Method Lock

pkg/memory/database/lock.go:72–125

Lock blocks until the exclusive advisory lock is acquired or ctx is canceled.

(ctx context.Context)

// Lock blocks until the exclusive advisory lock is acquired or ctx is canceled.
func (l *FileLock) Lock(ctx context.Context) error {
	if ctx == nil {
		ctx = context.Background()
	}
	if err := ctx.Err(); err != nil {
		return err
	}

	l.mu.Lock()
	defer l.mu.Unlock()

	if l.file != nil {
		return nil
	}

	if err := l.lockProcess(ctx); err != nil {
		return err
	}
	processLocked := true
	defer func() {
		if processLocked {
			l.processLock.Unlock()
		}
	}()

	if err := os.MkdirAll(filepath.Dir(l.path), 0o700); err != nil {
		return fmt.Errorf("creating memory lock directory %q: %w", filepath.Dir(l.path), err)
	}

	f, err := os.OpenFile(l.path, os.O_RDWR|os.O_CREATE, 0o600)
	if err != nil {
		return fmt.Errorf("opening memory lock file %q: %w", l.path, err)
	}

	for {
		err = lockFileExclusive(f)
		if err == nil {
			l.file = f
			processLocked = false
			return nil
		}
		if !isLockUnavailable(err) {
			_ = f.Close()
			return fmt.Errorf("locking memory lock file %q: %w", l.path, err)
		}

		select {
		case <-ctx.Done():
			_ = f.Close()
			return ctx.Err()
		case <-time.After(lockRetryInterval):
		}
	}
}

func (l *FileLock) lockProcess(ctx context.Context) error {
	return l.processLock.Lock(ctx)