// injectReactError returns an error when the test requested given action to
// fail. nil is returned otherwise.
func (r *volumeReactor) injectReactError(action core.Action) error {
	if len(r.errors) == 0 {
		// No more errors to inject, everything should succeed.
		return nil
	}

	for i, expected := range r.errors {
		glog.V(4).Infof("trying to match %q %q with %q %q", expected.verb, expected.resource, action.GetVerb(), action.GetResource())
		if action.Matches(expected.verb, expected.resource) {
			// That's the action we're waiting for, remove it from injectedErrors
			r.errors = append(r.errors[:i], r.errors[i+1:]...)
			glog.V(4).Infof("reactor found matching error at index %d: %q %q, returning %v", i, expected.verb, expected.resource, expected.error)
			return expected.error
		}
	}
	return nil
}

// React is a callback called by fake kubeClient from the controller.
// In other words, every claim/volume change performed by the controller ends
// here.
// This callback checks versions of the updated objects and refuse those that
// are too old (simulating real etcd).
// All updated objects are stored locally to keep track of object versions and
// to evaluate test results.
// All updated objects are also inserted into changedObjects queue and
// optionally sent back to the controller via its watchers.
func (r *volumeReactor) React(action core.Action) (handled bool, ret runtime.Object, err error) {
	r.lock.Lock()
	defer r.lock.Unlock()

	glog.V(4).Infof("reactor got operation %q on %q", action.GetVerb(), action.GetResource())

	// Inject error when requested
	err = r.injectReactError(action)
	if err != nil {
		return true, nil, err
	}

	// Test did not requst to inject an error, continue simulating API server.
	switch {
	case action.Matches("create", "persistentvolumes"):
		obj := action.(core.UpdateAction).GetObject()
		volume := obj.(*api.PersistentVolume)

		// check the volume does not exist
		_, found := r.volumes[volume.Name]
		if found {
			return true, nil, fmt.Errorf("Cannot create volume %s: volume already exists", volume.Name)
		}

		// Store the updated object to appropriate places.
		if r.volumeSource != nil {
			r.volumeSource.Add(volume)
		}
		r.volumes[volume.Name] = volume
		r.changedObjects = append(r.changedObjects, volume)
		r.changedSinceLastSync++
		glog.V(4).Infof("created volume %s", volume.Name)
		return true, volume, nil

	case action.Matches("update", "persistentvolumes"):
		obj := action.(core.UpdateAction).GetObject()
		volume := obj.(*api.PersistentVolume)

		// Check and bump object version
		storedVolume, found := r.volumes[volume.Name]
		if found {
			storedVer, _ := strconv.Atoi(storedVolume.ResourceVersion)
			requestedVer, _ := strconv.Atoi(volume.ResourceVersion)
			if storedVer != requestedVer {
				return true, obj, versionConflictError
			}
			volume.ResourceVersion = strconv.Itoa(storedVer + 1)
		} else {
			return true, nil, fmt.Errorf("Cannot update volume %s: volume not found", volume.Name)
		}

		// Store the updated object to appropriate places.
		if r.volumeSource != nil {
			r.volumeSource.Modify(volume)
		}
		r.volumes[volume.Name] = volume
		r.changedObjects = append(r.changedObjects, volume)
		r.changedSinceLastSync++
		glog.V(4).Infof("saved updated volume %s", volume.Name)
		return true, volume, nil

	case action.Matches("update", "persistentvolumeclaims"):
		obj := action.(core.UpdateAction).GetObject()
		claim := obj.(*api.PersistentVolumeClaim)

		// Check and bump object version
		storedClaim, found := r.claims[claim.Name]
		if found {
			storedVer, _ := strconv.Atoi(storedClaim.ResourceVersion)
			requestedVer, _ := strconv.Atoi(claim.ResourceVersion)
			if storedVer != requestedVer {
				return true, obj, versionConflictError
			}
			claim.ResourceVersion = strconv.Itoa(storedVer + 1)
		} else {
			return true, nil, fmt.Errorf("Cannot update claim %s: claim not found", claim.Name)
		}

		// Store the updated object to appropriate places.
		r.claims[claim.Name] = claim
		if r.claimSource != nil {
			r.claimSource.Modify(claim)
		}
		r.changedObjects = append(r.changedObjects, claim)
		r.changedSinceLastSync++
		glog.V(4).Infof("saved updated claim %s", claim.Name)
		return true, claim, nil

	case action.Matches("get", "persistentvolumes"):
		name := action.(core.GetAction).GetName()
		volume, found := r.volumes[name]
//.........这里部分代码省略.........