From 01c2c181ab8ca09e8a860d82bae3295e2b52717c Mon Sep 17 00:00:00 2001
From: Damian Galli <damian.galli@galli.site>
Date: Sat, 13 May 2023 17:00:02 +0200
Subject: [PATCH] Automaticaly reconnect mqtt Connection

---
 main.go           | 35 +++++++++++------------------------
 mqtt-to-device.go | 44 ++++++++++++++++++++++++++++++--------------
 shared.go         |  6 ++++++
 3 files changed, 47 insertions(+), 38 deletions(-)
 create mode 100644 shared.go

diff --git a/main.go b/main.go
index 71a23d3..4ed2a0b 100644
--- a/main.go
+++ b/main.go
@@ -1,12 +1,12 @@
 package main
 
 import (
-  "bufio"
-  "flag"
-  mqtt "github.com/eclipse/paho.mqtt.golang"
-  filename "github.com/keepeye/logrus-filename"
-  log "github.com/sirupsen/logrus"
-  "go.bug.st/serial"
+	"bufio"
+	"flag"
+
+	filename "github.com/keepeye/logrus-filename"
+	log "github.com/sirupsen/logrus"
+	"go.bug.st/serial"
 )
 
 type SerialMessage struct {
@@ -50,12 +50,11 @@ func main() {
     log.SetLevel(log.TraceLevel)
   }
 
-  serialPort := openSerialPort(*serialPortAddress)
-  mqttClient := startMQTT(*brokerAddress)
-
-  go mqttToDevice(serialPort, mqttClient, *inputTopic)
-  go deviceToMqtt(bufio.NewReader(serialPort), mqttClient, *outputTopic)
-  select {}
+	serialPort := openSerialPort(*serialPortAddress)
+	go mqttToDevice(serialPort, *brokerAddress, *inputTopic)
+	mqttClient := <-MqttChannel
+	go deviceToMqtt(bufio.NewReader(serialPort), mqttClient, *outputTopic)
+	select {}
 }
 
 func openSerialPort(serialPort string) serial.Port {
@@ -71,15 +70,3 @@ func openSerialPort(serialPort string) serial.Port {
 
   return port
 }
-
-func startMQTT(address string) mqtt.Client {
-  client := mqtt.NewClient(mqtt.NewClientOptions().AddBroker(address))
-
-  if token := client.Connect(); token.Wait() && token.Error() != nil {
-    log.Fatal(token.Error())
-  }
-
-  log.WithField("broker", address).Info("connected to mqtt broker")
-
-  return client
-}
diff --git a/mqtt-to-device.go b/mqtt-to-device.go
index 708a8d8..1817085 100644
--- a/mqtt-to-device.go
+++ b/mqtt-to-device.go
@@ -10,27 +10,43 @@ import (
 	"time"
 )
 
-func mqttToDevice(serialPort serial.Port, client mqtt.Client, topic string) {
-	log.WithField("topic", topic).Info("listening for commands to send to device")
-
-	client.Subscribe(topic, 0, func(client mqtt.Client, msg mqtt.Message) {
-		jsonString := string(msg.Payload())
-		serialMessage := jsonToSerialMessage(jsonString)
-
-		log.WithFields(log.Fields{
-			"json":  jsonString,
-			"topic": topic,
-		}).Trace("message received from mqtt")
+func mqttToDevice(serialPort serial.Port, address string, topic string) {
+
+	clientOptions := mqtt.NewClientOptions().AddBroker(address)
+	clientOptions.SetPingTimeout(30 * time.Second)
+	clientOptions.SetKeepAlive(30 * time.Second)
+	clientOptions.SetAutoReconnect(true)
+	clientOptions.SetMaxReconnectInterval(10 * time.Second)
+	clientOptions.SetOnConnectHandler(func(client mqtt.Client) {
+		client.Subscribe(topic, 0, func(client mqtt.Client, msg mqtt.Message) {
+			jsonString := string(msg.Payload())
+			serialMessage := jsonToSerialMessage(jsonString)
+
+			log.WithFields(log.Fields{
+				"json":  jsonString,
+				"topic": topic,
+			}).Trace("message received from mqtt")
 
 		if serialMessage.Command == "" || serialMessage.Value == "" {
 			log.WithField("json", jsonString).Debug("tried to send unsupported command to device")
 			return
 		}
 
-		// And finally send the command to the device
-		var mutex sync.Mutex
-		sendCommand(serialPort, serialMessage, &mutex)
+			// And finally send the command to the device
+			var mutex sync.Mutex
+			sendCommand(serialPort, serialMessage, &mutex)
+		})
 	})
+	client := mqtt.NewClient(clientOptions)
+	MqttChannel <- client
+	if token := client.Connect(); token.Wait() && token.Error() != nil {
+		log.Fatal(token.Error())
+	}
+
+	log.WithField("broker", address).Info("connected to mqtt broker")
+
+	log.WithField("topic", topic).Info("listening for commands to send to device")
+
 }
 
 func jsonToSerialMessage(jsonString string) SerialMessage {
diff --git a/shared.go b/shared.go
new file mode 100644
index 0000000..72925bc
--- /dev/null
+++ b/shared.go
@@ -0,0 +1,6 @@
+package main
+
+import mqtt "github.com/eclipse/paho.mqtt.golang"
+
+// Declare a shared channel
+var MqttChannel = make(chan mqtt.Client)