Support per-handler resync periods

Add the ability for each event handler of a shared informer to specify
its own resync period. If not specified, a handler will resync at the
informer's default interval.

staging/src/k8s.io/client-go/tools/cache/controller.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/util/clock"
 )
 
 // Config contains all the settings for a Controller.
@@ -50,6 +51,11 @@ type Config struct {
 	// queue.
 	FullResyncPeriod time.Duration
 
+	// ShouldResync, if specified, is invoked when the controller's reflector determines the next
+	// periodic sync should occur. If this returns true, it means the reflector should proceed with
+	// the resync.
+	ShouldResync ShouldResyncFunc
+
 	// If true, when Process() returns an error, re-enqueue the object.
 	// TODO: add interface to let you inject a delay/backoff or drop
 	//       the object completely if desired. Pass the object in
@@ -57,6 +63,11 @@ type Config struct {
 	RetryOnError bool
 }
 
+// ShouldResyncFunc is a type of function that indicates if a reflector should perform a
+// resync or not. It can be used by a shared informer to support multiple event handlers with custom
+// resync periods.
+type ShouldResyncFunc func() bool
+
 // ProcessFunc processes a single object.
 type ProcessFunc func(obj interface{}) error
 
@@ -65,6 +76,7 @@ type controller struct {
 	config         Config
 	reflector      *Reflector
 	reflectorMutex sync.RWMutex
+	clock          clock.Clock
 }
 
 type Controller interface {
@@ -77,6 +89,7 @@ type Controller interface {
 func New(c *Config) Controller {
 	ctlr := &controller{
 		config: *c,
+		clock:  &clock.RealClock{},
 	}
 	return ctlr
 }
@@ -92,6 +105,8 @@ func (c *controller) Run(stopCh <-chan struct{}) {
 		c.config.Queue,
 		c.config.FullResyncPeriod,
 	)
+	r.ShouldResync = c.config.ShouldResync
+	r.clock = c.clock
 
 	c.reflectorMutex.Lock()
 	c.reflector = r

staging/src/k8s.io/client-go/tools/cache/processor_listener_test.go

@@ -26,7 +26,7 @@ import (
 // TestPopReleaseLock tests that when processor listener blocks on chan,
 // it should release the lock for pendingNotifications.
 func TestPopReleaseLock(t *testing.T) {
-	pl := newProcessListener(nil)
+	pl := newProcessListener(nil, 0, 0, time.Now())
 	stopCh := make(chan struct{})
 	defer close(stopCh)
 	// make pop() block on nextCh: waiting for receiver to get notification.

staging/src/k8s.io/client-go/tools/cache/reflector.go

@@ -41,6 +41,7 @@ import (
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/apimachinery/pkg/watch"
+	"k8s.io/client-go/util/clock"
 )
 
 // Reflector watches a specified resource and causes all changes to be reflected in the given store.
@@ -58,8 +59,9 @@ type Reflector struct {
 	// the beginning of the next one.
 	period       time.Duration
 	resyncPeriod time.Duration
-	// now() returns current time - exposed for testing purposes
+	ShouldResync func() bool
-	now func() time.Time
+	// clock allows tests to manipulate time
+	clock clock.Clock
 	// lastSyncResourceVersion is the resource version token last
 	// observed when doing a sync with the underlying store
 	// it is thread safe, but not synchronized with the underlying store
@@ -103,7 +105,7 @@ func NewNamedReflector(name string, lw ListerWatcher, expectedType interface{},
 		expectedType:  reflect.TypeOf(expectedType),
 		period:        time.Second,
 		resyncPeriod:  resyncPeriod,
-		now:           time.Now,
+		clock:         &clock.RealClock{},
 	}
 	return r
 }
@@ -223,8 +225,8 @@ func (r *Reflector) resyncChan() (<-chan time.Time, func() bool) {
 	// always fail so we end up listing frequently. Then, if we don't
 	// manually stop the timer, we could end up with many timers active
 	// concurrently.
-	t := time.NewTimer(r.resyncPeriod)
+	t := r.clock.NewTimer(r.resyncPeriod)
-	return t.C, t.Stop
+	return t.C(), t.Stop
 }
 
 // ListAndWatch first lists all items and get the resource version at the moment of call,
@@ -270,11 +272,13 @@ func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error {
 			case <-cancelCh:
 				return
 			}
+			if r.ShouldResync == nil || r.ShouldResync() {
 				glog.V(4).Infof("%s: forcing resync", r.name)
 				if err := r.store.Resync(); err != nil {
 					resyncerrc <- err
 					return
 				}
+			}
 			cleanup()
 			resyncCh, cleanup = r.resyncChan()
 		}
@@ -334,7 +338,7 @@ func (r *Reflector) syncWith(items []runtime.Object, resourceVersion string) err
 
 // watchHandler watches w and keeps *resourceVersion up to date.
 func (r *Reflector) watchHandler(w watch.Interface, resourceVersion *string, errc chan error, stopCh <-chan struct{}) error {
-	start := time.Now()
+	start := r.clock.Now()
 	eventCount := 0
 
 	// Stopping the watcher should be idempotent and if we return from this function there's no way
@@ -393,7 +397,7 @@ loop:
 		}
 	}
 
-	watchDuration := time.Now().Sub(start)
+	watchDuration := r.clock.Now().Sub(start)
 	if watchDuration < 1*time.Second && eventCount == 0 {
 		glog.V(4).Infof("%s: Unexpected watch close - watch lasted less than a second and no items received", r.name)
 		return errors.New("very short watch")

staging/src/k8s.io/client-go/tools/cache/shared_informer.go

@@ -24,28 +24,40 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/util/clock"
 
 	"github.com/golang/glog"
 )
 
-// if you use this, there is one behavior change compared to a standard Informer.
+// SharedInformer has a shared data cache and is capable of distributing notifications for changes
-// When you receive a notification, the cache will be AT LEAST as fresh as the
+// to the cache to multiple listeners who registered via AddEventHandler. If you use this, there is
-// notification, but it MAY be more fresh.  You should NOT depend on the contents
+// one behavior change compared to a standard Informer.  When you receive a notification, the cache
-// of the cache exactly matching the notification you've received in handler
+// will be AT LEAST as fresh as the notification, but it MAY be more fresh.  You should NOT depend
-// functions.  If there was a create, followed by a delete, the cache may NOT
+// on the contents of the cache exactly matching the notification you've received in handler
-// have your item.  This has advantages over the broadcaster since it allows us
+// functions.  If there was a create, followed by a delete, the cache may NOT have your item.  This
-// to share a common cache across many controllers. Extending the broadcaster
+// has advantages over the broadcaster since it allows us to share a common cache across many
-// would have required us keep duplicate caches for each watch.
+// controllers. Extending the broadcaster would have required us keep duplicate caches for each
+// watch.
 type SharedInformer interface {
-	// events to a single handler are delivered sequentially, but there is no coordination between different handlers
+	// AddEventHandler adds an event handler to the shared informer using the shared informer's resync
-	// You may NOT add a handler *after* the SharedInformer is running.  That will result in an error being returned.
+	// period.  Events to a single handler are delivered sequentially, but there is no coordination
-	// TODO we should try to remove this restriction eventually.
+	// between different handlers.
-	AddEventHandler(handler ResourceEventHandler) error
+	AddEventHandler(handler ResourceEventHandler)
+	// AddEventHandlerWithResyncPeriod adds an event handler to the shared informer using the
+	// specified resync period.  Events to a single handler are delivered sequentially, but there is
+	// no coordination between different handlers.
+	AddEventHandlerWithResyncPeriod(handler ResourceEventHandler, resyncPeriod time.Duration)
+	// GetStore returns the Store.
 	GetStore() Store
 	// GetController gives back a synthetic interface that "votes" to start the informer
 	GetController() Controller
+	// Run starts the shared informer, which will be stopped when stopCh is closed.
 	Run(stopCh <-chan struct{})
+	// HasSynced returns true if the shared informer's store has synced.
 	HasSynced() bool
+	// LastSyncResourceVersion is the resource version observed when last synced with the underlying
+	// store. The value returned is not synchronized with access to the underlying store and is not
+	// thread-safe.
 	LastSyncResourceVersion() string
 }
 
@@ -57,23 +69,22 @@ type SharedIndexInformer interface {
 }
 
 // NewSharedInformer creates a new instance for the listwatcher.
-// TODO: create a cache/factory of these at a higher level for the list all, watch all of a given resource that can
-// be shared amongst all consumers.
 func NewSharedInformer(lw ListerWatcher, objType runtime.Object, resyncPeriod time.Duration) SharedInformer {
 	return NewSharedIndexInformer(lw, objType, resyncPeriod, Indexers{})
 }
 
 // NewSharedIndexInformer creates a new instance for the listwatcher.
-// TODO: create a cache/factory of these at a higher level for the list all, watch all of a given resource that can
+func NewSharedIndexInformer(lw ListerWatcher, objType runtime.Object, defaultEventHandlerResyncPeriod time.Duration, indexers Indexers) SharedIndexInformer {
-// be shared amongst all consumers.
+	realClock := &clock.RealClock{}
-func NewSharedIndexInformer(lw ListerWatcher, objType runtime.Object, resyncPeriod time.Duration, indexers Indexers) SharedIndexInformer {
 	sharedIndexInformer := &sharedIndexInformer{
-		processor:             &sharedProcessor{},
+		processor:                       &sharedProcessor{clock: realClock},
 		indexer:                         NewIndexer(DeletionHandlingMetaNamespaceKeyFunc, indexers),
 		listerWatcher:                   lw,
 		objectType:                      objType,
-		fullResyncPeriod:      resyncPeriod,
+		resyncCheckPeriod:               defaultEventHandlerResyncPeriod,
+		defaultEventHandlerResyncPeriod: defaultEventHandlerResyncPeriod,
 		cacheMutationDetector:           NewCacheMutationDetector(fmt.Sprintf("%T", objType)),
+		clock: realClock,
 	}
 	return sharedIndexInformer
 }
@@ -116,7 +127,16 @@ type sharedIndexInformer struct {
 	// This block is tracked to handle late initialization of the controller
 	listerWatcher ListerWatcher
 	objectType    runtime.Object
-	fullResyncPeriod time.Duration
+
+	// resyncCheckPeriod is how often we want the reflector's resync timer to fire so it can call
+	// shouldResync to check if any of our listeners need a resync.
+	resyncCheckPeriod time.Duration
+	// defaultEventHandlerResyncPeriod is the default resync period for any handlers added via
+	// AddEventHandler (i.e. they don't specify one and just want to use the shared informer's default
+	// value).
+	defaultEventHandlerResyncPeriod time.Duration
+	// clock allows for testability
+	clock clock.Clock
 
 	started     bool
 	startedLock sync.Mutex
@@ -171,8 +191,9 @@ func (s *sharedIndexInformer) Run(stopCh <-chan struct{}) {
 		Queue:            fifo,
 		ListerWatcher:    s.listerWatcher,
 		ObjectType:       s.objectType,
-		FullResyncPeriod: s.fullResyncPeriod,
+		FullResyncPeriod: s.resyncCheckPeriod,
 		RetryOnError:     false,
+		ShouldResync:     s.processor.shouldResync,
 
 		Process: s.HandleDeltas,
 	}
@@ -182,6 +203,7 @@ func (s *sharedIndexInformer) Run(stopCh <-chan struct{}) {
 		defer s.startedLock.Unlock()
 
 		s.controller = New(cfg)
+		s.controller.(*controller).clock = s.clock
 		s.started = true
 	}()
 
@@ -240,14 +262,56 @@ func (s *sharedIndexInformer) GetController() Controller {
 	return &dummyController{informer: s}
 }
 
-func (s *sharedIndexInformer) AddEventHandler(handler ResourceEventHandler) error {
+func (s *sharedIndexInformer) AddEventHandler(handler ResourceEventHandler) {
+	s.AddEventHandlerWithResyncPeriod(handler, s.defaultEventHandlerResyncPeriod)
+}
+
+func determineResyncPeriod(desired, check time.Duration) time.Duration {
+	if desired == 0 {
+		return desired
+	}
+	if check == 0 {
+		glog.Warningf("The specified resyncPeriod %v is invalid because this shared informer doesn't support resyncing", desired)
+		return 0
+	}
+	if desired < check {
+		glog.Warningf("The specified resyncPeriod %v is being increased to the minimum resyncCheckPeriod %v", desired, check)
+		return check
+	}
+	return desired
+}
+
+const minimumResyncPeriod = 1 * time.Second
+
+func (s *sharedIndexInformer) AddEventHandlerWithResyncPeriod(handler ResourceEventHandler, resyncPeriod time.Duration) {
 	s.startedLock.Lock()
 	defer s.startedLock.Unlock()
 
+	if resyncPeriod > 0 {
+		if resyncPeriod < minimumResyncPeriod {
+			glog.Warningf("resyncPeriod %d is too small. Changing it to the minimum allowed value of %d", resyncPeriod, minimumResyncPeriod)
+			resyncPeriod = minimumResyncPeriod
+		}
+
+		if resyncPeriod < s.resyncCheckPeriod {
+			if s.started {
+				glog.Warningf("resyncPeriod %d is smaller than resyncCheckPeriod %d and the informer has already started. Changing it to %d", resyncPeriod, s.resyncCheckPeriod, s.resyncCheckPeriod)
+				resyncPeriod = s.resyncCheckPeriod
+			} else {
+				// if the event handler's resyncPeriod is smaller than the current resyncCheckPeriod, update
+				// resyncCheckPeriod to match resyncPeriod and adjust the resync periods of all the listeners
+				// accordingly
+				s.resyncCheckPeriod = resyncPeriod
+				s.processor.resyncCheckPeriodChanged(resyncPeriod)
+			}
+		}
+	}
+
+	listener := newProcessListener(handler, resyncPeriod, determineResyncPeriod(resyncPeriod, s.resyncCheckPeriod), s.clock.Now())
+
 	if !s.started {
-		listener := newProcessListener(handler)
+		s.processor.addListener(listener)
-		s.processor.listeners = append(s.processor.listeners, listener)
+		return
-		return nil
 	}
 
 	// in order to safely join, we have to
@@ -258,8 +322,7 @@ func (s *sharedIndexInformer) AddEventHandler(handler ResourceEventHandler) erro
 	s.blockDeltas.Lock()
 	defer s.blockDeltas.Unlock()
 
-	listener := newProcessListener(handler)
+	s.processor.addListener(listener)
-	s.processor.listeners = append(s.processor.listeners, listener)
 
 	go listener.run(s.stopCh)
 	go listener.pop(s.stopCh)
@@ -268,8 +331,6 @@ func (s *sharedIndexInformer) AddEventHandler(handler ResourceEventHandler) erro
 	for i := range items {
 		listener.add(addNotification{newObj: items[i]})
 	}
-
-	return nil
 }
 
 func (s *sharedIndexInformer) HandleDeltas(obj interface{}) error {
@@ -280,45 +341,101 @@ func (s *sharedIndexInformer) HandleDeltas(obj interface{}) error {
 	for _, d := range obj.(Deltas) {
 		switch d.Type {
 		case Sync, Added, Updated:
+			isSync := d.Type == Sync
 			s.cacheMutationDetector.AddObject(d.Object)
 			if old, exists, err := s.indexer.Get(d.Object); err == nil && exists {
 				if err := s.indexer.Update(d.Object); err != nil {
 					return err
 				}
-				s.processor.distribute(updateNotification{oldObj: old, newObj: d.Object})
+				s.processor.distribute(updateNotification{oldObj: old, newObj: d.Object}, isSync)
 			} else {
 				if err := s.indexer.Add(d.Object); err != nil {
 					return err
 				}
-				s.processor.distribute(addNotification{newObj: d.Object})
+				s.processor.distribute(addNotification{newObj: d.Object}, isSync)
 			}
 		case Deleted:
 			if err := s.indexer.Delete(d.Object); err != nil {
 				return err
 			}
-			s.processor.distribute(deleteNotification{oldObj: d.Object})
+			s.processor.distribute(deleteNotification{oldObj: d.Object}, false)
 		}
 	}
 	return nil
 }
 
 type sharedProcessor struct {
+	listenersLock    sync.RWMutex
 	listeners        []*processorListener
+	syncingListeners []*processorListener
+	clock            clock.Clock
 }
 
-func (p *sharedProcessor) distribute(obj interface{}) {
+func (p *sharedProcessor) addListener(listener *processorListener) {
+	p.listenersLock.Lock()
+	defer p.listenersLock.Unlock()
+
+	p.listeners = append(p.listeners, listener)
+	p.syncingListeners = append(p.syncingListeners, listener)
+}
+
+func (p *sharedProcessor) distribute(obj interface{}, sync bool) {
+	p.listenersLock.RLock()
+	defer p.listenersLock.RUnlock()
+
+	if sync {
+		for _, listener := range p.syncingListeners {
+			listener.add(obj)
+		}
+	} else {
 		for _, listener := range p.listeners {
 			listener.add(obj)
 		}
 	}
+}
 
 func (p *sharedProcessor) run(stopCh <-chan struct{}) {
+	p.listenersLock.RLock()
+	defer p.listenersLock.RUnlock()
+
 	for _, listener := range p.listeners {
 		go listener.run(stopCh)
 		go listener.pop(stopCh)
 	}
 }
 
+// shouldResync queries every listener to determine if any of them need a resync, based on each
+// listener's resyncPeriod.
+func (p *sharedProcessor) shouldResync() bool {
+	p.listenersLock.Lock()
+	defer p.listenersLock.Unlock()
+
+	p.syncingListeners = []*processorListener{}
+
+	resyncNeeded := false
+	now := p.clock.Now()
+	for _, listener := range p.listeners {
+		// need to loop through all the listeners to see if they need to resync so we can prepare any
+		// listeners that are going to be resyncing.
+		if listener.shouldResync(now) {
+			resyncNeeded = true
+			p.syncingListeners = append(p.syncingListeners, listener)
+			listener.determineNextResync(now)
+		}
+	}
+	return resyncNeeded
+}
+
+func (p *sharedProcessor) resyncCheckPeriodChanged(resyncCheckPeriod time.Duration) {
+	p.listenersLock.RLock()
+	defer p.listenersLock.RUnlock()
+
+	for _, listener := range p.listeners {
+		resyncPeriod := determineResyncPeriod(listener.requestedResyncPeriod, resyncCheckPeriod)
+		listener.setResyncPeriod(resyncPeriod)
+	}
+}
+
 type processorListener struct {
 	// lock/cond protects access to 'pendingNotifications'.
 	lock sync.RWMutex
@@ -334,16 +451,32 @@ type processorListener struct {
 	nextCh chan interface{}
 
 	handler ResourceEventHandler
+
+	// requestedResyncPeriod is how frequently the listener wants a full resync from the shared informer
+	requestedResyncPeriod time.Duration
+	// resyncPeriod is how frequently the listener wants a full resync from the shared informer. This
+	// value may differ from requestedResyncPeriod if the shared informer adjusts it to align with the
+	// informer's overall resync check period.
+	resyncPeriod time.Duration
+	// nextResync is the earliest time the listener should get a full resync
+	nextResync time.Time
+	// resyncLock guards access to resyncPeriod and nextResync
+	resyncLock sync.Mutex
 }
 
-func newProcessListener(handler ResourceEventHandler) *processorListener {
+func newProcessListener(handler ResourceEventHandler, requestedResyncPeriod, resyncPeriod time.Duration, now time.Time) *processorListener {
 	ret := &processorListener{
 		pendingNotifications:  []interface{}{},
 		nextCh:                make(chan interface{}),
 		handler:               handler,
+		requestedResyncPeriod: requestedResyncPeriod,
+		resyncPeriod:          resyncPeriod,
 	}
 
 	ret.cond.L = &ret.lock
+
+	ret.determineNextResync(now)
+
 	return ret
 }
 
@@ -419,3 +552,30 @@ func (p *processorListener) run(stopCh <-chan struct{}) {
 		}
 	}
 }
+
+// shouldResync deterimines if the listener needs a resync. If the listener's resyncPeriod is 0,
+// this always returns false.
+func (p *processorListener) shouldResync(now time.Time) bool {
+	p.resyncLock.Lock()
+	defer p.resyncLock.Unlock()
+
+	if p.resyncPeriod == 0 {
+		return false
+	}
+
+	return now.After(p.nextResync) || now.Equal(p.nextResync)
+}
+
+func (p *processorListener) determineNextResync(now time.Time) {
+	p.resyncLock.Lock()
+	defer p.resyncLock.Unlock()
+
+	p.nextResync = now.Add(p.resyncPeriod)
+}
+
+func (p *processorListener) setResyncPeriod(resyncPeriod time.Duration) {
+	p.resyncLock.Lock()
+	defer p.resyncLock.Unlock()
+
+	p.resyncPeriod = resyncPeriod
+}

staging/src/k8s.io/client-go/tools/cache/shared_informer_test.go

@@ -0,0 +1,253 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cache
+
+import (
+	"fmt"
+	"sync"
+	"testing"
+	"time"
+
+	"k8s.io/apimachinery/pkg/api/meta"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/pkg/api"
+	fcache "k8s.io/client-go/tools/cache/testing"
+	"k8s.io/client-go/util/clock"
+)
+
+type testListener struct {
+	lock              sync.RWMutex
+	resyncPeriod      time.Duration
+	expectedItemNames sets.String
+	receivedItemNames []string
+	name              string
+}
+
+func newTestListener(name string, resyncPeriod time.Duration, expected ...string) *testListener {
+	l := &testListener{
+		resyncPeriod:      resyncPeriod,
+		expectedItemNames: sets.NewString(expected...),
+		name:              name,
+	}
+	return l
+}
+
+func (l *testListener) OnAdd(obj interface{}) {
+	l.handle(obj)
+}
+
+func (l *testListener) OnUpdate(old, new interface{}) {
+	l.handle(new)
+}
+
+func (l *testListener) OnDelete(obj interface{}) {
+}
+
+func (l *testListener) handle(obj interface{}) {
+	key, _ := MetaNamespaceKeyFunc(obj)
+	fmt.Printf("%s: handle: %v\n", l.name, key)
+	l.lock.Lock()
+	defer l.lock.Unlock()
+
+	objectMeta, _ := meta.Accessor(obj)
+	l.receivedItemNames = append(l.receivedItemNames, objectMeta.GetName())
+}
+
+func (l *testListener) ok() bool {
+	fmt.Println("polling")
+	err := wait.PollImmediate(100*time.Millisecond, 2*time.Second, func() (bool, error) {
+		if l.satisfiedExpectations() {
+			return true, nil
+		}
+		return false, nil
+	})
+	if err != nil {
+		return false
+	}
+
+	// wait just a bit to allow any unexpected stragglers to come in
+	fmt.Println("sleeping")
+	time.Sleep(1 * time.Second)
+	fmt.Println("final check")
+	return l.satisfiedExpectations()
+}
+
+func (l *testListener) satisfiedExpectations() bool {
+	l.lock.RLock()
+	defer l.lock.RUnlock()
+
+	return len(l.receivedItemNames) == l.expectedItemNames.Len() && sets.NewString(l.receivedItemNames...).Equal(l.expectedItemNames)
+}
+
+func TestListenerResyncPeriods(t *testing.T) {
+	// source simulates an apiserver object endpoint.
+	source := fcache.NewFakeControllerSource()
+	source.Add(&api.Pod{ObjectMeta: metav1.ObjectMeta{Name: "pod1"}})
+	source.Add(&api.Pod{ObjectMeta: metav1.ObjectMeta{Name: "pod2"}})
+
+	// create the shared informer and resync every 1s
+	informer := NewSharedInformer(source, &api.Pod{}, 1*time.Second).(*sharedIndexInformer)
+
+	clock := clock.NewFakeClock(time.Now())
+	informer.clock = clock
+	informer.processor.clock = clock
+
+	// listener 1, never resync
+	listener1 := newTestListener("listener1", 0, "pod1", "pod2")
+	informer.AddEventHandlerWithResyncPeriod(listener1, listener1.resyncPeriod)
+
+	// listener 2, resync every 2s
+	listener2 := newTestListener("listener2", 2*time.Second, "pod1", "pod2")
+	informer.AddEventHandlerWithResyncPeriod(listener2, listener2.resyncPeriod)
+
+	// listener 3, resync every 3s
+	listener3 := newTestListener("listener3", 3*time.Second, "pod1", "pod2")
+	informer.AddEventHandlerWithResyncPeriod(listener3, listener3.resyncPeriod)
+	listeners := []*testListener{listener1, listener2, listener3}
+
+	stop := make(chan struct{})
+	defer close(stop)
+
+	go informer.Run(stop)
+
+	// ensure all listeners got the initial List
+	for _, listener := range listeners {
+		if !listener.ok() {
+			t.Errorf("%s: expected %v, got %v", listener.name, listener.expectedItemNames, listener.receivedItemNames)
+		}
+	}
+
+	// reset
+	for _, listener := range listeners {
+		listener.receivedItemNames = []string{}
+	}
+
+	// advance so listener2 gets a resync
+	clock.Step(2 * time.Second)
+
+	// make sure listener2 got the resync
+	if !listener2.ok() {
+		t.Errorf("%s: expected %v, got %v", listener2.name, listener2.expectedItemNames, listener2.receivedItemNames)
+	}
+
+	// wait a bit to give errant items a chance to go to 1 and 3
+	time.Sleep(1 * time.Second)
+
+	// make sure listeners 1 and 3 got nothing
+	if len(listener1.receivedItemNames) != 0 {
+		t.Errorf("listener1: should not have resynced (got %d)", len(listener1.receivedItemNames))
+	}
+	if len(listener3.receivedItemNames) != 0 {
+		t.Errorf("listener3: should not have resynced (got %d)", len(listener3.receivedItemNames))
+	}
+
+	// reset
+	for _, listener := range listeners {
+		listener.receivedItemNames = []string{}
+	}
+
+	// advance so listener3 gets a resync
+	clock.Step(1 * time.Second)
+
+	// make sure listener3 got the resync
+	if !listener3.ok() {
+		t.Errorf("%s: expected %v, got %v", listener3.name, listener3.expectedItemNames, listener3.receivedItemNames)
+	}
+
+	// wait a bit to give errant items a chance to go to 1 and 2
+	time.Sleep(1 * time.Second)
+
+	// make sure listeners 1 and 2 got nothing
+	if len(listener1.receivedItemNames) != 0 {
+		t.Errorf("listener1: should not have resynced (got %d)", len(listener1.receivedItemNames))
+	}
+	if len(listener2.receivedItemNames) != 0 {
+		t.Errorf("listener2: should not have resynced (got %d)", len(listener2.receivedItemNames))
+	}
+}
+
+func TestResyncCheckPeriod(t *testing.T) {
+	// source simulates an apiserver object endpoint.
+	source := fcache.NewFakeControllerSource()
+
+	// create the shared informer and resync every 12 hours
+	informer := NewSharedInformer(source, &api.Pod{}, 12*time.Hour).(*sharedIndexInformer)
+
+	clock := clock.NewFakeClock(time.Now())
+	informer.clock = clock
+	informer.processor.clock = clock
+
+	// listener 1, never resync
+	listener1 := newTestListener("listener1", 0)
+	informer.AddEventHandlerWithResyncPeriod(listener1, listener1.resyncPeriod)
+	if e, a := 12*time.Hour, informer.resyncCheckPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+	if e, a := time.Duration(0), informer.processor.listeners[0].resyncPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+
+	// listener 2, resync every minute
+	listener2 := newTestListener("listener2", 1*time.Minute)
+	informer.AddEventHandlerWithResyncPeriod(listener2, listener2.resyncPeriod)
+	if e, a := 1*time.Minute, informer.resyncCheckPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+	if e, a := time.Duration(0), informer.processor.listeners[0].resyncPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+	if e, a := 1*time.Minute, informer.processor.listeners[1].resyncPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+
+	// listener 3, resync every 55 seconds
+	listener3 := newTestListener("listener3", 55*time.Second)
+	informer.AddEventHandlerWithResyncPeriod(listener3, listener3.resyncPeriod)
+	if e, a := 55*time.Second, informer.resyncCheckPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+	if e, a := time.Duration(0), informer.processor.listeners[0].resyncPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+	if e, a := 1*time.Minute, informer.processor.listeners[1].resyncPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+	if e, a := 55*time.Second, informer.processor.listeners[2].resyncPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+
+	// listener 4, resync every 5 seconds
+	listener4 := newTestListener("listener4", 5*time.Second)
+	informer.AddEventHandlerWithResyncPeriod(listener4, listener4.resyncPeriod)
+	if e, a := 5*time.Second, informer.resyncCheckPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+	if e, a := time.Duration(0), informer.processor.listeners[0].resyncPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+	if e, a := 1*time.Minute, informer.processor.listeners[1].resyncPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+	if e, a := 55*time.Second, informer.processor.listeners[2].resyncPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+	if e, a := 5*time.Second, informer.processor.listeners[3].resyncPeriod; e != a {
+		t.Errorf("expected %d, got %d", e, a)
+	}
+}

vendor/BUILD

@@ -12403,6 +12403,7 @@ go_test(
         "k8s.io/client-go/tools/cache/mutation_detector_test.go",
         "k8s.io/client-go/tools/cache/processor_listener_test.go",
         "k8s.io/client-go/tools/cache/reflector_test.go",
+        "k8s.io/client-go/tools/cache/shared_informer_test.go",
         "k8s.io/client-go/tools/cache/store_test.go",
         "k8s.io/client-go/tools/cache/undelta_store_test.go",
     ],
@@ -12410,6 +12411,7 @@ go_test(
     tags = ["automanaged"],
     deps = [
         "//vendor:github.com/google/gofuzz",
+        "//vendor:k8s.io/apimachinery/pkg/api/meta",
         "//vendor:k8s.io/apimachinery/pkg/apis/meta/v1",
         "//vendor:k8s.io/apimachinery/pkg/runtime",
         "//vendor:k8s.io/apimachinery/pkg/util/sets",