Flask 2.0: Issues with async/await and SQLAlchemy session management in a webhook handler
I'm collaborating on a project where I'm writing unit tests and I'm facing issues when trying to use async/await in a Flask 2.0 webhook handler that interacts with SQLAlchemy. My setup involves an asynchronous route that processes incoming requests and makes database calls. However, I keep running into the following error: ``` RuntimeError: Task <Task pending name='Task-1' coro=<MyFlaskApp.webhook() running at ...> cb=[_run_until_complete_cb() at /usr/lib/python3.9/asyncio/base_events.py:184]> got Future <Future pending> attached to a different loop ``` I initially tried to configure my SQLAlchemy session to work with async calls by using `AsyncSession` and `create_async_engine`. Here’s a simplified version of my code: ```python from flask import Flask, request from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine, async_sessionmaker from sqlalchemy.orm import sessionmaker import asyncio app = Flask(__name__) engine = create_async_engine('postgresql+asyncpg://user:password@localhost/dbname') AsyncSessionLocal = async_sessionmaker(bind=engine, class_=AsyncSession) @app.route('/webhook', methods=['POST']) async def webhook(): data = request.json async with AsyncSessionLocal() as session: # Insert your data processing logic here await session.commit() return 'Processed', 200 ``` I’ve also tried ensuring that the event loop is properly set up by using `asyncio.run()` in the main entry point of my program, but that just leads to more confusion since Flask’s built-in server doesn’t support it well. I attempted to run everything under an `async def main()` function, but then I ran into issues with the Flask app context. My attempts to resolve this include using `quart`, which is an async-compatible Flask alternative, but I’d prefer to keep using Flask if possible. Any insights into how I can properly manage my SQLAlchemy sessions in an async Flask route would be greatly appreciated. Is there a correct way to integrate async SQLAlchemy with Flask without encountering the event loop errors? For context: I'm using Python on Windows 10. Is this even possible? I appreciate any insights!