From 1561fce81ce0b9bf9239d2249cd447390d5018e2 Mon Sep 17 00:00:00 2001
From: Justin Santa Barbara <justin@fathomdb.com>
Date: Tue, 16 Jun 2015 18:59:03 -0400
Subject: [PATCH] servicecontroller: last state applied to LB vs last state
 seen

We need the last state seen for interpreting the change-stream,
separately we need to track the last state we successfully applied to the
load balancer.
---
 .../servicecontroller/servicecontroller.go    | 21 ++++++++++++-------
 .../servicecontroller_test.go                 |  2 +-
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/pkg/cloudprovider/servicecontroller/servicecontroller.go b/pkg/cloudprovider/servicecontroller/servicecontroller.go
index 3e4d5e9d099..a13c867b2e5 100644
--- a/pkg/cloudprovider/servicecontroller/servicecontroller.go
+++ b/pkg/cloudprovider/servicecontroller/servicecontroller.go
@@ -52,7 +52,11 @@ const (
 )
 
 type cachedService struct {
-	service *api.Service
+	// 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
 }
@@ -191,8 +195,8 @@ func (s *ServiceController) processDelta(delta *cache.Delta) (error, bool) {
 		if !ok {
 			return fmt.Errorf("Service %s not in cache even though the watcher thought it was. Ignoring the deletion.", key), notRetryable
 		}
-		service = cachedService.service
-		delta.Object = cachedService.service
+		service = cachedService.lastState
+		delta.Object = cachedService.lastState
 		namespacedName = types.NamespacedName{service.Namespace, service.Name}
 	} else {
 		namespacedName.Namespace = service.Namespace
@@ -206,6 +210,9 @@ func (s *ServiceController) processDelta(delta *cache.Delta) (error, bool) {
 	cachedService.mu.Lock()
 	defer cachedService.mu.Unlock()
 
+	// Update the cached service (used above for populating synthetic deletes)
+	cachedService.lastState = service
+
 	// TODO: Handle added, updated, and sync differently?
 	switch delta.Type {
 	case cache.Added:
@@ -213,7 +220,7 @@ func (s *ServiceController) processDelta(delta *cache.Delta) (error, bool) {
 	case cache.Updated:
 		fallthrough
 	case cache.Sync:
-		err, retry := s.createLoadBalancerIfNeeded(namespacedName, service, cachedService.service)
+		err, retry := s.createLoadBalancerIfNeeded(namespacedName, service, cachedService.appliedState)
 		if err != nil {
 			s.eventRecorder.Event(service, "creating loadbalancer failed", err.Error())
 			return err, retry
@@ -222,7 +229,7 @@ func (s *ServiceController) processDelta(delta *cache.Delta) (error, bool) {
 		// NOTE: Since we update the cached service if and only if we successully
 		// processed it, a cached service being nil implies that it hasn't yet
 		// been successfully processed.
-		cachedService.service = service
+		cachedService.appliedState = service
 		s.cache.set(namespacedName.String(), cachedService)
 	case cache.Deleted:
 		err := s.balancer.EnsureTCPLoadBalancerDeleted(s.loadBalancerName(service), s.zone.Region)
@@ -609,10 +616,10 @@ func (s *ServiceController) updateLoadBalancerHosts(services []*cachedService, h
 			// with by the load balancer reconciler. We can trust the load balancer
 			// reconciler to ensure the service's load balancer is created to target
 			// the correct nodes.
-			if service.service == nil {
+			if service.appliedState == nil {
 				return
 			}
-			if err := s.lockedUpdateLoadBalancerHosts(service.service, hosts); err != nil {
+			if err := s.lockedUpdateLoadBalancerHosts(service.appliedState, hosts); err != nil {
 				glog.Errorf("External error while updating TCP load balancer: %v.", err)
 				servicesToRetry = append(servicesToRetry, service)
 			}
diff --git a/pkg/cloudprovider/servicecontroller/servicecontroller_test.go b/pkg/cloudprovider/servicecontroller/servicecontroller_test.go
index d39112219f4..d62b3a47162 100644
--- a/pkg/cloudprovider/servicecontroller/servicecontroller_test.go
+++ b/pkg/cloudprovider/servicecontroller/servicecontroller_test.go
@@ -206,7 +206,7 @@ func TestUpdateNodesInExternalLoadBalancer(t *testing.T) {
 
 		var services []*cachedService
 		for _, service := range item.services {
-			services = append(services, &cachedService{service: service})
+			services = append(services, &cachedService{lastState: service, appliedState: service})
 		}
 		if err := controller.updateLoadBalancerHosts(services, hosts); err != nil {
 			t.Errorf("unexpected error: %v", err)