Add keepalive

Signed-off-by: Knut Ahlers <knut@ahlers.me>

main.go

@@ -68,8 +68,9 @@ func main() {
 		mqtt.NewClientOptions().
 			AddBroker(cfg.MQTTBroker).
 			SetClientID(cfg.MQTTClientID).
-			SetUsername(cfg.MQTTUser).
+			SetKeepAlive(cfg.MQTTTimeout).
-			SetPassword(cfg.MQTTPass),
+			SetPassword(cfg.MQTTPass).
+			SetUsername(cfg.MQTTUser),
 	)
 
 	tok := client.Connect()

mqtt.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"os"
 
@@ -9,17 +10,19 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
-func publish(client mqtt.Client) error {
+func mqttTokenToError(tok mqtt.Token) error {
-	for _, t := range cfg.Topics {
-		tok := client.Publish(t, byte(cfg.QOS), cfg.Retain, cfg.Message)
-
-		logger := log.WithField("topic", t)
-
 	if !tok.WaitTimeout(cfg.MQTTTimeout) {
-			logger.Error("Unable to publish message within timeout")
+		return errors.New("token wait timed out")
 	}
 
-		if err := tok.Error(); err != nil {
+	return tok.Error()
+}
+
+func publish(client mqtt.Client) error {
+	for _, t := range cfg.Topics {
+		logger := log.WithField("topic", t)
+
+		if err := mqttTokenToError(client.Publish(t, byte(cfg.QOS), cfg.Retain, cfg.Message)); err != nil {
 			logger.WithError(err).Fatal("Unable to publish message")
 		}
 
@@ -54,8 +57,7 @@ func subscribe(client mqtt.Client) error {
 		log.WithField("format", cfg.OutputFormat).Fatal("Invalid output format specified")
 	}
 
-	tok := client.SubscribeMultiple(topics, callback)
+	if err := mqttTokenToError(client.SubscribeMultiple(topics, callback)); err != nil {
-	if err := tok.Error(); err != nil {
 		log.WithError(err).Fatal("Unable to subscribe topics")
 	}