FastAPI Docker Setup Tutorial: Building a Scalable API with Docker Compose

In today’s software development landscape, building scalable and efficient APIs is crucial. FastAPI, a modern web framework for Python, offers high performance and easy integration. Combining FastAPI with Docker and Docker Compose allows developers to create portable, scalable, and maintainable APIs. This tutorial guides you through setting up a FastAPI application using Docker Compose.

Prerequisites

Python 3.8 or higher installed on your machine
Docker and Docker Compose installed
Basic knowledge of Python and Docker

Creating the FastAPI Application

Start by creating a project directory and initializing a Python environment. Inside your project folder, create a virtual environment and install FastAPI along with Uvicorn, an ASGI server.

Run the following commands:

mkdir fastapi-docker
cd fastapi-docker
python -m venv venv
source venv/bin/activate  # On Windows use: venv\Scripts\activate
pip install fastapi uvicorn

Next, create a file named main.py with the following code:

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return {"message": "Hello, FastAPI with Docker!"}

Creating the Dockerfile

In the project directory, create a Dockerfile to containerize your FastAPI app:

FROM python:3.11-slim

WORKDIR /app

COPY requirements.txt .

RUN pip install --no-cache-dir -r requirements.txt

COPY . .

CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]

Also, create a requirements.txt file to specify dependencies:

fastapi
uvicorn

Setting Up Docker Compose

Create a docker-compose.yml file to define your service:

version: "3.8"

services:
  fastapi:
    build: .
    ports:
      - "8000:8000"
    volumes:
      - ./:/app
    environment:
      - PYTHONPATH=/app

Building and Running the Application

Use Docker Compose to build and start your FastAPI application:

docker-compose up --build

Once running, access your API at http://localhost:8000. You should see the JSON response:

{"message": "Hello, FastAPI with Docker!"}

Conclusion

By following this tutorial, you have set up a scalable FastAPI application using Docker and Docker Compose. This setup provides a solid foundation for deploying robust APIs in development and production environments. You can extend this configuration by adding databases, background workers, or other microservices as needed.

Table of Contents