GoogleContainerTools/skaffold · error

writing config file: %w

Error message

writing config file: %w

What it means

After backing up (if --overwrite) and generating the upgraded YAML, `skaffold fix` writes the new config with os.WriteFile(outFile, newCfg, 0644). This error wraps a write failure — the fix result was produced but could not be persisted to disk. Note: if the earlier backup write also failed, fix dumps the old v2 config to stdout as a fallback.

Source

Thrown at cmd/skaffold/app/cmd/fix.go:136

	if err != nil {
		return fmt.Errorf("marshaling new config: %w", err)
	}
	if outFile != "" {
		var writeErr error
		if overwrite {
			oldCfg, readErr := os.ReadFile(configFile)
			if readErr != nil {
				return fmt.Errorf("reading config file: %w", readErr)
			}
			newFile := fmt.Sprintf("%s.v2", outFile)

			writeErr = os.WriteFile(newFile, oldCfg, 0644)
			if writeErr == nil {
				output.Default.Fprintln(out, "Backed up previous skaffold.yaml at ", newFile)
			}
		}
		if err := os.WriteFile(outFile, newCfg, 0644); err != nil {
			return fmt.Errorf("writing config file: %w", err)
		}
		output.Default.Fprintf(out, "New config at version %s generated and written to %s\n", toVersion, outFile)
		if writeErr != nil {
			output.Yellow.Fprintln(out, "Error moving old config. Dumping old v2 config on stdout:")
			output.Default.Fprintln(out, getOldConfigYaml(versionedCfgs))
		}
	} else {
		out.Write(newCfg)
	}
	return nil
}

func getOldConfigYaml(cfgs []util.VersionedConfig) string {
	yamlStr, err := yaml.MarshalWithSeparator(cfgs)
	if err != nil {
		return fmt.Sprintf("marshaling old config: %v", err)
	}
	return string(yamlStr)

View on GitHub (pinned to a1189de023)

Solutions

1. Check the output path's parent directory exists and is writable (`ls -ld $(dirname <outFile>)`).
2. Fix permissions on the target file/directory or run with a user that can write it.
3. Free disk space if the filesystem is full.
4. Note the fallback: the old v2 config is printed to stdout when the backup move failed — capture stdout and save it manually.

Example fix

// before: output directory does not exist
skaffold fix --output ./build/skaffold.yaml
// after
mkdir -p ./build
skaffold fix --output ./build/skaffold.yaml

// Ensure the output destination is writable before running skaffold fix
const fs = require('fs');
const out = process.env.OUT_FILE ?? 'skaffold.fixed.yaml';
fs.mkdirSync(require('path').dirname(out), {recursive: true});
fs.accessSync(require('path').dirname(out), fs.constants.W_OK);
if (fs.existsSync(out)) fs.accessSync(out, fs.constants.W_OK);

try {
  execFileSync('skaffold', ['fix', '--output', outFile]);
} catch (e) {
  const msg = e.stderr?.toString() ?? '';
  if (msg.includes('writing config file')) {
    console.error(`Could not write ${outFile}; check dir existence, permissions, and disk space.`);
    // capture stdout, where fix may dump the old config
    console.error(e.stdout?.toString() ?? '');
  } else throw e;
}

When it happens

Trigger: `os.WriteFile(outFile, ...)` fails: the output path is in a read-only directory, the disk is full, an existing output file is not writable, or outFile's parent directory does not exist.

Common situations: Using `--output` pointing to a non-existent directory; running in a container/CI where the workspace is mounted read-only; overwriting skaffold.yaml owned by root while running as a non-root user; full disk on a dev machine.

Understand the failure class

Background: "Permission denied" / "Failed to write" file errors: why a library can't write its files to disk (EACCES, EPERM, ENOSPC) and how to fix them — this error's family across 43 libraries.

Related errors

• reading config file: %w
• INSPECT_PROFILE_NOT_FOUND_ERR
• cannot resolve active Kubernetes context - multiple contexts
• filename not specified
• getting run context: %w

AI-assisted analysis of GoogleContainerTools/skaffold@a1189de023 (2026-09-05). Data as JSON: /api/errors/471755a48078ddc2. Report an issue: GitHub.