CI Exercise - GitHub Actions

This repository demonstrates how to build a Continuous Integration (CI) pipeline step by step using GitHub Actions.

Project Structure

ci_exercise/
├── src/
│   ├── __init__.py
│   ├── calculator.py      # Simple math operations
│   └── string_utils.py    # String manipulation utilities
├── tests/
│   ├── __init__.py
│   ├── test_calculator.py
│   └── test_string_utils.py
├── .github/
│   └── workflows/         # GitHub Actions workflows
├── requirements.txt       # Production dependencies
├── requirements-dev.txt   # Development dependencies
├── pyproject.toml         # Tool configurations
└── README.md

Branches - Learning Path

Each branch builds upon the previous one, adding new CI capabilities:

Branch	Description	What You'll Learn
main	Basic project skeleton	Project structure, no CI yet
01-tests	Run unit tests	Setting up pytest in GitHub Actions
02-code-format	Code formatting check	Using Black for code formatting
03-linting	Static analysis	Using Flake8 for linting
04-security	Security scanning	Using Bandit and Safety for security
05-build	Build artifacts	Creating and uploading build artifacts
06-complete	Full CI pipeline	Complete pipeline with all stages

How to Use This Exercise

1. Start with the main branch to understand the project structure
2. Check out each branch sequentially to see how the CI pipeline evolves
3. Examine the .github/workflows/ci.yml file in each branch
4. Try modifying the code and see how the CI reacts

Commands to switch branches:

git checkout main           # Start here
git checkout 01-tests       # Add testing
git checkout 02-code-format # Add formatting
git checkout 03-linting     # Add linting
git checkout 04-security    # Add security checks
git checkout 05-build       # Add build step
git checkout 06-complete    # See complete pipeline

Local Development

Setup

# Create virtual environment
python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

# Install dependencies
pip install -r requirements-dev.txt

Running Tests Locally

pytest
pytest --cov=src  # With coverage

Running Formatters/Linters Locally

black --check src tests        # Check formatting
black src tests                # Fix formatting
flake8 src tests               # Run linter
mypy src                       # Type checking
bandit -r src                  # Security scan

CI Pipeline Stages Explained

1. Tests (01-tests)

• Runs unit tests with pytest
• Ensures code functionality works as expected
• Generates test reports

2. Code Formatting (02-code-format)

• Checks code follows consistent style using Black
• Ensures readability and maintainability

3. Linting (03-linting)

• Static code analysis with Flake8
• Catches potential bugs and style issues

4. Security (04-security)

• Bandit: Finds common security issues in Python code
• Safety: Checks dependencies for known vulnerabilities

5. Build (05-build)

• Creates distributable packages
• Uploads artifacts for later use

6. Complete Pipeline (06-complete)

• Combines all stages
• Runs stages in parallel where possible
• Uses job dependencies for proper ordering