Difficulty using asyncio with FastAPI when integrating with SQLAlchemy for database queries
I'm writing unit tests and I'm following best practices but I'm currently building a FastAPI application that uses SQLAlchemy for ORM and async/await for handling requests... However, I'm running into a question when trying to perform database queries asynchronously. My application hangs indefinitely when I attempt to fetch data from the database using an async function. Here’s a simplified version of my code: ```python from fastapi import FastAPI from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine from sqlalchemy.orm import sessionmaker from sqlalchemy.future import select from models import MyModel # Assume MyModel is a SQLAlchemy model DATABASE_URL = 'postgresql+asyncpg://user:password@localhost/dbname' engine = create_async_engine(DATABASE_URL, echo=True) AsyncSessionLocal = sessionmaker(bind=engine, class_=AsyncSession, expire_on_commit=False) app = FastAPI() @app.get("/items/") async def read_items(): async with AsyncSessionLocal() as session: async with session.begin(): result = await session.execute(select(MyModel)) items = result.scalars().all() # This line causes the hang return items ``` I’ve confirmed that the database is reachable and that my SQLAlchemy models are correctly defined. When I try to hit the `/items/` endpoint, I see logs indicating the request is being processed, but the response never returns, and the server seems to hang. I've also tried running my code with different configurations of SQLAlchemy’s sessionmaker, but the behavior remains the same. I’ve looked at the FastAPI documentation and examples, but I’m not sure if I’m missing something in how I’m managing the sessions or the async context. I would really appreciate any insight into why this might be happening or how to debug the scenario further. For reference, this is a production service. Am I approaching this the right way?