ntfy: Support authentication via access-tokens

Implements: https://todo.xenrox.net/~xenrox/ntfy-alertmanager/14

README.md

@@ -67,9 +67,12 @@ resolved {
 ntfy {
     # URL of the ntfy topic - required
     topic https://ntfy.sh/alertmanager-alerts
-    # ntfy access control (https://ntfy.sh/docs/config/#access-control)
+    # ntfy authentication via Basic Auth (https://docs.ntfy.sh/publish/#username-password)
     user user
     password pass
+    # ntfy authentication via access tokens (https://docs.ntfy.sh/publish/#access-tokens)
+    # Either access-token or a user/password combination can be used - not both.
+    access-token foobar
 }
 
 alertmanager {

config.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"fmt"
 	"strings"
 	"time"
@@ -33,6 +34,7 @@ type ntfyConfig struct {
 	Topic       string
 	User        string
 	Password    string
+	AccessToken string
 }
 
 type labels struct {
@@ -212,6 +214,17 @@ func readConfig(path string) (*config, error) {
 		}
 	}
 
+	d = ntfyDir.Children.Get("access-token")
+	if d != nil {
+		if err := d.ParseParams(&config.ntfy.AccessToken); err != nil {
+			return nil, err
+		}
+	}
+
+	if config.ntfy.User != "" && config.ntfy.AccessToken != "" {
+		return nil, errors.New("ntfy: cannot use both an access-token and a user/password at the same time")
+	}
+
 	cacheDir := cfg.Get("cache")
 
 	if cacheDir != nil {

main.go

@@ -244,10 +244,12 @@ func (rcv *receiver) publish(n *notification) error {
 		return err
 	}
 
-	// Basic auth
+	// ntfy authentication
 	if rcv.cfg.ntfy.Password != "" && rcv.cfg.ntfy.User != "" {
 		auth := base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("%s:%s", rcv.cfg.ntfy.User, rcv.cfg.ntfy.Password)))
 		req.Header.Set("Authorization", fmt.Sprintf("Basic %s", auth))
+	} else if rcv.cfg.ntfy.AccessToken != "" {
+		req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", rcv.cfg.ntfy.AccessToken))
 	}
 
 	req.Header.Set("X-Title", n.title)