saunaservice/main.go

package main

import (
	"encoding/json"
	"log"
	"time"

	"periph.io/x/conn/v3/onewire"
	"periph.io/x/conn/v3/physic"
	"periph.io/x/devices/v3/ds18b20"
	"periph.io/x/host/v3"
	"periph.io/x/host/v3/netlink"

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

type sample struct {
	Value float64 `json:"value"`
	Unit  string  `json:"unit"`
}

var (
	logger log.Logger = *log.Default()
)

func init() {
	logger.SetPrefix("Temperature: ")
}

var messagePubHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
	logger.Printf("Received message: %s from topic: %s\n", msg.Payload(), msg.Topic())
}

var connectHandler mqtt.OnConnectHandler = func(client mqtt.Client) {
	logger.Println("Connected")
}

var connectLostHandler mqtt.ConnectionLostHandler = func(client mqtt.Client, err error) {
	logger.Printf("Connect lost: %v", err)
}

func main() {
	logger.Println("Starting")

	// MQTT connection
	opts := mqtt.NewClientOptions()
	opts.AddBroker("tcp://nuc:1883")
	opts.SetClientID("saunaservice")
	opts.SetDefaultPublishHandler(messagePubHandler)
	opts.OnConnect = connectHandler
	opts.OnConnectionLost = connectLostHandler
	client := mqtt.NewClient(opts)
	if token := client.Connect(); token.Wait() && token.Error() != nil {
		panic(token.Error())
	}

	var addr onewire.Address = 0x8f01193726f5fd28
	if _, err := host.Init(); err != nil {
		logger.Fatal(err)
	}

	// get 1wire bus
	bus, err := netlink.New(1)
	if err != nil {
		logger.Fatal(err)
	}
	defer bus.Close()

	// res, err := bus.Search(false)
	// log.Print(res)

	sensor, err := ds18b20.New(bus, addr, 9)
	if err != nil {
		log.Fatal(err)
	}

	var res physic.Env
	var measure = sample{
		Value: 0.0,
		Unit:  "°C",
	}
	var last_value = float64(0.0)
	for {
		sensor.Sense(&res)
		log.Print(res.Temperature.String())

		measure.Value = float64(res.Temperature.Celsius())

		topic := "sauna/temperature"
		if measure.Value != last_value {
			res, err := json.Marshal(measure)
			if err != nil {
				logger.Print(err)
			} else {
				token := client.Publish(topic, 0, false, res)
				token.Wait()
			}
		}

		last_value = measure.Value
		time.Sleep(time.Second)
	}

}