Full Stack Learning Hub

Comprehensive guides, cheat sheets, and code examples for full stack development.

View on GitHub

CI/CD Pipeline Guide: Automating with GitHub Actions

Continuous Integration (CI) and Continuous Deployment (CD) are essential practices for modern software development, ensuring that code changes are automatically tested and safely deployed.

1. Core Concepts

Continuous Integration (CI)

The practice of frequently merging code changes into a central repository. Each merge triggers an automated build and test sequence to detect errors early.

Continuous Deployment (CD)

The practice of automatically deploying every change that passes the CI stage to production.

2. GitHub Actions Fundamentals

GitHub Actions allows you to automate your workflow directly in your GitHub repository.

Workflow File Structure

Workflows are defined in .github/workflows/*.yaml files.

Component Description
Name The name of your workflow.
On The GitHub event that triggers the workflow (e.g., push, pull_request).
Jobs A group of steps that run on the same runner (e.g., ubuntu-latest).
Steps Individual tasks (running a command or using an “Action”).

3. Example: Flask CI Pipeline

This workflow automates environment setup, dependency installation, and testing for a Flask application.

name: Flask Testing CI

on:
  push:
    branches: [main, master]
  pull_request:
    branches: [main]

jobs:
  test:
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout Code
        uses: actions/checkout@v4 # Downloads your repo code

      - name: Set Up Python
        uses: actions/setup-python@v5
        with:
          python-version: 3.11 # Matches your development environment
        
      - name: Create Virtual Environment
        run: |
          python -m venv venv
          source venv/lib/activate

      - name: Install Dependencies
        run: |
          python -m pip install -U pip
          python -m pip install -r requirements.txt
      
      - name: Run Tests
        # Runs all files matching 'test_*.py' in the 'tests' directory
        run: python -m unittest discover -s tests -p 'test_*.py'

4. Handling Environment Variables

Secrets (like API keys) should never be committed to YAML files. Use GitHub Secrets.

  1. Go to Settings > Secrets and variables > Actions in your repo.
  2. Add a secret (e.g., DATABASE_URL).
  3. Reference it in your workflow:
      - name: Run App with Secrets
        env:
          DB_URL: $
        run: python app.py

5. Integrating with TDD

CI/CD is most effective when paired with Test-Driven Development (TDD).

  1. Write a Test: Define the expected behavior (e.g., a test for a new /login route).
  2. Push to GitHub: The CI pipeline runs and fails (because the feature isn’t implemented).
  3. Implement Code: Write the logic to make the test pass.
  4. Push Again: The CI pipeline runs and passes.

See Also