lab1_fastapi_example

Docker FastAPI Tutorial

This tutorial demonstrates how to containerize a FastAPI application using Docker and Docker Compose.

Project Structure

Lab1/
├── app/
│   └── main.py           # FastAPI application
├── Dockerfile            # Docker configuration
├── docker-compose.yml    # Docker Compose configuration
├── requirements.txt      # Python dependencies
└── README.md             # This file

Prerequisites

• Docker installed on your system
• Docker Compose (included with Docker Desktop for Windows/Mac)

Step-by-Step Guide

1. Understanding the Application

The application is a simple FastAPI REST API with the following endpoints:

• GET /: Returns a welcome message
• GET /items/{item_id}: Returns item details for a given ID
• POST /items/: Creates a new item

2. Building and Running with Docker CLI

Build the Docker Image

cd Lab1
docker build -t fastapi-tutorial .

Run the Container

docker run -p 8000:8000 --name fastapi-app fastapi-tutorial

Additional Docker CLI Commands

Stop the container:

docker stop fastapi-app

Remove the container:

docker rm fastapi-app

List all containers:

docker ps -a

List all images:

docker images

3. Using Docker Compose

Start the Services

cd Lab1
docker compose up

To run in detached mode (background):

docker compose up -d

Stop the Services

docker compose down

4. Testing the API

Once the application is running, you can access:

• API documentation: http://localhost:8000/docs
• API root endpoint: http://localhost:8000/

Example to create an item using curl:

curl -X POST http://localhost:8000/items/ \
  -H "Content-Type: application/json" \
  -d '{"name": "Test Item", "price": 10.5, "description": "This is a test item"}'

Example to get an item:

curl http://localhost:8000/items/1

5. Development with Volume Mounting

When using Docker Compose, changes to the files in the app directory will automatically be reflected in the container due to the volume mounting configuration.

Explanation of Docker Concepts

Dockerfile

• FROM python:3.9-slim: Uses Python 3.9 slim as the base image
• WORKDIR /app: Sets the working directory
• COPY requirements.txt .: Copies the requirements file
• RUN pip install...: Installs the dependencies
• COPY ./app /app: Copies the application code
• EXPOSE 8000: Documents that the container listens on port 8000
• CMD ["uvicorn"...]: Specifies the command to run the application

Docker Compose

The docker-compose.yml file defines the service configuration:

• build: Builds the image from the Dockerfile
• ports: Maps host port 8000 to container port 8000
• volumes: Mounts local app directory to container /app
• restart: Automatically restarts the container unless stopped