Git Hooks and Automation

40 min

Git hooks are scripts that run automatically at certain points in the Git workflow, enabling automation of tasks like testing, linting, notifications, and deployments. Hooks are stored in the `.git/hooks` directory and can be written in any scripting language. Hooks enable enforcing standards, automating workflows, and integrating with external systems. Understanding hooks enables powerful Git automation. Hooks are essential for maintaining code quality and automating repetitive tasks.

Pre-commit hooks can run tests, linting, and formatting before allowing a commit, ensuring code quality and preventing bad commits. Pre-commit hooks can reject commits if tests fail or code doesn't meet standards. This prevents low-quality code from entering the repository. Understanding pre-commit hooks enables automated quality control. Pre-commit hooks are powerful for maintaining code standards.

Post-commit hooks can trigger notifications, deployments, or other automated processes after a commit is made. Post-commit hooks run after successful commits, enabling actions like sending notifications, updating documentation, or triggering builds. Understanding post-commit hooks enables workflow automation. Post-commit hooks are useful for notifications and integrations.

Git aliases allow you to create shortcuts for commonly used Git commands, saving time and reducing typing. Aliases are defined with `git config --global alias.<name> '<command>'`. Common aliases include `st` for `status`, `co` for `checkout`, and `br` for `branch`. Understanding aliases enables efficient Git usage. Aliases make Git commands faster and more convenient.

Custom Git commands can be created using shell scripts or other programming languages, extending Git's functionality. Custom commands are scripts named `git-<command>` in your PATH. Git will recognize them as Git commands. Understanding custom commands enables extending Git. Custom commands are powerful for team-specific workflows.

Best practices include using hooks for quality control, keeping hooks fast (don't block commits too long), sharing hooks with teams (using tools like husky), creating useful aliases, and documenting custom commands. Understanding hooks and automation enables powerful Git workflows. Automation improves consistency and reduces errors. Git hooks and aliases are essential productivity tools.

Key Concepts

Git hooks are scripts that run automatically at workflow points.
Pre-commit hooks run tests, linting, and formatting before commits.
Post-commit hooks trigger notifications and automated processes.
Git aliases create shortcuts for commonly used commands.
Custom Git commands extend Git's functionality.

Learning Objectives

Master

Creating and using Git hooks for automation
Setting up pre-commit and post-commit hooks
Creating Git aliases for efficiency
Understanding custom Git commands

Develop

Understanding Git automation
Designing effective automation workflows
Appreciating hooks' role in code quality

Tips

Use pre-commit hooks to enforce code quality standards.
Keep hooks fast—don't block commits with slow operations.
Create useful aliases for frequently used commands.
Share hooks with your team for consistency.

Common Pitfalls

Creating hooks that are too slow, blocking commits.
Not sharing hooks with team, causing inconsistent behavior.
Not testing hooks, causing unexpected failures.
Creating too many aliases, making commands confusing.

Summary

Git hooks automate tasks at workflow points.
Pre-commit hooks enforce code quality.
Post-commit hooks trigger automated processes.
Git aliases create command shortcuts.
Understanding hooks and automation enables powerful workflows.

Exercise

Create a pre-commit hook that runs linting and a post-commit hook that sends notifications.

# .git/hooks/pre-commit
#!/bin/sh
echo "Running pre-commit checks..."

# Run linting
npm run lint
if [ $? -ne 0 ]; then
    echo "Linting failed. Commit aborted."
    exit 1
fi

# Run tests
npm test
if [ $? -ne 0 ]; then
    echo "Tests failed. Commit aborted."
    exit 1
fi

echo "Pre-commit checks passed!"

# .git/hooks/post-commit
#!/bin/sh
echo "Commit successful! Sending notification..."
# Add your notification logic here
curl -X POST https://hooks.slack.com/services/YOUR_WEBHOOK_URL \
     -H 'Content-type: application/json' \
     -d '{"text":"New commit: $GIT_COMMIT"}'

# Make hooks executable
chmod +x .git/hooks/pre-commit
chmod +x .git/hooks/post-commit

Git Hooks and Automation