controller/service: minor cleanup

pkg/controller/service/servicecontroller.go

@@ -57,14 +57,14 @@ const (
 )
 
 type cachedService struct {
+	// Ensures only one goroutine can operate on this service at any given time.
+	mu sync.Mutex
+
 	// The last-known state of the service
 	lastState *api.Service
 	// The state as successfully applied to the load balancer
 	appliedState *api.Service
 
-	// Ensures only one goroutine can operate on this service at any given time.
-	mu sync.Mutex
-
 	// Controls error back-off
 	lastRetryDelay time.Duration
 }
@@ -217,28 +217,31 @@ func (s *ServiceController) watchServices(serviceQueue *cache.DeltaFIFO) {
 // indicating whether processing should be retried; zero means no-retry; otherwise
 // we should retry in that Duration.
 func (s *ServiceController) processDelta(delta *cache.Delta) (error, time.Duration) {
+	var (
+		namespacedName types.NamespacedName
+		cachedService  *cachedService
+	)
+
 	deltaService, ok := delta.Object.(*api.Service)
-	var namespacedName types.NamespacedName
-	var cachedService *cachedService
-	if !ok {
+	if ok {
+		namespacedName.Namespace = deltaService.Namespace
+		namespacedName.Name = deltaService.Name
+		cachedService = s.cache.getOrCreate(namespacedName.String())
+	} else {
 		// If the DeltaFIFO saw a key in our cache that it didn't know about, it
 		// can send a deletion with an unknown state. Grab the service from our
 		// cache for deleting.
 		key, ok := delta.Object.(cache.DeletedFinalStateUnknown)
 		if !ok {
-			return fmt.Errorf("Delta contained object that wasn't a service or a deleted key: %+v", delta), doNotRetry
+			return fmt.Errorf("delta contained object that wasn't a service or a deleted key: %+v", delta), doNotRetry
 		}
 		cachedService, ok = s.cache.get(key.Key)
 		if !ok {
-			return fmt.Errorf("Service %s not in cache even though the watcher thought it was. Ignoring the deletion.", key), doNotRetry
+			return fmt.Errorf("service %s not in cache even though the watcher thought it was. Ignoring the deletion.", key), doNotRetry
 		}
 		deltaService = cachedService.lastState
 		delta.Object = deltaService
 		namespacedName = types.NamespacedName{Namespace: deltaService.Namespace, Name: deltaService.Name}
-	} else {
-		namespacedName.Namespace = deltaService.Namespace
-		namespacedName.Name = deltaService.Name
-		cachedService = s.cache.getOrCreate(namespacedName.String())
 	}
 	glog.V(2).Infof("Got new %s delta for service: %v", delta.Type, namespacedName)
 
@@ -255,7 +258,8 @@ func (s *ServiceController) processDelta(delta *cache.Delta) (error, time.Durati
 	if err != nil && !errors.IsNotFound(err) {
 		glog.Warningf("Failed to get most recent state of service %v from API (will retry): %v", namespacedName, err)
 		return err, cachedService.nextRetryDelay()
-	} else if errors.IsNotFound(err) {
+	}
+	if errors.IsNotFound(err) {
 		glog.V(2).Infof("Service %v not found, ensuring load balancer is deleted", namespacedName)
 		s.eventRecorder.Event(deltaService, api.EventTypeNormal, "DeletingLoadBalancer", "Deleting load balancer")
 		err := s.balancer.EnsureLoadBalancerDeleted(deltaService)
@@ -312,7 +316,19 @@ func (s *ServiceController) createLoadBalancerIfNeeded(namespacedName types.Name
 	// Save the state so we can avoid a write if it doesn't change
 	previousState := api.LoadBalancerStatusDeepCopy(&service.Status.LoadBalancer)
 
-	if !wantsLoadBalancer(service) {
+	if wantsLoadBalancer(service) {
+		glog.V(2).Infof("Ensuring LB for service %s", namespacedName)
+
+		// TODO: We could do a dry-run here if wanted to avoid the spurious cloud-calls & events when we restart
+
+		// The load balancer doesn't exist yet, so create it.
+		s.eventRecorder.Event(service, api.EventTypeNormal, "CreatingLoadBalancer", "Creating load balancer")
+		err := s.createLoadBalancer(service)
+		if err != nil {
+			return fmt.Errorf("failed to create load balancer for service %s: %v", namespacedName, err), retryable
+		}
+		s.eventRecorder.Event(service, api.EventTypeNormal, "CreatedLoadBalancer", "Created load balancer")
+	} else {
 		needDelete := true
 		if appliedState != nil {
 			if !wantsLoadBalancer(appliedState) {
@@ -324,7 +340,7 @@ func (s *ServiceController) createLoadBalancerIfNeeded(namespacedName types.Name
 			// Technically EnsureLoadBalancerDeleted can cope, but we want to post meaningful events
 			_, exists, err := s.balancer.GetLoadBalancer(service)
 			if err != nil {
-				return fmt.Errorf("Error getting LB for service %s: %v", namespacedName, err), retryable
+				return fmt.Errorf("error getting LB for service %s: %v", namespacedName, err), retryable
 			}
 			if !exists {
 				needDelete = false
@@ -341,28 +357,16 @@ func (s *ServiceController) createLoadBalancerIfNeeded(namespacedName types.Name
 		}
 
 		service.Status.LoadBalancer = api.LoadBalancerStatus{}
-	} else {
-		glog.V(2).Infof("Ensuring LB for service %s", namespacedName)
-
-		// TODO: We could do a dry-run here if wanted to avoid the spurious cloud-calls & events when we restart
-
-		// The load balancer doesn't exist yet, so create it.
-		s.eventRecorder.Event(service, api.EventTypeNormal, "CreatingLoadBalancer", "Creating load balancer")
-		err := s.createLoadBalancer(service)
-		if err != nil {
-			return fmt.Errorf("Failed to create load balancer for service %s: %v", namespacedName, err), retryable
-		}
-		s.eventRecorder.Event(service, api.EventTypeNormal, "CreatedLoadBalancer", "Created load balancer")
 	}
 
 	// Write the state if changed
 	// TODO: Be careful here ... what if there were other changes to the service?
-	if !api.LoadBalancerStatusEqual(previousState, &service.Status.LoadBalancer) {
+	if api.LoadBalancerStatusEqual(previousState, &service.Status.LoadBalancer) {
+		glog.V(2).Infof("Not persisting unchanged LoadBalancerStatus to registry.")
+	} else {
 		if err := s.persistUpdate(service); err != nil {
-			return fmt.Errorf("Failed to persist updated status to apiserver, even after retries. Giving up: %v", err), notRetryable
+			return fmt.Errorf("failed to persist updated status to apiserver, even after retries. Giving up: %v", err), notRetryable
 		}
-	} else {
-		glog.V(2).Infof("Not persisting unchanged LoadBalancerStatus to registry.")
 	}
 
 	return nil, notRetryable
@@ -372,25 +376,26 @@ func (s *ServiceController) persistUpdate(service *api.Service) error {
 	var err error
 	for i := 0; i < clientRetryCount; i++ {
 		_, err = s.kubeClient.Core().Services(service.Namespace).UpdateStatus(service)
-		if err == nil {
+
+		switch {
+		case err == nil:
 			return nil
-		}
-		// If the object no longer exists, we don't want to recreate it. Just bail
-		// out so that we can process the delete, which we should soon be receiving
-		// if we haven't already.
-		if errors.IsNotFound(err) {
+		case errors.IsNotFound(err):
+			// If the object no longer exists, we don't want to recreate it. Just bail
+			// out so that we can process the delete, which we should soon be receiving
+			// if we haven't already.
 			glog.Infof("Not persisting update to service '%s/%s' that no longer exists: %v",
 				service.Namespace, service.Name, err)
 			return nil
-		}
-		// TODO: Try to resolve the conflict if the change was unrelated to load
-		// balancer status. For now, just rely on the fact that we'll
-		// also process the update that caused the resource version to change.
-		if errors.IsConflict(err) {
+		case errors.IsConflict(err):
+			// TODO: Try to resolve the conflict if the change was unrelated to load
+			// balancer status. For now, just rely on the fact that we'll
+			// also process the update that caused the resource version to change.
 			glog.V(4).Infof("Not persisting update to service '%s/%s' that has been changed since we received it: %v",
 				service.Namespace, service.Name, err)
 			return nil
 		}
+
 		glog.Warningf("Failed to persist updated LoadBalancerStatus to service '%s/%s' after creating its load balancer: %v",
 			service.Namespace, service.Name, err)
 		time.Sleep(clientRetryInterval)
@@ -410,10 +415,9 @@ func (s *ServiceController) createLoadBalancer(service *api.Service) error {
 	status, err := s.balancer.EnsureLoadBalancer(service, hostsFromNodeList(&nodes))
 	if err != nil {
 		return err
-	} else {
-		service.Status.LoadBalancer = *status
 	}
 
+	service.Status.LoadBalancer = *status
 	return nil
 }