diff options
Diffstat (limited to 'vendor/k8s.io/apimachinery/pkg/watch/mux.go')
-rw-r--r-- | vendor/k8s.io/apimachinery/pkg/watch/mux.go | 299 |
1 files changed, 0 insertions, 299 deletions
diff --git a/vendor/k8s.io/apimachinery/pkg/watch/mux.go b/vendor/k8s.io/apimachinery/pkg/watch/mux.go deleted file mode 100644 index e01d51906..000000000 --- a/vendor/k8s.io/apimachinery/pkg/watch/mux.go +++ /dev/null @@ -1,299 +0,0 @@ -/* -Copyright 2014 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 watch - -import ( - "sync" - - "k8s.io/apimachinery/pkg/runtime" - "k8s.io/apimachinery/pkg/runtime/schema" -) - -// FullChannelBehavior controls how the Broadcaster reacts if a watcher's watch -// channel is full. -type FullChannelBehavior int - -const ( - WaitIfChannelFull FullChannelBehavior = iota - DropIfChannelFull -) - -// Buffer the incoming queue a little bit even though it should rarely ever accumulate -// anything, just in case a few events are received in such a short window that -// Broadcaster can't move them onto the watchers' queues fast enough. -const incomingQueueLength = 25 - -// Broadcaster distributes event notifications among any number of watchers. Every event -// is delivered to every watcher. -type Broadcaster struct { - watchers map[int64]*broadcasterWatcher - nextWatcher int64 - distributing sync.WaitGroup - - incoming chan Event - stopped chan struct{} - - // How large to make watcher's channel. - watchQueueLength int - // If one of the watch channels is full, don't wait for it to become empty. - // Instead just deliver it to the watchers that do have space in their - // channels and move on to the next event. - // It's more fair to do this on a per-watcher basis than to do it on the - // "incoming" channel, which would allow one slow watcher to prevent all - // other watchers from getting new events. - fullChannelBehavior FullChannelBehavior -} - -// NewBroadcaster creates a new Broadcaster. queueLength is the maximum number of events to queue per watcher. -// It is guaranteed that events will be distributed in the order in which they occur, -// but the order in which a single event is distributed among all of the watchers is unspecified. -func NewBroadcaster(queueLength int, fullChannelBehavior FullChannelBehavior) *Broadcaster { - m := &Broadcaster{ - watchers: map[int64]*broadcasterWatcher{}, - incoming: make(chan Event, incomingQueueLength), - stopped: make(chan struct{}), - watchQueueLength: queueLength, - fullChannelBehavior: fullChannelBehavior, - } - m.distributing.Add(1) - go m.loop() - return m -} - -// NewLongQueueBroadcaster functions nearly identically to NewBroadcaster, -// except that the incoming queue is the same size as the outgoing queues -// (specified by queueLength). -func NewLongQueueBroadcaster(queueLength int, fullChannelBehavior FullChannelBehavior) *Broadcaster { - m := &Broadcaster{ - watchers: map[int64]*broadcasterWatcher{}, - incoming: make(chan Event, queueLength), - stopped: make(chan struct{}), - watchQueueLength: queueLength, - fullChannelBehavior: fullChannelBehavior, - } - m.distributing.Add(1) - go m.loop() - return m -} - -const internalRunFunctionMarker = "internal-do-function" - -// a function type we can shoehorn into the queue. -type functionFakeRuntimeObject func() - -func (obj functionFakeRuntimeObject) GetObjectKind() schema.ObjectKind { - return schema.EmptyObjectKind -} -func (obj functionFakeRuntimeObject) DeepCopyObject() runtime.Object { - if obj == nil { - return nil - } - // funcs are immutable. Hence, just return the original func. - return obj -} - -// Execute f, blocking the incoming queue (and waiting for it to drain first). -// The purpose of this terrible hack is so that watchers added after an event -// won't ever see that event, and will always see any event after they are -// added. -func (m *Broadcaster) blockQueue(f func()) { - select { - case <-m.stopped: - return - default: - } - var wg sync.WaitGroup - wg.Add(1) - m.incoming <- Event{ - Type: internalRunFunctionMarker, - Object: functionFakeRuntimeObject(func() { - defer wg.Done() - f() - }), - } - wg.Wait() -} - -// Watch adds a new watcher to the list and returns an Interface for it. -// Note: new watchers will only receive new events. They won't get an entire history -// of previous events. It will block until the watcher is actually added to the -// broadcaster. -func (m *Broadcaster) Watch() Interface { - var w *broadcasterWatcher - m.blockQueue(func() { - id := m.nextWatcher - m.nextWatcher++ - w = &broadcasterWatcher{ - result: make(chan Event, m.watchQueueLength), - stopped: make(chan struct{}), - id: id, - m: m, - } - m.watchers[id] = w - }) - if w == nil { - // The panic here is to be consistent with the previous interface behavior - // we are willing to re-evaluate in the future. - panic("broadcaster already stopped") - } - return w -} - -// WatchWithPrefix adds a new watcher to the list and returns an Interface for it. It sends -// queuedEvents down the new watch before beginning to send ordinary events from Broadcaster. -// The returned watch will have a queue length that is at least large enough to accommodate -// all of the items in queuedEvents. It will block until the watcher is actually added to -// the broadcaster. -func (m *Broadcaster) WatchWithPrefix(queuedEvents []Event) Interface { - var w *broadcasterWatcher - m.blockQueue(func() { - id := m.nextWatcher - m.nextWatcher++ - length := m.watchQueueLength - if n := len(queuedEvents) + 1; n > length { - length = n - } - w = &broadcasterWatcher{ - result: make(chan Event, length), - stopped: make(chan struct{}), - id: id, - m: m, - } - m.watchers[id] = w - for _, e := range queuedEvents { - w.result <- e - } - }) - if w == nil { - // The panic here is to be consistent with the previous interface behavior - // we are willing to re-evaluate in the future. - panic("broadcaster already stopped") - } - return w -} - -// stopWatching stops the given watcher and removes it from the list. -func (m *Broadcaster) stopWatching(id int64) { - m.blockQueue(func() { - w, ok := m.watchers[id] - if !ok { - // No need to do anything, it's already been removed from the list. - return - } - delete(m.watchers, id) - close(w.result) - }) -} - -// closeAll disconnects all watchers (presumably in response to a Shutdown call). -func (m *Broadcaster) closeAll() { - for _, w := range m.watchers { - close(w.result) - } - // Delete everything from the map, since presence/absence in the map is used - // by stopWatching to avoid double-closing the channel. - m.watchers = map[int64]*broadcasterWatcher{} -} - -// Action distributes the given event among all watchers. -func (m *Broadcaster) Action(action EventType, obj runtime.Object) { - m.incoming <- Event{action, obj} -} - -// Action distributes the given event among all watchers, or drops it on the floor -// if too many incoming actions are queued up. Returns true if the action was sent, -// false if dropped. -func (m *Broadcaster) ActionOrDrop(action EventType, obj runtime.Object) bool { - select { - case m.incoming <- Event{action, obj}: - return true - default: - return false - } -} - -// Shutdown disconnects all watchers (but any queued events will still be distributed). -// You must not call Action or Watch* after calling Shutdown. This call blocks -// until all events have been distributed through the outbound channels. Note -// that since they can be buffered, this means that the watchers might not -// have received the data yet as it can remain sitting in the buffered -// channel. It will block until the broadcaster stop request is actually executed -func (m *Broadcaster) Shutdown() { - m.blockQueue(func() { - close(m.stopped) - close(m.incoming) - }) - m.distributing.Wait() -} - -// loop receives from m.incoming and distributes to all watchers. -func (m *Broadcaster) loop() { - // Deliberately not catching crashes here. Yes, bring down the process if there's a - // bug in watch.Broadcaster. - for event := range m.incoming { - if event.Type == internalRunFunctionMarker { - event.Object.(functionFakeRuntimeObject)() - continue - } - m.distribute(event) - } - m.closeAll() - m.distributing.Done() -} - -// distribute sends event to all watchers. Blocking. -func (m *Broadcaster) distribute(event Event) { - if m.fullChannelBehavior == DropIfChannelFull { - for _, w := range m.watchers { - select { - case w.result <- event: - case <-w.stopped: - default: // Don't block if the event can't be queued. - } - } - } else { - for _, w := range m.watchers { - select { - case w.result <- event: - case <-w.stopped: - } - } - } -} - -// broadcasterWatcher handles a single watcher of a broadcaster -type broadcasterWatcher struct { - result chan Event - stopped chan struct{} - stop sync.Once - id int64 - m *Broadcaster -} - -// ResultChan returns a channel to use for waiting on events. -func (mw *broadcasterWatcher) ResultChan() <-chan Event { - return mw.result -} - -// Stop stops watching and removes mw from its list. -// It will block until the watcher stop request is actually executed -func (mw *broadcasterWatcher) Stop() { - mw.stop.Do(func() { - close(mw.stopped) - mw.m.stopWatching(mw.id) - }) -} |