Add support for Twilio alerts (#7)

README.md

@@ -23,6 +23,7 @@ core applications: https://status.twinnation.org/
 - [FAQ](#faq)
   - [Sending a GraphQL request](#sending-a-graphql-request)
   - [Configuring Slack alerts](#configuring-slack-alerts)
+  - [Configuring Twilio alerts](#configuring-twilio-alerts)
   - [Configuring custom alert](#configuring-custom-alerts)
 
 
@@ -83,12 +84,17 @@ Note that you can also add environment variables in the your configuration file
 | `services[].graphql`              | Whether to wrap the body in a query param (`{"query":"$body"}`) | `false`        |
 | `services[].body`                 | Request body                                                    | `""`           |
 | `services[].headers`              | Request headers                                                 | `{}`           |
-| `services[].alerts[].type`        | Type of alert. Valid types: `slack`, `custom`                   | Required `""`  |
+| `services[].alerts[].type`        | Type of alert. Valid types: `slack`, `twilio`, `custom`         | Required `""`  |
 | `services[].alerts[].enabled`     | Whether to enable the alert                                     | `false`        |
 | `services[].alerts[].threshold`   | Number of failures in a row needed before triggering the alert  | `3`            |
 | `services[].alerts[].description` | Description of the alert. Will be included in the alert sent    | `""`           |
 | `alerting`                        | Configuration for alerting                                      | `{}`           |
 | `alerting.slack`                  | Webhook to use for alerts of type `slack`                       | `""`           |
+| `alerting.twilio`                 | Settings for alerts of type `twilio`                            | `""`           |
+| `alerting.twilio.sid`             | Twilio account SID                                              | Required `""`  |
+| `alerting.twilio.token`           | Twilio auth token                                               | Required `""`  |
+| `alerting.twilio.from`            | Number to send Twilio alerts from                               | Required `""`  |
+| `alerting.twilio.to`              | Number to send twilio alerts to                                 | Required `""`  |
 | `alerting.custom`                 | Configuration for custom actions on failure or alerts           | `""`           |
 | `alerting.custom.url`             | Custom alerting request url                                     | `""`           |
 | `alerting.custom.body`            | Custom alerting request body.                                   | `""`           |
@@ -198,6 +204,33 @@ services:
       - "[RESPONSE_TIME] < 300"
 ```
 
+### Configuring Twilio alerts
+
+```yaml
+alerting:
+  twilio:
+    sid: ****
+    token: ****
+    from: +1-234-567-8901
+    to: +1-234-567-8901
+services:
+  - name: twinnation
+    interval: 30s
+    url: "https://twinnation.org/health"
+    alerts:
+      - type: twilio
+        enabled: true
+        description: "healthcheck failed 3 times in a row"
+      - type: twilio
+        enabled: true
+        threshold: 5
+        description: "healthcheck failed 5 times in a row"
+    conditions:
+      - "[STATUS] == 200"
+      - "[BODY].status == UP"
+      - "[RESPONSE_TIME] < 300"
+```
+
 
 ### Configuring custom alerts
 
@@ -235,4 +268,4 @@ services:
       - "[STATUS] == 200"
       - "[BODY].status == UP"
       - "[RESPONSE_TIME] < 300"
-```
+```

core/alert.go

@@ -19,5 +19,6 @@ type AlertType string
 
 const (
 	SlackAlert  AlertType = "slack"
+	TwilioAlert AlertType = "twilio"
 	CustomAlert AlertType = "custom"
 )

core/alerting.go

@@ -10,9 +10,17 @@ import (
 
 type AlertingConfig struct {
 	Slack  string               `yaml:"slack"`
+	Twilio *TwilioAlertProvider `yaml:"twilio"`
 	Custom *CustomAlertProvider `yaml:"custom"`
 }
 
+type TwilioAlertProvider struct {
+	SID   string `yaml:"sid"`
+	Token string `yaml:"token"`
+	From  string `yaml:"from"`
+	To    string `yaml:"to"`
+}
+
 type CustomAlertProvider struct {
 	Url     string            `yaml:"url"`
 	Method  string            `yaml:"method,omitempty"`

watchdog/watchdog.go

@@ -1,11 +1,13 @@
 package watchdog
 
 import (
+	"encoding/base64"
 	"fmt"
 	"github.com/TwinProduction/gatus/config"
 	"github.com/TwinProduction/gatus/core"
 	"github.com/TwinProduction/gatus/metric"
 	"log"
+	"net/url"
 	"sync"
 	"time"
 )
@@ -71,6 +73,28 @@ func monitor(service *core.Service) {
 					} else {
 						log.Printf("[watchdog][monitor] Not sending Slack alert despite being triggered, because there is no Slack webhook configured")
 					}
+				} else if alertTriggered.Type == core.TwilioAlert {
+					if len(cfg.Alerting.Twilio.Token) > 0 &&
+						len(cfg.Alerting.Twilio.SID) > 0 &&
+						len(cfg.Alerting.Twilio.From) > 0 &&
+						len(cfg.Alerting.Twilio.To) > 0 {
+						log.Printf("[watchdog][monitor] Sending Twilio alert because alert with description=%s has been triggered", alertTriggered.Description)
+						alertProvider = &core.CustomAlertProvider{
+							Url:    fmt.Sprintf("https://api.twilio.com/2010-04-01/Accounts/%s/Messages.json", cfg.Alerting.Twilio.SID),
+							Method: "POST",
+							Body: url.Values{
+								"To":   {cfg.Alerting.Twilio.To},
+								"From": {cfg.Alerting.Twilio.From},
+								"Body": {fmt.Sprintf("%s - %s", service.Name, alertTriggered.Description)},
+							}.Encode(),
+							Headers: map[string]string{
+								"Content-Type":  "application/x-www-form-urlencoded",
+								"Authorization": fmt.Sprintf("Basic %s", base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("%s:%s", cfg.Alerting.Twilio.SID, cfg.Alerting.Twilio.Token)))),
+							},
+						}
+					} else {
+						log.Printf("[watchdog][monitor] Not sending Twilio alert despite being triggered, because twilio config settings missing")
+					}
 				} else if alertTriggered.Type == core.CustomAlert {
 					if cfg.Alerting.Custom != nil && len(cfg.Alerting.Custom.Url) > 0 {
 						log.Printf("[watchdog][monitor] Sending custom alert because alert with description=%s has been triggered", alertTriggered.Description)