Ejemplo n.º 1
0
// finishRequest makes a given resultFunc asynchronous and handles errors returned by the response.
// Any api.Status object returned is considered an "error", which interrupts the normal response flow.
func finishRequest(timeout time.Duration, fn resultFunc) (result runtime.Object, err error) {
	// these channels need to be buffered to prevent the goroutine below from hanging indefinitely
	// when the select statement reads something other than the one the goroutine sends on.
	ch := make(chan runtime.Object, 1)
	errCh := make(chan error, 1)
	panicCh := make(chan interface{}, 1)
	go func() {
		// panics don't cross goroutine boundaries, so we have to handle ourselves
		defer utilruntime.HandleCrash(func(panicReason interface{}) {
			// Propagate to parent goroutine
			panicCh <- panicReason
		})

		if result, err := fn(); err != nil {
			errCh <- err
		} else {
			ch <- result
		}
	}()

	select {
	case result = <-ch:
		if status, ok := result.(*unversioned.Status); ok {
			return nil, errors.FromObject(status)
		}
		return result, nil
	case err = <-errCh:
		return nil, err
	case p := <-panicCh:
		panic(p)
	case <-time.After(timeout):
		return nil, errors.NewTimeoutError("request did not complete within allowed duration", 0)
	}
}
Ejemplo n.º 2
0
// watchHandler watches w and keeps *resourceVersion up to date.
func (r *Reflector) watchHandler(w watch.Interface, resourceVersion *string, errc chan error, 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 err := <-errc:
			return err
		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
}