feat(alerting): add telegram overriding token and id (#826)

* feat(alerting): add telegram overriding token and id

* Update alerting/provider/telegram/telegram_test.go

* Update alerting/provider/telegram/telegram_test.go

* Update alerting/provider/telegram/telegram_test.go

---------

Co-authored-by: TwiN <twin@linux.com>

README.md

@@ -279,7 +279,7 @@ This allows you to monitor anything you want, even when what you want to check l
 
 For instance:
 - You can create your own agent that lives in a private network and pushes the status of your services to a publicly-exposed Gatus instance
-- You can monitor services that are not supported by Gatus 
+- You can monitor services that are not supported by Gatus
 - You can implement your own monitoring system while using Gatus as the dashboard
 
 | Parameter                      | Description                                                                                                            | Default       |
@@ -1185,14 +1185,18 @@ Here's an example of what the notifications look like:
 
 
 #### Configuring Telegram alerts
-| Parameter                         | Description                                                                                | Default                    |
+| Parameter                             | Description                                                                                | Default                    |
-|:----------------------------------|:-------------------------------------------------------------------------------------------|:---------------------------|
+|:--------------------------------------|:-------------------------------------------------------------------------------------------|:---------------------------|
-| `alerting.telegram`               | Configuration for alerts of type `telegram`                                                | `{}`                       |
+| `alerting.telegram`                   | Configuration for alerts of type `telegram`                                                | `{}`                       |
-| `alerting.telegram.token`         | Telegram Bot Token                                                                         | Required `""`              |
+| `alerting.telegram.token`             | Telegram Bot Token                                                                         | Required `""`              |
-| `alerting.telegram.id`            | Telegram User ID                                                                           | Required `""`              |
+| `alerting.telegram.id`                | Telegram User ID                                                                           | Required `""`              |
-| `alerting.telegram.api-url`       | Telegram API URL                                                                           | `https://api.telegram.org` |
+| `alerting.telegram.api-url`           | Telegram API URL                                                                           | `https://api.telegram.org` |
-| `alerting.telegram.client`        | Client configuration. <br />See [Client configuration](#client-configuration).             | `{}`                       |
+| `alerting.telegram.client`            | Client configuration. <br />See [Client configuration](#client-configuration).             | `{}`                       |
-| `alerting.telegram.default-alert` | Default alert configuration. <br />See [Setting a default alert](#setting-a-default-alert) | N/A                        |
+| `alerting.telegram.default-alert`     | Default alert configuration. <br />See [Setting a default alert](#setting-a-default-alert) | N/A                        |
+| `alerting.telegram.overrides`         | List of overrides that may be prioritized over the default configuration                   | `[]`                       |
+| `alerting.telegram.overrides[].group` | Endpoint group for which the configuration will be overridden by this configuration        | `""`                       |
+| `alerting.telegram.overrides[].token` | Telegram Bot Token for override default value                                              | `""`                       |
+| `alerting.telegram.overrides[].id`    | Telegram User ID for override default value                                                | `""`                       |
 
 ```yaml
 alerting:

alerting/provider/telegram/telegram.go

@@ -25,6 +25,16 @@ type AlertProvider struct {
 
 	// DefaultAlert is the default alert configuration to use for endpoints with an alert of the appropriate type
 	DefaultAlert *alert.Alert `yaml:"default-alert,omitempty"`
+
+	// Overrides is a list of Overrid that may be prioritized over the default configuration
+	Overrides []*Override `yaml:"overrides,omitempty"`
+}
+
+// Override is a configuration that may be prioritized over the default configuration
+type Override struct {
+	group string `yaml:"group"`
+	token string `yaml:"token"`
+	id    string `yaml:"id"`
 }
 
 // IsValid returns whether the provider's configuration is valid
@@ -32,6 +42,18 @@ func (provider *AlertProvider) IsValid() bool {
 	if provider.ClientConfig == nil {
 		provider.ClientConfig = client.GetDefaultConfig()
 	}
+
+	registerGroups := make(map[string]bool)
+	for _, override := range provider.Overrides {
+		if len(override.group) == 0 {
+			return false
+		}
+		if _, ok := registerGroups[override.group]; ok {
+			return false
+		}
+		registerGroups[override.group] = true
+	}
+
 	return len(provider.Token) > 0 && len(provider.ID) > 0
 }
 
@@ -42,7 +64,7 @@ func (provider *AlertProvider) Send(ep *endpoint.Endpoint, alert *alert.Alert, r
 	if apiURL == "" {
 		apiURL = defaultAPIURL
 	}
-	request, err := http.NewRequest(http.MethodPost, fmt.Sprintf("%s/bot%s/sendMessage", apiURL, provider.Token), buffer)
+	request, err := http.NewRequest(http.MethodPost, fmt.Sprintf("%s/bot%s/sendMessage", apiURL, provider.getTokenForGroup(ep.Group)), buffer)
 	if err != nil {
 		return err
 	}
@@ -59,6 +81,15 @@ func (provider *AlertProvider) Send(ep *endpoint.Endpoint, alert *alert.Alert, r
 	return err
 }
 
+func (provider *AlertProvider) getTokenForGroup(group string) string {
+	for _, override := range provider.Overrides {
+		if override.group == group && len(override.token) > 0 {
+			return override.token
+		}
+	}
+	return provider.Token
+}
+
 type Body struct {
 	ChatID    string `json:"chat_id"`
 	Text      string `json:"text"`
@@ -93,13 +124,22 @@ func (provider *AlertProvider) buildRequestBody(ep *endpoint.Endpoint, alert *al
 		text = fmt.Sprintf("⛑ *Gatus* \n%s%s", message, formattedConditionResults)
 	}
 	bodyAsJSON, _ := json.Marshal(Body{
-		ChatID:    provider.ID,
+		ChatID:    provider.getIDForGroup(ep.Group),
 		Text:      text,
 		ParseMode: "MARKDOWN",
 	})
 	return bodyAsJSON
 }
 
+func (provider *AlertProvider) getIDForGroup(group string) string {
+	for _, override := range provider.Overrides {
+		if override.group == group && len(override.id) > 0 {
+			return override.id
+		}
+	}
+	return provider.ID
+}
+
 // GetDefaultAlert returns the provider's default alert configuration
 func (provider *AlertProvider) GetDefaultAlert() *alert.Alert {
 	return provider.DefaultAlert

alerting/provider/telegram/telegram_test.go

@@ -11,7 +11,7 @@ import (
 	"github.com/TwiN/gatus/v5/test"
 )
 
-func TestAlertProvider_IsValid(t *testing.T) {
+func TestAlertDefaultProvider_IsValid(t *testing.T) {
 	t.Run("invalid-provider", func(t *testing.T) {
 		invalidProvider := AlertProvider{Token: "", ID: ""}
 		if invalidProvider.IsValid() {
@@ -32,6 +32,69 @@ func TestAlertProvider_IsValid(t *testing.T) {
 	})
 }
 
+func TestAlertProvider_IsValidWithOverrides(t *testing.T) {
+	t.Run("invalid-provider-override-nonexist-group", func(t *testing.T) {
+		invalidProvider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "12345678", Overrides: []*Override{{token: "token", id: "id"}}}
+		if invalidProvider.IsValid() {
+			t.Error("provider shouldn't have been valid")
+		}
+	})
+	t.Run("invalid-provider-override-duplicate-group", func(t *testing.T) {
+		invalidProvider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "12345678", Overrides: []*Override{{group: "group1", token: "token", id: "id"}, {group: "group1", id: "id2"}}}
+		if invalidProvider.IsValid() {
+			t.Error("provider shouldn't have been valid")
+		}
+	})
+	t.Run("valid-provider", func(t *testing.T) {
+		validProvider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "12345678", Overrides: []*Override{{group: "group", token: "token", id: "id"}}}
+		if validProvider.ClientConfig != nil {
+			t.Error("provider client config should have been nil prior to IsValid() being executed")
+		}
+		if !validProvider.IsValid() {
+			t.Error("provider should've been valid")
+		}
+		if validProvider.ClientConfig == nil {
+			t.Error("provider client config should have been set after IsValid() was executed")
+		}
+	})
+}
+
+func TestAlertProvider_getTokenAndIDForGroup(t *testing.T) {
+	t.Run("get-token-with-override", func(t *testing.T) {
+		provider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "12345678", Overrides: []*Override{{group: "group", token: "overrideToken", id: "overrideID"}}}
+		token := provider.getTokenForGroup("group")
+		if token != "overrideToken" {
+			t.Error("token should have been 'overrideToken'")
+		}
+		id := provider.getIDForGroup("group")
+		if id != "overrideID" {
+			t.Error("id should have been 'overrideID'")
+		}
+	})
+	t.Run("get-default-token-with-overridden-id", func(t *testing.T) {
+		provider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "12345678", Overrides: []*Override{{group: "group", id: "overrideID"}}}
+		token := provider.getTokenForGroup("group")
+		if token != provider.Token {
+			t.Error("token should have been the default token")
+		}
+		id := provider.getIDForGroup("group")
+		if id != "overrideID" {
+			t.Error("id should have been 'overrideID'")
+		}
+	})
+	t.Run("get-default-token-with-overridden-token", func(t *testing.T) {
+		provider := AlertProvider{Token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", ID: "12345678", Overrides: []*Override{{group: "group", token: "overrideToken"}}}
+		token := provider.getTokenForGroup("group")
+		if token != "overrideToken" {
+			t.Error("token should have been 'overrideToken'")
+		}
+		id := provider.getIDForGroup("group")
+		if id != provider.ID {
+			t.Error("id should have been the default id")
+		}
+	})
+}
+
 func TestAlertProvider_Send(t *testing.T) {
 	defer client.InjectHTTPClient(nil)
 	firstDescription := "description-1"