FastAPI 14‑Day Series Day 13: Background Tasks and Docker Deployment – From Development to Production

1. Background Tasks: BackgroundTasks

Some operations do not need to wait for completion, such as sending notification emails, messaging, or logging.

from fastapi import BackgroundTasks

@app.post("/send-notification")
def send_notification(email: str, background_tasks: BackgroundTasks):
    background_tasks.add_task(notify_user, email)
    return {"message": "Notification queued"}

def notify_user(email: str):
    # actual notification logic
    ...

BackgroundTasks

is built into FastAPI and requires no extra dependencies; the task runs asynchronously after the response is sent.

Note: This is a lightweight solution. Production‑grade scheduled or long‑running tasks should use Celery + Redis or FastAPI + RQ.

2. Docker Deployment: Standard Practice

Create a Dockerfile:

FROM python:3.10-slim

WORKDIR /app

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

COPY . .
CMD ["fastapi", "run", "main.py", "--host", "0.0.0.0", "--port", "8000"]

Build and run the image:

docker build -t fastapi-14days .
docker run -p 8000:8000 fastapi-14days

3. Production Run: Using fastapi run

The fastapi run command uses Uvicorn under the hood. In production you can add workers:

uvicorn main:app --host 0.0.0.0 --port 8000 --workers 4

Multi‑worker mode with Gunicorn and Uvicorn workers:

gunicorn main:app --workers 4 --worker-class uvicorn.workers.UvicornWorker --bind 0.0.0.0:8000

4. Day 13 Checklist

BackgroundTasks

for asynchronous notifications Dockerfile to containerize the FastAPI app docker build + docker run to verify containerization

Understanding production run options (Uvicorn / Gunicorn workers)

5. Next Steps

Day 14 will create a comprehensive knowledge map of FastAPI core concepts and answer the most common interview questions.

Related Links

Official documentation (Chinese): https://fastapi.tiangolo.com/zh/tutorial/background-tasks/

Official documentation (Chinese): https://fastapi.tiangolo.com/zh/deployment/docker/