Flask and Redis App with Docker Compose and GitHub Actions

This is a Flask application that uses Redis to count visits and have a healthcheck. It includes:

• A main page (/)
• A health check endpoint (/health)
• A visits counter endpoint (/visits)
• Dockerized services using Docker Compose
• CI pipeline via GitHub Actions with Docker healthcheck integration

Features

• Flask for web serving
• Redis to store a persistent visit counter
• Docker Compose to orchestrate services
• Health checks for both Redis and Flask
• GitHub Actions CI pipeline that uses container health status

Project Structure

flask_redis_app/
├── .gitignore
├── Dockerfile
├── README.md
├── app.py
├── docker-compose.yml
├── requirements.txt
└── .github/
└── workflows/

How to build and run the application locally

In bash:
docker-compose up --build

Visit in browser:
http://localhost:8000 → Main page
http://localhost:8000/health → Health check
http://localhost:8000/visits → Visit counter (stored in Redis)

To stop (in bash):
docker-compose down

Health Checks & GitHub Actions pipeline Testing

Health Checks

Both the Redis and Flask services are configured with health checks to ensure reliable startup and operation:

• Redis: Uses the command redis-cli ping to confirm the Redis server is responsive.
• Flask App: Periodically checks the /health endpoint to verify that the application is running and accessible.

The Flask service will only start after Redis passes its health check, ensuring service dependencies are met before proceeding.

GitHub Actions CI Workflow

This project includes a GitHub Actions workflow that automatically tests the application on each push or pull request to the main branch.

The CI pipeline performs the following steps:

1. Checkout Code: Pulls the latest version of the repository.
2. Build & Start Services: Uses Docker Compose to build and run the Flask and Redis containers in detached mode.
3. Wait for Service Availability: Repeatedly checks the /healthz endpoint to ensure the Flask service is up and responsive.
4. Validate Health Endpoint: Verifies that the /health endpoint returns HTTP status 200, confirming the app is healthy.
5. Cleanup: Shuts down and removes the Docker containers after the tests complete.