Golang Stopper.Sleep方法代碼示例

func findTask(datastore database.Datastore, renotifyInterval time.Duration, whoAmI string, stopper *utils.Stopper) *database.VulnerabilityNotification {
	for {
		// Find a notification to send.
		notification, err := datastore.GetAvailableNotification(renotifyInterval)
		if err != nil {
			// There is no notification or an error occurred.
			if err != cerrors.ErrNotFound {
				log.Warningf("could not get notification to send: %s", err)
			}

			// Wait.
			if !stopper.Sleep(checkInterval) {
				return nil
			}

			continue
		}

		// Lock the notification.
		if hasLock, _ := datastore.Lock(notification.Name, whoAmI, lockDuration, false); hasLock {
			log.Infof("found and locked a notification: %s", notification.Name)
			return &notification
		}
	}
}

func handleTask(notification database.Notification, st *utils.Stopper, maxAttempts int) (bool, bool) {
	// Get notification content.
	// TODO(Quentin-M): Split big notifications.
	notificationContent, err := notification.GetContent()
	if err != nil {
		log.Warningf("could not get content of notification '%s': %s", notification.GetName(), err)
		return false, false
	}

	// Create notification.
	payload := &Notification{
		Name:    notification.GetName(),
		Type:    notification.GetType(),
		Content: notificationContent,
	}

	// Send notification.
	for notifierName, notifier := range notifiers {
		var attempts int
		var backOff time.Duration
		for {
			// Max attempts exceeded.
			if attempts >= maxAttempts {
				log.Infof("giving up on sending notification '%s' to notifier '%s': max attempts exceeded (%d)\n", notification.GetName(), notifierName, maxAttempts)
				return false, false
			}

			// Backoff.
			if backOff > 0 {
				log.Infof("waiting %v before retrying to send notification '%s' to notifier '%s' (Attempt %d / %d)\n", backOff, notification.GetName(), notifierName, attempts+1, maxAttempts)
				if !st.Sleep(backOff) {
					return false, true
				}
			}

			// Send using the current notifier.
			if err := notifier.Send(payload); err == nil {
				// Send has been successful. Go to the next one.
				break
			}

			// Send failed; increase attempts/backoff and retry.
			log.Errorf("could not send notification '%s' to notifier '%s': %s", notification.GetName(), notifierName, err)
			backOff = timeutil.ExpBackoff(backOff, maxBackOff)
			attempts++
		}
	}

	log.Infof("successfully sent notification '%s'\n", notification.GetName())
	return true, false
}

func handleTask(notification database.VulnerabilityNotification, st *utils.Stopper, maxAttempts int) (bool, bool) {
	// Send notification.
	for notifierName, notifier := range notifiers {
		var attempts int
		var backOff time.Duration
		for {
			// Max attempts exceeded.
			if attempts >= maxAttempts {
				log.Infof("giving up on sending notification '%s' via notifier '%s': max attempts exceeded (%d)\n", notification.Name, notifierName, maxAttempts)
				return false, false
			}

			// Backoff.
			if backOff > 0 {
				log.Infof("waiting %v before retrying to send notification '%s' via notifier '%s' (Attempt %d / %d)\n", backOff, notification.Name, notifierName, attempts+1, maxAttempts)
				if !st.Sleep(backOff) {
					return false, true
				}
			}

			// Send using the current notifier.
			if err := notifier.Send(notification); err != nil {
				// Send failed; increase attempts/backoff and retry.
				promNotifierBackendErrorsTotal.WithLabelValues(notifierName).Inc()
				log.Errorf("could not send notification '%s' via notifier '%s': %v", notification.Name, notifierName, err)
				backOff = timeutil.ExpBackoff(backOff, maxBackOff)
				attempts++
				continue
			}

			// Send has been successful. Go to the next notifier.
			break
		}
	}

	log.Infof("successfully sent notification '%s'\n", notification.Name)
	return true, false
}

func findTask(whoAmI string, stopper *utils.Stopper) (string, database.Notification) {
	for {
		// Find a notification to send.
		node, notification, err := database.FindOneNotificationToSend(database.GetDefaultNotificationWrapper())
		if err != nil {
			log.Warningf("could not get notification to send: %s", err)
		}

		// No notification or error: wait.
		if notification == nil || err != nil {
			if !stopper.Sleep(checkInterval) {
				return "", nil
			}
			continue
		}

		// Lock the notification.
		if hasLock, _ := database.Lock(node, lockDuration, whoAmI); hasLock {
			log.Infof("found and locked a notification: %s", notification.GetName())
			return node, notification
		}
	}
}

// Run updates the vulnerability database at regular intervals
func Run(interval time.Duration, st *utils.Stopper) {
	defer st.End()

	// Do not run the updater if the interval is 0
	if interval == 0 {
		log.Infof("updater service is disabled.")
		return
	}

	whoAmI := uuid.New()
	healthIdentifier = whoAmI
	log.Infof("updater service started. lock identifier: %s", whoAmI)

	for {
		// Set the next update time to (last update time + interval) or now if there
		// is no last update time stored in database (first update) or if an error
		// occurs
		nextUpdate := time.Now().UTC()
		if lastUpdateTSS, err := database.GetFlagValue(flagName); err == nil && lastUpdateTSS != "" {
			if lastUpdateTS, err := strconv.ParseInt(lastUpdateTSS, 10, 64); err == nil {
				healthLatestSuccessfulUpdate = time.Unix(lastUpdateTS, 0)
				nextUpdate = time.Unix(lastUpdateTS, 0).Add(interval)
			}
		}

		// If the next update timer is in the past, then try to update.
		if nextUpdate.Before(time.Now().UTC()) {
			// Attempt to get a lock on the the update.
			log.Debug("attempting to obtain update lock")
			hasLock, hasLockUntil := database.Lock(flagName, lockDuration, whoAmI)
			if hasLock {
				healthLockOwner = healthIdentifier

				// Launch update in a new go routine.
				doneC := make(chan bool, 1)
				go func() {
					Update()
					doneC <- true
				}()

				for done := false; !done; {
					select {
					case <-doneC:
						done = true
					case <-time.After(refreshLockDuration):
						// Refresh the lock until the update is done.
						database.Lock(flagName, lockDuration, whoAmI)
					}
				}

				// Unlock the update.
				database.Unlock(flagName, whoAmI)
			} else {
				lockOwner, lockExpiration, err := database.LockInfo(flagName)
				if err != nil {
					log.Debug("update lock is already taken")
					nextUpdate = hasLockUntil
				} else {
					log.Debugf("update lock is already taken by %s until %v", lockOwner, lockExpiration)
					nextUpdate = lockExpiration
					healthLockOwner = lockOwner
				}
			}
		}

		// Sleep, but remain stoppable until approximately the next update time.
		now := time.Now().UTC()
		waitUntil := nextUpdate.Add(time.Duration(rand.ExpFloat64()/0.5) * time.Second)
		log.Debugf("next update attempt scheduled for %v.", waitUntil)
		if !waitUntil.Before(now) {
			if !st.Sleep(waitUntil.Sub(time.Now())) {
				break
			}
		}
	}

	log.Info("updater service stopped")
}

// Run updates the vulnerability database at regular intervals.
func Run(config *config.UpdaterConfig, datastore database.Datastore, st *utils.Stopper) {
	defer st.End()

	// Do not run the updater if there is no config or if the interval is 0.
	if config == nil || config.Interval == 0 {
		log.Infof("updater service is disabled.")
		return
	}

	whoAmI := uuid.New()
	log.Infof("updater service started. lock identifier: %s", whoAmI)

	for {
		var stop bool

		// Determine if this is the first update and define the next update time.
		// The next update time is (last update time + interval) or now if this is the first update.
		nextUpdate := time.Now().UTC()
		lastUpdate, firstUpdate, err := getLastUpdate(datastore)
		if err != nil {
			log.Errorf("an error occured while getting the last update time")
			nextUpdate = nextUpdate.Add(config.Interval)
		} else if firstUpdate == false {
			nextUpdate = lastUpdate.Add(config.Interval)
		}

		// If the next update timer is in the past, then try to update.
		if nextUpdate.Before(time.Now().UTC()) {
			// Attempt to get a lock on the the update.
			log.Debug("attempting to obtain update lock")
			hasLock, hasLockUntil := datastore.Lock(lockName, whoAmI, lockDuration, false)
			if hasLock {
				// Launch update in a new go routine.
				doneC := make(chan bool, 1)
				go func() {
					Update(datastore, firstUpdate)
					doneC <- true
				}()

				for done := false; !done && !stop; {
					select {
					case <-doneC:
						done = true
					case <-time.After(refreshLockDuration):
						// Refresh the lock until the update is done.
						datastore.Lock(lockName, whoAmI, lockDuration, true)
					case <-st.Chan():
						stop = true
					}
				}

				// Unlock the update.
				datastore.Unlock(lockName, whoAmI)

				if stop {
					break
				}
				continue
			} else {
				lockOwner, lockExpiration, err := datastore.FindLock(lockName)
				if err != nil {
					log.Debug("update lock is already taken")
					nextUpdate = hasLockUntil
				} else {
					log.Debugf("update lock is already taken by %s until %v", lockOwner, lockExpiration)
					nextUpdate = lockExpiration
				}
			}
		}

		// Sleep, but remain stoppable until approximately the next update time.
		now := time.Now().UTC()
		waitUntil := nextUpdate.Add(time.Duration(rand.ExpFloat64()/0.5) * time.Second)
		log.Debugf("next update attempt scheduled for %v.", waitUntil)
		if !waitUntil.Before(now) {
			if !st.Sleep(waitUntil.Sub(time.Now())) {
				break
			}
		}
	}

	// Clean resources.
	for _, metadataFetcher := range metadataFetchers {
		metadataFetcher.Clean()
	}
	for _, fetcher := range fetchers {
		fetcher.Clean()
	}

	log.Info("updater service stopped")
}

// Run updates the vulnerability database at regular intervals.
func Run(config *config.UpdaterConfig, st *utils.Stopper) {
	defer st.End()

	// Do not run the updater if there is no config or if the interval is 0.
	if config == nil || config.Interval == 0 {
		log.Infof("updater service is disabled.")
		return
	}

	// Register healthchecker.
	health.RegisterHealthchecker("updater", Healthcheck)

	whoAmI := uuid.New()
	log.Infof("updater service started. lock identifier: %s", whoAmI)

	for {
		// Set the next update time to (last update time + interval) or now if there
		// is no last update time stored in database (first update) or if an error
		// occurs.
		var nextUpdate time.Time
		var stop bool
		if lastUpdate := getLastUpdate(); !lastUpdate.IsZero() {
			nextUpdate = lastUpdate.Add(config.Interval)
		} else {
			nextUpdate = time.Now().UTC()
		}

		// If the next update timer is in the past, then try to update.
		if nextUpdate.Before(time.Now().UTC()) {
			// Attempt to get a lock on the the update.
			log.Debug("attempting to obtain update lock")
			hasLock, hasLockUntil := database.Lock(flagName, lockDuration, whoAmI)
			if hasLock {
				// Launch update in a new go routine.
				doneC := make(chan bool, 1)
				go func() {
					Update()
					doneC <- true
				}()

				for done := false; !done && !stop; {
					select {
					case <-doneC:
						done = true
					case <-time.After(refreshLockDuration):
						// Refresh the lock until the update is done.
						database.Lock(flagName, lockDuration, whoAmI)
					case <-st.Chan():
						stop = true
					}
				}

				// Unlock the update.
				database.Unlock(flagName, whoAmI)

				if stop {
					break
				}
				continue
			} else {
				lockOwner, lockExpiration, err := database.LockInfo(flagName)
				if err != nil {
					log.Debug("update lock is already taken")
					nextUpdate = hasLockUntil
				} else {
					log.Debugf("update lock is already taken by %s until %v", lockOwner, lockExpiration)
					nextUpdate = lockExpiration
				}
			}
		}

		// Sleep, but remain stoppable until approximately the next update time.
		now := time.Now().UTC()
		waitUntil := nextUpdate.Add(time.Duration(rand.ExpFloat64()/0.5) * time.Second)
		log.Debugf("next update attempt scheduled for %v.", waitUntil)
		if !waitUntil.Before(now) {
			if !st.Sleep(waitUntil.Sub(time.Now())) {
				break
			}
		}
	}

	log.Info("updater service stopped")
}

// Run pops notifications from the database, lock them, send them, mark them as
// send and unlock them
//
// It uses an exponential backoff when POST requests fail
func (notifier *HTTPNotifier) Run(st *utils.Stopper) {
	defer st.End()

	whoAmI := uuid.New()
	log.Infof("HTTP notifier started. URL: %s. Lock Identifier: %s", notifier.url, whoAmI)

	for {
		node, notification, err := database.FindOneNotificationToSend(database.GetDefaultNotificationWrapper())
		if notification == nil || err != nil {
			if err != nil {
				log.Warningf("could not get notification to send: %s.", err)
			}

			if !st.Sleep(checkInterval) {
				break
			}

			continue
		}

		// Try to lock the notification
		hasLock, hasLockUntil := database.Lock(node, lockDuration, whoAmI)
		if !hasLock {
			continue
		}

		for backOff := time.Duration(0); ; backOff = timeutil.ExpBackoff(backOff, maxBackOff) {
			// Backoff, it happens when an error occurs during the communication
			// with the notification endpoint
			if backOff > 0 {
				// Renew lock before going to sleep if necessary
				if time.Now().Add(backOff).After(hasLockUntil.Add(-refreshLockAnticipation)) {
					hasLock, hasLockUntil = database.Lock(node, lockDuration, whoAmI)
					if !hasLock {
						log.Warning("lost lock ownership, aborting")
						break
					}
				}

				// Sleep
				if !st.Sleep(backOff) {
					return
				}
			}

			// Get notification content
			content, err := notification.GetContent()
			if err != nil {
				log.Warningf("could not get content of notification '%s': %s", notification.GetName(), err.Error())
				break
			}

			// Marshal the notification content
			jsonContent, err := json.Marshal(struct {
				Name, Type string
				Content    interface{}
			}{
				Name:    notification.GetName(),
				Type:    notification.GetType(),
				Content: content,
			})
			if err != nil {
				log.Errorf("could not marshal content of notification '%s': %s", notification.GetName(), err.Error())
				break
			}

			// Post notification
			req, _ := http.NewRequest("POST", notifier.url, bytes.NewBuffer(jsonContent))
			req.Header.Set("Content-Type", "application/json")

			client := &http.Client{}
			res, err := client.Do(req)
			if err != nil {
				log.Warningf("could not post notification '%s': %s", notification.GetName(), err.Error())
				continue
			}
			res.Body.Close()

			if res.StatusCode != 200 && res.StatusCode != 201 {
				log.Warningf("could not post notification '%s': got status code %d", notification.GetName(), res.StatusCode)
				continue
			}

			// Mark the notification as sent
			database.MarkNotificationAsSent(node)

			log.Infof("sent notification '%s' successfully", notification.GetName())
			break
		}

		if hasLock {
			database.Unlock(node, whoAmI)
		}
	}

	log.Info("HTTP notifier stopped")
//.........這裏部分代碼省略.........