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Diffstat (limited to 'vendor/k8s.io/client-go/tools/cache/shared_informer.go')
| -rw-r--r-- | vendor/k8s.io/client-go/tools/cache/shared_informer.go | 581 |
1 files changed, 581 insertions, 0 deletions
diff --git a/vendor/k8s.io/client-go/tools/cache/shared_informer.go b/vendor/k8s.io/client-go/tools/cache/shared_informer.go new file mode 100644 index 000000000..a0dbbb697 --- /dev/null +++ b/vendor/k8s.io/client-go/tools/cache/shared_informer.go @@ -0,0 +1,581 @@ +/* +Copyright 2015 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" + "time" + + "k8s.io/apimachinery/pkg/runtime" + "k8s.io/apimachinery/pkg/util/clock" + utilruntime "k8s.io/apimachinery/pkg/util/runtime" + "k8s.io/apimachinery/pkg/util/wait" + + "github.com/golang/glog" +) + +// SharedInformer has a shared data cache and is capable of distributing notifications for changes +// to the cache to multiple listeners who registered via AddEventHandler. If you use this, there is +// one behavior change compared to a standard Informer. When you receive a notification, the cache +// will be AT LEAST as fresh as the notification, but it MAY be more fresh. You should NOT depend +// on the contents of the cache exactly matching the notification you've received in handler +// functions. If there was a create, followed by a delete, the cache may NOT have your item. This +// has advantages over the broadcaster since it allows us to share a common cache across many +// controllers. Extending the broadcaster would have required us keep duplicate caches for each +// watch. +type SharedInformer interface { + // AddEventHandler adds an event handler to the shared informer using the shared informer's resync + // period. Events to a single handler are delivered sequentially, but there is no coordination + // between different handlers. + 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 +} + +type SharedIndexInformer interface { + SharedInformer + // AddIndexers add indexers to the informer before it starts. + AddIndexers(indexers Indexers) error + GetIndexer() Indexer +} + +// NewSharedInformer creates a new instance for the listwatcher. +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. +func NewSharedIndexInformer(lw ListerWatcher, objType runtime.Object, defaultEventHandlerResyncPeriod time.Duration, indexers Indexers) SharedIndexInformer { + realClock := &clock.RealClock{} + sharedIndexInformer := &sharedIndexInformer{ + processor: &sharedProcessor{clock: realClock}, + indexer: NewIndexer(DeletionHandlingMetaNamespaceKeyFunc, indexers), + listerWatcher: lw, + objectType: objType, + resyncCheckPeriod: defaultEventHandlerResyncPeriod, + defaultEventHandlerResyncPeriod: defaultEventHandlerResyncPeriod, + cacheMutationDetector: NewCacheMutationDetector(fmt.Sprintf("%T", objType)), + clock: realClock, + } + return sharedIndexInformer +} + +// InformerSynced is a function that can be used to determine if an informer has synced. This is useful for determining if caches have synced. +type InformerSynced func() bool + +// syncedPollPeriod controls how often you look at the status of your sync funcs +const syncedPollPeriod = 100 * time.Millisecond + +// WaitForCacheSync waits for caches to populate. It returns true if it was successful, false +// if the controller should shutdown +func WaitForCacheSync(stopCh <-chan struct{}, cacheSyncs ...InformerSynced) bool { + err := wait.PollUntil(syncedPollPeriod, + func() (bool, error) { + for _, syncFunc := range cacheSyncs { + if !syncFunc() { + return false, nil + } + } + return true, nil + }, + stopCh) + if err != nil { + glog.V(2).Infof("stop requested") + return false + } + + glog.V(4).Infof("caches populated") + return true +} + +type sharedIndexInformer struct { + indexer Indexer + controller Controller + + processor *sharedProcessor + cacheMutationDetector CacheMutationDetector + + // This block is tracked to handle late initialization of the controller + listerWatcher ListerWatcher + objectType runtime.Object + + // 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 + + // blockDeltas gives a way to stop all event distribution so that a late event handler + // can safely join the shared informer. + blockDeltas sync.Mutex + // stopCh is the channel used to stop the main Run process. We have to track it so that + // late joiners can have a proper stop + stopCh <-chan struct{} +} + +// dummyController hides the fact that a SharedInformer is different from a dedicated one +// where a caller can `Run`. The run method is disconnected in this case, because higher +// level logic will decide when to start the SharedInformer and related controller. +// Because returning information back is always asynchronous, the legacy callers shouldn't +// notice any change in behavior. +type dummyController struct { + informer *sharedIndexInformer +} + +func (v *dummyController) Run(stopCh <-chan struct{}) { +} + +func (v *dummyController) HasSynced() bool { + return v.informer.HasSynced() +} + +func (c *dummyController) LastSyncResourceVersion() string { + return "" +} + +type updateNotification struct { + oldObj interface{} + newObj interface{} +} + +type addNotification struct { + newObj interface{} +} + +type deleteNotification struct { + oldObj interface{} +} + +func (s *sharedIndexInformer) Run(stopCh <-chan struct{}) { + defer utilruntime.HandleCrash() + + fifo := NewDeltaFIFO(MetaNamespaceKeyFunc, nil, s.indexer) + + cfg := &Config{ + Queue: fifo, + ListerWatcher: s.listerWatcher, + ObjectType: s.objectType, + FullResyncPeriod: s.resyncCheckPeriod, + RetryOnError: false, + ShouldResync: s.processor.shouldResync, + + Process: s.HandleDeltas, + } + + func() { + s.startedLock.Lock() + defer s.startedLock.Unlock() + + s.controller = New(cfg) + s.controller.(*controller).clock = s.clock + s.started = true + }() + + s.stopCh = stopCh + s.cacheMutationDetector.Run(stopCh) + s.processor.run(stopCh) + s.controller.Run(stopCh) +} + +func (s *sharedIndexInformer) isStarted() bool { + s.startedLock.Lock() + defer s.startedLock.Unlock() + return s.started +} + +func (s *sharedIndexInformer) HasSynced() bool { + s.startedLock.Lock() + defer s.startedLock.Unlock() + + if s.controller == nil { + return false + } + return s.controller.HasSynced() +} + +func (s *sharedIndexInformer) LastSyncResourceVersion() string { + s.startedLock.Lock() + defer s.startedLock.Unlock() + + if s.controller == nil { + return "" + } + return s.controller.LastSyncResourceVersion() +} + +func (s *sharedIndexInformer) GetStore() Store { + return s.indexer +} + +func (s *sharedIndexInformer) GetIndexer() Indexer { + return s.indexer +} + +func (s *sharedIndexInformer) AddIndexers(indexers Indexers) error { + s.startedLock.Lock() + defer s.startedLock.Unlock() + + if s.started { + return fmt.Errorf("informer has already started") + } + + return s.indexer.AddIndexers(indexers) +} + +func (s *sharedIndexInformer) GetController() Controller { + return &dummyController{informer: s} +} + +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 { + s.processor.addListener(listener) + return + } + + // in order to safely join, we have to + // 1. stop sending add/update/delete notifications + // 2. do a list against the store + // 3. send synthetic "Add" events to the new handler + // 4. unblock + s.blockDeltas.Lock() + defer s.blockDeltas.Unlock() + + s.processor.addListener(listener) + + go listener.run(s.stopCh) + go listener.pop(s.stopCh) + + items := s.indexer.List() + for i := range items { + listener.add(addNotification{newObj: items[i]}) + } +} + +func (s *sharedIndexInformer) HandleDeltas(obj interface{}) error { + s.blockDeltas.Lock() + defer s.blockDeltas.Unlock() + + // from oldest to newest + 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}, isSync) + } else { + if err := s.indexer.Add(d.Object); err != nil { + return err + } + 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}, false) + } + } + return nil +} + +type sharedProcessor struct { + listenersLock sync.RWMutex + listeners []*processorListener + syncingListeners []*processorListener + clock clock.Clock +} + +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 + cond sync.Cond + + // pendingNotifications is an unbounded slice that holds all notifications not yet distributed + // there is one per listener, but a failing/stalled listener will have infinite pendingNotifications + // added until we OOM. + // TODO This is no worse that before, since reflectors were backed by unbounded DeltaFIFOs, but + // we should try to do something better + pendingNotifications []interface{} + + 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, 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 +} + +func (p *processorListener) add(notification interface{}) { + p.lock.Lock() + defer p.lock.Unlock() + + p.pendingNotifications = append(p.pendingNotifications, notification) + p.cond.Broadcast() +} + +func (p *processorListener) pop(stopCh <-chan struct{}) { + defer utilruntime.HandleCrash() + + for { + blockingGet := func() (interface{}, bool) { + p.lock.Lock() + defer p.lock.Unlock() + + for len(p.pendingNotifications) == 0 { + // check if we're shutdown + select { + case <-stopCh: + return nil, true + default: + } + p.cond.Wait() + } + + nt := p.pendingNotifications[0] + p.pendingNotifications = p.pendingNotifications[1:] + return nt, false + } + + notification, stopped := blockingGet() + if stopped { + return + } + + select { + case <-stopCh: + return + case p.nextCh <- notification: + } + } +} + +func (p *processorListener) run(stopCh <-chan struct{}) { + defer utilruntime.HandleCrash() + + for { + var next interface{} + select { + case <-stopCh: + func() { + p.lock.Lock() + defer p.lock.Unlock() + p.cond.Broadcast() + }() + return + case next = <-p.nextCh: + } + + switch notification := next.(type) { + case updateNotification: + p.handler.OnUpdate(notification.oldObj, notification.newObj) + case addNotification: + p.handler.OnAdd(notification.newObj) + case deleteNotification: + p.handler.OnDelete(notification.oldObj) + default: + utilruntime.HandleError(fmt.Errorf("unrecognized notification: %#v", next)) + } + } +} + +// 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 +} |