Implementation:Apache Airflow CustomBuild Hatch Plugin

Knowledge Sources	Apache Airflow
Domains	Build_System, Release_Engineering
Last Updated	2026-02-08 00:00 GMT

Overview

Concrete tool for building Airflow release artifacts provided by the CustomBuild hatch plugin, towncrier, and sign.sh.

Description

The CustomBuild class extends hatchling's BuilderInterface to compile UI assets and generate git version metadata during build. Towncrier generates RELEASE_NOTES.rst from newsfragment files. The sign.sh script creates GPG signatures and checksums.

Usage

Run hatch build for source distributions. Use towncrier for release notes. Sign with sign.sh.

Code Reference

Source Location

• Repository: Apache Airflow
• File: airflow-core/hatch_build.py (L36-120)
• File: airflow-core/newsfragments/config.toml (L1-52)
• File: dev/sign.sh (L1-32)

Signature

class CustomBuild(BuilderInterface[BuilderConfig, PluginManager]):
    PLUGIN_NAME = "custom"

    def get_git_version(self) -> str:
        """Extract version from git describe."""
        ...

    def write_git_version(self) -> None:
        """Write git version to metadata file."""
        ...

    def build_standard(self, directory: str, artifacts: Any, **build_data: Any) -> str:
        """Build source distribution with UI assets."""
        ...

# sign.sh
set -euo pipefail
SIGN_WITH="${SIGN_WITH:-apache.org}"
for name in "${@}"; do
    gpg --yes --armor --local-user "$SIGN_WITH" --output "${name}.asc" --detach-sig "${name}"
    shasum -a 512 "${name}" > "${name}.sha512"
done

Import

# Build source distribution
hatch build

# Generate release notes
towncrier build --yes

# Sign artifacts
./dev/sign.sh dist/*.tar.gz

I/O Contract

Inputs

Name	Type	Required	Description
Git-tagged source	Repository	Yes	Source code with release tag
Newsfragments	RST files	Yes	Change descriptions in newsfragments/
GPG key	Key	Yes	Apache signing key identity

Outputs

Name	Type	Description
Source distribution	.tar.gz	Built source package
Release notes	RST	Generated RELEASE_NOTES.rst
Signatures	.asc files	GPG detached signatures
Checksums	.sha512 files	SHA512 checksums
Build metadata	YAML	reproducible_build.yaml

Usage Examples

Build Release Candidate

# 1. Generate release notes
cd airflow-core
towncrier build --yes

# 2. Build source distribution
hatch build

# 3. Sign artifacts
cd ..
./dev/sign.sh dist/apache_airflow-3.1.0rc1.tar.gz

Related Pages

Implements Principle

• Principle:Apache_Airflow_RC_Build_Signing

Requires Environment

• Environment:Apache_Airflow_Development_Contributor_Environment