initial

main.go

@@ -0,0 +1,74 @@
+package main
+
+import "log"
+import "fmt"
+import "os"
+import "os/signal"
+import "strings"
+import MQTT "github.com/eclipse/paho.mqtt.golang"
+import "github.com/google/uuid"
+
+
+
+func onMessageReceived(client MQTT.Client, message MQTT.Message) {
+  log.Printf("Message received, topic: %s, payload: %s\n", message.Topic(), message.Payload())
+}
+
+func onConnectionLost(client MQTT.Client, error error) {
+  log.Printf("Connection lost, error %s", error)
+}
+
+func onReconnecting(client MQTT.Client, clientOpts *MQTT.ClientOptions) {
+  log.Println("Oops, connection lost, already reconnecting ...")
+}
+
+
+func onConnect(client MQTT.Client) {
+  topicsStr := os.Getenv("MQTT_SUBSCRIBE_TOPICS")
+  topics := strings.Split(topicsStr, ",")
+  for _, topic := range topics {
+    if token := client.Subscribe(topic, 0, onMessageReceived); token.Wait() && token.Error() != nil {
+      log.Fatalf("Unable to subscribe to topic %s, error %s", topic, token.Error())
+    }
+    log.Printf("Successfully subscribed to topic %s", topic)
+  }
+}
+
+
+func main() {
+  log.SetPrefix("UDI: ")
+  log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
+
+  log.Println("UDI starting")
+
+  broker := os.Getenv("MQTT_BROKER")
+
+  prefix := "UDI"
+  uuid := uuid.New()
+  clientId := fmt.Sprintf("%s-%s", prefix, uuid)
+
+  mqttOpts := MQTT.NewClientOptions().
+    AddBroker(broker).
+    SetClientID(clientId).
+    SetConnectionLostHandler(onConnectionLost).
+    SetOnConnectHandler(onConnect).
+    SetReconnectingHandler(onReconnecting).
+    SetConnectRetry(true)
+
+  client := MQTT.NewClient(mqttOpts)
+  if token := client.Connect(); token.Wait() && token.Error() != nil {
+    log.Fatalf("Unable to connect to broker %s, error %s", broker, token.Error())
+  }
+  log.Printf("Successfully connected to broker %s", broker)
+
+
+  log.Println("UDI running")
+
+  c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt, os.Kill)
+	<-c
+
+  log.Println("Terminating UDI")
+  client.Disconnect(250)
+}
+