fix(alerting): Support custom slack title (#1079)

README.md

@@ -1903,9 +1903,10 @@ endpoints:
 
 #### Configuring Slack alerts
 | Parameter                          | Description                                                                                | Default                             |
-|:-----------------------------------|:-------------------------------------------------------------------------------------------|:--------------|
+|:-----------------------------------|:-------------------------------------------------------------------------------------------|:------------------------------------|
 | `alerting.slack`                   | Configuration for alerts of type `slack`                                                   | `{}`                                |
 | `alerting.slack.webhook-url`       | Slack Webhook URL                                                                          | Required `""`                       |
+| `alerting.slack.title`             | Title of the notification                                                                  | `":helmet_with_white_cross: Gatus"` |
 | `alerting.slack.default-alert`     | Default alert configuration. <br />See [Setting a default alert](#setting-a-default-alert) | N/A                                 |
 | `alerting.slack.overrides`         | List of overrides that may be prioritized over the default configuration                   | `[]`                                |
 | `alerting.slack.overrides[].group` | Endpoint group for which the configuration will be overridden by this configuration        | `""`                                |

alerting/provider/slack/slack.go

@@ -21,6 +21,7 @@ var (
 
 type Config struct {
 	WebhookURL string `yaml:"webhook-url"`     // Slack webhook URL
+	Title      string `yaml:"title,omitempty"` // Title of the message that will be sent
 }
 
 func (cfg *Config) Validate() error {
@@ -34,6 +35,9 @@ func (cfg *Config) Merge(override *Config) {
 	if len(override.WebhookURL) > 0 {
 		cfg.WebhookURL = override.WebhookURL
 	}
+	if len(override.Title) > 0 {
+		cfg.Title = override.Title
+	}
 }
 
 // AlertProvider is the configuration necessary for sending an alert using Slack
@@ -73,7 +77,7 @@ func (provider *AlertProvider) Send(ep *endpoint.Endpoint, alert *alert.Alert, r
 	if err != nil {
 		return err
 	}
-	buffer := bytes.NewBuffer(provider.buildRequestBody(ep, alert, result, resolved))
+	buffer := bytes.NewBuffer(provider.buildRequestBody(cfg, ep, alert, result, resolved))
 	request, err := http.NewRequest(http.MethodPost, cfg.WebhookURL, buffer)
 	if err != nil {
 		return err
@@ -111,7 +115,7 @@ type Field struct {
 }
 
 // buildRequestBody builds the request body for the provider
-func (provider *AlertProvider) buildRequestBody(ep *endpoint.Endpoint, alert *alert.Alert, result *endpoint.Result, resolved bool) []byte {
+func (provider *AlertProvider) buildRequestBody(cfg *Config, ep *endpoint.Endpoint, alert *alert.Alert, result *endpoint.Result, resolved bool) []byte {
 	var message, color string
 	if resolved {
 		message = fmt.Sprintf("An alert for *%s* has been resolved after passing successfully %d time(s) in a row", ep.DisplayName(), alert.SuccessThreshold)
@@ -138,13 +142,16 @@ func (provider *AlertProvider) buildRequestBody(ep *endpoint.Endpoint, alert *al
 		Text: "",
 		Attachments: []Attachment{
 			{
-				Title: ":helmet_with_white_cross: Gatus",
+				Title: cfg.Title,
 				Text:  message + description,
 				Short: false,
 				Color: color,
 			},
 		},
 	}
+	if len(body.Attachments[0].Title) == 0 {
+		body.Attachments[0].Title = ":helmet_with_white_cross: Gatus"
+	}
 	if len(formattedConditionResults) > 0 {
 		body.Attachments[0].Fields = append(body.Attachments[0].Fields, Field{
 			Title: "Condition results",

alerting/provider/slack/slack_test.go

@@ -150,7 +150,7 @@ func TestAlertProvider_buildRequestBody(t *testing.T) {
 	}{
 		{
 			Name:         "triggered",
-			Provider:     AlertProvider{},
+			Provider:     AlertProvider{DefaultConfig: Config{WebhookURL: "http://example.com"}},
 			Endpoint:     endpoint.Endpoint{Name: "name"},
 			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
 			Resolved:     false,
@@ -158,7 +158,7 @@ func TestAlertProvider_buildRequestBody(t *testing.T) {
 		},
 		{
 			Name:         "triggered-with-group",
-			Provider:     AlertProvider{},
+			Provider:     AlertProvider{DefaultConfig: Config{WebhookURL: "http://example.com"}},
 			Endpoint:     endpoint.Endpoint{Name: "name", Group: "group"},
 			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
 			Resolved:     false,
@@ -167,7 +167,7 @@ func TestAlertProvider_buildRequestBody(t *testing.T) {
 		{
 			Name:         "triggered-with-no-conditions",
 			NoConditions: true,
-			Provider:     AlertProvider{},
+			Provider:     AlertProvider{DefaultConfig: Config{WebhookURL: "http://example.com"}},
 			Endpoint:     endpoint.Endpoint{Name: "name"},
 			Alert:        alert.Alert{Description: &firstDescription, SuccessThreshold: 5, FailureThreshold: 3},
 			Resolved:     false,
@@ -175,7 +175,7 @@ func TestAlertProvider_buildRequestBody(t *testing.T) {
 		},
 		{
 			Name:         "resolved",
-			Provider:     AlertProvider{},
+			Provider:     AlertProvider{DefaultConfig: Config{WebhookURL: "http://example.com"}},
 			Endpoint:     endpoint.Endpoint{Name: "name"},
 			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
 			Resolved:     true,
@@ -183,12 +183,20 @@ func TestAlertProvider_buildRequestBody(t *testing.T) {
 		},
 		{
 			Name:         "resolved-with-group",
-			Provider:     AlertProvider{},
+			Provider:     AlertProvider{DefaultConfig: Config{WebhookURL: "http://example.com"}},
 			Endpoint:     endpoint.Endpoint{Name: "name", Group: "group"},
 			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
 			Resolved:     true,
 			ExpectedBody: "{\"text\":\"\",\"attachments\":[{\"title\":\":helmet_with_white_cross: Gatus\",\"text\":\"An alert for *group/name* has been resolved after passing successfully 5 time(s) in a row:\\n\\u003e description-2\",\"short\":false,\"color\":\"#36A64F\",\"fields\":[{\"title\":\"Condition results\",\"value\":\":white_check_mark: - `[CONNECTED] == true`\\n:white_check_mark: - `[STATUS] == 200`\\n\",\"short\":false}]}]}",
 		},
+		{
+			Name:         "resolved-with-group-and-custom-title",
+			Provider:     AlertProvider{DefaultConfig: Config{WebhookURL: "http://example.com", Title: "custom title"}},
+			Endpoint:     endpoint.Endpoint{Name: "name", Group: "group"},
+			Alert:        alert.Alert{Description: &secondDescription, SuccessThreshold: 5, FailureThreshold: 3},
+			Resolved:     true,
+			ExpectedBody: "{\"text\":\"\",\"attachments\":[{\"title\":\"custom title\",\"text\":\"An alert for *group/name* has been resolved after passing successfully 5 time(s) in a row:\\n\\u003e description-2\",\"short\":false,\"color\":\"#36A64F\",\"fields\":[{\"title\":\"Condition results\",\"value\":\":white_check_mark: - `[CONNECTED] == true`\\n:white_check_mark: - `[STATUS] == 200`\\n\",\"short\":false}]}]}",
+		},
 	}
 	for _, scenario := range scenarios {
 		t.Run(scenario.Name, func(t *testing.T) {
@@ -199,7 +207,12 @@ func TestAlertProvider_buildRequestBody(t *testing.T) {
 					{Condition: "[STATUS] == 200", Success: scenario.Resolved},
 				}
 			}
+			cfg, err := scenario.Provider.GetConfig(scenario.Endpoint.Group, &scenario.Alert)
+			if err != nil {
+				t.Fatal("couldn't get config:", err.Error())
+			}
 			body := scenario.Provider.buildRequestBody(
+				cfg,
 				&scenario.Endpoint,
 				&scenario.Alert,
 				&endpoint.Result{