started refactoring the AMPQ session, WIP #74

helper/amqp_session.go

@@ -0,0 +1,277 @@
+package helper
+
+import (
+	"fmt"
+	"github.com/streadway/amqp"
+	"log"
+	"time"
+)
+
+type AMQPsession struct {
+	connection          *amqp.Connection
+	sendCh              *amqp.Channel
+	recvCh              *amqp.Channel
+	notifyConnClose     chan *amqp.Error
+	notifySendChanClose chan *amqp.Error
+	notifySendConfirm   chan amqp.Confirmation
+	notifyRecvChanClose chan *amqp.Error
+	notifyRecvConfirm   chan amqp.Confirmation
+	IsReady             bool
+	done                chan bool
+	name                string
+	exchange            string
+	processMessage      func(delivery amqp.Delivery)
+}
+
+const (
+	// When reconnecting to the server after connection failure
+	reconnectDelay = 5 * time.Second
+
+	// When setting up the channel after a channel exception
+	reInitDelay = 2 * time.Second
+
+	// When resending messages the server didn't confirm
+	resendDelay = 5 * time.Second
+)
+
+//var client AMQPsession
+
+// NewAMQPSession creates a new consumer state instance, and automatically
+// attempts to connect to the server.
+func NewAMQPSession(name string, AMQPurl string, exchange string, processMessage func(delivery amqp.Delivery)) *AMQPsession {
+	if AMQPurl != "" {
+		log.Println("Starting AMQP client")
+
+		session := AMQPsession{
+			name:           name,
+			exchange:       exchange,
+			done:           make(chan bool),
+			processMessage: processMessage,
+		}
+		go session.handleReconnect(AMQPurl)
+
+		return &session
+	}
+
+	return nil
+}
+
+// handleReconnect will wait for a connection error on
+// notifyConnClose, and then continuously attempt to reconnect.
+func (session *AMQPsession) handleReconnect(addr string) {
+	for {
+		session.IsReady = false
+		log.Println("Attempting to connect to AMQP broker ", addr)
+
+		conn, err := session.connect(addr)
+
+		if err != nil {
+			log.Println("Failed to connect. Retrying...")
+
+			select {
+			case <-session.done:
+				return
+			case <-time.After(reconnectDelay):
+			}
+			continue
+		}
+
+		if done := session.handleReInit(conn); done {
+			break
+		}
+	}
+}
+
+// connect will create a new AMQP connection
+func (session *AMQPsession) connect(addr string) (*amqp.Connection, error) {
+	conn, err := amqp.Dial(addr)
+
+	if err != nil {
+		return nil, err
+	}
+
+	// take a new connection to the queue, and updates the close listener to reflect this.
+	session.connection = conn
+	session.notifyConnClose = make(chan *amqp.Error)
+	session.connection.NotifyClose(session.notifyConnClose)
+
+	log.Println("Connected!")
+	return conn, nil
+}
+
+// handleReInit will wait for a channel error
+// and then continuously attempt to re-initialize both channels
+func (session *AMQPsession) handleReInit(conn *amqp.Connection) bool {
+	for {
+		session.IsReady = false
+
+		err := session.init(conn)
+
+		if err != nil {
+			log.Println("Failed to initialize channel. Retrying...")
+
+			select {
+			case <-session.done:
+				return true
+			case <-time.After(reInitDelay):
+			}
+			continue
+		}
+
+		select {
+		case <-session.done:
+			return true
+		case <-session.notifyConnClose:
+			log.Println("Connection closed. Reconnecting...")
+			return false
+		case <-session.notifySendChanClose:
+			log.Println("Send channel closed. Re-running init...")
+		case <-session.notifyRecvChanClose:
+			log.Println("Receive channel closed. Re-running init...")
+		}
+	}
+}
+
+// init will initialize channel & declare queue
+func (session *AMQPsession) init(conn *amqp.Connection) error {
+	ch, err := conn.Channel()
+
+	if err != nil {
+		return err
+	}
+
+	err = ch.Confirm(false)
+
+	if err != nil {
+		return err
+	}
+	_, err = ch.QueueDeclare(
+		session.name,
+		false, // Durable
+		false, // Delete when unused
+		false, // Exclusive
+		false, // No-wait
+		nil,   // Arguments
+	)
+
+	if err != nil {
+		return err
+	}
+
+	// create sendCh
+	sendCh, err := conn.Channel()
+	if err != nil {
+		return fmt.Errorf("AMQP: failed to open a sendCh, error: %v", err)
+	}
+	// declare exchange
+	err = sendCh.ExchangeDeclare(session.exchange,
+		"headers",
+		true,
+		false,
+		false,
+		false,
+		nil)
+	if err != nil {
+		return fmt.Errorf("AMQP: failed to declare the exchange, error: %v", err)
+	}
+
+	// add a queue for the ICs
+	ICQueue, err := sendCh.QueueDeclare("infrastructure_components",
+		true,
+		false,
+		false,
+		false,
+		nil)
+	if err != nil {
+		return fmt.Errorf("AMQP: failed to declare the queue, error: %v", err)
+	}
+
+	err = sendCh.QueueBind(ICQueue.Name, "", session.exchange, false, nil)
+	if err != nil {
+		return fmt.Errorf("AMQP: failed to bind the queue, error: %v", err)
+	}
+
+	session.sendCh = sendCh
+	session.notifySendChanClose = make(chan *amqp.Error)
+	session.notifySendConfirm = make(chan amqp.Confirmation, 1)
+	session.sendCh.NotifyClose(session.notifySendChanClose)
+	session.sendCh.NotifyPublish(session.notifySendConfirm)
+
+	// create receive channel
+	recvCh, err := conn.Channel()
+	if err != nil {
+		return fmt.Errorf("AMQP: failed to open a recvCh, error: %v", err)
+	}
+
+	session.recvCh = recvCh
+	session.notifyRecvChanClose = make(chan *amqp.Error)
+	session.notifyRecvConfirm = make(chan amqp.Confirmation, 1)
+	session.recvCh.NotifyClose(session.notifyRecvChanClose)
+	session.recvCh.NotifyPublish(session.notifyRecvConfirm)
+
+	// start deliveries
+	messages, err := session.recvCh.Consume(ICQueue.Name,
+		"",
+		true,
+		false,
+		false,
+		false,
+		nil)
+	if err != nil {
+		return fmt.Errorf("AMQP: failed to start deliveries: %v", err)
+	}
+
+	// consume deliveries
+	go func() {
+		for {
+			for message := range messages {
+				session.processMessage(message)
+			}
+		}
+	}()
+	session.IsReady = true
+	log.Println("AMQP channels setup! Waiting for messages...")
+
+	return nil
+}
+
+func (session *AMQPsession) CheckConnection() error {
+
+	if session.connection != nil {
+		if session.connection.IsClosed() {
+			return fmt.Errorf("connection to broker is closed")
+		}
+	} else {
+		return fmt.Errorf("connection is nil")
+	}
+
+	return nil
+}
+
+func (session *AMQPsession) Send(payload []byte, destinationUuid string) error {
+
+	message := amqp.Publishing{
+		DeliveryMode:    2,
+		Timestamp:       time.Now(),
+		ContentType:     "application/json",
+		ContentEncoding: "utf-8",
+		Priority:        0,
+		Body:            payload,
+	}
+
+	// set message headers
+	message.Headers = make(map[string]interface{}) // empty map
+	message.Headers["uuid"] = destinationUuid      // leave uuid empty if message should go to all ICs
+
+	err := session.CheckConnection()
+	if err != nil {
+		return err
+	}
+
+	err = session.sendCh.Publish(session.exchange,
+		"",
+		false,
+		false,
+		message)
+	return err
+}

routes/healthz/healthz_endpoint.go

@@ -29,15 +29,20 @@ import (
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/configuration"
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/database"
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/helper"
-	infrastructure_component "git.rwth-aachen.de/acs/public/villas/web-backend-go/routes/infrastructure-component"
 	"github.com/gin-gonic/gin"
 )
 
+var session *helper.AMQPsession
+
 func RegisterHealthzEndpoint(r *gin.RouterGroup) {
 
 	r.GET("", getHealth)
 }
 
+func SetAMQPSession(s *helper.AMQPsession) {
+	session = s
+}
+
 // getHealth godoc
 // @Summary Get health status of backend
 // @ID getHealth
@@ -69,7 +74,7 @@ func getHealth(c *gin.Context) {
 	}
 
 	if len(url) != 0 {
-		err = infrastructure_component.CheckConnection()
+		err = session.CheckConnection()
 		if err != nil {
 			log.Println(err.Error())
 			c.JSON(http.StatusInternalServerError, gin.H{

routes/healthz/healthz_test.go

@@ -80,8 +80,14 @@ func TestHealthz(t *testing.T) {
 	amqpURI := "amqp://" + user + ":" + pass + "@" + host
 	log.Println("AMQP URI is", amqpURI)
 
-	err = infrastructure_component.ConnectAMQP(amqpURI)
-	assert.NoError(t, err)
+	session = helper.NewAMQPSession("villas-test-session", amqpURI, "villas", infrastructure_component.ProcessMessage)
+	SetAMQPSession(session)
+
+	for {
+		if session.IsReady {
+			break
+		}
+	}
 
 	// test healthz endpoint for connected DB and AMQP client
 	code, resp, err = helper.TestEndpoint(router, "", "/api/v2/healthz", http.MethodGet, nil)

routes/infrastructure-component/ic_amqpmethods.go

@@ -24,25 +24,14 @@ package infrastructure_component
 import (
 	"encoding/json"
 	"fmt"
-	"log"
-	"strings"
-	"time"
-
-	"github.com/gin-gonic/gin"
 	"github.com/google/uuid"
 	"github.com/jinzhu/gorm"
 	"github.com/jinzhu/gorm/dialects/postgres"
 	"github.com/streadway/amqp"
+	"log"
+	"strings"
 )
 
-const VILLAS_EXCHANGE = "villas"
-
-type AMQPclient struct {
-	connection *amqp.Connection
-	sendCh     *amqp.Channel
-	recvCh     *amqp.Channel
-}
-
 type Action struct {
 	Act        string          `json:"action"`
 	When       int64           `json:"when"`
@@ -85,205 +74,24 @@ type ICUpdate struct {
 	Action     string       `json:"action"`
 }
 
-var client AMQPclient
-
-func ConnectAMQP(uri string) error {
-
-	var err error
-
-	// connect to broker
-	client.connection, err = amqp.Dial(uri)
-	if err != nil {
-		return fmt.Errorf("AMQP: failed to connect to RabbitMQ broker %v, error: %v", uri, err)
-	}
-
-	// create sendCh
-	client.sendCh, err = client.connection.Channel()
-	if err != nil {
-		return fmt.Errorf("AMQP: failed to open a sendCh, error: %v", err)
-	}
-	// declare exchange
-	err = client.sendCh.ExchangeDeclare(VILLAS_EXCHANGE,
-		"headers",
-		true,
-		false,
-		false,
-		false,
-		nil)
-	if err != nil {
-		return fmt.Errorf("AMQP: failed to declare the exchange, error: %v", err)
-	}
-
-	// add a queue for the ICs
-	ICQueue, err := client.sendCh.QueueDeclare("infrastructure_components",
-		true,
-		false,
-		false,
-		false,
-		nil)
-	if err != nil {
-		return fmt.Errorf("AMQP: failed to declare the queue, error: %v", err)
-	}
-
-	err = client.sendCh.QueueBind(ICQueue.Name, "", VILLAS_EXCHANGE, false, nil)
-	if err != nil {
-		return fmt.Errorf("AMQP: failed to bind the queue, error: %v", err)
-	}
-
-	// create receive channel
-	client.recvCh, err = client.connection.Channel()
-	if err != nil {
-		return fmt.Errorf("AMQP: failed to open a recvCh, error: %v", err)
-	}
-
-	// start deliveries
-	messages, err := client.recvCh.Consume(ICQueue.Name,
-		"",
-		true,
-		false,
-		false,
-		false,
-		nil)
-	if err != nil {
-		return fmt.Errorf("AMQP: failed to start deliveries: %v", err)
-	}
-
-	// consume deliveries
-	go func() {
-		for {
-			for message := range messages {
-				err = processMessage(message)
-				if err != nil {
-					log.Println("AMQP: Error processing message: ", err.Error())
-				}
-			}
-		}
-	}()
-
-	log.Printf(" AMQP: Waiting for messages... ")
-
-	return nil
-}
-
-func sendActionAMQP(action Action, destinationUUID string) error {
-
-	payload, err := json.Marshal(action)
-	if err != nil {
-		return err
-	}
-
-	msg := amqp.Publishing{
-		DeliveryMode:    2,
-		Timestamp:       time.Now(),
-		ContentType:     "application/json",
-		ContentEncoding: "utf-8",
-		Priority:        0,
-		Body:            payload,
-	}
-
-	// set message headers
-	msg.Headers = make(map[string]interface{}) // empty map
-	msg.Headers["uuid"] = destinationUUID
-
-	err = CheckConnection()
-	if err != nil {
-		return err
-	}
-
-	//log.Println("AMQP: Sending message", string(msg.Body))
-	err = client.sendCh.Publish(VILLAS_EXCHANGE,
-		"",
-		false,
-		false,
-		msg)
-	return err
-
-}
-
-func SendPing(uuid string) error {
-	var ping Action
-	ping.Act = "ping"
-
-	payload, err := json.Marshal(ping)
-	if err != nil {
-		return err
-	}
-
-	msg := amqp.Publishing{
-		DeliveryMode:    2,
-		Timestamp:       time.Now(),
-		ContentType:     "application/json",
-		ContentEncoding: "utf-8",
-		Priority:        0,
-		Body:            payload,
-	}
-
-	// set message headers
-	msg.Headers = make(map[string]interface{}) // empty map
-	msg.Headers["uuid"] = uuid                 // leave uuid empty if ping should go to all ICs
-
-	err = CheckConnection()
-	if err != nil {
-		return err
-	}
-
-	err = client.sendCh.Publish(VILLAS_EXCHANGE,
-		"",
-		false,
-		false,
-		msg)
-	return err
-}
-
-func CheckConnection() error {
-
-	if client.connection != nil {
-		if client.connection.IsClosed() {
-			return fmt.Errorf("connection to broker is closed")
-		}
-	} else {
-		return fmt.Errorf("connection is nil")
-	}
-
-	return nil
-}
-
-func StartAMQP(AMQPurl string, api *gin.RouterGroup) error {
-	if AMQPurl != "" {
-		log.Println("Starting AMQP client")
-
-		err := ConnectAMQP(AMQPurl)
-		if err != nil {
-			return err
-		}
-
-		// register IC action endpoint only if AMQP client is used
-		RegisterAMQPEndpoint(api.Group("/ic"))
-
-		log.Printf("Connected AMQP client to %s", AMQPurl)
-	}
-
-	return nil
-}
-
-func processMessage(message amqp.Delivery) error {
+func ProcessMessage(message amqp.Delivery) {
 
 	var payload ICUpdate
 	err := json.Unmarshal(message.Body, &payload)
 	if err != nil {
-		return fmt.Errorf("AMQP: Could not unmarshal message to JSON: %v err: %v", string(message.Body), err)
+		log.Printf("AMQP: Could not unmarshal message to JSON: %v err: %v", string(message.Body), err)
 	}
 
 	if payload.Action != "" {
 		// if a message contains an action, it is not intended for the backend
 		//log.Println("AMQP: Ignoring action message ", payload)
-		return nil
+		return
 	}
 
 	ICUUID := payload.Properties.UUID
 	_, err = uuid.Parse(ICUUID)
 	if err != nil {
-		return fmt.Errorf("AMQP: UUID not valid: %v, message ignored: %v \n", ICUUID, string(message.Body))
+		log.Printf("AMQP: UUID not valid: %v, message ignored: %v \n", ICUUID, string(message.Body))
 	}
 
 	var sToBeUpdated InfrastructureComponent
@@ -299,8 +107,10 @@ func processMessage(message amqp.Delivery) error {
 		// update record based on payload
 		err = sToBeUpdated.updateExternalIC(payload, message.Body)
 	}
+	if err != nil {
+		log.Printf(err.Error())
+	}
 
-	return err
 }
 
 func createExternalIC(payload ICUpdate, ICUUID string, body []byte) error {
@@ -358,7 +168,11 @@ func createExternalIC(payload ICUpdate, ICUUID string, body []byte) error {
 	log.Println("AMQP: Created IC with UUID ", newIC.UUID)
 
 	// send ping to get full status update of this IC
-	err = SendPing(ICUUID)
+	if session != nil {
+		err = SendPing(ICUUID)
+	} else {
+		err = fmt.Errorf("cannot sent ping to %v because AMQP session is nil", ICUUID)
+	}
 	return err
 }
 
@@ -433,3 +247,27 @@ func newFalse() *bool {
 	b := false
 	return &b
 }
+
+func SendPing(uuid string) error {
+	var ping Action
+	ping.Act = "ping"
+
+	payload, err := json.Marshal(ping)
+	if err != nil {
+		return err
+	}
+
+	err = session.Send(payload, uuid)
+	return err
+}
+
+func sendActionAMQP(action Action, destinationUUID string) error {
+
+	payload, err := json.Marshal(action)
+	if err != nil {
+		return err
+	}
+
+	err = session.Send(payload, destinationUUID)
+	return err
+}

routes/infrastructure-component/ic_endpoints.go

@@ -37,10 +37,13 @@ func RegisterICEndpoints(r *gin.RouterGroup) {
 	r.GET("/:ICID", getIC)
 	r.DELETE("/:ICID", deleteIC)
 	r.GET("/:ICID/configs", getConfigsOfIC)
+	r.POST("/:ICID/action", sendActionToIC)
 }
 
-func RegisterAMQPEndpoint(r *gin.RouterGroup) {
-	r.POST("/:ICID/action", sendActionToIC)
+var session *helper.AMQPsession
+
+func SetAMQPSession(s *helper.AMQPsession) {
+	session = s
 }
 
 // getICs godoc

routes/infrastructure-component/ic_test.go

@@ -24,13 +24,10 @@ package infrastructure_component
 import (
 	"encoding/json"
 	"fmt"
-	"log"
 	"os"
 	"testing"
 	"time"
 
-	"github.com/streadway/amqp"
-
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/helper"
 	component_configuration "git.rwth-aachen.de/acs/public/villas/web-backend-go/routes/component-configuration"
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/routes/scenario"
@@ -133,12 +130,6 @@ func TestMain(m *testing.M) {
 	// that can be associated with a new component configuration
 	scenario.RegisterScenarioEndpoints(api.Group("/scenarios"))
 
-	// check AMQP connection
-	err = CheckConnection()
-	if err.Error() != "connection is nil" {
-		return
-	}
-
 	// connect AMQP client
 	// Make sure that AMQP_HOST, AMQP_USER, AMQP_PASS are set
 	host, err := configuration.GlobalConfig.String("amqp.host")
@@ -148,11 +139,8 @@ func TestMain(m *testing.M) {
 
 	// AMQP Connection startup is tested here
 	// Not repeated in other tests because it is only needed once
-	err = StartAMQP(amqpURI, api)
-	if err != nil {
-		log.Println("unable to connect to AMQP")
-		return
-	}
+	session = helper.NewAMQPSession("villas-test-session", amqpURI, "villas", ProcessMessage)
+	SetAMQPSession(session)
 
 	os.Exit(m.Run())
 }
@@ -306,28 +294,14 @@ func TestUpdateICAsAdmin(t *testing.T) {
 	payload, err := json.Marshal(update)
 	assert.NoError(t, err)
 
-	var headers map[string]interface{}
-	headers = make(map[string]interface{}) // empty map
-	headers["uuid"] = newIC2.Manager       // set uuid
+	//var headers map[string]interface{}
+	//headers = make(map[string]interface{}) // empty map
+	//headers["uuid"] = newIC2.Manager       // set uuid
 
-	msg := amqp.Publishing{
-		DeliveryMode:    2,
-		Timestamp:       time.Now(),
-		ContentType:     "application/json",
-		ContentEncoding: "utf-8",
-		Priority:        0,
-		Body:            payload,
-		Headers:         headers,
-	}
-
-	err = CheckConnection()
+	err = session.CheckConnection()
 	assert.NoError(t, err)
 
-	err = client.sendCh.Publish(VILLAS_EXCHANGE,
-		"",
-		false,
-		false,
-		msg)
+	err = session.Send(payload, newIC2.Manager)
 	assert.NoError(t, err)
 
 	// Wait until externally managed IC is created (happens async)
@@ -430,28 +404,10 @@ func TestDeleteICAsAdmin(t *testing.T) {
 	payload, err := json.Marshal(update)
 	assert.NoError(t, err)
 
-	var headers map[string]interface{}
-	headers = make(map[string]interface{}) // empty map
-	headers["uuid"] = newIC2.UUID          // set uuid
-
-	msg := amqp.Publishing{
-		DeliveryMode:    2,
-		Timestamp:       time.Now(),
-		ContentType:     "application/json",
-		ContentEncoding: "utf-8",
-		Priority:        0,
-		Body:            payload,
-		Headers:         headers,
-	}
-
-	err = CheckConnection()
+	err = session.CheckConnection()
 	assert.NoError(t, err)
 
-	err = client.sendCh.Publish(VILLAS_EXCHANGE,
-		"",
-		false,
-		false,
-		msg)
+	err = session.Send(payload, newIC2.UUID)
 	assert.NoError(t, err)
 
 	// Wait until externally managed IC is created (happens async)
@@ -662,28 +618,10 @@ func TestCreateUpdateViaAMQPRecv(t *testing.T) {
 	payload, err := json.Marshal(update)
 	assert.NoError(t, err)
 
-	var headers map[string]interface{}
-	headers = make(map[string]interface{}) // empty map
-	headers["uuid"] = newIC1.Manager       // set uuid
-
-	msg := amqp.Publishing{
-		DeliveryMode:    2,
-		Timestamp:       time.Now(),
-		ContentType:     "application/json",
-		ContentEncoding: "utf-8",
-		Priority:        0,
-		Body:            payload,
-		Headers:         headers,
-	}
-
-	err = CheckConnection()
+	err = session.CheckConnection()
 	assert.NoError(t, err)
 
-	err = client.sendCh.Publish(VILLAS_EXCHANGE,
-		"",
-		false,
-		false,
-		msg)
+	err = session.Send(payload, newIC1.Manager)
 	assert.NoError(t, err)
 
 	time.Sleep(waitingTime * time.Second)
@@ -709,25 +647,7 @@ func TestCreateUpdateViaAMQPRecv(t *testing.T) {
 	payload, err = json.Marshal(update)
 	assert.NoError(t, err)
 
-	var headersA map[string]interface{}
-	headersA = make(map[string]interface{}) // empty map
-	headersA["uuid"] = newIC1.Manager
-
-	msg = amqp.Publishing{
-		DeliveryMode:    2,
-		Timestamp:       time.Now(),
-		ContentType:     "application/json",
-		ContentEncoding: "utf-8",
-		Priority:        0,
-		Body:            payload,
-		Headers:         headersA,
-	}
-
-	err = client.sendCh.Publish(VILLAS_EXCHANGE,
-		"",
-		false,
-		false,
-		msg)
+	err = session.Send(payload, newIC1.Manager)
 	assert.NoError(t, err)
 
 	time.Sleep(waitingTime * time.Second)
@@ -743,21 +663,7 @@ func TestCreateUpdateViaAMQPRecv(t *testing.T) {
 	payload, err = json.Marshal(update)
 	assert.NoError(t, err)
 
-	msg = amqp.Publishing{
-		DeliveryMode:    2,
-		Timestamp:       time.Now(),
-		ContentType:     "application/json",
-		ContentEncoding: "utf-8",
-		Priority:        0,
-		Body:            payload,
-		Headers:         headersA,
-	}
-
-	err = client.sendCh.Publish(VILLAS_EXCHANGE,
-		"",
-		false,
-		false,
-		msg)
+	err = session.Send(payload, newIC1.Manager)
 	assert.NoError(t, err)
 
 	time.Sleep(waitingTime * time.Second)
@@ -797,27 +703,10 @@ func TestDeleteICViaAMQPRecv(t *testing.T) {
 	payload, err := json.Marshal(update)
 	assert.NoError(t, err)
 
-	var headers map[string]interface{}
-	headers = make(map[string]interface{}) // empty map
-	headers["uuid"] = newIC1.Manager       // set uuid
-
-	msg := amqp.Publishing{
-		DeliveryMode:    2,
-		Timestamp:       time.Now(),
-		ContentType:     "application/json",
-		ContentEncoding: "utf-8",
-		Priority:        0,
-		Body:            payload,
-		Headers:         headers,
-	}
-
-	err = CheckConnection()
+	err = session.CheckConnection()
 	assert.NoError(t, err)
-	err = client.sendCh.Publish(VILLAS_EXCHANGE,
-		"",
-		false,
-		false,
-		msg)
+
+	err = session.Send(payload, newIC1.Manager)
 	assert.NoError(t, err)
 
 	time.Sleep(waitingTime * time.Second)
@@ -874,22 +763,7 @@ func TestDeleteICViaAMQPRecv(t *testing.T) {
 	payload, err = json.Marshal(update)
 	assert.NoError(t, err)
 
-	msg = amqp.Publishing{
-		DeliveryMode:    2,
-		Timestamp:       time.Now(),
-		ContentType:     "application/json",
-		ContentEncoding: "utf-8",
-		Priority:        0,
-		Body:            payload,
-		Headers:         headers,
-	}
-
-	// attempt to delete IC (should not work immediately because IC is still associated with component config)
-	err = client.sendCh.Publish(VILLAS_EXCHANGE,
-		"",
-		false,
-		false,
-		msg)
+	err = session.Send(payload, newIC1.Manager)
 	assert.NoError(t, err)
 
 	time.Sleep(waitingTime * time.Second)

routes/register_test.go

@@ -26,8 +26,6 @@ import (
 	"os"
 	"testing"
 
-	infrastructure_component "git.rwth-aachen.de/acs/public/villas/web-backend-go/routes/infrastructure-component"
-
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/configuration"
 	"git.rwth-aachen.de/acs/public/villas/web-backend-go/database"
 	"github.com/gin-gonic/gin"
@@ -55,27 +53,6 @@ func TestMain(m *testing.M) {
 	os.Exit(m.Run())
 }
 
-/*
- * The order of test functions is important here
- * 1. Start and connect AMQP
- * 2. Register endpoints
- * 3. Add test data
- */
-
-func TestStartAMQP(t *testing.T) {
-	// connect AMQP client
-	// Make sure that AMQP_HOST, AMQP_USER, AMQP_PASS are set
-	host, err := configuration.GlobalConfig.String("amqp.host")
-	user, err := configuration.GlobalConfig.String("amqp.user")
-	pass, err := configuration.GlobalConfig.String("amqp.pass")
-	amqpURI := "amqp://" + user + ":" + pass + "@" + host
-
-	// AMQP Connection startup is tested here
-	// Not repeated in other tests because it is only needed once
-	err = infrastructure_component.StartAMQP(amqpURI, api)
-	assert.NoError(t, err)
-}
-
 func TestRegisterEndpoints(t *testing.T) {
 	database.DropTables()
 	database.MigrateModels()

start.go

@@ -23,6 +23,8 @@ package main
 
 import (
 	"fmt"
+	"git.rwth-aachen.de/acs/public/villas/web-backend-go/helper"
+	"git.rwth-aachen.de/acs/public/villas/web-backend-go/routes/healthz"
 	"log"
 	"time"
 
@@ -122,15 +124,19 @@ func main() {
 	if AMQPhost != "" {
 		// create amqp URL based on username, password and host
 		amqpurl := "amqp://" + AMQPuser + ":" + AMQPpass + "@" + AMQPhost
-		err = infrastructure_component.StartAMQP(amqpurl, api)
-		if err != nil {
-			log.Fatal(err)
-		}
+		session := helper.NewAMQPSession("villas-amqp-session", amqpurl, "villas", infrastructure_component.ProcessMessage)
+		healthz.SetAMQPSession(session)                  // healthz needs to know the amqp session to check the health of the backend
+		infrastructure_component.SetAMQPSession(session) // IC needs to know the session to send amqp messages
 
 		// send Ping to all externally managed ICs
-		err = infrastructure_component.SendPing("")
-		if err != nil {
-			log.Println("error sending ping action via AMQP: ", err)
+		for {
+			if session.IsReady {
+				err = infrastructure_component.SendPing("")
+				if err != nil {
+					log.Println("error sending ping action via AMQP: ", err.Error())
+				}
+				break
+			}
 		}
 	}