https://github.com/tiangolo/fastapi/pull/10353

context_managers_test_app.py

from fastapi import FastAPI, Depends
from contextlib import asynccontextmanager, contextmanager


app = FastAPI()


@contextmanager
def get_answer():
    yield 42
    print("cleanup get_answer")


@asynccontextmanager
async def get_async_answer():
    yield 43
    print("cleanup get_async_answer")


@app.get("/")
def route_get_answer(
    answer: int = Depends(get_answer),
    async_answer: int = Depends(get_async_answer),
):
    return {
        "answer": answer,
        "async_answer": async_answer,
    }