python

FastAPI lifespan state not accessible

fastapi.*LifespanState.*not available

Fixes

1.Use the new lifespan context manager pattern with async generator
2.Access state via request.state instead of app.state in routes
3.Ensure lifespan is passed to FastAPI constructor: FastAPI(lifespan=lifespan)

fastapilifespan

Related Errors

Asyncio event loop already running

RuntimeError: This event loop is already running

•Use nest_asyncio.apply() to allow nested event loops
•Use asyncio.run_coroutine_threadsafe() instead of asyncio.run()

Coroutine never awaited

RuntimeWarning: coroutine '.*' was never awaited

•Add 'await' before the coroutine call
•Use asyncio.create_task() to schedule the coroutine

Asyncio task was cancelled

asyncio\.CancelledError

•Handle CancelledError in try/except within the task
•Use asyncio.shield() to protect critical sections from cancellation