Esempio di Client MQTT implementato in go tramite paho.mqtt.golang

mqtt_test.go

package main

import (
	"fmt"
	"github.com/eclipse/paho.mqtt.golang"
	"log"
	"os"
	"os/signal"
	"syscall"
)

const (
	brokAddr = "localhost"
	port     = 1883
	hostId   = "Main"
	topic    = "test"
)

func receiveCallback(client mqtt.Client, message mqtt.Message) {
        fmt.Printf("Topic: %v\tPayload: %s\n", message.Topic(), message.Payload())
}

func main() {
	quit := make(chan os.Signal)
	signal.Notify(quit, os.Interrupt, syscall.SIGTERM)

	opts := mqtt.NewClientOptions().AddBroker(fmt.Sprintf("tcp://%v:%v", brokAddr, port))
	opts.SetClientID(hostId)

	client := mqtt.NewClient(opts)
	connectionToken := client.Connect()

	if connectionToken.Wait() && connectionToken.Error() != nil {
		log.Fatal(connectionToken.Error())
	}

	subscriptionToken := client.Subscribe(topic, 0, receiveCallback)

	if subscriptionToken.Wait() && subscriptionToken.Error() != nil {
		log.Fatal(subscriptionToken.Error())
	}

	<-quit
	client.Disconnect(200)
	fmt.Println("Bye!")

}