my own modifications, part 1

src/smq/mqtt/mqtt.go

@@ -0,0 +1,113 @@
+package mqtt
+
+import "log"
+import "fmt"
+import MQTT "github.com/eclipse/paho.mqtt.golang"
+import "github.com/google/uuid"
+import "crypto/tls"
+import "smq/config"
+// import "smq/counter"
+
+type Message struct {
+  Topic string
+  Payload []byte
+}
+
+var OutputChannel chan Message = make(chan Message, 100)
+
+var mqttClient MQTT.Client
+
+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) {
+  log.Println("Connected")
+}
+
+func outputDispatcher(client MQTT.Client) {
+  for {
+    select {
+    case message := <- OutputChannel:
+      log.Printf("Message arrived in outputDispatcher, topic: %s, payload: %s\n", message.Topic, message.Payload)
+      if token := client.Publish(message.Topic, 0, false, message.Payload); token.Wait() && token.Error() != nil {
+        log.Printf("Unable to publish, error %s", token.Error())
+      }
+      log.Println("Successfully published")
+    }
+  }
+}
+
+func Publish(msg []byte) {
+  message := Message {
+    Topic: config.Config.Mqtt.Topic,
+    Payload: msg,
+  }
+  select {
+  case OutputChannel <- message:
+    {}
+  default:
+    log.Printf("Channel full, message %s lost")
+  }
+}
+
+
+func Start() {
+  broker := config.Config.Mqtt.Broker
+  if broker == "" {
+    log.Fatal("No broker given")
+  }
+
+  prefix := "SMQ"
+  uuid := uuid.New()
+  clientId := fmt.Sprintf("%s-%s", prefix, uuid)
+
+  opts := MQTT.NewClientOptions().
+    AddBroker(broker).
+    SetClientID(clientId).
+    SetConnectionLostHandler(onConnectionLost).
+    SetOnConnectHandler(onConnect).
+    SetReconnectingHandler(onReconnecting).
+    SetConnectRetry(true)
+
+  username := config.Config.Mqtt.Username
+  if username != "" {
+    opts.SetUsername(username)
+  }
+
+  password := config.Config.Mqtt.Password
+  if password != "" {
+    opts.SetPassword(password)
+  }
+
+  enableTls := config.Config.Mqtt.TlsEnable
+  if enableTls == "true" {
+    //log.Println("Enabling TLS connection")
+    tlsConfig := &tls.Config { 
+      InsecureSkipVerify: true, 
+    }
+    opts.SetTLSConfig(tlsConfig)
+	}
+
+  log.Println("Broker connecting")
+  mqttClient = MQTT.NewClient(opts)
+  if token := mqttClient.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)
+
+  go outputDispatcher(mqttClient)
+
+  return
+}
+
+func Stop() {
+  log.Println("Disconnecting from broker")
+  mqttClient.Disconnect(250)
+}
+