Git Lifecycle Hooks

For too long time I've ignored this powerful tool that I use for

• local pre-commit formatting and checks

• add branch name to a commit message

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Implement your own hook

The folder .git/hooks of every git repo contains some sample

• pre-commit.sample

• pre-push.sample

• prepare-commit-msg.sample

A hook implementation has to have a specific name (e. g. pre-commit) and needs to be executable. You can either/or

• create it manually

• create a ~/.git-templates/hooks folder containing all hooks that should be copied during git init

  • git init is not only used for the initial git-repo setup but you can use it anytime when you want to have the ~/.git-templates applied

For the pre-commit hook there was a framework (Plugin-based) implemented that gets contributions for a wide range of technologies and use-cases (see below).

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Pre-Commit Hook Project

THIS is about the pre-commit open-source project that provides some tooling around the pre-commit hook

• official documentation

One drawback of the core git lifecycle hooks is that there is only a single file per lifecycle trigger to be used, e. g. ALL pre-commit actions have to be implemeted in .git/hooks/pre-commit. The pre-commit open-source project offers a plugin approach based on a (.pre-commit-config.yaml) that can reference different sources

repos:
- repo: https://github.com/antonbabenko/pre-commit-terraform
  rev: v1.83.5
  hooks:
    - id: terraform_fmt
- repo: https://github.com/mattlqx/pre-commit-search-and-replace
  rev: v1.0.5
  hooks:
  - id: search-and-replace

The core pre-commit git hook (residing in .git/hooks/pre-commit) is installed via pre-commit install. Its implementation is based on the configuration in .pre-commit-config.yaml. Each plugin is using a specific configuration file (e. g. .pre-commit-search-and-replace.yaml for https://github.com/mattlqx/pre-commit-search-and-replace). You can reuse this code within GitHub workflows via pre-commit GitHub Action.

There are quite a lot of (plugins) available.

Here's an example how it could look like:

• https://github.com/mattlqx/pre-commit-search-and-replace/blob/main/.pre-commit-config.yaml

Install

pip install pre-commit

Setup

• adding .pre-commit-config.yaml](.pre-commit-config.yaml) to the root of your repo

• cd my-git-repo

• pre-commit install

  • this adds .git/hooks/pre-commit implementation based on .pre-commit-config.yaml into the repository

Manual Usage

pre-commit run --all-files

Auto Usage

Every git commit will FIRST check and change all files (depending on which hooks are enabled). If there is no changed file it will report that it was running like that:

pre-commit-hook-nochange.png

Update

pre-commit autoupdate will change the .pre-commit-config.yaml