81 lines
2.1 KiB
Go
81 lines
2.1 KiB
Go
package main
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import "log"
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import "fmt"
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import "os"
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import "os/signal"
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import "strings"
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import MQTT "github.com/eclipse/paho.mqtt.golang"
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import "github.com/google/uuid"
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func onMessageReceived(client MQTT.Client, message MQTT.Message) {
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log.Printf("Message received, topic: %s, payload: %s\n", message.Topic(), message.Payload())
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}
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func onConnectionLost(client MQTT.Client, error error) {
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log.Printf("Connection lost, error %s", error)
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}
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func onReconnecting(client MQTT.Client, clientOpts *MQTT.ClientOptions) {
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log.Println("Oops, connection lost, already reconnecting ...")
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}
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func onConnect(client MQTT.Client) {
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topicsStr := os.Getenv("MQTT_SUBSCRIBE_TOPICS")
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if topicsStr == "" {
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log.Fatal("No topics given, set env var MQTT_SUBSCRIBE_TOPICS")
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}
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topics := strings.Split(topicsStr, ",")
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for _, topic := range topics {
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if token := client.Subscribe(topic, 0, onMessageReceived); token.Wait() && token.Error() != nil {
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log.Fatalf("Unable to subscribe to topic %s, error %s", topic, token.Error())
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}
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log.Printf("Successfully subscribed to topic %s", topic)
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}
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}
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func main() {
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log.SetPrefix("UDI: ")
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log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
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log.Println("UDI starting")
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broker := os.Getenv("MQTT_BROKER")
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if broker == "" {
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log.Fatal("No broker given, set env var MQTT_BROKER")
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}
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prefix := "UDI"
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uuid := uuid.New()
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clientId := fmt.Sprintf("%s-%s", prefix, uuid)
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mqttOpts := MQTT.NewClientOptions().
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AddBroker(broker).
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SetClientID(clientId).
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SetConnectionLostHandler(onConnectionLost).
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SetOnConnectHandler(onConnect).
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SetReconnectingHandler(onReconnecting).
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SetConnectRetry(true)
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client := MQTT.NewClient(mqttOpts)
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if token := client.Connect(); token.Wait() && token.Error() != nil {
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log.Fatalf("Unable to connect to broker %s, error %s", broker, token.Error())
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}
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log.Printf("Successfully connected to broker %s", broker)
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log.Println("UDI running")
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c := make(chan os.Signal, 1)
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signal.Notify(c, os.Interrupt, os.Kill)
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<-c
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log.Println("Terminating UDI")
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client.Disconnect(250)
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}
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