDefaults() {
 	// Set default values
 	if service.Interval == 0 {
 		service.Interval = 1 * time.Minute
@@ -83,7 +88,8 @@ func (service *Service) Validate() {
 	}
 }
 
-func (service *Service) EvaluateConditions() *Result {
+// EvaluateHealth sends a request to the service's URL and evaluates the conditions of the service.
+func (service *Service) EvaluateHealth() *Result {
 	result := &Result{Success: true, Errors: []string{}}
 	service.getIp(result)
 	if len(result.Errors) == 0 {
@@ -131,19 +137,30 @@ func (service *Service) getIp(result *Result) {
 }
 
 func (service *Service) call(result *Result) {
-	request := service.buildRequest()
-	startTime := time.Now()
-	response, err := client.GetHttpClient().Do(request)
-	if err != nil {
-		result.Duration = time.Since(startTime)
-		result.Errors = append(result.Errors, err.Error())
-		return
+	isServiceTcp := strings.HasPrefix(service.Url, "tcp://")
+	var request *http.Request
+	var response *http.Response
+	var err error
+	if !isServiceTcp {
+		request = service.buildRequest()
 	}
-	result.Duration = time.Since(startTime)
-	result.HttpStatus = response.StatusCode
-	result.Body, err = ioutil.ReadAll(response.Body)
-	if err != nil {
-		result.Errors = append(result.Errors, err.Error())
+	startTime := time.Now()
+	if isServiceTcp {
+		result.Connected = client.CanCreateConnectionToTcpService(strings.TrimPrefix(service.Url, "tcp://"))
+		result.Duration = time.Since(startTime)
+	} else {
+		response, err = client.GetHttpClient(service.Insecure).Do(request)
+		result.Duration = time.Since(startTime)
+		if err != nil {
+			result.Errors = append(result.Errors, err.Error())
+			return
+		}
+		result.HttpStatus = response.StatusCode
+		result.Connected = response.StatusCode > 0
+		result.Body, err = ioutil.ReadAll(response.Body)
+		if err != nil {
+			result.Errors = append(result.Errors, err.Error())
+		}
 	}
 }
 

core/service_test.go

@@ -4,33 +4,39 @@ import (
 	"testing"
 )
 
-func TestIntegrationEvaluateConditions(t *testing.T) {
+func TestIntegrationEvaluateHealth(t *testing.T) {
 	condition := Condition("[STATUS] == 200")
 	service := Service{
 		Name:       "TwiNNatioN",
 		Url:        "https://twinnation.org/health",
 		Conditions: []*Condition{&condition},
 	}
-	result := service.EvaluateConditions()
+	result := service.EvaluateHealth()
 	if !result.ConditionResults[0].Success {
 		t.Errorf("Condition '%s' should have been a success", condition)
 	}
+	if !result.Connected {
+		t.Error("Because the connection has been established, result.Connected should've been true")
+	}
 	if !result.Success {
 		t.Error("Because all conditions passed, this should have been a success")
 	}
 }
 
-func TestIntegrationEvaluateConditionsWithFailure(t *testing.T) {
+func TestIntegrationEvaluateHealthWithFailure(t *testing.T) {
 	condition := Condition("[STATUS] == 500")
 	service := Service{
 		Name:       "TwiNNatioN",
 		Url:        "https://twinnation.org/health",
 		Conditions: []*Condition{&condition},
 	}
-	result := service.EvaluateConditions()
+	result := service.EvaluateHealth()
 	if result.ConditionResults[0].Success {
 		t.Errorf("Condition '%s' should have been a failure", condition)
 	}
+	if !result.Connected {
+		t.Error("Because the connection has been established, result.Connected should've been true")
+	}
 	if result.Success {
 		t.Error("Because one of the conditions failed, success should have been false")
 	}

core/types.go

@@ -9,16 +9,37 @@ type HealthStatus struct {
 	Message string `json:"message,omitempty"`
 }
 
+// Result of the evaluation of a Service
 type Result struct {
-	HttpStatus       int                `json:"status"`
-	Body             []byte             `json:"-"`
-	Hostname         string             `json:"hostname"`
-	Ip               string             `json:"-"`
-	Duration         time.Duration      `json:"duration"`
-	Errors           []string           `json:"errors"`
+	// HttpStatus is the HTTP response status code
+	HttpStatus int `json:"status"`
+
+	// Body is the response body
+	Body []byte `json:"-"`
+
+	// Hostname extracted from the Service Url
+	Hostname string `json:"hostname"`
+
+	// Ip resolved from the Service Url
+	Ip string `json:"-"`
+
+	// Connected whether a connection to the host was established successfully
+	Connected bool `json:"-"`
+
+	// Duration time that the request took
+	Duration time.Duration `json:"duration"`
+
+	// Errors encountered during the evaluation of the service's health
+	Errors []string `json:"errors"`
+
+	// ConditionResults results of the service's conditions
 	ConditionResults []*ConditionResult `json:"condition-results"`
-	Success          bool               `json:"success"`
-	Timestamp        time.Time          `json:"timestamp"`
+
+	// Success whether the result signifies a success or not
+	Success bool `json:"success"`
+
+	// Timestamp when the request was sent
+	Timestamp time.Time `json:"timestamp"`
 }
 
 type ConditionResult struct {

core/util.go

@@ -1,74 +0,0 @@
-package core
-
-import (
-	"fmt"
-	"github.com/TwinProduction/gatus/jsonpath"
-	"strconv"
-	"strings"
-)
-
-const (
-	StatusPlaceholder       = "[STATUS]"
-	IPPlaceHolder           = "[IP]"
-	ResponseTimePlaceHolder = "[RESPONSE_TIME]"
-	BodyPlaceHolder         = "[BODY]"
-
-	LengthFunctionPrefix = "len("
-	FunctionSuffix       = ")"
-
-	InvalidConditionElementSuffix = "(INVALID)"
-)
-
-func sanitizeAndResolve(list []string, result *Result) []string {
-	var sanitizedList []string
-	body := strings.TrimSpace(string(result.Body))
-	for _, element := range list {
-		element = strings.TrimSpace(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
-		default:
-			// if starts with BodyPlaceHolder, then evaluate json path
-			if strings.Contains(element, BodyPlaceHolder) {
-				wantLength := false
-				if strings.HasPrefix(element, LengthFunctionPrefix) && strings.HasSuffix(element, FunctionSuffix) {
-					wantLength = true
-					element = strings.TrimSuffix(strings.TrimPrefix(element, LengthFunctionPrefix), FunctionSuffix)
-				}
-				resolvedElement, resolvedElementLength, err := jsonpath.Eval(strings.Replace(element, fmt.Sprintf("%s.", BodyPlaceHolder), "", 1), result.Body)
-				if err != nil {
-					result.Errors = append(result.Errors, err.Error())
-					element = fmt.Sprintf("%s %s", element, InvalidConditionElementSuffix)
-				} else {
-					if wantLength {
-						element = fmt.Sprintf("%d", resolvedElementLength)
-					} else {
-						element = resolvedElement
-					}
-				}
-			}
-		}
-		sanitizedList = append(sanitizedList, element)
-	}
-	return sanitizedList
-}
-
-func sanitizeAndResolveNumerical(list []string, result *Result) []int {
-	var sanitizedNumbers []int
-	sanitizedList := sanitizeAndResolve(list, result)
-	for _, element := range sanitizedList {
-		if number, err := strconv.Atoi(element); err != nil {
-			// Default to 0 if the string couldn't be converted to an integer
-			sanitizedNumbers = append(sanitizedNumbers, 0)
-		} else {
-			sanitizedNumbers = append(sanitizedNumbers, number)
-		}
-	}
-	return sanitizedNumbers
-}

example/kubernetes/gatus.yaml

@@ -49,10 +49,10 @@ spec:
               protocol: TCP
           resources:
             limits:
-              cpu: 50m
+              cpu: 200m
               memory: 50M
             requests:
-              cpu: 20m
+              cpu: 50m
               memory: 20M
           volumeMounts:
             - mountPath: /config

pattern/pattern.go

@@ -0,0 +1,12 @@
+package pattern
+
+import "path/filepath"
+
+// Match checks whether a string matches a pattern
+func Match(pattern, s string) bool {
+	if pattern == "*" {
+		return true
+	}
+	matched, _ := filepath.Match(pattern, s)
+	return matched
+}

pattern/pattern_test.go

@@ -0,0 +1,37 @@
+package pattern
+
+import "testing"
+
+func TestMatch(t *testing.T) {
+	testMatch(t, "*", "livingroom_123", true)
+	testMatch(t, "**", "livingroom_123", true)
+	testMatch(t, "living*", "livingroom_123", true)
+	testMatch(t, "*living*", "livingroom_123", true)
+	testMatch(t, "*123", "livingroom_123", true)
+	testMatch(t, "*_*", "livingroom_123", true)
+	testMatch(t, "living*_*3", "livingroom_123", true)
+	testMatch(t, "living*room_*3", "livingroom_123", true)
+	testMatch(t, "living*room_*3", "livingroom_123", true)
+	testMatch(t, "*vin*om*2*", "livingroom_123", true)
+	testMatch(t, "livingroom_123", "livingroom_123", true)
+	testMatch(t, "*livingroom_123*", "livingroom_123", true)
+	testMatch(t, "livingroom", "livingroom_123", false)
+	testMatch(t, "livingroom123", "livingroom_123", false)
+	testMatch(t, "what", "livingroom_123", false)
+	testMatch(t, "*what*", "livingroom_123", false)
+	testMatch(t, "*.*", "livingroom_123", false)
+	testMatch(t, "room*123", "livingroom_123", false)
+}
+
+func testMatch(t *testing.T, pattern, key string, expectedToMatch bool) {
+	matched := Match(pattern, key)
+	if expectedToMatch {
+		if !matched {
+			t.Errorf("%s should've matched pattern '%s'", key, pattern)
+		}
+	} else {
+		if matched {
+			t.Errorf("%s shouldn't have matched pattern '%s'", key, pattern)
+		}
+	}
+}

static/index.html

@@ -90,6 +90,15 @@
 		#social img:hover {
 			opacity: 1;
 		}
+		#settings {
+			position: fixed;
+			left: 5px;
+			bottom: 5px;
+			padding: 5px;
+		}
+		#settings select:focus {
+			box-shadow: none;
+		}
 	</style>
 </head>
 <body>
@@ -128,9 +137,26 @@
 		</a>
 	</div>
 
+	<div id="settings">
+		<div class="input-group input-group-sm">
+			<div class="input-group-prepend">
+				<div class="input-group-text">&#x21bb;</div>
+			</div>
+			<select class="form-control form-control-sm" id="refresh-rate">
+				<option value="10">10s</option>
+				<option value="30" selected>30s</option>
+				<option value="60">1m</option>
+				<option value="120">2m</option>
+				<option value="300">5m</option>
+				<option value="600">10m</option>
+			</select>
+		</div>
+	</div>
+
 	<script>
 		let serviceStatuses = {};
 		let timerHandler = 0;
+		let refreshIntervalHandler = 0;
 		let userClickedStatus = false;
 
 		function showTooltip(serviceName, index, element) {
@@ -291,10 +317,19 @@
 				.replace(/'/g, '&apos;');
 		}
 
-		refreshResults();
-		setInterval(function() {
+		function setRefreshInterval(seconds) {
 			refreshResults();
-		}, 30000);
+			refreshIntervalHandler = setInterval(function() {
+				refreshResults();
+			}, seconds * 1000)
+		}
+
+		$("#refresh-rate").change(function() {
+			clearInterval(refreshIntervalHandler);
+			setRefreshInterval($(this).val())
+		});
+		setRefreshInterval(30);
+		$("#refresh-rate").val(30);
 	</script>
 </body>
 </html>

watchdog/alerting.go

@@ -2,8 +2,6 @@ package watchdog
 
 import (
 	"encoding/json"
-	"fmt"
-	"github.com/TwinProduction/gatus/alerting/provider/custom"
 	"github.com/TwinProduction/gatus/config"
 	"github.com/TwinProduction/gatus/core"
 	"log"
@@ -32,46 +30,20 @@ func handleAlertsToTrigger(service *core.Service, result *core.Result, cfg *conf
 		}
 		if alert.Triggered {
 			if cfg.Debug {
-				log.Printf("[watchdog][handleAlertsToTrigger] Alert with description='%s' has already been triggered, skipping", alert.Description)
+				log.Printf("[watchdog][handleAlertsToTrigger] Alert with description='%s' has already been TRIGGERED, skipping", alert.Description)
 			}
 			continue
 		}
-		var alertProvider *custom.AlertProvider
-		if alert.Type == core.SlackAlert {
-			if cfg.Alerting.Slack != nil && cfg.Alerting.Slack.IsValid() {
-				log.Printf("[watchdog][handleAlertsToTrigger] Sending Slack alert because alert with description='%s' has been triggered", alert.Description)
-				alertProvider = cfg.Alerting.Slack.ToCustomAlertProvider(service, alert, result, false)
-			} else {
-				log.Printf("[watchdog][handleAlertsToTrigger] Not sending Slack alert despite being triggered, because there is no Slack webhook configured")
-			}
-		} else if alert.Type == core.PagerDutyAlert {
-			if cfg.Alerting.PagerDuty != nil && cfg.Alerting.PagerDuty.IsValid() {
-				log.Printf("[watchdog][handleAlertsToTrigger] Sending PagerDuty alert because alert with description='%s' has been triggered", alert.Description)
-				alertProvider = cfg.Alerting.PagerDuty.ToCustomAlertProvider("trigger", "", service, fmt.Sprintf("TRIGGERED: %s - %s", service.Name, alert.Description))
-			} else {
-				log.Printf("[watchdog][handleAlertsToTrigger] Not sending PagerDuty alert despite being triggered, because PagerDuty isn't configured properly")
-			}
-		} else if alert.Type == core.TwilioAlert {
-			if cfg.Alerting.Twilio != nil && cfg.Alerting.Twilio.IsValid() {
-				log.Printf("[watchdog][handleAlertsToTrigger] Sending Twilio alert because alert with description='%s' has been triggered", alert.Description)
-				alertProvider = cfg.Alerting.Twilio.ToCustomAlertProvider(fmt.Sprintf("TRIGGERED: %s - %s", service.Name, alert.Description))
-			} else {
-				log.Printf("[watchdog][handleAlertsToTrigger] Not sending Twilio alert despite being triggered, because Twilio config settings missing")
-			}
-		} else if alert.Type == core.CustomAlert {
-			if cfg.Alerting.Custom != nil && cfg.Alerting.Custom.IsValid() {
-				log.Printf("[watchdog][handleAlertsToTrigger] Sending custom alert because alert with description='%s' has been triggered", alert.Description)
-				alertProvider = cfg.Alerting.Custom
-			} else {
-				log.Printf("[watchdog][handleAlertsToTrigger] Not sending custom alert despite being triggered, because there is no custom url configured")
-			}
-		}
-		if alertProvider != nil {
+		alertProvider := config.GetAlertingProviderByAlertType(cfg, alert.Type)
+		if alertProvider != nil && alertProvider.IsValid() {
+			log.Printf("[watchdog][handleAlertsToTrigger] Sending %s alert because alert with description='%s' has been TRIGGERED", alert.Type, alert.Description)
+			customAlertProvider := alertProvider.ToCustomAlertProvider(service, alert, result, false)
 			// TODO: retry on error
 			var err error
+			// We need to extract the DedupKey from PagerDuty's response
 			if alert.Type == core.PagerDutyAlert {
 				var body []byte
-				body, err = alertProvider.Send(service.Name, alert.Description, true)
+				body, err = customAlertProvider.Send(service.Name, alert.Description, false)
 				if err == nil {
 					var response pagerDutyResponse
 					err = json.Unmarshal(body, &response)
@@ -82,13 +54,17 @@ func handleAlertsToTrigger(service *core.Service, result *core.Result, cfg *conf
 					}
 				}
 			} else {
-				_, err = alertProvider.Send(service.Name, alert.Description, false)
+				// All other alert types don't need to extract anything from the body, so we can just send the request right away
+				_, err = customAlertProvider.Send(service.Name, alert.Description, false)
 			}
 			if err != nil {
 				log.Printf("[watchdog][handleAlertsToTrigger] Ran into error sending an alert: %s", err.Error())
 			} else {
 				alert.Triggered = true
 			}
+
+		} else {
+			log.Printf("[watchdog][handleAlertsToResolve] Not sending alert of type=%s despite being TRIGGERED, because the provider wasn't configured properly", alert.Type)
 		}
 	}
 }
@@ -103,44 +79,12 @@ func handleAlertsToResolve(service *core.Service, result *core.Result, cfg *conf
 		if !alert.SendOnResolved {
 			continue
 		}
-		var alertProvider *custom.AlertProvider
-		if alert.Type == core.SlackAlert {
-			if cfg.Alerting.Slack != nil && cfg.Alerting.Slack.IsValid() {
-				log.Printf("[watchdog][handleAlertsToResolve] Sending Slack alert because alert with description='%s' has been resolved", alert.Description)
-				alertProvider = cfg.Alerting.Slack.ToCustomAlertProvider(service, alert, result, true)
-			} else {
-				log.Printf("[watchdog][handleAlertsToResolve] Not sending Slack alert despite being resolved, because there is no Slack webhook configured")
-			}
-		} else if alert.Type == core.PagerDutyAlert {
-			if cfg.Alerting.PagerDuty != nil && cfg.Alerting.PagerDuty.IsValid() {
-				log.Printf("[watchdog][handleAlertsToResolve] Sending PagerDuty alert because alert with description='%s' has been resolved", alert.Description)
-				alertProvider = cfg.Alerting.PagerDuty.ToCustomAlertProvider("resolve", alert.ResolveKey, service, fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.Description))
-			} else {
-				log.Printf("[watchdog][handleAlertsToResolve] Not sending PagerDuty alert despite being resolved, because PagerDuty isn't configured properly")
-			}
-		} else if alert.Type == core.TwilioAlert {
-			if cfg.Alerting.Twilio != nil && cfg.Alerting.Twilio.IsValid() {
-				log.Printf("[watchdog][handleAlertsToResolve] Sending Twilio alert because alert with description='%s' has been resolved", alert.Description)
-				alertProvider = cfg.Alerting.Twilio.ToCustomAlertProvider(fmt.Sprintf("RESOLVED: %s - %s", service.Name, alert.Description))
-			} else {
-				log.Printf("[watchdog][handleAlertsToResolve] Not sending Twilio alert despite being resolved, because Twilio isn't configured properly")
-			}
-		} else if alert.Type == core.CustomAlert {
-			if cfg.Alerting.Custom != nil && cfg.Alerting.Custom.IsValid() {
-				log.Printf("[watchdog][handleAlertsToResolve] Sending custom alert because alert with description='%s' has been resolved", alert.Description)
-				alertProvider = &custom.AlertProvider{
-					Url:     cfg.Alerting.Custom.Url,
-					Method:  cfg.Alerting.Custom.Method,
-					Body:    cfg.Alerting.Custom.Body,
-					Headers: cfg.Alerting.Custom.Headers,
-				}
-			} else {
-				log.Printf("[watchdog][handleAlertsToResolve] Not sending custom alert despite being resolved, because the custom provider isn't configured properly")
-			}
-		}
-		if alertProvider != nil {
+		alertProvider := config.GetAlertingProviderByAlertType(cfg, alert.Type)
+		if alertProvider != nil && alertProvider.IsValid() {
+			log.Printf("[watchdog][handleAlertsToResolve] Sending %s alert because alert with description='%s' has been RESOLVED", alert.Type, alert.Description)
+			customAlertProvider := alertProvider.ToCustomAlertProvider(service, alert, result, true)
 			// TODO: retry on error
-			_, err := alertProvider.Send(service.Name, alert.Description, true)
+			_, err := customAlertProvider.Send(service.Name, alert.Description, true)
 			if err != nil {
 				log.Printf("[watchdog][handleAlertsToResolve] Ran into error sending an alert: %s", err.Error())
 			} else {
@@ -148,6 +92,8 @@ func handleAlertsToResolve(service *core.Service, result *core.Result, cfg *conf
 					alert.ResolveKey = ""
 				}
 			}
+		} else {
+			log.Printf("[watchdog][handleAlertsToResolve] Not sending alert of type=%s despite being RESOLVED, because the provider wasn't configured properly", alert.Type)
 		}
 	}
 	service.NumberOfFailuresInARow = 0

watchdog/watchdog.go

@@ -50,7 +50,7 @@ func monitor(service *core.Service) {
 		if cfg.Debug {
 			log.Printf("[watchdog][monitor] Monitoring serviceName=%s", service.Name)
 		}
-		result := service.EvaluateConditions()
+		result := service.EvaluateHealth()
 		metric.PublishMetricsForService(service, result)
 		serviceResultsMutex.Lock()
 		serviceResults[service.Name] = append(serviceResults[service.Name], result)