ahmetb/kubectx · error

write error: %w

Error message

write error: %w

What it means

After resolving the namespace, CurrentOp.Run prints it to stdout with fmt.Fprintln. If that write fails, the error is wrapped as "write error: %w". Like the kubectx version write error, this signals the output stream rejected the data rather than any kubeconfig problem.

Source

Thrown at cmd/kubens/current.go:47

	defer kc.Close()
	if err := kc.Parse(); err != nil {
		return fmt.Errorf("kubeconfig error: %w", err)
	}

	ctx, err := kc.GetCurrentContext()
	if err != nil {
		return fmt.Errorf("failed to get current context: %w", err)
	}
	if ctx == "" {
		return errors.New("current-context is not set")
	}
	ns, err := kc.NamespaceOfContext(ctx)
	if err != nil {
		return fmt.Errorf("failed to read namespace of \"%s\": %w", ctx, err)
	}
	_, err = fmt.Fprintln(stdout, ns)
	if err != nil {
		return fmt.Errorf("write error: %w", err)
	}
	return nil
}

View on GitHub (pinned to 12ad6fb22e)

Solutions

1. Re-run with stdout attached to a terminal to confirm the command itself works
2. Inspect the wrapped error for EPIPE (fix the pipe consumer) vs ENOSPC (free disk space)
3. Avoid piping into commands that exit immediately; use a file or tee instead
4. In scripts, check exit codes and stderr rather than swallowing the failure

Example fix

// before
kubens -c | head -0   # broken pipe
// after
kubens -c > current-ns.txt

if f, ok := stdout.(*os.File); ok {
    if _, err := f.Stat(); err != nil {
        return fmt.Errorf("stdout unusable: %w", err)
    }
}

if err := op.Run(stdout, stderr); err != nil {
    if strings.Contains(err.Error(), "write error:") {
        if errors.Is(err, syscall.EPIPE) {
            return nil // consumer closed the pipe
        }
    }
    return err
}

When it happens

Trigger: fmt.Fprintln(stdout, ns) fails because stdout is a broken/closed pipe, a full disk, or an otherwise invalid output stream.

Common situations: `kubens -c | head -0` style pipelines that close the reader early; CI runners with detached stdout; disk-full conditions when redirecting to a file.

Related errors

• write error: %w
• write error: %w
• failed to close encoder for file %d: %w
• kubeconfig error: %w
• failed to get current context: %w

AI-assisted analysis of ahmetb/kubectx@12ad6fb22e (2026-09-02). Data as JSON: /api/errors/86b5dbe47f5fdb26. Report an issue: GitHub.