Method Lock

gateway/modules/global/letsencrypt/sc_store.go:219–259

Lock obtains a lock named by the given key. It blocks until the lock can be obtained or an error is returned.

(ctx context.Context, key string)

// Lock obtains a lock named by the given key. It blocks
// until the lock can be obtained or an error is returned.
func (s *Storage) Lock(ctx context.Context, key string) error {
	start := time.Now()
	lockFile := s.lockFileName(key)

	for {
		err := s.createLockFile(lockFile)
		if err == nil {
			// got the lock
			return nil
		}

		if err.Error() != lockFileExists {
			// unexpected error
			return helpers.Logger.LogError(helpers.GetRequestID(context.TODO()), "Unable to create lock file in lets encrypt", err, nil)
		}

		// lock file already exists
		info, err := s.Stat(lockFile)
		switch {
		case err != nil:
			return helpers.Logger.LogError(helpers.GetRequestID(context.TODO()), "Unable to get stats of lock file in lets encrypt", err, nil)

		case s.fileLockIsStale(info):
			helpers.Logger.LogWarn(helpers.GetRequestID(context.TODO()), "lets encrypt lock file is in stale state removing and trying again", nil)
			if err := s.deleteLockFile(lockFile); err != nil {
				return err
			}
			continue

		case time.Since(start) > staleLockDuration*2:
			// should never happen, hopefully
			return helpers.Logger.LogError(helpers.GetRequestID(context.TODO()), "Lets encrypt dead lock by passing", fmt.Errorf("possible deadlock: %s passed trying to obtain lock for %s", time.Since(start), key), nil)

		default:
			// lockfile exists and is not stale;
			// just wait a moment and try again
			time.Sleep(fileLockPollInterval)

		}
	}
}

// Unlock releases the lock for name.
func (s *Storage) Unlock(key string) error {