Mqtt forwarder command

[Steph10]

Hi,

I use the mqtt forwarder on kerlink gateway. it work perfectly. I have custom script to put metadata on chirpstack server etc.

But I want to try the command section.
I try the example reboot, but I don’t now how to send command. I have try through mqtt topic, but i not found any documentation about this.

Have you try this ?

thanks you for help

[devleesch001]

@Steph10

I use the mqtt forwarder on kerlink gateway. it work perfectly. I have custom scri

Hello,
I think there is no documentation available, and you will need to send the Gateway Command Exec Request yourself.

To do this, you can use the SDK to create commands for the MQTT forwarder in various programming languages.

ChirpStack API GitHub Repository

When you have your Gateway Command Exec Request payload ready, send it to the following topic:

eu868/gateway/{gw_id}/command/exec

You will receive the response on this topic:

eu868/gateway/{gw_id}/event/exec

Example in Go

package main

import (
	"github.com/chirpstack/chirpstack/api/go/v4/gw"
	mqtt "github.com/eclipse/paho.mqtt.golang"
	"google.golang.org/protobuf/proto"
	"log"
	"os"
)

func main() {
	// setup mqtt client option
	opts := mqtt.NewClientOptions().
		AddBroker("tcp://test.mosquitto.org:1883").
		SetClientID("go_mqtt_client")

	client := mqtt.NewClient(opts)

	// connect and catch error
	if token := client.Connect(); token.Wait() && token.Error() != nil {
		panic(token.Error())
	}

	// random number to check if response of your command
	var execID uint32 = 1234

	// Prepare the Command Request
	gatewayCommandExecRequest := gw.GatewayCommandExecRequest{
		GatewayId:   "ac1f09fffe0caeb5",
		Command:     "reboot",
		ExecId:      execID,
		Stdin:       nil,
		Environment: nil,
	}

	// Subscribe to the response topic
	client.Subscribe("eu868/gateway/00aa00aa00aa00aa/event/exec", 0, func(client mqtt.Client, message mqtt.Message) {
		response := &gw.GatewayCommandExecResponse{}
		_ = proto.Unmarshal(message.Payload(), response)
 
		// this check are optional
		if response.ExecId == execID {
			println(response.String())
			os.Exit(0)
		}
	})

	payload, _ := proto.Marshal(&gatewayCommandExecRequest)

	// Publish the command and catch error
	if token := client.Publish("eu868/gateway/00aa00aa00aa00aa/command/exec", 0, false, payload); token.Wait() && token.Error() != nil {
		log.Println(token.Error())
	}

	// Wait forever
	select {}
}

You can replace proto.Marshal by json.Marshal if you use json config instead of protobuf in chirpstack config