config: Allow to separate the ntfy topic from the server

config.scfg

@@ -51,7 +51,7 @@ labels {
     }
 
     instance "example.com" {
-        topic https://ntfy.sh/homeserver
+        topic homeserver
         tags "computer,example"
     }
 }
@@ -64,10 +64,14 @@ resolved {
 }
 
 ntfy {
-    # URL of the ntfy topic.
+    # URL of the ntfy server.
+    # Default: "https://ntfy.sh"
+    server https://ntfy.sh
+    # Name of the ntfy topic. For backwards compatibility you can specify the full URL of the
+    # topic (e.g. https://ntfy.sh/alertmanager-alerts) and the server will be parsed from it.
     # This setting is required.
     # Default: ""
-    topic https://ntfy.sh/alertmanager-alerts
+    topic alertmanager-alerts
     # ntfy authentication via Basic Auth (https://docs.ntfy.sh/publish/#username-password)
     # Default: ""
     user user

config/config.go

@@ -37,6 +37,7 @@ type Config struct {
 }
 
 type ntfyConfig struct {
+	Server            string
 	Topic             string
 	User              string
 	Password          string
@@ -230,6 +231,13 @@ func parseBlock(block scfg.Block, config *Config) error {
 
 	ntfyDir := block.Get("ntfy")
 	if ntfyDir != nil {
+		d = ntfyDir.Children.Get("server")
+		if d != nil {
+			if err := d.ParseParams(&config.Ntfy.Server); err != nil {
+				return err
+			}
+		}
+
 		d = ntfyDir.Children.Get("topic")
 		if d != nil {
 			if err := d.ParseParams(&config.Ntfy.Topic); err != nil {
@@ -422,6 +430,8 @@ func Read(path string) (*Config, error) {
 	config.LogFormat = "text"
 	config.AlertMode = Multi
 
+	config.Ntfy.Server = "https://ntfy.sh"
+
 	config.Cache.Type = "disabled"
 	config.Cache.Duration = time.Hour * 24
 	// memory

config/config_test.go

@@ -36,7 +36,7 @@ labels {
 
     instance "example.com" {
         tags "computer,example"
-        topic https://ntfy.sh/homeserver
+        topic homeserver
     }
 }
 
@@ -78,6 +78,7 @@ cache {
 		User:        "webhookUser",
 		Password:    "webhookPass",
 		Ntfy: ntfyConfig{
+			Server:            "https://ntfy.sh",
 			Topic:             "https://ntfy.sh/alertmanager-alerts",
 			User:              "user",
 			Password:          "pass",
@@ -96,7 +97,7 @@ cache {
 				"severity:info": {Priority: "1"},
 				"instance:example.com": {
 					Tags:  []string{"computer", "example"},
-					Topic: "https://ntfy.sh/homeserver"},
+					Topic: "homeserver"},
 			},
 		},
 		Cache: CacheConfig{

main.go

@@ -17,6 +17,7 @@ import (
 	"io"
 	"log/slog"
 	"net/http"
+	"net/url"
 	"os"
 	"os/signal"
 	"slices"
@@ -304,9 +305,9 @@ func (br *bridge) multiAlertNotification(p *payload) *notification {
 }
 
 func (br *bridge) publish(n *notification) error {
-	url := br.cfg.Ntfy.Topic
+	url, err := br.topicURL(n.topic)
-	if n.topic != "" {
+	if err != nil {
-		url = n.topic
+		return err
 	}
 
 	req, err := http.NewRequest(http.MethodPost, url, strings.NewReader(n.body))
@@ -616,3 +617,22 @@ func main() {
 			slog.String("error", err.Error()))
 	}
 }
+
+func (br *bridge) topicURL(topic string) (string, error) {
+	if topic == "" {
+		topic = br.cfg.Ntfy.Topic
+	}
+
+	// Check if the configured topic name already contains the ntfy server
+	i := strings.Index(topic, "://")
+	if i != -1 {
+		return topic, nil
+	}
+
+	s, err := url.JoinPath(br.cfg.Ntfy.Server, topic)
+	if err != nil {
+		return "", err
+	}
+
+	return s, nil
+}