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Graph/async-lifecycle-context-mock-mismatch

AntiPattern

Async Execution Lifecycles Miswired

async-lifecycle-context-mock-mismatch

Async code misbehaves because context managers, mocks, and startup/scheduler tasks are wired incorrectly—creating coroutines where aenter/aexit are expected or running code only at app start—breaking FastAPI background jobs and async tests.

Node Details

Public graph metadata

Updated7/1/2026

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30 linked nodes

MATCHESSolution

Manage the refreshing state more robustly — ensuring it only turns off after all async operations are complete. Tension: remove the arbitrary timeout. Outcome: ensure no state updates occur after the component begins to unmount.

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post-start failures. Tension: it skipped durable user transcript append, synthetic assistant error append, and session-store terminalization.

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delete the async from `fake_execute` — your `AsyncContextMock` needs to handle both use cases in your endpoint `await conn.execute()` and `async with conn.execute()`. Outcome: just make it a regular function so it returns your context manager directly, no coroutine wrapper.

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single worker running async loop. Outcome: So you have a single worker running async loop and you block that loop.

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Pass `BackgroundTasks` from the route into your dependency. — when declared inside an async dependency. Tension: the background job never runs. Outcome: async def test_route(bg: BackgroundTasks, data=Depends(dependency)):.

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If you convert all operations to perform asynchronously (using `aiosqlite`) , the issue will be mitigated. — When a route in FastAPI is listed as asynchronous (`async def`). Tension: that doesn't fully solve the inherent single writer problem of Sqlite. Outcome: Here's a fully operational update of the FastAPI server logic:.

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Removing `async` before the function definition solved it. — class LoggingAPIRoute(APIRoute):. Outcome: def get_route_handler(self) -> Callable:.

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To manage background processes. Outcome: consider increasing resource allocations or using asynchronous task queues like Celery.

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python interpreter just pauses one task and looks at other — In your scenerio where you use asynchronous. Tension: it is not completly usesless. Outcome: Think it like a round-robin.

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Move the initialization of `qdrant_client` into lifespan. Outcome: override using standard FastAPI mechanism.

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You can use a global dependency: — FastAPI. Tension: there's no way to set auth tokens in the docs. Outcome: app.openapi = custom_openapi.

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Move the persistence/cleanup logic into code that runs at the end of the background task (or otherwise extend lifecycle explicitly for the background task), rather than relying on the request-scoped `asynccontextmanager` teardown for those updates.

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You need to install helper packages, such as `anyio` or `pytest-asyncio`. — Async fixtures do not work out of the box. Tension: NB. Use pytest_asyncio.fixture NOT pytest.fixture. Outcome: Example.

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Change the engine async fixture from session scope to function scope (remove scope="session") so all async fixtures/tests run on the same event loop, preventing the cross-loop Future/Task error.

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Create a lifespan-managed shared state (e.g., instantiate a state manager/model in FastAPI lifespan) and store the loaded model in that state so request handlers can access it via Request/app state or a dependency that reads from lifespan.

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Using `asyncio.sleep()` in a loop is perfectly fine. Tension: every time you `await` the sleep, you effectively yield control back to the event loop. Outcome: calling `asyncio.sleep(0)` does not sleep at all, but only yields control back to the event loop.

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You can benefit from the lazy initialization inside the `startup` event. Outcome: async def startup_event(): await SINGLETON.initialize().

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the reason for the various threads appearing in the logs — when you pass a synchronous generator to `EventSourceResponse`. Tension: a normal `def` function instead of `async def`. Outcome: please take a look at the implementation of the `EventSourceResponse` class.

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use `pytest_asyncio` and the async fixture — If you don't want to utilize an `AsyncClient` like the one by `httpx`. Tension: ensuring that the FastAPI app's lifespan context correctly works.

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ASGIMiddleware. Tension: Currently i add ASGIMiddleware to fastapi app, it catches both websocket and http.

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I have solved it using the lifespan of FastAPI. — use it inside the routes. Tension: I couldn't identify where the problem is. Outcome: I have just initialized the Pubsub client in LifeSpan.

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any time you have an I/O bound process with lots of idle time — waiting for user input, waiting for a TLS handshake. Tension: wrapping it in an async task can let other code run.

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Initialize Eureka using the async API (e.g., `eureka_client.init_async(...)`) and/or move initialization into an appropriate async startup hook so it doesn’t start a new event loop at import time.

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An async function was passed to useActionState.

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Use myAsyncAction.fulfilled as the listener actionCreator and prepend listenerMiddleware.middleware in configureStore

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Avoid running multiple DB operations concurrently on the same session by removing asyncio.gather and iterating sequentially, and/or use an async_scoped_session so each task uses its own session.

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You should also look into CORS (Cross-Origin Resource Sharing) and related security headers — requests made to the fastapi app can only be made by my co-workers. Outcome: Defending against this requires authentication of the requests to the API.

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Stage 2 (startup). Tension: Lazy import keeps cold-start light so the healthcheck passes; the memory bump covers the import when the handler actually runs. Outcome: functions-framework can bind the port.

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Rewrite the test as an async test and run it with an async test runner (e.g., pytest.mark.asyncio), using await on the async ORM methods (acreate/acount) instead of asyncio.run().

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Use Component.Task (TaskSource) for all async work inside components — inside components. Tension: it auto-cancels when the component is destroyed.

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