Dockerizing a FastAPI application

Demo application

This is a simple FastAPI application that allows you to return invoice information.

Create Invoice

• Endpoint: /invoice

• Method: POST

• Description: Creates a new invoice with customer details and line items

• Request Body:

  {
    "customer_name": "Acme Corp",
    "customer_email": "billing@acme.com",
    "items": [
      {
        "description": "Consulting Services",
        "quantity": 10,
        "unit_price": 150.00
      }
    ]
  }

Example response:

{"customer_name":"Acme Corp","customer_email":"billing@acme.com","items":[{"description":"Consulting Services","quantity":"10","unit_price":"150.0"}],"invoice_number":"INV-202412-5caff017","created_at":"2024-12-15T23:29:45.876903","total_amount":"1500.0"}%

Launching the application locally

pip install -r src/requirements.txt

gunicorn --workers 4 \
         --worker-class uvicorn.workers.UvicornWorker \
         --bind 0.0.0.0:8080 \
         --reload \
         src.server:app

Refer to Testing the application for more details

Buiilding the Docker image

docker build -t python-docker:v1.0.0 .

Running the Docker image

docker run --rm -it -e PORT=8080 -p 8080:8080 python-docker:v1.0.0

Testing the Docker image

Open the API Docs page:

    http://0.0.0.0:8080/docs

Testing the application

curl -X POST http://localhost:8080/invoice \
-H "Content-Type: application/json" \
-d '{
    "customer_name": "Acme Corp",
    "customer_email": "billing@acme.com",
    "items": [
        {
            "description": "Consulting Services",
            "quantity": 10,
            "unit_price": 150.00
        }
    ]
}'

Using a docker-slim (4x size reduction; 201MB -> 50MB)

Docker Slim Documentation

    slim build --target python-docker:v1.0.0  --tag python-docker:v1.0.0-slim
    docker run --rm -it -e PORT=8080 -p 8080:8080 python-docker:v1.0.0-slim

Look for artifacts in the build directory (in log outputs)