Fix: re-subscribe after mqtt connection lost

sauna.go

@@ -33,7 +33,7 @@ var messagePubHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Me
 }
 
 var saunaHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
-	log.Printf("Received message: %s from topic: %s\n", msg.Payload(), msg.Topic())
+	logger.Printf("Received message: %s from topic: %s\n", msg.Payload(), msg.Topic())
 	sauna_mutex.Lock()
 	err := json.Unmarshal(msg.Payload(), &sauna_temperature)
 	sauna_temperature.Time = time.Now()
@@ -49,6 +49,7 @@ var saunaHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message
 
 var connectHandler mqtt.OnConnectHandler = func(client mqtt.Client) {
 	logger.Println("Connected")
+	subscribe(client)
 }
 
 var connectLostHandler mqtt.ConnectionLostHandler = func(client mqtt.Client, err error) {
@@ -77,7 +78,7 @@ func http_endpoint_sauna(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
-func Start() {
+func connect() mqtt.Client {
 	// MQTT connection
 	opts := mqtt.NewClientOptions()
 	opts.AddBroker("tcp://nuc:1883")
@@ -87,14 +88,22 @@ func Start() {
 	opts.OnConnectionLost = connectLostHandler
 	client := mqtt.NewClient(opts)
 	if token := client.Connect(); token.Wait() && token.Error() != nil {
-		panic(token.Error())
+		logger.Panic(token.Error())
+	}
+	return client
 }
 
+func subscribe(client mqtt.Client) {
 	// MQTT subscribtion
 	topic := "sauna/temperature"
 	token := client.Subscribe(topic, 1, saunaHandler)
 	token.Wait()
 	logger.Printf("Subscribed to topic %s", topic)
+}
+
+func Start() {
+	client := connect()
+	subscribe(client)
 
 	http.HandleFunc("/api/sauna", http_endpoint_sauna)
 }