husky vs git hooks

Git Hooks and Husky

Git Hooks

• Git supports hooks, which are scripts that run at various stages (such as before a commit, after a push, etc.).
• The Git hooks directory is located at:.git/hooks

Categorized

Git hooks are categorized into client-sideand server-side hooks, each triggered at different stages of Git operations. Here's a list of all the available Git hooks:

Client-Side Hooks

These hooks run on the developer's machine during operations like commits, merges, and checkouts.

1. pre-commit:
2. prepare-commit-msg:
3. commit-msg:
4. post-commit:
5. pre-rebase:
6. post-checkout:
7. post-merge:
8. pre-push:
9. pre-applypatch:
10. post-applypatch:
11. pre-commit-msg (for interactive rebases):

Server-Side Hooks

These hooks run on the Git server, typically during a push operation or when interacting with remote repositories.

1. pre-receive:
2. update:
3. post-receive:
4. post-update:
5. push-to-checkout:

Commit Process in Git

When the commit command is executed:

git commit -m &quottest&quot

1. hook : Pre-commit
2. hook : prepare-commit-msg -
3. A file named .git/COMMIT_EDITMSGis created.
4. The commit message is written into this file.
5. Hook : commit-msg
6. hook : pre-applypatch
7. commit is completed.
8. Hook : post-commit
9. Hook : post-applypatch

Note: .git/COMMIT_EDITMSGis file is not removed after the commit.

Relationship Between Husky and Git

• Git: A version control system that supports hooks.
• Husky: A tool for managing Git hooks more easily, allowing you to handle hooks automatically with simple code, without needing to manually edit hook files.
• Summary: Husky is an external tool that integrates with Git to simplify hook management, but it is not part of Git itself.
• It is true that Husky changes Git hooks, but it does so in a streamlined and user-friendly way.

note : example of server side git hooks -> CI/CD pipelines run on a server (such as Jenkins, GitHub Actions, GitLab CI) after the code is pushed to a remote repository.

Installing Husky

To install Husky:
npm install --save-dev husky

1. To initialize Husky (for older versions):

npx husky-init && husky install

Installing Commitlint

1. To install Commitlint for validating commit messages:

npm install --save-dev @commitlint/config-conventional @commitlint/cli

1. Create a file named commitlint.config.js in the root of your project with the following content:

module.exports = {
  extends: ['@commitlint/config-conventional']
};

1. Add a hook to validate commit messages using Husky:

npx husky add .husky/commit-msg 'npx --no-install commitlint --edit $1'

npx: Executes the tool without installing it permanently.
--no-install: Prevents reinstalling a package that's already installed.
commitlint: Validates the commit message.
--edit "$1": Retrieves the commit message from the file generated by Git.

Configuring Commitlint Rules

1. Example Commitlint configuration:

module.exports = {
  extends: ['@commitlint/config-conventional'],
  rules: { 
    'header-max-length': [2, 'always', 100], 
    'type-enum': [2, 'always', [ 'feat', 'fix', 'docs', 'style', 'refactor', 'test', 'chore', 'merge' ]],
    'header-case': [2, 'always', 'sentence-case'], 
    'merge-message-format': [2, 'always', 'merged: <branch> into <target>'] 
  },
};

1. Explanation of values in the configuration:
   level: Specifies the strictness of the rule.
   0: The rule is ignored.
   1: Warning, the commit is not blocked.
   2: Error, the commit is blocked.
   when: Specifies whether the rule should always ('always') or never ('never') be applied.
   value: The expected value or format.

Adding a Pre-commit Hook

To run tests before committing:

npx husky add .husky/pre-commit &quotnpm test&quot

Summary

• Git hooks are tools that allow running specific scripts during different stages of the commit and push process.
• Husky improves this process by providing a simple, maintainable tool for managing Git hooks.
• Commitlint is used to ensure that commit messages follow a consistent structure and meet quality standards.