YAML formatter for pre-commit git hooks

YAML formatter for pre-commit.

This hook formats the indentation of YAML files and optionally aligns top-level colons.
It uses ruamel.yaml to do the heavy lifting and preserve comments within YAML files.

• How-to
  • Configure pre-commit
    • Use defaults
    • Combine with yamllint
    • Override defaults
  • Invoke pre-commit
    • On every commit
    • On demand
• Contributing
• Testing
• License

How-to

Configure pre-commit

Use defaults

Add to .pre-commit-config.yaml in your git repo:

- repo: https://github.com/jumanjihouse/pre-commit-hook-yamlfmt
  rev: 0.0.10  # or specific tag
  hooks:
      - id: yamlfmt

💡 If a pre-commit hook changes a file, the hook fails with a warning that files were changed.

The default settings are:

• mapping: 4 spaces
• sequence: 6 spaces
• offset: 4 spaces
• colons: do not align top-level colons
• width: None (use ruamel default)

Given this input:

foo:
  bar:
    - baz1
    - baz2

The default settings result in this output:

---
foo:
    bar:
        - baz1
        - baz2

Combine with yamllint

yamlfmt only works with valid YAML files, so I recommend to use yamllint and yamlfmt together.

- repo: https://github.com/adrienverge/yamllint.git
  rev: v1.21.0  # or higher tag
  hooks:
      - id: yamllint
        args: [--format, parsable, --strict]

- repo: https://github.com/jumanjihouse/pre-commit-hook-yamlfmt
  rev: 0.0.10  # or specific tag
  hooks:
      - id: yamlfmt

Override defaults

Add to .pre-commit-config.yaml in your git repo:

- repo: https://github.com/jumanjihouse/pre-commit-hook-yamlfmt
  rev: 0.0.10  # or specific tag
  hooks:
      - id: yamlfmt
        args: [--mapping, '2', --sequence, '2', --offset, '0', --colons, --width, '150']

Invoke pre-commit

On every commit

If you want to invoke the checks as a git pre-commit hook, run:

# Run on every commit.
pre-commit install

On demand

If you want to run the checks on-demand (outside of git hooks), run:

# Run on-demand.
pre-commit run --all-files

The test harness of this git repo uses this approach.

Contributing

Please see CONTRIBUTING.md.

Testing

Please see TESTING.md.

License

The code in this repo is licensed under the MIT License.