code beautifying

main.go

@@ -65,6 +65,48 @@ func dispatcher() {
   }
 }
 
+func startMqttClient() MQTT.Client {
+  broker := os.Getenv("MQTT_BROKER")
+  if broker == "" {
+    log.Fatal("No broker given, set env var MQTT_BROKER")
+  }
+
+  prefix := "UDI"
+  uuid := uuid.New()
+  clientId := fmt.Sprintf("%s-%s", prefix, uuid)
+
+  opts := MQTT.NewClientOptions().
+    AddBroker(broker).
+    SetClientID(clientId).
+    SetConnectionLostHandler(onConnectionLost).
+    SetOnConnectHandler(onConnect).
+    SetReconnectingHandler(onReconnecting).
+    SetConnectRetry(true)
+
+  username := os.Getenv("MQTT_USERNAME")
+  if username != "" {
+    opts.SetUsername(username)
+  }
+
+  password := os.Getenv("MQTT_PASSWORD")
+  if password != "" {
+    opts.SetPassword(password)
+  }
+
+  log.Println("Trying to connect to broker")
+  client := MQTT.NewClient(opts)
+  if token := client.Connect(); token.Wait() && token.Error() != nil {
+    log.Fatalf("Unable to connect to broker %s, error %s", broker, token.Error())
+  }
+  log.Printf("Successfully connected to broker %s", broker)
+
+  return client
+}
+
+func stopMqttClient(client MQTT.Client) {
+  log.Println("Disconnecting from broker")
+  client.Disconnect(250)
+}
 
 func main() {
   log.SetPrefix("UDI: ")
@@ -75,29 +117,8 @@ func main() {
   messageChannel = make(chan Message, 100)
   go dispatcher()
 
-  broker := os.Getenv("MQTT_BROKER")
+  mqttClient := startMqttClient()
-  if broker == "" {
+  defer stopMqttClient(mqttClient)
-    log.Fatal("No broker given, set env var MQTT_BROKER")
-  }
-
-  prefix := "UDI"
-  uuid := uuid.New()
-  clientId := fmt.Sprintf("%s-%s", prefix, uuid)
-
-  mqttOpts := MQTT.NewClientOptions().
-    AddBroker(broker).
-    SetClientID(clientId).
-    SetConnectionLostHandler(onConnectionLost).
-    SetOnConnectHandler(onConnect).
-    SetReconnectingHandler(onReconnecting).
-    SetConnectRetry(true)
-
-  client := MQTT.NewClient(mqttOpts)
-  if token := client.Connect(); token.Wait() && token.Error() != nil {
-    log.Fatalf("Unable to connect to broker %s, error %s", broker, token.Error())
-  }
-  log.Printf("Successfully connected to broker %s", broker)
-
 
   log.Println("UDI running")
 
@@ -106,6 +127,5 @@ func main() {
 	<-c
 
   log.Println("Terminating UDI")
-  client.Disconnect(250)
 }