Week 8: Docker & Documentation

Goal

Containerize the full application so anyone can clone the repo and start everything with a single command. Add descriptions to Swagger so the API is self-documenting.

Essential (70% of time)

Core skills:

• Write a Dockerfile for the API
• Write a docker-compose.yml that starts API and PostgreSQL together
• Run the full stack with docker-compose up
• Add basic descriptions to Swagger endpoints

Key resources

• Docker Compose Overview
• Docker Compose Getting Started
• Compose File Reference
• Containerize a .NET App
• Docker for .NET
• Dockerfile Best Practices

LLM prompts

“Create a docker-compose.yml for my .NET 8 API and PostgreSQL. Simplest version that works. Include environment variables for the database connection.”

“Show me a basic Dockerfile for my .NET 8 API.”

“How do I make my API wait for PostgreSQL to be ready before starting in Docker Compose?”

“Show me how to add a description and tag to a Swagger endpoint in a Minimal API. One example is enough.”

Brief (20% of time)

• Add basic console logging using ILogger
• Write a README.md with setup and run instructions
• Auto-apply EF Core migrations on startup inside the container

Optional (skip if needed)

• Advanced Swagger customization
• Logging to files
• Health check endpoints

Practical project

Containerize the full application so it runs with a single command.

Learning activities

1. Create a Dockerfile in the project root
2. Build the Docker image locally: docker build -t booksapi .
3. Create a docker-compose.yml with two services: postgres and api
4. Configure environment variables in docker-compose for the database connection string
5. Add a health check on the postgres service so the API waits for it to be ready
6. Add code to auto-apply EF Core migrations when the app starts
7. Run docker-compose up and verify the API is accessible at http://localhost:5000
8. Test endpoints in Swagger running inside Docker
9. Add .WithDescription() and .WithTags() to a few key endpoints
10. Write a README.md explaining how to clone and run the project

Useful Docker Compose commands

docker-compose up           # Start everything (shows logs)
docker-compose up -d        # Start in background
docker-compose down         # Stop everything
docker-compose down -v      # Stop and delete database volume (fresh start)
docker-compose logs -f api  # Follow logs from the API container

Key concepts to master

• Dockerfile structure (build stage vs runtime stage)
• docker-compose.yml services, ports, and environment variables
• depends_on with a health check so the API waits for PostgreSQL
• Passing connection strings via environment variables
• Auto-applying migrations on startup
• Running and stopping the full stack

Deliverable

docker-compose up starts everything. API is reachable at http://localhost:5000. Swagger has endpoint descriptions.

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