diff options
Diffstat (limited to 'vendor/k8s.io/apimachinery/pkg/watch/filter.go')
-rw-r--r-- | vendor/k8s.io/apimachinery/pkg/watch/filter.go | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/vendor/k8s.io/apimachinery/pkg/watch/filter.go b/vendor/k8s.io/apimachinery/pkg/watch/filter.go new file mode 100644 index 000000000..3ca27f22c --- /dev/null +++ b/vendor/k8s.io/apimachinery/pkg/watch/filter.go @@ -0,0 +1,109 @@ +/* +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" +) + +// FilterFunc should take an event, possibly modify it in some way, and return +// the modified event. If the event should be ignored, then return keep=false. +type FilterFunc func(in Event) (out Event, keep bool) + +// Filter passes all events through f before allowing them to pass on. +// Putting a filter on a watch, as an unavoidable side-effect due to the way +// go channels work, effectively causes the watch's event channel to have its +// queue length increased by one. +// +// WARNING: filter has a fatal flaw, in that it can't properly update the +// Type field (Add/Modified/Deleted) to reflect items beginning to pass the +// filter when they previously didn't. +// +func Filter(w Interface, f FilterFunc) Interface { + fw := &filteredWatch{ + incoming: w, + result: make(chan Event), + f: f, + } + go fw.loop() + return fw +} + +type filteredWatch struct { + incoming Interface + result chan Event + f FilterFunc +} + +// ResultChan returns a channel which will receive filtered events. +func (fw *filteredWatch) ResultChan() <-chan Event { + return fw.result +} + +// Stop stops the upstream watch, which will eventually stop this watch. +func (fw *filteredWatch) Stop() { + fw.incoming.Stop() +} + +// loop waits for new values, filters them, and resends them. +func (fw *filteredWatch) loop() { + defer close(fw.result) + for { + event, ok := <-fw.incoming.ResultChan() + if !ok { + break + } + filtered, keep := fw.f(event) + if keep { + fw.result <- filtered + } + } +} + +// Recorder records all events that are sent from the watch until it is closed. +type Recorder struct { + Interface + + lock sync.Mutex + events []Event +} + +var _ Interface = &Recorder{} + +// NewRecorder wraps an Interface and records any changes sent across it. +func NewRecorder(w Interface) *Recorder { + r := &Recorder{} + r.Interface = Filter(w, r.record) + return r +} + +// record is a FilterFunc and tracks each received event. +func (r *Recorder) record(in Event) (Event, bool) { + r.lock.Lock() + defer r.lock.Unlock() + r.events = append(r.events, in) + return in, true +} + +// Events returns a copy of the events sent across this recorder. +func (r *Recorder) Events() []Event { + r.lock.Lock() + defer r.lock.Unlock() + copied := make([]Event, len(r.events)) + copy(copied, r.events) + return copied +} |