Close #48: Implement Discord alerting providers

alerting/config.go

@@ -2,6 +2,7 @@ package alerting
 
 import (
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
+	"github.com/TwinProduction/gatus/alerting/provider/discord"
 	"github.com/TwinProduction/gatus/alerting/provider/mattermost"
 	"github.com/TwinProduction/gatus/alerting/provider/messagebird"
 	"github.com/TwinProduction/gatus/alerting/provider/pagerduty"
@@ -11,8 +12,11 @@ import (
 
 // Config is the configuration for alerting providers
 type Config struct {
-	// Slack is the configuration for the slack alerting provider
-	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"`
@@ -20,12 +24,12 @@ type Config struct {
 	// Messagebird is the configuration for the messagebird alerting provider
 	Messagebird *messagebird.AlertProvider `yaml:"messagebird"`
 
-	// Pagerduty is the configuration for the pagerduty alerting provider
+	// PagerDuty is the configuration for the pagerduty alerting provider
 	PagerDuty *pagerduty.AlertProvider `yaml:"pagerduty"`
 
+	// Slack is the configuration for the slack alerting provider
+	Slack *slack.AlertProvider `yaml:"slack"`
+
 	// Twilio is the configuration for the twilio alerting provider
 	Twilio *twilio.AlertProvider `yaml:"twilio"`
-
-	// Custom is the configuration for the custom alerting provider
-	Custom *custom.AlertProvider `yaml:"custom"`
 }

alerting/provider/discord/discord.go

@@ -0,0 +1,63 @@
+package discord
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/TwinProduction/gatus/alerting/provider/custom"
+	"github.com/TwinProduction/gatus/core"
+)
+
+// AlertProvider is the configuration necessary for sending an alert using Discord
+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, 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", service.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", service.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)
+	}
+	return &custom.AlertProvider{
+		URL:    provider.WebhookURL,
+		Method: http.MethodPost,
+		Body: fmt.Sprintf(`{
+  "content": "",
+  "embeds": [
+    {
+      "title": ":helmet_with_white_cross: Gatus",
+      "description": "%s:\n> %s",
+      "color": %d,
+      "fields": [
+        {
+          "name": "Condition results",
+          "value": "%s",
+          "inline": false
+        }
+      ]
+    }
+  ]
+}`, message, alert.Description, colorCode, results),
+		Headers: map[string]string{"Content-Type": "application/json"},
+	}
+}

alerting/provider/discord/discord_test.go

@@ -0,0 +1,65 @@
+package discord
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwinProduction/gatus/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"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.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 != "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())
+	}
+}
+
+func TestAlertProvider_ToCustomAlertProviderWithTriggeredAlert(t *testing.T) {
+	provider := AlertProvider{WebhookURL: "http://example.com"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.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/provider.go

@@ -2,6 +2,7 @@ package provider
 
 import (
 	"github.com/TwinProduction/gatus/alerting/provider/custom"
+	"github.com/TwinProduction/gatus/alerting/provider/discord"
 	"github.com/TwinProduction/gatus/alerting/provider/mattermost"
 	"github.com/TwinProduction/gatus/alerting/provider/messagebird"
 	"github.com/TwinProduction/gatus/alerting/provider/pagerduty"
@@ -22,9 +23,10 @@ type AlertProvider interface {
 var (
 	// Validate interface implementation on compile
 	_ AlertProvider = (*custom.AlertProvider)(nil)
-	_ AlertProvider = (*twilio.AlertProvider)(nil)
-	_ AlertProvider = (*slack.AlertProvider)(nil)
+	_ AlertProvider = (*discord.AlertProvider)(nil)
 	_ AlertProvider = (*mattermost.AlertProvider)(nil)
 	_ AlertProvider = (*messagebird.AlertProvider)(nil)
 	_ AlertProvider = (*pagerduty.AlertProvider)(nil)
+	_ AlertProvider = (*slack.AlertProvider)(nil)
+	_ AlertProvider = (*twilio.AlertProvider)(nil)
 )