Concurrent task execution in FastAPI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is concurrent task execution in FastAPI?

It means running multiple tasks at the same time without waiting for each to finish before starting the next. FastAPI uses async functions and Python's async features to do this efficiently.

beginner

Which Python keyword is used in FastAPI to define a function that can run concurrently?

The async keyword is used to define asynchronous functions that can run concurrently in FastAPI.

intermediate

How does FastAPI handle multiple requests concurrently?

FastAPI uses Python's async/await syntax and an async server (like Uvicorn) to handle many requests at once without blocking, improving speed and responsiveness.

intermediate

What is the role of asyncio.gather() in concurrent task execution?

asyncio.gather() runs multiple async tasks at the same time and waits for all of them to finish, making it easy to manage concurrent tasks in FastAPI.

intermediate

Why should blocking code be avoided in FastAPI async functions?

Blocking code stops the event loop, preventing other tasks from running concurrently. This slows down FastAPI's ability to handle multiple requests efficiently.

Which keyword defines an asynchronous function in FastAPI?

A async

B sync

C await

D def

The async keyword defines an asynchronous function that can run concurrently.

What does asyncio.gather() do?

A Stops all running tasks

B Runs tasks one after another synchronously

C Runs multiple async tasks concurrently and waits for all to finish

D Converts async functions to sync

asyncio.gather() runs multiple async tasks at the same time and waits for all to complete.

Why avoid blocking code in FastAPI async functions?

A It speeds up the server

B It automatically runs tasks in parallel

C It makes code easier to read

D It stops other tasks from running concurrently

Blocking code stops the event loop, preventing other tasks from running concurrently.

Which server is commonly used with FastAPI to support async concurrency?

A Uvicorn

B Gunicorn

C Apache

D Nginx

Uvicorn is an async server that supports FastAPI's concurrency features.

What happens if you call a blocking function inside an async FastAPI endpoint?

A It runs faster

B It blocks the event loop and slows down handling other requests

C It automatically becomes async

D It crashes the server

Blocking functions stop the event loop, slowing down concurrent request handling.

Explain how FastAPI uses async and await to run tasks concurrently.

Think about how you can do many things at once without waiting for each to finish.

Describe why blocking code is a problem in FastAPI's concurrent task execution.

Imagine waiting in line blocking others from going forward.