diff options
Diffstat (limited to 'vendor/k8s.io/apimachinery/pkg/watch/streamwatcher.go')
-rw-r--r-- | vendor/k8s.io/apimachinery/pkg/watch/streamwatcher.go | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/vendor/k8s.io/apimachinery/pkg/watch/streamwatcher.go b/vendor/k8s.io/apimachinery/pkg/watch/streamwatcher.go new file mode 100644 index 000000000..93bb1cdf7 --- /dev/null +++ b/vendor/k8s.io/apimachinery/pkg/watch/streamwatcher.go @@ -0,0 +1,119 @@ +/* +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 ( + "io" + "sync" + + "github.com/golang/glog" + "k8s.io/apimachinery/pkg/runtime" + "k8s.io/apimachinery/pkg/util/net" + utilruntime "k8s.io/apimachinery/pkg/util/runtime" +) + +// Decoder allows StreamWatcher to watch any stream for which a Decoder can be written. +type Decoder interface { + // Decode should return the type of event, the decoded object, or an error. + // An error will cause StreamWatcher to call Close(). Decode should block until + // it has data or an error occurs. + Decode() (action EventType, object runtime.Object, err error) + + // Close should close the underlying io.Reader, signalling to the source of + // the stream that it is no longer being watched. Close() must cause any + // outstanding call to Decode() to return with an error of some sort. + Close() +} + +// StreamWatcher turns any stream for which you can write a Decoder interface +// into a watch.Interface. +type StreamWatcher struct { + sync.Mutex + source Decoder + result chan Event + stopped bool +} + +// NewStreamWatcher creates a StreamWatcher from the given decoder. +func NewStreamWatcher(d Decoder) *StreamWatcher { + sw := &StreamWatcher{ + source: d, + // It's easy for a consumer to add buffering via an extra + // goroutine/channel, but impossible for them to remove it, + // so nonbuffered is better. + result: make(chan Event), + } + go sw.receive() + return sw +} + +// ResultChan implements Interface. +func (sw *StreamWatcher) ResultChan() <-chan Event { + return sw.result +} + +// Stop implements Interface. +func (sw *StreamWatcher) Stop() { + // Call Close() exactly once by locking and setting a flag. + sw.Lock() + defer sw.Unlock() + if !sw.stopped { + sw.stopped = true + sw.source.Close() + } +} + +// stopping returns true if Stop() was called previously. +func (sw *StreamWatcher) stopping() bool { + sw.Lock() + defer sw.Unlock() + return sw.stopped +} + +// receive reads result from the decoder in a loop and sends down the result channel. +func (sw *StreamWatcher) receive() { + defer close(sw.result) + defer sw.Stop() + defer utilruntime.HandleCrash() + for { + action, obj, err := sw.source.Decode() + if err != nil { + // Ignore expected error. + if sw.stopping() { + return + } + switch err { + case io.EOF: + // watch closed normally + case io.ErrUnexpectedEOF: + glog.V(1).Infof("Unexpected EOF during watch stream event decoding: %v", err) + default: + msg := "Unable to decode an event from the watch stream: %v" + if net.IsProbableEOF(err) { + glog.V(5).Infof(msg, err) + } else { + glog.Errorf(msg, err) + } + } + return + } + sw.result <- Event{ + Type: action, + Object: obj, + } + } +} |