MQTT Go Client library

    3. import (
    4.     "fmt"
    5.     "log"
    6.     "os"
    7.     "time"
    9.     "github.com/eclipse/paho.mqtt.golang"
    10. )
    12. var f mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
    13.     fmt.Printf("TOPIC: %s\n", msg.Topic())
    14.     fmt.Printf("MSG: %s\n", msg.Payload())
    15. }
    16. func main() {
    18.     mqtt.ERROR = log.New(os.Stdout, "", 0)
    19.     opts := mqtt.NewClientOptions().AddBroker("tcp://broker.emqx.io:1883").SetClientID("emqx_test_client")
    21.     opts.SetKeepAlive(60 * time.Second)
    22.     // Set the message callback handler
    23.     opts.SetDefaultPublishHandler(f)
    24.     opts.SetPingTimeout(1 * time.Second)
    26.     c := mqtt.NewClient(opts)
    27.     if token := c.Connect(); token.Wait() && token.Error() != nil {
    28.         panic(token.Error())
    29.     }
    31.     // Subscribe to a topic
    32.     if token := c.Subscribe("testtopic/#", 0, nil); token.Wait() && token.Error() != nil {
    34.     }
    36.     // Publish a message
    37.     token := c.Publish("testtopic/1", 0, false, "Hello World")
    38.     token.Wait()
    40.     time.Sleep(6 * time.Second)
    42.     // Unscribe
    43.     if token := c.Unsubscribe("testtopic/#"); token.Wait() && token.Error() != nil {
    44.         fmt.Println(token.Error())
    45.         os.Exit(1)
    46.     }
    48.   // Disconnect
    49.     c.Disconnect(250)
    50. }

    Paho Golang MQTT 5.0 support