pre-commit framework¶

pre-commit is a framework for managing and maintaining multilingual commit hooks.

An essential task is to make the same scripts available to the entire development team. pre-commit by yelp manages such hooks and distributes them to different projects and developers.

Git hooks are mostly used to automatically point out problems in the code before code reviews, for example to check the formatting or to find debug statements. pre-commit simplifies the sharing of hooks across projects. The language in which a linter was written, for example, is abstracted away – scss-lint is written in Ruby, but you can use it with pre-commit without having to add a Gemfile to your project.

Installation¶

Before you can execute the hooks, the pre-commit framework must be installed:

Windows

Before the pre-commit framework can be installed with Pipenv, the Microsoft Build Tools for C++ must be downloaded and executed so that the Desktop development with C++ can be selected and installed with the standard options.

Only then can the pre-commit framework be installed with:

$ pipenv install pre-commit

Debian/Ubuntu

$ apt install pre-commit

macOS

$ brew install pre-commit

Others

$ pipenv install pre-commit

Check the installation for example with

$ pipenv run pre-commit -V
pre-commit 2.21.0

Configuration¶

After Pre-Commit is installed, the .pre-commit-config.yaml file in the root directory of your project can be used to configure plugins for this project.

repos:
  - repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v3.2.0
    hooks:
    -   id: trailing-whitespace
    -   id: end-of-file-fixer
    -   id: check-yaml
    -   id: check-added-large-files

You can also generate such an initial .pre-commit-config.yaml file with

$ pipenv run pre-commit sample-config > .pre-commit-config.yaml

If you want to apply check-json to your Jupyter notebooks, you must first configure that the check should also be used for the file suffix .ipynb:

 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v3.2.0
     hooks:
     …
     - id: check-json
       types: [file]
       files: \.(json|ipynb)$

Installing the git hook scripts¶

To ensure that pre-commit is also reliably executed before each commit, the script is installed in our project:

$ pre-commit install
pre-commit installed at .git/hooks/pre-commit

If you want to uninstall the git hook scripts, you can do so with pre-commit uninstall.

Run¶

pre-commit run --all-files

runs all pre-commit hooks independently of git commit:

$ pipenv run pre-commit run --all-files
Trim Trailing Whitespace.................................................Passed
Fix End of Files.........................................................Passed
Check Yaml...............................................................Passed
Check for added large files..............................................Passed

pre-commit run HOOK: executes single pre-commit hooks, for example pre-commit run trailing-whitespace

Note

When a pre-commit hook is called for the first time, it is first downloaded and then installed. This may take some time, for example if a copy of node has to be created.

pre-commit autoupdate

updates the hooks automatically: