- remove ack of message in AMQP client

- add a command line parameter to activate AMQP client

common/amqpclient.go

@@ -85,13 +85,14 @@ func ConnectAMQP(uri string) error {
 	// consuming queue
 	go func() {
 		for message := range client.replies {
-			err = message.Ack(false)
+			//err = message.Ack(false)
-			if err != nil {
+			//if err != nil {
-				fmt.Println("AMQP: Unable to ack message:", err)
+			//	fmt.Println("AMQP: Unable to ack message:", err)
-			}
+			//}
 
 			content := string(message.Body)
 
+			// any action message sent by the VILLAScontroller should be ignored by the web backend
 			if strings.Contains(content, "action") {
 				continue
 			}

common/database.go

@@ -13,6 +13,7 @@ var DB_HOST string
 var DB_NAME string
 var DB_DUMMY string
 var DB_SSLMODE string
+var WITH_AMQP bool
 
 var DBpool *gorm.DB
 
@@ -22,11 +23,13 @@ func init() {
 	flag.StringVar(&DB_NAME, "dbname", "villasdb", "Name of the database to use (default is villasdb)")
 	flag.StringVar(&DB_DUMMY, "dbdummy", "testvillasdb", "Name of the test database to use (default is testvillasdb)")
 	flag.StringVar(&DB_SSLMODE, "dbsslmode", "disable", "SSL mode of DB (default is disable)") // TODO: change default for production
+	flag.BoolVar(&WITH_AMQP, "amqp", false, "If AMQP client for simulators shall be enabled, set this option to true (default is false)")
 	flag.Parse()
 	fmt.Println("DB_HOST has value ", DB_HOST)
 	fmt.Println("DB_NAME has value ", DB_NAME)
 	fmt.Println("DB_DUMMY has value ", DB_DUMMY)
 	fmt.Println("DB_SSLMODE has value ", DB_SSLMODE)
+	fmt.Println("WITH_AMQP has value ", WITH_AMQP)
 }
 
 // Initialize connection to the database

routes/simulator/simulatorEndpoints.go

@@ -18,7 +18,10 @@ func RegisterSimulatorEndpoints(r *gin.RouterGroup) {
 	r.GET("/:simulatorID", getSimulator)
 	r.DELETE("/:simulatorID", deleteSimulator)
 	r.GET("/:simulatorID/models", getModelsOfSimulator)
-	r.POST("/:simulatorID/action", sendActionToSimulator)
+	// register action endpoint only if AMQP client is used
+	if common.WITH_AMQP == true {
+		r.POST("/:simulatorID/action", sendActionToSimulator)
+	}
 }
 
 // getSimulators godoc
@@ -280,7 +283,7 @@ func getModelsOfSimulator(c *gin.Context) {
 }
 
 // sendActionToSimulator godoc
-// @Summary Send an action to simulator
+// @Summary Send an action to simulator (only available if backend server is started with -amqp parameter)
 // @ID sendActionToSimulator
 // @Tags simulators
 // @Produce json

start.go

@@ -65,27 +65,29 @@ func main() {
 
 	r.GET("swagger/*any", ginSwagger.WrapHandler(swaggerFiles.Handler))
 
-	err := common.ConnectAMQP("amqp://localhost")
+	if common.WITH_AMQP == true {
-	if err != nil {
+		fmt.Println("Starting AMQP client")
-		panic(err)
+		err := common.ConnectAMQP("amqp://localhost")
-	}
+		if err != nil {
-
+			panic(err)
-	// Periodically call the Ping function to check which simulators are still there
-	ticker := time.NewTicker(10 * time.Second)
-	go func() {
-
-		for {
-			select {
-			case <-ticker.C:
-				err = common.PingAMQP()
-				if err != nil {
-					fmt.Println("AMQP Error: ", err.Error())
-				}
-			}
 		}
 
-	}()
+		// Periodically call the Ping function to check which simulators are still there
+		ticker := time.NewTicker(10 * time.Second)
+		go func() {
 
+			for {
+				select {
+				case <-ticker.C:
+					err = common.PingAMQP()
+					if err != nil {
+						fmt.Println("AMQP Error: ", err.Error())
+					}
+				}
+			}
+
+		}()
+	}
 	// server at port 4000 to match frontend's redirect path
 	r.Run(":4000")
 }