GoogleContainerTools/skaffold · error

writing string: %w

Error message

writing string: %w

What it means

After successful marshalling, SaveEventsToFile writes each serialized event plus a newline with f.WriteString. Failure is wrapped as 'writing string: %w'. Since the file was just opened for append/write, failures are almost always I/O-level (disk full, closed file, device error).

Source

Thrown at pkg/skaffold/event/event.go:851

	handler.logLock.Lock()
	// Ensure that the filepath provided has the directories available when attemping to save the file.
	dir := filepath.Dir(fp)
	if err := os.MkdirAll(dir, 0700); err != nil {
		return fmt.Errorf("unable to create directory %q: %w", dir, err)
	}
	f, err := os.OpenFile(fp, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0600)
	if err != nil {
		return fmt.Errorf("opening %s: %w", fp, err)
	}
	defer f.Close()
	marshaller := jsonpb.Marshaler{}
	for _, ev := range handler.eventLog {
		contents := bytes.NewBuffer([]byte{})
		if err := marshaller.Marshal(contents, ev); err != nil {
			return fmt.Errorf("marshalling event: %w", err)
		}
		if _, err := f.WriteString(contents.String() + "\n"); err != nil {
			return fmt.Errorf("writing string: %w", err)
		}
	}
	handler.logLock.Unlock()
	return nil
}

View on GitHub (pinned to a1189de023)

Solutions

1. Check free disk space (df -h) on the filesystem holding the output file and free space if needed
2. Write the event log to a different filesystem with available space
3. Check storage quota (quota -s) if on a quota-limited home or network volume
4. Retry after the transient I/O condition clears — the file is opened in append mode so partial logs persist

var lastErr error
for attempt := 0; attempt < 3; attempt++ {
    if err := SaveEventsToFile(fp); err == nil {
        return nil
    } else if strings.Contains(err.Error(), "writing string") {
        lastErr = err
        time.Sleep(time.Second)
        continue
    }
    return err
}
return lastErr

When it happens

Trigger: Disk becomes full (ENOSPC) mid-write; underlying storage error on network volumes; file descriptor closed or invalidated by an external process during the loop.

Common situations: Small tmpfs or container overlay filling up during long skaffold sessions with many events; NFS/EFS volumes dropping connections; quota exceeded on user storage.

Related errors

• writing string: %w
• unable to create directory %q: %w
• opening %s: %w
• unable to create directory %q: %w
• opening %s: %w

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/f64c06ba8c64fe39. Report an issue: GitHub.