[2024 Edition] Effortlessly Building a Python API Server (Docker + FastAPI + MongoDB)

What do I want to do?

This is about easily setting up a Python-based API server using Docker and FastAPI.
Note that this article is intended as a personal memo for myself.

I won't provide specific explanations for the commands. Just Google it.

This time, I've pieced together information found online (official references, etc.) without thinking too much. There might be some redundant commands, so please adjust them as needed.

By the way, I'm using MongoDB as the database, which is influenced by a hand-over of a system that used ElasticSearch. So, feel free to use whatever database you prefer.

Prerequisites

This guide assumes the following are already installed.
The environment used is WSL2 on Windows 11, but the commands should work similarly on Linux.

• python3
• docker

Configuration

0. File Hierarchy

The default file hierarchy is as follows.
Please use it as a reference. Items with a trailing / are folders.

• /
  • api-src/
    • main.py
    • requirements.txt
  • mongo/
  • docker-compose.yml
  • Dockerfile-api
  • .env

1. Docker File Configuration

docker-compose.yml

services:

  mongo:
    image: mongo
    networks:
      - mongo-compose-network
    ports:
      - 27017:27017      
    environment:
      MONGO_INITDB_ROOT_USERNAME: root
      MONGO_INITDB_ROOT_PASSWORD: example
    volumes:
      - ./mongo:/data/db
    user: ${UID}:${GID}

  mongo-express:
    networks:
      - mongo-compose-network
    image: mongo-express
    ports:
      - 8081:8081
    environment:
      ME_CONFIG_MONGODB_ADMINUSERNAME: root
      ME_CONFIG_MONGODB_ADMINPASSWORD: example
      ME_CONFIG_BASICAUTH_USERNAME: admin
      ME_CONFIG_BASICAUTH_PASSWORD: password
      ME_CONFIG_MONGODB_URL: "mongodb://root:example@mongo:27017/"
        
  api-sever:
    networks:
    - mongo-compose-network
    build:
      context: .
      dockerfile: Dockerfile-api
    ports:
      - 8080:8000
    volumes:
        - ./api-src:/usr/src/app:ro

networks:
  mongo-compose-network:
    driver: bridge

Dockerfile-api

FROM python:3

WORKDIR /usr/src/app

COPY ./api-src/requirements.txt ./
RUN pip install --no-cache-dir -r requirements.txt

COPY . .

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

UID=1002
GID=1002

For .env, please enter the UID and GID of the Linux account you are using.

2. Python Hello World and requirements.txt

main.py

from fastapi import FastAPI
app = FastAPI()


@app.get("/hello")
async def hello():
    return {"message": "hello world! (/Hello)"}

@app.get("/")
async def hello():
    return {"message": "hello world (Home)!"}

Generate requirements.txt by running the following command.
Note that you should regenerate requirements.txt every time you add a library.

python3 -m pip freeze > requirements.txt

Startup

When Updating Dockerfile or requirements.txt

docker compose up --build

For General Startup or Source Code Changes

docker compose up

Note: If you change the source code, it will automatically reload without having to restart the container.

The API server can be accessed at port 8080 (http://localhost:8080).
Also, if you want to check the database contents, you can do so at port 8081 (http://localhost:8081).

The End!

Thank you for reading this far! Great job!!!