Simple Golang dashboard to show MQTT server activity by subscribing to all messages.

mqttdash.go

// how to run:
// go run mqtt.go tcp://iot.eclipse.org:1883 /topic/name
package main

import (
	"os"

	mqtt "github.com/eclipse/paho.mqtt.golang"
	"github.com/gizak/termui"
)

func main() {
	var count float64
	elapsed := 0

	opts := mqtt.NewClientOptions().AddBroker(os.Args[1]).SetClientID("termui")
	c := mqtt.NewClient(opts)
	if token := c.Connect(); token.Wait() && token.Error() != nil {
		panic(token.Error())
	}

	topic := "#"
	if len(os.Args) > 2 {
		topic = os.Args[2]
	}

	c.Subscribe(topic, 0, func(client mqtt.Client, msg mqtt.Message) {
		count++
	})

	err := termui.Init()
	if err != nil {
		panic(err)
	}
	defer termui.Close()

	data := make([]float64, 10)
	lc0 := termui.NewLineChart()
	lc0.BorderLabel = "MQTT Messages Per Second"
	lc0.Data = data
	lc0.Width = 60
	lc0.Height = 30
	lc0.X = 0
	lc0.Y = 0
	lc0.AxesColor = termui.ColorWhite
	lc0.LineColor = termui.ColorGreen | termui.AttrBold

	termui.Render(lc0)

	termui.Handle("/sys/kbd/q", func(termui.Event) {
		c.Disconnect(250)
		termui.StopLoop()
	})

	termui.Handle("/timer/1s", func(e termui.Event) {
		if elapsed >= 60 {
			elapsed = 0
			count = 0
			data = nil
		}

		data = append(data, count)
		elapsed++
		count = 0
		lc0.Data = data
		termui.Render(lc0)
	})

	termui.Loop()
}