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Diffstat (limited to 'vendor/k8s.io/client-go/tools/cache/controller.go')
| -rw-r--r-- | vendor/k8s.io/client-go/tools/cache/controller.go | 391 |
1 files changed, 391 insertions, 0 deletions
diff --git a/vendor/k8s.io/client-go/tools/cache/controller.go b/vendor/k8s.io/client-go/tools/cache/controller.go new file mode 100644 index 000000000..2c97b8658 --- /dev/null +++ b/vendor/k8s.io/client-go/tools/cache/controller.go @@ -0,0 +1,391 @@ +/* +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 ( + "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" +) + +// Config contains all the settings for a Controller. +type Config struct { + // The queue for your objects; either a FIFO or + // a DeltaFIFO. Your Process() function should accept + // the output of this Queue's Pop() method. + Queue + + // Something that can list and watch your objects. + ListerWatcher + + // Something that can process your objects. + Process ProcessFunc + + // The type of your objects. + ObjectType runtime.Object + + // Reprocess everything at least this often. + // Note that if it takes longer for you to clear the queue than this + // period, you will end up processing items in the order determined + // by FIFO.Replace(). Currently, this is random. If this is a + // problem, we can change that replacement policy to append new + // things to the end of the queue instead of replacing the entire + // 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 + // question to this interface as a parameter. + 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 + +// Controller is a generic controller framework. +type controller struct { + config Config + reflector *Reflector + reflectorMutex sync.RWMutex + clock clock.Clock +} + +type Controller interface { + Run(stopCh <-chan struct{}) + HasSynced() bool + LastSyncResourceVersion() string +} + +// New makes a new Controller from the given Config. +func New(c *Config) Controller { + ctlr := &controller{ + config: *c, + clock: &clock.RealClock{}, + } + return ctlr +} + +// Run begins processing items, and will continue until a value is sent down stopCh. +// It's an error to call Run more than once. +// Run blocks; call via go. +func (c *controller) Run(stopCh <-chan struct{}) { + defer utilruntime.HandleCrash() + go func() { + <-stopCh + c.config.Queue.Close() + }() + r := NewReflector( + c.config.ListerWatcher, + c.config.ObjectType, + c.config.Queue, + c.config.FullResyncPeriod, + ) + r.ShouldResync = c.config.ShouldResync + r.clock = c.clock + + c.reflectorMutex.Lock() + c.reflector = r + c.reflectorMutex.Unlock() + + r.RunUntil(stopCh) + + wait.Until(c.processLoop, time.Second, stopCh) +} + +// Returns true once this controller has completed an initial resource listing +func (c *controller) HasSynced() bool { + return c.config.Queue.HasSynced() +} + +func (c *controller) LastSyncResourceVersion() string { + if c.reflector == nil { + return "" + } + return c.reflector.LastSyncResourceVersion() +} + +// processLoop drains the work queue. +// TODO: Consider doing the processing in parallel. This will require a little thought +// to make sure that we don't end up processing the same object multiple times +// concurrently. +// +// TODO: Plumb through the stopCh here (and down to the queue) so that this can +// actually exit when the controller is stopped. Or just give up on this stuff +// ever being stoppable. Converting this whole package to use Context would +// also be helpful. +func (c *controller) processLoop() { + for { + obj, err := c.config.Queue.Pop(PopProcessFunc(c.config.Process)) + if err != nil { + if err == FIFOClosedError { + return + } + if c.config.RetryOnError { + // This is the safe way to re-enqueue. + c.config.Queue.AddIfNotPresent(obj) + } + } + } +} + +// ResourceEventHandler can handle notifications for events that happen to a +// resource. The events are informational only, so you can't return an +// error. +// * OnAdd is called when an object is added. +// * OnUpdate is called when an object is modified. Note that oldObj is the +// last known state of the object-- it is possible that several changes +// were combined together, so you can't use this to see every single +// change. OnUpdate is also called when a re-list happens, and it will +// get called even if nothing changed. This is useful for periodically +// evaluating or syncing something. +// * OnDelete will get the final state of the item if it is known, otherwise +// it will get an object of type DeletedFinalStateUnknown. This can +// happen if the watch is closed and misses the delete event and we don't +// notice the deletion until the subsequent re-list. +type ResourceEventHandler interface { + OnAdd(obj interface{}) + OnUpdate(oldObj, newObj interface{}) + OnDelete(obj interface{}) +} + +// ResourceEventHandlerFuncs is an adaptor to let you easily specify as many or +// as few of the notification functions as you want while still implementing +// ResourceEventHandler. +type ResourceEventHandlerFuncs struct { + AddFunc func(obj interface{}) + UpdateFunc func(oldObj, newObj interface{}) + DeleteFunc func(obj interface{}) +} + +// OnAdd calls AddFunc if it's not nil. +func (r ResourceEventHandlerFuncs) OnAdd(obj interface{}) { + if r.AddFunc != nil { + r.AddFunc(obj) + } +} + +// OnUpdate calls UpdateFunc if it's not nil. +func (r ResourceEventHandlerFuncs) OnUpdate(oldObj, newObj interface{}) { + if r.UpdateFunc != nil { + r.UpdateFunc(oldObj, newObj) + } +} + +// OnDelete calls DeleteFunc if it's not nil. +func (r ResourceEventHandlerFuncs) OnDelete(obj interface{}) { + if r.DeleteFunc != nil { + r.DeleteFunc(obj) + } +} + +// FilteringResourceEventHandler applies the provided filter to all events coming +// in, ensuring the appropriate nested handler method is invoked. An object +// that starts passing the filter after an update is considered an add, and an +// object that stops passing the filter after an update is considered a delete. +type FilteringResourceEventHandler struct { + FilterFunc func(obj interface{}) bool + Handler ResourceEventHandler +} + +// OnAdd calls the nested handler only if the filter succeeds +func (r FilteringResourceEventHandler) OnAdd(obj interface{}) { + if !r.FilterFunc(obj) { + return + } + r.Handler.OnAdd(obj) +} + +// OnUpdate ensures the proper handler is called depending on whether the filter matches +func (r FilteringResourceEventHandler) OnUpdate(oldObj, newObj interface{}) { + newer := r.FilterFunc(newObj) + older := r.FilterFunc(oldObj) + switch { + case newer && older: + r.Handler.OnUpdate(oldObj, newObj) + case newer && !older: + r.Handler.OnAdd(newObj) + case !newer && older: + r.Handler.OnDelete(oldObj) + default: + // do nothing + } +} + +// OnDelete calls the nested handler only if the filter succeeds +func (r FilteringResourceEventHandler) OnDelete(obj interface{}) { + if !r.FilterFunc(obj) { + return + } + r.Handler.OnDelete(obj) +} + +// DeletionHandlingMetaNamespaceKeyFunc checks for +// DeletedFinalStateUnknown objects before calling +// MetaNamespaceKeyFunc. +func DeletionHandlingMetaNamespaceKeyFunc(obj interface{}) (string, error) { + if d, ok := obj.(DeletedFinalStateUnknown); ok { + return d.Key, nil + } + return MetaNamespaceKeyFunc(obj) +} + +// NewInformer returns a Store and a controller for populating the store +// while also providing event notifications. You should only used the returned +// Store for Get/List operations; Add/Modify/Deletes will cause the event +// notifications to be faulty. +// +// Parameters: +// * lw is list and watch functions for the source of the resource you want to +// be informed of. +// * objType is an object of the type that you expect to receive. +// * resyncPeriod: if non-zero, will re-list this often (you will get OnUpdate +// calls, even if nothing changed). Otherwise, re-list will be delayed as +// long as possible (until the upstream source closes the watch or times out, +// or you stop the controller). +// * h is the object you want notifications sent to. +// +func NewInformer( + lw ListerWatcher, + objType runtime.Object, + resyncPeriod time.Duration, + h ResourceEventHandler, +) (Store, Controller) { + // This will hold the client state, as we know it. + clientState := NewStore(DeletionHandlingMetaNamespaceKeyFunc) + + // This will hold incoming changes. Note how we pass clientState in as a + // KeyLister, that way resync operations will result in the correct set + // of update/delete deltas. + fifo := NewDeltaFIFO(MetaNamespaceKeyFunc, nil, clientState) + + cfg := &Config{ + Queue: fifo, + ListerWatcher: lw, + ObjectType: objType, + FullResyncPeriod: resyncPeriod, + RetryOnError: false, + + Process: func(obj interface{}) error { + // from oldest to newest + for _, d := range obj.(Deltas) { + switch d.Type { + case Sync, Added, Updated: + if old, exists, err := clientState.Get(d.Object); err == nil && exists { + if err := clientState.Update(d.Object); err != nil { + return err + } + h.OnUpdate(old, d.Object) + } else { + if err := clientState.Add(d.Object); err != nil { + return err + } + h.OnAdd(d.Object) + } + case Deleted: + if err := clientState.Delete(d.Object); err != nil { + return err + } + h.OnDelete(d.Object) + } + } + return nil + }, + } + return clientState, New(cfg) +} + +// NewIndexerInformer returns a Indexer and a controller for populating the index +// while also providing event notifications. You should only used the returned +// Index for Get/List operations; Add/Modify/Deletes will cause the event +// notifications to be faulty. +// +// Parameters: +// * lw is list and watch functions for the source of the resource you want to +// be informed of. +// * objType is an object of the type that you expect to receive. +// * resyncPeriod: if non-zero, will re-list this often (you will get OnUpdate +// calls, even if nothing changed). Otherwise, re-list will be delayed as +// long as possible (until the upstream source closes the watch or times out, +// or you stop the controller). +// * h is the object you want notifications sent to. +// * indexers is the indexer for the received object type. +// +func NewIndexerInformer( + lw ListerWatcher, + objType runtime.Object, + resyncPeriod time.Duration, + h ResourceEventHandler, + indexers Indexers, +) (Indexer, Controller) { + // This will hold the client state, as we know it. + clientState := NewIndexer(DeletionHandlingMetaNamespaceKeyFunc, indexers) + + // This will hold incoming changes. Note how we pass clientState in as a + // KeyLister, that way resync operations will result in the correct set + // of update/delete deltas. + fifo := NewDeltaFIFO(MetaNamespaceKeyFunc, nil, clientState) + + cfg := &Config{ + Queue: fifo, + ListerWatcher: lw, + ObjectType: objType, + FullResyncPeriod: resyncPeriod, + RetryOnError: false, + + Process: func(obj interface{}) error { + // from oldest to newest + for _, d := range obj.(Deltas) { + switch d.Type { + case Sync, Added, Updated: + if old, exists, err := clientState.Get(d.Object); err == nil && exists { + if err := clientState.Update(d.Object); err != nil { + return err + } + h.OnUpdate(old, d.Object) + } else { + if err := clientState.Add(d.Object); err != nil { + return err + } + h.OnAdd(d.Object) + } + case Deleted: + if err := clientState.Delete(d.Object); err != nil { + return err + } + h.OnDelete(d.Object) + } + } + return nil + }, + } + return clientState, New(cfg) +} |