3.6 Pre-Commit Hooks

Pre-commit hooks automatically validate code before Git commits, catching errors early in the development process.

Installation

# Install pre-commit framework
pip install pre-commit

# Verify
pre-commit --version

Configuration

Create .pre-commit-config.yaml in repository root:

---
repos:
  - repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v4.5.0
    hooks:
      - id: trailing-whitespace
      - id: end-of-file-fixer
      - id: check-yaml
      - id: check-json
      - id: check-added-large-files
        args: ['--maxkb=500']

  - repo: https://github.com/antonbabenko/pre-commit-terraform
    rev: v1.88.0
    hooks:
      - id: terraform_fmt
      - id: terraform_validate

  - repo: https://github.com/ansible/ansible-lint
    rev: v24.2.0
    hooks:
      - id: ansible-lint
        files: \.(yaml|yml)$

Enable Hooks

# Install hooks in .git/hooks/
pre-commit install

# Run manually on all files
pre-commit run --all-files

What It Does

Before every git commit, pre-commit automatically:

1. Removes trailing whitespace
2. Ensures files end with newline
3. Validates YAML/JSON syntax
4. Formats Terraform code
5. Validates Terraform configuration
6. Lints Ansible playbooks

If any check fails, commit is blocked until fixed.

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Related Sections: - 3.5 Git Repository Structure - Chapter 5: Git Workflow