👀 Views: 150 💬 Answers: 1 📅 Created: 2025-06-06

flask sqlalchemy asyncio Python

After trying multiple solutions online, I still can't figure this out. I'm sure I'm missing something obvious here, but I'm working with a frustrating scenario with Flask and SQLAlchemy while using scoped sessions in an asyncio context. My setup involves Flask 2.1.2 and SQLAlchemy 1.4.27. I'm trying to handle database operations asynchronously, but I keep running into a `sqlalchemy.exc.InvalidRequestError: This session is expired and can no longer be used.` behavior when I try to access the session after performing an asynchronous operation. Here's a simplified version of my code: ```python from flask import Flask, jsonify from flask_sqlalchemy import SQLAlchemy from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine from sqlalchemy.orm import sessionmaker, scoped_session import asyncio app = Flask(__name__) app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql+asyncpg://user:password@localhost/dbname' engine = create_async_engine(app.config['SQLALCHEMY_DATABASE_URI'], echo=True) AsyncSessionLocal = sessionmaker(bind=engine, class_=AsyncSession, expire_on_commit=False) async def get_db(): async with AsyncSessionLocal() as session: yield session @app.route('/data') async def get_data(): async with get_db() as session: result = await session.execute('SELECT * FROM my_table') return jsonify(result.all()) ``` The behavior occurs when I try to make multiple requests to `/data`, and it seems like the session is expiring too quickly for some reason. I've tried changing the `expire_on_commit` flag, but it didn't help. I also attempted to manage session lifecycle manually but ran into issues with the async context. Has anyone encountered this scenario or have an idea on how to handle scoped sessions with SQLAlchemy in an async context without running into session expiration issues? Any help or direction would be greatly appreciated! For context: I'm using Python on Ubuntu. Any help would be greatly appreciated!