Function startTail

pkg/logging/logging.go:447–472

startTail wait for the next log write. the boolean value indicates if the log file was recreated; the error is error happens during waiting new logs.

(ctx context.Context, logName string, w *fsnotify.Watcher)

// the boolean value indicates if the log file was recreated;
// the error is error happens during waiting new logs.
func startTail(ctx context.Context, logName string, w *fsnotify.Watcher) (bool, error) {
	errRetry := 5
	for {
		select {
		case <-ctx.Done():
			return false, fmt.Errorf("context cancelled")
		case e := <-w.Events:
			switch {
			case e.Has(fsnotify.Write):
				return false, nil
			case e.Has(fsnotify.Create):
				return filepath.Base(e.Name) == logName, nil
			default:
				log.L.Debugf("Received unexpected fsnotify event: %v, retrying", e)
			}
		case err := <-w.Errors:
			log.L.WithError(err).Debugf("Received fsnotify watch error, retrying unless no more retries left, retries: %d", errRetry)
			if errRetry == 0 {
				return false, err
			}
			errRetry--
		case <-time.After(logForceCheckPeriod):
			return false, nil
		}
	}
}