55 lines
1.3 KiB
Go
55 lines
1.3 KiB
Go
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"io/ioutil"
|
|
"strings"
|
|
|
|
mqtt "github.com/eclipse/paho.mqtt.golang"
|
|
)
|
|
|
|
type PublishRequest struct {
|
|
Topic string
|
|
Qos byte
|
|
Retained bool
|
|
Payload interface{}
|
|
}
|
|
|
|
func publisherLoop(requests <-chan PublishRequest) error {
|
|
const configFn = "/perm/dhcp4d/mqtt-broker.txt"
|
|
b, err := ioutil.ReadFile(configFn)
|
|
if err != nil {
|
|
// discard requests:
|
|
for range requests {
|
|
}
|
|
return nil
|
|
}
|
|
// e.g. tcp://10.0.0.54:1883, which is a static DHCP lease for the dr.lan
|
|
// Raspberry Pi, which is running an MQTT broker in my network.
|
|
broker := strings.TrimSpace(string(b))
|
|
log.Printf("Connecting to MQTT broker %q (configured in %s)", broker, configFn)
|
|
opts := mqtt.NewClientOptions().AddBroker(broker)
|
|
opts.SetClientID("dhcp4d")
|
|
opts.SetConnectRetry(true)
|
|
mqttClient := mqtt.NewClient(opts)
|
|
if token := mqttClient.Connect(); token.Wait() && token.Error() != nil {
|
|
return fmt.Errorf("MQTT connection failed: %v", token.Error())
|
|
}
|
|
|
|
for r := range requests {
|
|
// discard Token, MQTT publishing is best-effort
|
|
_ = mqttClient.Publish(r.Topic, r.Qos, r.Retained, r.Payload)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func MQTT() chan<- PublishRequest {
|
|
result := make(chan PublishRequest)
|
|
go func() {
|
|
if err := publisherLoop(result); err != nil {
|
|
log.Print(err)
|
|
}
|
|
}()
|
|
return result
|
|
}
|