Async ORM Queries in FastAPI with SQLAlchemy and Handling Connection Errors
After trying multiple solutions online, I still can't figure this out. I'm working on a personal project and I've looked through the documentation and I'm still confused about I'm building a FastAPI application that uses SQLAlchemy for ORM. I've set up asynchronous database connections using `asyncpg` and `databases`. Everything works fine until I try to fetch data from the database in an async route. When the database is down or unreachable, I get errors that I need to seem to handle gracefully. I have the following route defined: ```python from fastapi import FastAPI, HTTPException from sqlalchemy import select from databases import Database app = FastAPI() database = Database('postgresql://user:password@localhost/dbname') @app.on_event("startup") async def startup(): await database.connect() @app.on_event("shutdown") async def shutdown(): await database.disconnect() @app.get("/items/{item_id}") async def read_item(item_id: int): query = select(Item).where(Item.id == item_id) try: item = await database.fetch_one(query) if item is None: raise HTTPException(status_code=404, detail="Item not found") return item except Exception as e: raise HTTPException(status_code=500, detail=f"Database query failed: {str(e)}") ``` The question arises when I try to access this endpoint while the database is down. Instead of returning a 500 behavior with a message about the database being unavailable, the application crashes, and I get a traceback in my console: ``` behavior: Exception in ASGI application ... sqlalchemy.exc.OperationalError: (asyncpg.exceptions.CannotConnectNow) want to connect to server: Connection refused ``` I've tried enclosing the fetch statement in a try-except block as shown above, but I still receive the traceback in the console and nothing is returned to the client. How can I catch this behavior and return a proper response to the client without crashing the application? I'm using FastAPI version 0.75.0 and SQLAlchemy version 1.4.27. For context: I'm using Python on macOS. I'd really appreciate any guidance on this. Any examples would be super helpful.