What causes "error writing chaincode package to %s" in hyperledger/fabric?

Create the output directory first (mkdir -p) or point OutputFile at an existing writable directory.

error writing chaincode package to %s

Error message

error writing chaincode package to %s

What it means

After getTarGzBytes builds the package, Package writes the tar.gz bytes to p.Input.OutputFile via the injected Writer.WriteFile. If that filesystem write fails, the error is wrapped with 'error writing chaincode package to <output file>'. It is a filesystem-level failure, not a chaincode or network issue.

Source

Thrown at internal/peer/lifecycle/chaincode/package.go:148

	err := p.Input.Validate()
	if err != nil {
		return err
	}

	pkgTarGzBytes, err := p.getTarGzBytes()
	if err != nil {
		return err
	}

	dir, name := filepath.Split(p.Input.OutputFile)
	// if p.Input.OutputFile is only file name, dir becomes an empty string that creates problem
	// while invoking 'WriteFile' function below. So, irrespective, translate dir into absolute path
	if dir, err = filepath.Abs(dir); err != nil {
		return err
	}
	err = p.Writer.WriteFile(dir, name, pkgTarGzBytes)
	if err != nil {
		err = errors.Wrapf(err, "error writing chaincode package to %s", p.Input.OutputFile)
		logger.Error(err.Error())
		return err
	}

	return nil
}

func (p *Packager) getTarGzBytes() ([]byte, error) {
	payload := bytes.NewBuffer(nil)
	gw := gzip.NewWriter(payload)
	tw := tar.NewWriter(gw)

	normalizedPath, err := p.PlatformRegistry.NormalizePath(strings.ToUpper(p.Input.Type), p.Input.Path)
	if err != nil {
		return nil, errors.WithMessage(err, "failed to normalize chaincode path")
	}
	metadataBytes, err := toJSON(normalizedPath, p.Input.Type, p.Input.Label)
	if err != nil {

View on GitHub (pinned to 2736b63f8f)

Solutions

Create the output directory first (mkdir -p) or point OutputFile at an existing writable directory.
Check permissions/ownership of the target directory (ls -ld) and run as a user with write access.
Verify free disk space (df -h) and that the target is not a directory.
Read the wrapped inner error after the colon — it states the exact OS reason (permission denied, no such file, etc.).

Example fix

// before: parent dir may not exist
peer lifecycle chaincode package /output/basic.tar.gz --path . --lang golang --label basic_1.0
// after (ensure dir exists and is writable)
mkdir -p /output
peer lifecycle chaincode package /output/basic.tar.gz --path . --lang golang --label basic_1.0

Defensive patterns

Strategy: try-catch

Validate before calling

#!/bin/bash
OUT_DIR=$(dirname "$OUT")
mkdir -p "$OUT_DIR"
[ -w "$OUT_DIR" ] || { echo "not writable: $OUT_DIR"; exit 1; }
[ ! -d "$OUT" ] || { echo "$OUT is a directory"; exit 1; }
df -h "$OUT_DIR" | awk 'NR==2 {exit ($5+0 > 95 ? 1 : 0)}' || { echo "low disk space"; exit 1; }

Try / catch

if ! out=$(peer lifecycle chaincode package "$OUT" ... 2>&1); then
  case "$out" in
    *"error writing chaincode package to"*)
      echo "Filesystem write failed: $out"
      echo "Check dir exists, permissions, disk space"; exit 3 ;;
    *) echo "$out"; exit 1 ;;
  esac
fi

Prevention

mkdir -p the output directory before packaging.
Run the CLI as a user with write access to the target dir.
Monitor disk space in CI runners.
Never point the output file at an existing directory.

When it happens

Trigger: Output path in a non-existent directory; no write permission on the target directory; disk full; output path is a directory rather than a file.

Common situations: CI writing to a read-only volume; containerized peer running as non-root writing to /; NFS mounts with permission issues; typos in the output path creating a deep nonexistent directory.

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

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/25be41caa65e46f5. Report an issue: GitHub.