Golang wait.Jitter函數代碼示例

// run loops forever looking for changes to endpoints.
func (s *endpointsReflector) run(resourceVersion *string) {
	if len(*resourceVersion) == 0 {
		endpoints, err := s.watcher.List(labels.Everything())
		if err != nil {
			glog.Errorf("Unable to load endpoints: %v", err)
			time.Sleep(wait.Jitter(s.waitDuration, 0.0))
			return
		}
		*resourceVersion = endpoints.ResourceVersion
		s.endpoints <- EndpointsUpdate{Op: SET, Endpoints: endpoints.Items}
	}

	watcher, err := s.watcher.Watch(labels.Everything(), fields.Everything(), *resourceVersion)
	if err != nil {
		glog.Errorf("Unable to watch for endpoints changes: %v", err)
		if !client.IsTimeout(err) {
			// Reset so that we do a fresh get request
			*resourceVersion = ""
		}

		time.Sleep(wait.Jitter(s.waitDuration, 0.0))
		return
	}
	defer watcher.Stop()

	ch := watcher.ResultChan()
	s.watchHandler(resourceVersion, ch, s.endpoints)
}

// secretDeleted reacts to a Secret being deleted by removing a reference from the corresponding ServiceAccount if needed
func (e *TokensController) secretDeleted(obj interface{}) {
	secret, ok := obj.(*api.Secret)
	if !ok {
		// Unknown type. If we missed a Secret deletion, the corresponding ServiceAccount (if it exists)
		// will get a secret recreated (if needed) during the ServiceAccount re-list
		return
	}

	serviceAccount, err := e.getServiceAccount(secret, false)
	if err != nil {
		glog.Error(err)
		return
	}
	if serviceAccount == nil {
		return
	}

	for i := 1; i <= NumServiceAccountRemoveReferenceRetries; i++ {
		if _, err := e.removeSecretReferenceIfNeeded(serviceAccount, secret.Name); err != nil {
			if apierrors.IsConflict(err) && i < NumServiceAccountRemoveReferenceRetries {
				time.Sleep(wait.Jitter(100*time.Millisecond, 0.0))
				continue
			}
			glog.Error(err)
			break
		}
		break
	}
}

// secretDeleted reacts to a Secret being deleted by looking to see if it's a dockercfg secret for a service account, in which case it
// it removes the references from the service account and removes the token created to back the dockercfgSecret
func (e *DockercfgDeletedController) secretDeleted(obj interface{}) {
	dockercfgSecret, ok := obj.(*api.Secret)
	if !ok {
		return
	}
	if _, exists := dockercfgSecret.Annotations[ServiceAccountTokenSecretNameKey]; !exists {
		return
	}

	for i := 1; i <= NumServiceAccountUpdateRetries; i++ {
		if err := e.removeDockercfgSecretReference(dockercfgSecret); err != nil {
			if kapierrors.IsConflict(err) && i < NumServiceAccountUpdateRetries {
				time.Sleep(wait.Jitter(100*time.Millisecond, 0.0))
				continue
			}

			glog.Error(err)
			break
		}

		break
	}

	// remove the reference token secret
	if err := e.client.Secrets(dockercfgSecret.Namespace).Delete(dockercfgSecret.Annotations[ServiceAccountTokenSecretNameKey]); (err != nil) && !kapierrors.IsNotFound(err) {
		util.HandleError(err)
	}
}

// runServices loops forever looking for changes to services
func (s *SourceAPI) runServices(resourceVersion *uint64) {
	watcher, err := s.client.WatchServices(labels.Everything(), labels.Everything(), *resourceVersion)
	if err != nil {
		glog.Errorf("Unable to watch for services changes: %v", err)
		time.Sleep(wait.Jitter(s.waitDuration, 0.0))
		return
	}
	defer watcher.Stop()

	ch := watcher.ResultChan()
	handleServicesWatch(resourceVersion, ch, s.services)
}

// NewSourceAPI creates a config source that watches for changes to the services and endpoints
func NewSourceAPI(client Watcher, period time.Duration, services chan<- ServiceUpdate, endpoints chan<- EndpointsUpdate) *SourceAPI {
	config := &SourceAPI{
		client:    client,
		services:  services,
		endpoints: endpoints,

		waitDuration: period,
		// prevent hot loops if the server starts to misbehave
		reconnectDuration: time.Second * 1,
	}
	serviceVersion := uint64(0)
	go util.Forever(func() {
		config.runServices(&serviceVersion)
		time.Sleep(wait.Jitter(config.reconnectDuration, 0.0))
	}, period)
	endpointVersion := uint64(0)
	go util.Forever(func() {
		config.runEndpoints(&endpointVersion)
		time.Sleep(wait.Jitter(config.reconnectDuration, 0.0))
	}, period)
	return config
}

// runServices loops forever looking for changes to services.
func (s *SourceAPI) runServices(resourceVersion *uint64) {
	if *resourceVersion == 0 {
		services, err := s.client.ListServices(labels.Everything())
		if err != nil {
			glog.Errorf("Unable to load services: %v", err)
			time.Sleep(wait.Jitter(s.waitDuration, 0.0))
			return
		}
		*resourceVersion = services.ResourceVersion
		s.services <- ServiceUpdate{Op: SET, Services: services.Items}
	}

	watcher, err := s.client.WatchServices(labels.Everything(), labels.Everything(), *resourceVersion)
	if err != nil {
		glog.Errorf("Unable to watch for services changes: %v", err)
		time.Sleep(wait.Jitter(s.waitDuration, 0.0))
		return
	}
	defer watcher.Stop()

	ch := watcher.ResultChan()
	handleServicesWatch(resourceVersion, ch, s.services)
}

// runEndpoints loops forever looking for changes to endpoints.
func (s *SourceAPI) runEndpoints(resourceVersion *uint64) {
	if *resourceVersion == 0 {
		endpoints, err := s.client.ListEndpoints(labels.Everything())
		if err != nil {
			glog.Errorf("Unable to load endpoints: %v", err)
			time.Sleep(wait.Jitter(s.waitDuration, 0.0))
			return
		}
		*resourceVersion = endpoints.ResourceVersion
		s.endpoints <- EndpointsUpdate{Op: SET, Endpoints: endpoints.Items}
	}

	watcher, err := s.client.WatchEndpoints(labels.Everything(), labels.Everything(), *resourceVersion)
	if err != nil {
		glog.Errorf("Unable to watch for endpoints changes: %v", err)
		time.Sleep(wait.Jitter(s.waitDuration, 0.0))
		return
	}
	defer watcher.Stop()

	ch := watcher.ResultChan()
	handleEndpointsWatch(resourceVersion, ch, s.endpoints)
}

// createTokenSecret creates a token secret for a given service account.  Returns the name of the token
func (e *DockercfgController) createTokenSecret(serviceAccount *api.ServiceAccount) (*api.Secret, error) {
	tokenSecret := &api.Secret{
		ObjectMeta: api.ObjectMeta{
			Name:      secret.Strategy.GenerateName(getTokenSecretNamePrefix(serviceAccount)),
			Namespace: serviceAccount.Namespace,
			Annotations: map[string]string{
				api.ServiceAccountNameKey: serviceAccount.Name,
				api.ServiceAccountUIDKey:  string(serviceAccount.UID),
			},
		},
		Type: api.SecretTypeServiceAccountToken,
		Data: map[string][]byte{},
	}

	_, err := e.client.Secrets(tokenSecret.Namespace).Create(tokenSecret)
	if err != nil {
		return nil, err
	}

	// now we have to wait for the service account token controller to make this valid
	// TODO remove this once we have a create-token endpoint
	for i := 0; i <= tokenSecretWaitTimes; i++ {
		liveTokenSecret, err := e.client.Secrets(tokenSecret.Namespace).Get(tokenSecret.Name)
		if err != nil {
			return nil, err
		}

		if len(liveTokenSecret.Data[api.ServiceAccountTokenKey]) > 0 {
			return liveTokenSecret, nil
		}

		time.Sleep(wait.Jitter(tokenSecretWaitInterval, 0.0))

	}

	// the token wasn't ever created, attempt deletion
	glog.Warningf("Deleting unfilled token secret %s/%s", tokenSecret.Namespace, tokenSecret.Name)
	if err := e.client.Secrets(tokenSecret.Namespace).Delete(tokenSecret.Name); (err != nil) && !kapierrors.IsNotFound(err) {
		util.HandleError(err)
	}
	return nil, fmt.Errorf("token never generated for %s", tokenSecret.Name)
}

func (r *endpointsReflector) listAndWatch() {
	r.run(&r.resourceVersion)
	time.Sleep(wait.Jitter(r.reconnectDuration, 0.0))
}