day-18

FastAPI Docker Infrastructure Demo

This repository demonstrates a production-ready Docker setup for a FastAPI application integrated with PostgreSQL and Redis.

Features

• FastAPI: Core API application.
• PostgreSQL: Relational database for persistent data storage.
• Redis: In-memory data store for caching and real-time counters.
• Docker Compose: Orchestrates multi-container communication.
• Multi-Stage Build: Optimizes image size and security.
• Non-Root User: Runs the application as a non-privileged user for enhanced security.

Prerequisites

• Docker Desktop (Windows/Mac) or Docker Engine (Linux).
• [Verify with docker version or docker info]

Getting Started

1. Build and Run

To start the entire application stack, run:

docker compose up -d

2. Verify Services

Check the status of the containers:

docker compose ps

3. Test API Endpoints

• Root: http://localhost:8000/
• Hits Counter: http://localhost:8000/hits
• Create Item: POST http://localhost:8000/items/?name=MyItem
• List Items: http://localhost:8000/items/

4. Stop and Cleanup

To stop the services:

docker compose stop

To remove the containers and networks (retaining data):

docker compose down

To remove the containers, networks, AND database volumes:

docker compose down -v

Docker Concepts Learned

1. Images vs Containers: Used python:3.11-slim and postgres:15-alpine as base images.
2. Dockerfile: Defined multi-stage builds and non-root users.
3. Volumes: Configured postgres_data for database persistence.
4. Networks: Used a bridge network named backend for service communication.
5. Healthchecks: Ensured dependencies (PostgreSQL/Redis) are ready before the App starts.

Verification Results Automated Tests I verified the application’s functionality using curl:

FastAPI Root: Successfully returned {“message”:”FastAPI is running in Docker!”}. Redis Integration: Incremented the counter via GET /hits. PostgreSQL Integration: Successfully created and listed items via POST /items/ and GET /items/. TIP

You can visit http://localhost:8000/docs in your browser to interact with the API via Swagger UI!