👀 Views: 5 💬 Answers: 1 📅 Created: 2025-05-31

python fastapi sqlalchemy asyncio postgresql Python

I'm building a feature where I'm trying to implement asynchronous database queries in a FastAPI application using SQLAlchemy. However, I'm running into an scenario where my queries seem to hang indefinitely during execution. My code is structured to use the `async` and `await` keywords, but when I make a request to the endpoint, I end up with a timeout behavior instead of getting a response. Here’s a simplified version of my code: ```python from fastapi import FastAPI, HTTPException from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine from sqlalchemy.orm import sessionmaker, declarative_base from sqlalchemy import Column, Integer, String, select DATABASE_URL = "postgresql+asyncpg://user:password@localhost/dbname" engine = create_async_engine(DATABASE_URL, echo=True) Base = declarative_base() class User(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True, index=True) name = Column(String, index=True) async_session = sessionmaker(engine, expire_on_commit=False, class_=AsyncSession) app = FastAPI() @app.get("/users/{user_id}") async def read_user(user_id: int): async with async_session() as session: stmt = select(User).where(User.id == user_id) result = await session.execute(stmt) user = result.scalars().first() if user is None: raise HTTPException(status_code=404, detail="User not found") return user ``` When I hit the endpoint `/users/1`, I see the following behavior in my logs: ``` behavior:asyncio:Task was destroyed but it is pending! ``` I've verified that my database connection works properly with synchronous queries, and I'm using `asyncpg` as the database driver. I even tried increasing the timeout settings on the server but that didn’t help. Is there something I might be missing in the setup? I want to ensure that I'm properly utilizing asynchronous patterns with SQLAlchemy in a FastAPI context. Any insights would be greatly appreciated! I'm working with Python in a Docker container on Linux. Any ideas how to fix this?