project-flotta#118 ECOPROJECT-717 Implement registration-retry with …

…exponential backoff

internal/registration/registration.go

@@ -18,7 +18,8 @@ import (
 )
 
 const (
-	retryAfter = 10
+	retryAfter  = 10
+	maxInterval = 60
 )
 
 //go:generate mockgen -package=registration -destination=mock_deregistrable.go . Deregistrable
@@ -43,6 +44,7 @@ type Registration struct {
 	lock             sync.RWMutex
 	deregistrables   []Deregistrable
 	clientCert       *ClientCert
+	nbRetry          int
 }
 
 func NewRegistration(deviceID string, hardware *hardware2.Hardware, dispatcherClient DispatcherClient,
@@ -55,6 +57,7 @@ func NewRegistration(deviceID string, hardware *hardware2.Hardware, dispatcherCl
 		RetryAfter:       retryAfter,
 		workloads:        workloadsManager,
 		lock:             sync.RWMutex{},
+		nbRetry:          0,
 	}
 	err := reg.CreateClientCerts()
 	if err != nil {
@@ -111,18 +114,54 @@ func (r *Registration) RegisterDevice() {
 }
 
 func (r *Registration) registerDeviceWithRetries(interval int64) {
-	ticker := time.NewTicker(time.Second * time.Duration(interval))
-	for range ticker.C {
-		if !r.config.IsInitialConfig() {
-			ticker.Stop()
-			break
+	currentInterval := interval
+	ticker := time.NewTicker(time.Second * time.Duration(currentInterval))
+	var registrationSuccess bool
+
+	for {
+		select {
+		case <-ticker.C:
+			registrationSuccess, ticker = tryRegister(currentInterval, r, ticker)
+			if registrationSuccess {
+				break
+			}
+
 		}
-		log.Infof("configuration has not been initialized yet. Sending registration request. DeviceID: %s;", r.deviceID)
-		err := r.registerDeviceOnce()
-		if err != nil {
-			log.Errorf("cannot register device. DeviceID: %s; err: %v", r.deviceID, err)
+
+	}
+
+}
+
+func tryRegister(currentInterval int64, r *Registration, ticker *time.Ticker) (bool, *time.Ticker) {
+	log.Debugf("Current interval: %d", currentInterval)
+	if !r.config.IsInitialConfig() {
+		ticker.Stop()
+		return true, ticker
+	}
+	log.Infof("configuration has not been initialized yet. Sending registration request. DeviceID: %s;", r.deviceID)
+	err := r.registerDeviceOnce()
+	if err != nil {
+		log.Errorf("cannot register device. DeviceID: %s; err: %v", r.deviceID, err)
+	}
+	ticker = incrementIntervalAndApply(&currentInterval, ticker)
+	r.nbRetry++
+
+	return false, ticker
+}
+
+func incrementIntervalAndApply(currentInterval *int64, ticker *time.Ticker) *time.Ticker {
+	interval := *currentInterval
+
+	if interval < maxInterval {
+		interval = interval * 2
+		if interval > maxInterval {
+			interval = maxInterval
 		}
+		ticker.Stop()
+		ticker = time.NewTicker(time.Duration(interval) * time.Second)
+		*currentInterval = interval
 	}
+	return ticker
 }
 
 func (r *Registration) registerDeviceOnce() error {
@@ -172,7 +211,7 @@ func (r *Registration) registerDeviceOnce() error {
 	var message models.MessageResponse
 	err = json.Unmarshal(parsedResponse.Body, &message)
 	if err != nil {
-    return fmt.Errorf("Cannot unmarshal registration response content: %v", err)
+		return fmt.Errorf("Cannot unmarshal registration response content: %v", err)
 	}
 
 	parsedContent, ok := message.Content.(map[string]interface{})
@@ -222,6 +261,12 @@ func (r *Registration) Deregister() error {
 	return errors
 }
 
+func (r *Registration) NbRetry() int {
+	r.lock.RLock()
+	defer r.lock.RUnlock()
+	return r.nbRetry
+}
+
 type YGGDResponse struct {
 	// StatusCode response
 	StatusCode int

internal/registration/registration_test.go

@@ -279,7 +279,7 @@ var _ = Describe("Registration", func() {
 			Expect(content).To(Equal(clientCertPem))
 		})
 
-		It("Try to re-register", func() {
+		FIt("Try to re-register", func() {
 			// given
 			reg, err := registration.NewRegistration(deviceID, hw, dispatcherMock, configManager, wkManager)
 			Expect(err).NotTo(HaveOccurred())
@@ -288,21 +288,22 @@ var _ = Describe("Registration", func() {
 				Certificate: string(clientCertPem),
 			})
 
-			reg.RetryAfter = 1
-
 			// then
 			dispatcherMock.EXPECT().Send(gomock.Any(), gomock.Any()).Return(
-				nil, fmt.Errorf("failed")).Times(1)
+				nil, fmt.Errorf("failed")).Times(4)
 			dispatcherMock.EXPECT().
 				Send(gomock.Any(), RegistrationMatcher()).
 				Return(&pb.Response{Response: msgResponse}, nil).
 				Times(1)
 
+			reg.RetryAfter = 1 //will do try then wait for 1 sec, 2 sec, 4 sec => 7sec in total for 4 attempts
+
 			//  when
 			reg.RegisterDevice()
 
 			// then
-			Eventually(reg.IsRegistered, "5s").Should(BeTrue())
+			Eventually(reg.IsRegistered, "8s").Should(BeTrue())
+			Eventually(reg.NbRetry, "8s").Should(Equal(4))
 		})
 
 	})