feat: add completion webhook url

README.md

@@ -67,6 +67,11 @@ are only as many as this config variable.
 
 Default: `12`
 
+### `BACKUP_COMPLETION_WEBHOOK_URL`
+
+If provided, the tool will do an empty GET request to this URL to indicate it successfully completed the backup job.
+You can use this with other tools to monitor if backups are completed as they should.
+
 ## Building from source
 
 This project uses go modules, so you'll need at least go 1.11 to compile it.

config.go

@@ -17,6 +17,7 @@ type conf struct {
 	fullCurrentBackupPath string
 	Schedule              string
 	MaxBackups            int
+	CompletionWebhookURL  string
 }
 
 var (
@@ -25,9 +26,10 @@ var (
 )
 
 const (
-	envBackupFolder = `BACKUP_FOLDER`
+	envBackupFolder         = `BACKUP_FOLDER`
-	envSchedule     = `BACKUP_SCHEDULE`
+	envSchedule             = `BACKUP_SCHEDULE`
-	envMax          = `BACKUP_MAX`
+	envMax                  = `BACKUP_MAX`
+	envCompletionWebhookURL = `BACKUP_COMPLETION_WEBHOOK_URL`
 )
 
 func init() {
@@ -60,6 +62,11 @@ func init() {
 		config.MaxBackups = int(maxBackups)
 	}
 
+	webhookURL, has := os.LookupEnv(envCompletionWebhookURL)
+	if has {
+		config.CompletionWebhookURL = webhookURL
+	}
+
 	updateFullBackupPath()
 }
 

main.go

@@ -32,6 +32,11 @@ func main() {
 			log.Fatalf("Could not dump databases: %s", err)
 		}
 
+		err = callWebhook()
+		if err != nil {
+			log.Fatalf("Could not call completion webhook: %s", err)
+		}
+
 		log.Println("Done.")
 	})
 	if err != nil {

webhook.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"net/http"
+)
+
+func callWebhook() error {
+	if config.CompletionWebhookURL == "" {
+		return nil
+	}
+
+	res, err := http.Get(config.CompletionWebhookURL)
+	if err != nil {
+		return err
+	}
+
+	if res.StatusCode > 399 {
+		buf := bytes.Buffer{}
+		_, _ = buf.ReadFrom(res.Body)
+		return fmt.Errorf("recived an error status code while calling the webhook: %d, message: %s", res.StatusCode, buf.String())
+	}
+
+	return nil
+}