Add Telegram Alerting (#102)

.gitignore

@@ -2,3 +2,4 @@
 .vscode
 gatus
 db.db
+config/config.yml

README.md

@@ -31,6 +31,7 @@ core applications: https://status.twinnation.org/
     - [Configuring Twilio alerts](#configuring-twilio-alerts)
     - [Configuring Mattermost alerts](#configuring-mattermost-alerts)
     - [Configuring Messagebird alerts](#configuring-messagebird-alerts)    
+    - [Configuring Telegram alerts](#configuring-telegram-alerts)
     - [Configuring custom alerts](#configuring-custom-alerts)
   - [Kubernetes (ALPHA)](#kubernetes-alpha)
     - [Auto Discovery](#auto-discovery)
@@ -220,6 +221,9 @@ ignored.
 | `alerting.messagebird.access-key`        | Messagebird access key                                                        | Required `""`  |
 | `alerting.messagebird.originator`        | The sender of the message                                                     | Required `""`  |
 | `alerting.messagebird.recipients`        | The recipients of the message                                                 | Required `""`  |
+| `alerting.telegram`                      | Configuration for alerts of type `telegram`                                   | `{}`           |
+| `alerting.telegram.token`                | Telegram Bot Token                                                            | Required `""`  |
+| `alerting.telegram.id`                   | Telegram User ID                                                              | Required `""`  |
 | `alerting.custom`                        | Configuration for custom actions on failure or alerts                         | `{}`           |
 | `alerting.custom.url`                    | Custom alerting request url                                                   | Required `""`  |
 | `alerting.custom.method`                 | Request method                                                                | `GET`          |
@@ -395,6 +399,31 @@ services:
 ```
 
 
+#### Configuring Telegram alerts
+
+```yaml
+alerting:
+  telegram: 
+    token: "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11"
+    id: "0123456789"
+
+services:
+  - name: twinnation
+    url: "https://twinnation.org/health"
+    interval: 30s
+    alerts:
+      - type: telegram
+        enabled: true
+        send-on-resolved: true
+    conditions:
+      - "[STATUS] == 200"
+      - "[BODY].status == UP"
+```
+
+Here's an example of what the notifications look like:
+
+![Telegram notifications](.github/assets/telegram-alerts.png)
+
 #### Configuring custom alerts
 
 While they're called alerts, you can use this feature to call anything. 

alerting/config.go

@@ -7,6 +7,7 @@ import (
 	"github.com/TwinProduction/gatus/alerting/provider/messagebird"
 	"github.com/TwinProduction/gatus/alerting/provider/pagerduty"
 	"github.com/TwinProduction/gatus/alerting/provider/slack"
+	"github.com/TwinProduction/gatus/alerting/provider/telegram"
 	"github.com/TwinProduction/gatus/alerting/provider/twilio"
 )
 
@@ -30,6 +31,9 @@ type Config struct {
 	// Slack is the configuration for the slack alerting provider
 	Slack *slack.AlertProvider `yaml:"slack"`
 
+	// 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"`
 }

alerting/provider/provider.go

@@ -7,6 +7,7 @@ import (
 	"github.com/TwinProduction/gatus/alerting/provider/messagebird"
 	"github.com/TwinProduction/gatus/alerting/provider/pagerduty"
 	"github.com/TwinProduction/gatus/alerting/provider/slack"
+	"github.com/TwinProduction/gatus/alerting/provider/telegram"
 	"github.com/TwinProduction/gatus/alerting/provider/twilio"
 	"github.com/TwinProduction/gatus/core"
 )
@@ -28,5 +29,6 @@ var (
 	_ AlertProvider = (*messagebird.AlertProvider)(nil)
 	_ AlertProvider = (*pagerduty.AlertProvider)(nil)
 	_ AlertProvider = (*slack.AlertProvider)(nil)
+	_ AlertProvider = (*telegram.AlertProvider)(nil)
 	_ AlertProvider = (*twilio.AlertProvider)(nil)
 )

alerting/provider/telegram/telegram.go

@@ -0,0 +1,52 @@
+package telegram
+
+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 Telegram
+type AlertProvider struct {
+	Token string `yaml:"token"`
+	ID    string `yaml:"id"`
+}
+
+// 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(service *core.Service, alert *core.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—  ", service.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—  ", service.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.Description) > 0 {
+		text = fmt.Sprintf("⛑ *Gatus* \\n%s \\n*Description* \\n_%s_  \\n\\n*Condition results*\\n%s", message, alert.Description, 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"},
+	}
+}

alerting/provider/telegram/telegram_test.go

@@ -0,0 +1,89 @@
+package telegram
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/TwinProduction/gatus/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.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 != 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"}
+	customAlertProvider := provider.ToCustomAlertProvider(&core.Service{}, &core.Alert{Description: "Healthcheck Successful"}, &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.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 != 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())
+	}
+}

config/config.go

@@ -234,6 +234,7 @@ func validateAlertingConfig(config *Config) {
 		core.MessagebirdAlert,
 		core.PagerDutyAlert,
 		core.SlackAlert,
+		core.TelegramAlert,
 		core.TwilioAlert,
 	}
 	var validProviders, invalidProviders []core.AlertType
@@ -292,6 +293,12 @@ func GetAlertingProviderByAlertType(config *Config, alertType core.AlertType) pr
 			return nil
 		}
 		return config.Alerting.Slack
+	case core.TelegramAlert:
+		if config.Alerting.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.Alerting.Telegram
 	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

config/config_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/TwinProduction/gatus/alerting/provider/messagebird"
 	"github.com/TwinProduction/gatus/alerting/provider/pagerduty"
 	"github.com/TwinProduction/gatus/alerting/provider/slack"
+	"github.com/TwinProduction/gatus/alerting/provider/telegram"
 	"github.com/TwinProduction/gatus/alerting/provider/twilio"
 	"github.com/TwinProduction/gatus/core"
 	"github.com/TwinProduction/gatus/k8stest"
@@ -354,6 +355,9 @@ alerting:
     access-key: "1"
     originator: "31619191918"
     recipients: "31619191919"
+  telegram:
+    token: 123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11
+    id: 0123456789
 services:
   - name: twinnation
     url: https://twinnation.org/health
@@ -369,6 +373,8 @@ services:
       - type: discord
         enabled: true
         failure-threshold: 10
+      - type: telegram
+        enabled: true
     conditions:
       - "[STATUS] == 200"
 `))
@@ -394,12 +400,13 @@ services:
 	if config.Alerting.PagerDuty == nil || !config.Alerting.PagerDuty.IsValid() {
 		t.Fatal("PagerDuty alerting config should've been valid")
 	}
-	if config.Alerting.Messagebird == nil || !config.Alerting.Messagebird.IsValid() {
-		t.Fatal("Messagebird 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 config.Alerting.Messagebird == nil || !config.Alerting.Messagebird.IsValid() {
+		t.Fatal("Messagebird alerting config should've been valid")
+	}
 	if config.Alerting.Messagebird.AccessKey != "1" {
 		t.Errorf("Messagebird access key should've been %s, but was %s", "1", config.Alerting.Messagebird.AccessKey)
 	}
@@ -409,12 +416,20 @@ services:
 	if config.Alerting.Messagebird.Recipients != "31619191919" {
 		t.Errorf("Messagebird to recipients should've been %s, but was %s", "31619191919", config.Alerting.Messagebird.Recipients)
 	}
+
 	if config.Alerting.Discord == nil || !config.Alerting.Discord.IsValid() {
 		t.Fatal("Discord alerting config should've been valid")
 	}
 	if config.Alerting.Discord.WebhookURL != "http://example.org" {
 		t.Errorf("Discord webhook should've been %s, but was %s", "http://example.org", config.Alerting.Discord.WebhookURL)
 	}
+
+	if config.Alerting.Telegram.Token != "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11" {
+		t.Errorf("Telegram token should've been %s, but was %s", "123456:ABC-DEF1234ghIkl-zyx57W2v1u123ew11", config.Alerting.Telegram.Token)
+	}
+	if config.Alerting.Telegram.ID != "0123456789" {
+		t.Errorf("Telegram ID should've been %s, but was %s", "012345689", config.Alerting.Telegram.ID)
+	}
 	if GetAlertingProviderByAlertType(config, core.DiscordAlert) != config.Alerting.Discord {
 		t.Error("expected discord configuration")
 	}
@@ -428,8 +443,8 @@ services:
 	if config.Services[0].Interval != 60*time.Second {
 		t.Errorf("Interval should have been %s, because it is the default value", 60*time.Second)
 	}
-	if len(config.Services[0].Alerts) != 4 {
-		t.Fatal("There should've been 4 alerts configured")
+	if len(config.Services[0].Alerts) != 5 {
+		t.Fatal("There should've been 5 alerts configured")
 	}
 
 	if config.Services[0].Alerts[0].Type != core.SlackAlert {
@@ -451,9 +466,6 @@ services:
 	if config.Services[0].Alerts[1].Description != "Healthcheck failed 7 times in a row" {
 		t.Errorf("The description of the alert should've been %s, but it was %s", "Healthcheck failed 7 times in a row", config.Services[0].Alerts[1].Description)
 	}
-	if config.Services[0].Alerts[1].FailureThreshold != 7 {
-		t.Errorf("The failure threshold of the alert should've been %d, but it was %d", 7, config.Services[0].Alerts[1].FailureThreshold)
-	}
 	if config.Services[0].Alerts[1].SuccessThreshold != 5 {
 		t.Errorf("The success threshold of the alert should've been %d, but it was %d", 5, config.Services[0].Alerts[1].SuccessThreshold)
 	}
@@ -855,6 +867,7 @@ func TestGetAlertingProviderByAlertType(t *testing.T) {
 			Messagebird: &messagebird.AlertProvider{},
 			PagerDuty:   &pagerduty.AlertProvider{},
 			Slack:       &slack.AlertProvider{},
+			Telegram:    &telegram.AlertProvider{},
 			Twilio:      &twilio.AlertProvider{},
 		},
 	}
@@ -876,6 +889,9 @@ func TestGetAlertingProviderByAlertType(t *testing.T) {
 	if GetAlertingProviderByAlertType(cfg, core.SlackAlert) != cfg.Alerting.Slack {
 		t.Error("expected Slack configuration")
 	}
+	if GetAlertingProviderByAlertType(cfg, core.TelegramAlert) != cfg.Alerting.Telegram {
+		t.Error("expected Telegram configuration")
+	}
 	if GetAlertingProviderByAlertType(cfg, core.TwilioAlert) != cfg.Alerting.Twilio {
 		t.Error("expected Twilio configuration")
 	}

core/alert.go

@@ -58,6 +58,9 @@ const (
 	// SlackAlert is the AlertType for the slack alerting provider
 	SlackAlert AlertType = "slack"
 
+	// TelegramAlert is the AlertType for the telegram alerting provider
+	TelegramAlert AlertType = "telegram"
+
 	// TwilioAlert is the AlertType for the twilio alerting provider
 	TwilioAlert AlertType = "twilio"
 )