From cc2e90fe808c05e0a3794e733c0a2fc9b3068c29 Mon Sep 17 00:00:00 2001
From: gabriel-farache <gfarache@redhat.com>
Date: Tue, 12 Apr 2022 16:32:20 +0200
Subject: [PATCH]  #118 ECOPROJECT-717 Implement registration-retry with
 exponential backoff

---
 internal/registration/registration.go      | 51 +++++++++++++++++-----
 internal/registration/registration_test.go | 26 +++++++++++
 2 files changed, 65 insertions(+), 12 deletions(-)

diff --git a/internal/registration/registration.go b/internal/registration/registration.go
index 3da8281a..69317a51 100644
--- a/internal/registration/registration.go
+++ b/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 +114,36 @@ 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
-		}
-		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)
+	currentInterval := interval
+	ticker := time.NewTicker(time.Second * time.Duration(currentInterval))
+
+	for {
+		select {
+		case <-ticker.C:
+			log.Infof("Current interval: %d", currentInterval)
+			if !r.config.IsInitialConfig() {
+				ticker.Stop()
+				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)
+			}
+			if currentInterval < maxInterval {
+				currentInterval = currentInterval * 2
+				if currentInterval > maxInterval {
+					currentInterval = maxInterval
+				}
+				ticker.Stop()
+				ticker = time.NewTicker(time.Duration(currentInterval) * time.Second)
+			}
+			r.nbRetry++
+
 		}
+
 	}
+
 }
 
 func (r *Registration) registerDeviceOnce() error {
@@ -172,7 +193,7 @@ 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 +243,12 @@ 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
diff --git a/internal/registration/registration_test.go b/internal/registration/registration_test.go
index a4bddca1..d570848e 100644
--- a/internal/registration/registration_test.go
+++ b/internal/registration/registration_test.go
@@ -305,6 +305,32 @@ var _ = Describe("Registration", func() {
 			Eventually(reg.IsRegistered, "5s").Should(BeTrue())
 		})
 
+		It("Try to re-register exponetial", func() {
+			// given
+			reg, err := registration.NewRegistration(deviceID, hw, dispatcherMock, configManager, wkManager)
+			Expect(err).NotTo(HaveOccurred())
+
+			msgResponse := getYggdrasilResponse(models.RegistrationResponse{
+				Certificate: string(clientCertPem),
+			})
+
+			reg.RetryAfter = 1
+
+			// then
+			dispatcherMock.EXPECT().Send(gomock.Any(), gomock.Any()).Return(
+				nil, fmt.Errorf("failed")).Times(3)
+			dispatcherMock.EXPECT().
+				Send(gomock.Any(), RegistrationMatcher()).
+				Return(&pb.Response{Response: msgResponse}, nil).
+				Times(1)
+
+			//  when
+			reg.RegisterDevice()
+
+			// then
+			Eventually(reg.IsRegistered, "8s").Should(BeTrue())
+			Eventually(reg.NbRetry, "8s").Should(Equal(3))
+		})
 	})
 
 	Context("Deregister", func() {