Pre-Commit by Example

Pre-commit is an easy to use tool that allows you to add in git hooks for your repos. This means that every time you run a commit command pre-commit will run what ever apps you’ve told it to. This is great for things like linting and formatting.

install

There’s a couple of ways to install pre-commit but I use brew

brew install pre-commit

pre-commit-config.yaml

For pre-commit to run, you need to add a pre-commit-config.yaml file to the root of your git repo. Below is a common example I use of loading markdownlinter, detect-secrets and terraform fmt (Note these are from different pre-commit repos you can stack as many as you like!)

repos:
- repo: git://github.com/antonbabenko/pre-commit-terraform
  rev: v1.47.0 # Get the latest from: https://github.com/antonbabenko/pre-commit-terraform/releases
  hooks:
    - id: terraform_fmt

- repo: https://github.com/Yelp/detect-secrets
  rev: v1.0.1
  hooks:
    - id: detect-secrets
      args: ['--baseline', '.secrets.baseline']
      exclude: package.lock.json
  
- repo: https://github.com/igorshubovych/markdownlint-cli
  rev: v0.26.0
  hooks:
  - id: markdownlint

init

To connect your pre-commit file to a repo you need to run install in the root of the repo

pre-commit install

commands

Collection of common commands

run all hooks against all files

This will run all your hooks against all files in the repo

pre-commit run -a

run specific hook against all files

Note that terraform_ftm is the id of a hook you wish to run

pre-commit run terraform_fmt -a

Resources

pre-commit website

install#

pre-commit-config.yaml#

init#

commands#

run all hooks against all files#

run specific hook against all files#

Resources#