// watchHandler watches w and keeps *resourceVersion up to date. func (r *Reflector) watchHandler(w watch.Interface, resourceVersion *string, resyncCh <-chan time.Time, stopCh <-chan struct{}) error { start := time.Now() eventCount := 0 // Stopping the watcher should be idempotent and if we return from this function there's no way // we're coming back in with the same watch interface. defer w.Stop() loop: for { select { case <-stopCh: return errorStopRequested case <-resyncCh: return errorResyncRequested case event, ok := <-w.ResultChan(): if !ok { break loop } if event.Type == watch.Error { return apierrs.FromObject(event.Object) } if e, a := r.expectedType, reflect.TypeOf(event.Object); e != nil && e != a { utilruntime.HandleError(fmt.Errorf("%s: expected type %v, but watch event object had type %v", r.name, e, a)) continue } meta, err := meta.Accessor(event.Object) if err != nil { utilruntime.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", r.name, event)) continue } newResourceVersion := meta.GetResourceVersion() switch event.Type { case watch.Added: r.store.Add(event.Object) case watch.Modified: r.store.Update(event.Object) case watch.Deleted: // TODO: Will any consumers need access to the "last known // state", which is passed in event.Object? If so, may need // to change this. r.store.Delete(event.Object) default: utilruntime.HandleError(fmt.Errorf("%s: unable to understand watch event %#v", r.name, event)) } *resourceVersion = newResourceVersion r.setLastSyncResourceVersion(newResourceVersion) eventCount++ } } watchDuration := time.Now().Sub(start) if watchDuration < 1*time.Second && eventCount == 0 { glog.V(4).Infof("%s: Unexpected watch close - watch lasted less than a second and no items received", r.name) return errors.New("very short watch") } glog.V(4).Infof("%s: Watch close - %v total %v items received", r.name, r.expectedType, eventCount) return nil }
// ListAndWatch first lists all items and get the resource version at the moment of call, // and then use the resource version to watch. // It returns error if ListAndWatch didn't even try to initialize watch. func (r *Reflector) ListAndWatch(stopCh <-chan struct{}) error { var resourceVersion string resyncCh, cleanup := r.resyncChan() defer cleanup() // Explicitly set "0" as resource version - it's fine for the List() // to be served from cache and potentially be delayed relative to // etcd contents. Reflector framework will catch up via Watch() eventually. options := api.ListOptions{ResourceVersion: "0"} list, err := r.listerWatcher.List(options) if err != nil { return fmt.Errorf("%s: Failed to list %v: %v", r.name, r.expectedType, err) } metaInterface, err := meta.Accessor(list) if err != nil { return fmt.Errorf("%s: Unable to understand list result %#v", r.name, list) } resourceVersion = metaInterface.GetResourceVersion() items, err := meta.ExtractList(list) if err != nil { return fmt.Errorf("%s: Unable to understand list result %#v (%v)", r.name, list, err) } if err := r.syncWith(items, resourceVersion); err != nil { return fmt.Errorf("%s: Unable to sync list result: %v", r.name, err) } r.setLastSyncResourceVersion(resourceVersion) for { options := api.ListOptions{ ResourceVersion: resourceVersion, // We want to avoid situations when resyncing is breaking the TCP connection // - see comment for 'timeoutForWatch()' for more details. TimeoutSeconds: r.timeoutForWatch(), } w, err := r.listerWatcher.Watch(options) if err != nil { switch err { case io.EOF: // watch closed normally case io.ErrUnexpectedEOF: glog.V(1).Infof("%s: Watch for %v closed with unexpected EOF: %v", r.name, r.expectedType, err) default: utilruntime.HandleError(fmt.Errorf("%s: Failed to watch %v: %v", r.name, r.expectedType, err)) } // If this is "connection refused" error, it means that most likely apiserver is not responsive. // It doesn't make sense to re-list all objects because most likely we will be able to restart // watch where we ended. // If that's the case wait and resend watch request. if urlError, ok := err.(*url.Error); ok { if opError, ok := urlError.Err.(*net.OpError); ok { if errno, ok := opError.Err.(syscall.Errno); ok && errno == syscall.ECONNREFUSED { time.Sleep(time.Second) continue } } } return nil } if err := r.watchHandler(w, &resourceVersion, resyncCh, stopCh); err != nil { if err != errorResyncRequested && err != errorStopRequested { glog.Warningf("%s: watch of %v ended with: %v", r.name, r.expectedType, err) } return nil } if r.canForceResyncNow() { glog.V(4).Infof("%s: next resync planned for %#v, forcing now", r.name, r.nextResync) return nil } } }