lefthook

Lefthook

A Git hooks manager for Node.js, Ruby, Python and many other types of projects.

• Fast. It is written in Go. Can run commands in parallel.
• Powerful. It allows to control execution and files you pass to your commands.
• Simple. It is single dependency-free binary which can work in any environment.

📖 Introduction post

Lefthook is built by Evil Martians, an American design and engineering consultancy for developer tools, AI, and cybersecurity startups.

Install

With Go (>= 1.27):

go install github.com/evilmartians/lefthook/[email protected]

• or as a go tool

go get -tool github.com/evilmartians/lefthook/[email protected]

With NPM:

npm install lefthook --save-dev

For Ruby:

gem install lefthook

For Python:

pipx install lefthook

Installation guide with more ways to install lefthook: apt, brew, winget, and others.

Usage

Configure your hooks, install them once and forget about it: rely on the magic underneath.

TL;DR

# Configure your hooks
vim lefthook.yml

# Install them to the git project
lefthook install

# Enjoy your work with git
git add -A && git commit -m '...'

More details

• Configuration for lefthook.yml config options.
• Usage for lefthook CLI options, and features.
• Discussions for questions, ideas, suggestions.

Why Lefthook

• Parallel execution

Gives you more speed. docs

pre-push:
  parallel: true

• Flexible list of files

If you want your own list. Custom and prebuilt examples.

pre-commit:
  jobs:
    - name: lint frontend
      run: yarn eslint {staged_files}

    - name: lint backend
      run: bundle exec rubocop --force-exclusion -- {all_files}

    - name: stylelint frontend
      files: git diff --name-only HEAD @{push}
      run: yarn stylelint {files}

• Glob and regexp filters

If you want to filter list of files. You could find more glob pattern examples here.

pre-commit:
  jobs:
    - name: lint backend
      glob: "*.rb" # glob filter
      exclude:
        - "*/application.rb"
        - "*/routes.rb"
      run: bundle exec rubocop --force-exclusion -- {all_files}

• Execute in sub-directory

If you want to execute the commands in a relative path

pre-commit:
  jobs:
    - name: lint backend
      root: "api/" # Careful to have only trailing slash
      glob: "*.rb" # glob filter
      run: bundle exec rubocop -- {all_files}

• Run scripts

If oneline commands are not enough, you can execute files. docs

commit-msg:
  jobs:
    - script: "template_checker"
      runner: bash

• Tags

If you want to control a group of commands. docs

pre-push:
  jobs:
    - name: audit packages
      tags:
        - frontend
        - linters
      run: yarn lint

    - name: audit gems
      tags:
        - backend
        - security
      run: bundle audit

• Support Docker

If you are in the Docker environment. docs

pre-commit:
  jobs:
    - script: "good_job.js"
      runner: docker run -it --rm <container_id_or_name> {cmd}

• Local config

If you are a frontend/backend developer and want to skip unnecessary commands or override something in Docker. docs

# lefthook-local.yml
pre-push:
  exclude_tags:
    - frontend
  jobs:
    - name: audit packages
      skip: true

• Direct control

If you want to run hooks group directly.

$ lefthook run pre-commit

• Your own tasks

If you want to run specific group of commands directly.

fixer:
  jobs:
    - run: bundle exec rubocop --force-exclusion --safe-auto-correct -- {staged_files}
    - run: yarn eslint --fix {staged_files}

$ lefthook run fixer

• Control output

You can control what lefthook prints with output option.

output:
  - execution
  - failure

---

Guides

• Install with Node.js
• Install with Ruby
• Install with Homebrew
• Install with Winget
• Install for Debian-based Linux
• Install for RPM-based Linux
• Install for Arch Linux
• Install for Alpine Linux
• Usage
• Configuration

Examples

Check examples

Articles

• 5 cool (and surprising) ways to configure Lefthook for automation joy
• Lefthook: Knock your team’s code back into shape
• Lefthook + Crystalball
• Keeping OSS documentation in check with docsify, Lefthook, and friends
• Automatically linting docker containers
• Smooth PostgreSQL upgrades in DockerDev environments with Lefthook
• Lefthook for React/React Native apps