hyperledger/fabric · error

Error writing file to package: %s

Error message

Error writing file to package: %s

What it means

Wraps any failure from WriteFileToPackage while walking a chaincode source folder into a tar package (WriteFolderToTarPackage's walkFn). The underlying error - typically from os.Open, Stat, tar header creation, or writing to the tar stream - is wrapped with this message identifying the file that failed.

Source

Thrown at core/chaincode/platforms/util/writer.go:88

			fileBytes, err := os.ReadFile(localpath)
			if err != nil {
				return err
			}

			// Validate metadata file for inclusion in tar
			// Validation is based on the fully qualified path of the file
			err = ccmetadata.ValidateMetadataFile(packagepath, fileBytes)
			if err != nil {
				return err
			}
		} else { // file is not metadata, include in src
			packagepath = path.Join("src", packagepath)
		}

		err = WriteFileToPackage(localpath, packagepath, tw)
		if err != nil {
			return fmt.Errorf("Error writing file to package: %s", err)
		}

		success = true
		return nil
	}

	if err := filepath.Walk(rootDirectory, walkFn); err != nil {
		logger.Infof("Error walking rootDirectory: %s", err)
		return err
	}

	if !success {
		return errors.Errorf("no source files found in '%s'", srcPath)
	}
	return nil
}

// WriteFileToPackage writes a file to a tar stream.

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Check the wrapped underlying error for the specific file and cause (permissions vs missing file vs tar write failure)
2. Verify read permissions on the chaincode source files (chmod/chown)
3. Exclude volatile/irrelevant directories (e.g. node_modules churn) via excludeDirs to avoid race windows
4. Retry packaging if files were being modified concurrently; ensure the tar writer's destination stream is healthy

Example fix

// before: packaging while node_modules is being written
util.WriteFolderToTarPackage(tw, src, nil, nil, nil)
// after: exclude volatile directories and fix permissions
err := util.WriteFolderToTarPackage(tw, src, []string{"node_modules", ".git"}, nil, nil)
if err != nil {
    os.Chmod(src, 0o755) // ensure readable
}

// check source files are readable before packaging
err := filepath.Walk(srcPath, func(p string, info os.FileInfo, err error) error {
    if err != nil { return err }
    if !info.IsDir() {
        f, err := os.Open(p)
        if err != nil { return fmt.Errorf("unreadable: %s: %w", p, err) }
        f.Close()
    }
    return nil
})

// distinguish packaging failures and handle per-file
if err != nil && strings.Contains(err.Error(), "Error writing file to package") {
    log.Printf("packaging failed, cause: %v", err) // wrapped underlying error
    return err
}

When it happens

Trigger: A source file is deleted between the filepath.Walk listing and the open (race); the file cannot be opened due to permissions; the tar.Writer was closed or its underlying stream errored (e.g. HTTP connection to the peer dropped mid-package); the file info/stat fails on a special file (device, symlink issues).

Common situations: Chaincode directory contains files being concurrently modified/removed during packaging; packaging over a network stream that breaks; unreadable files due to restrictive permissions or SELinux; disk full when writing the tar.

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 writing %s to tar: %s
• no source files found in '%s'
• error writing package metadata to tar
• error writing package code bytes to tar
• failed to create tar for chaincode

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/ec20efa178aa556b. Report an issue: GitHub.