mirror of
https://github.com/tinygo-org/drivers.git
synced 2026-08-10 18:03:41 +00:00
Scott Feldman
101 lines
2.4 KiB
Go
101 lines
2.4 KiB
Go
// This example is a MQTT client. It sends machine.ReadTemparature() readings
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// to the broker every second for 10 seconds.
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//
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// Note: It may be necessary to increase the stack size when using
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// paho.mqtt.golang. Use the -stack-size=4KB command line option.
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package main
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import (
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"fmt"
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"log"
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"machine"
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"math/rand"
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"time"
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mqtt "github.com/eclipse/paho.mqtt.golang"
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)
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var (
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ssid string
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pass string
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broker string = "tcp://test.mosquitto.org:1883"
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)
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var messagePubHandler mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
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fmt.Printf("Message %s received on topic %s\n", msg.Payload(), msg.Topic())
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}
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var connectHandler mqtt.OnConnectHandler = func(client mqtt.Client) {
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fmt.Println("Connected")
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}
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var connectionLostHandler mqtt.ConnectionLostHandler = func(client mqtt.Client, err error) {
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fmt.Printf("Connection Lost: %s\n", err.Error())
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}
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func main() {
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waitSerial()
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if err := netdev.NetConnect(); err != nil {
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log.Fatal(err)
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}
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clientId := "tinygo-client-" + randomString(10)
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fmt.Printf("ClientId: %s\n", clientId)
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options := mqtt.NewClientOptions()
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options.AddBroker(broker)
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options.SetClientID(clientId)
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options.SetDefaultPublishHandler(messagePubHandler)
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options.OnConnect = connectHandler
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options.OnConnectionLost = connectionLostHandler
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fmt.Printf("Connecting to MQTT broker at %s\n", broker)
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client := mqtt.NewClient(options)
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token := client.Connect()
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if token.Wait() && token.Error() != nil {
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panic(token.Error())
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}
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topic := "cpu/freq"
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token = client.Subscribe(topic, 1, nil)
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if token.Wait() && token.Error() != nil {
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panic(token.Error())
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}
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fmt.Printf("Subscribed to topic %s\n", topic)
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for i := 0; i < 10; i++ {
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freq := float32(machine.CPUFrequency()) / 1000000
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payload := fmt.Sprintf("%.02fMhz", freq)
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token = client.Publish(topic, 0, false, payload)
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if token.Wait() && token.Error() != nil {
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panic(token.Error())
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}
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time.Sleep(time.Second)
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}
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client.Disconnect(100)
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}
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// Returns an int >= min, < max
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func randomInt(min, max int) int {
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return min + rand.Intn(max-min)
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}
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// Generate a random string of A-Z chars with len = l
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func randomString(len int) string {
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bytes := make([]byte, len)
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for i := 0; i < len; i++ {
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bytes[i] = byte(randomInt(65, 90))
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}
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return string(bytes)
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}
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// Wait for user to open serial console
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func waitSerial() {
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for !machine.Serial.DTR() {
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time.Sleep(100 * time.Millisecond)
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}
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}
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