apache/beam · error

error in packJar()

Error message

error in packJar(): %w

What it means

After chdir-ing into tmpDir, MakeJar calls packJar(".", tmpJar) to create a zip of the extracted contents at cacheDir/tmp.jar; any packing failure (zip create/write error) is wrapped as "error in packJar()".

Solutions

1. Ensure cacheDir is writable and has enough free space.
2. Stop concurrent processes touching tmpDir, clean it, and retry.
3. Unwrap the error to identify the specific file that failed to be written/read.
4. Check for unreadable files/symlinks in tmpDir before packing.

tmpJar := filepath.Join(cacheDir, "tmp.jar")
if f, err := os.Create(tmpJar); err != nil {
    return fmt.Errorf("cannot write tmp.jar in cacheDir: %w", err)
} else {
    f.Close()
    os.Remove(tmpJar)
}

jar, err := expansionx.MakeJar(ctx, target, repo, version)
var pe *fs.PathError
if err != nil && errors.As(err, &pe) && errors.Is(pe.Err, fs.ErrPermission) {
    return fmt.Errorf("check cacheDir permissions/disk space: %w", err)
}

When it happens

Trigger: packJar fails because tmp.jar cannot be created in cacheDir (permissions, disk full), or a file inside tmpDir cannot be read/zipped (disappeared mid-walk, symlink issues, unreadable entries).

Common situations: Cache directory not writable by the service user; files added/removed in tmpDir while packing due to concurrent runs; oversized contents exceeding disk quota.

Understand the failure class

Background: "failed to write file", "Could not save figure", "Error saving remote file" — file write failed: causes and fixes across languages and libraries — this error's family across 38 libraries.

Related errors

• error copying file
• error creating jarFile header
• error getting FileInfoHeader
• error in creating jar
• error in extractJar()

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/8dcb7111f01389c5. Report an issue: GitHub.

Appendix: source

Thrown at sdks/go/pkg/beam/core/runtime/xlangx/expansionx/download.go:313

	manifestLines = manifestLines[:len(manifestLines)-2]

	classpathString := fmt.Sprintf("%sClass-Path: %s\n", strings.Join(manifestLines, "\n"), strings.Join(relClasspath, " "))
	if err = os.WriteFile(tmpDir+"/META-INF/MANIFEST.MF", []byte(classpathString), 0660); err != nil {
		return "", fmt.Errorf("error writing ta manifest file: %w", err)
	}

	path, err := os.Getwd()
	if err != nil {
		return "", fmt.Errorf("can't get current working directory: %w", err)
	}

	if err = os.Chdir(tmpDir); err != nil {
		return "", fmt.Errorf("can't change to temp directory %s for creating JAR: %w", tmpDir, err)
	}

	tmpJar := filepath.Join(cacheDir, "tmp.jar")
	if err = packJar(".", tmpJar); err != nil {
		return "", fmt.Errorf("error in packJar(): %w", err)
	}

	if err = os.Chdir(path); err != nil {
		return "", fmt.Errorf("can't change to old working directory %s: %w", path, err)
	}

	return tmpJar, nil
}

// GetBeamJar checks a temporary directory for the desired Beam JAR, downloads the
// appropriate JAR from Maven if not present, then returns the file path to the
// JAR.
func GetBeamJar(gradleTarget, version string) (string, error) {
	return defaultJarGetter.getJar(gradleTarget, version)
}

func (j *jarGetter) getRepositoryURL() string {
	return string(j.repository)

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