# Ray serve: no attribute 'add\_done\_callback' **URL:** \ **Category:** Ray Serve\ **Created:** [May 17, 2023, 12:03pm UTC](https://discuss.ray.io/t/ray-serve-no-attribute-add-done-callback/10697 "2023-05-17T12:03:00Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![cedricdeboom](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/cedricdeboom/32/4447_2.png) [@cedricdeboom](https://discuss.ray.io/u/cedricdeboom)\ **Post date:** [May 17, 2023, 12:03pm UTC](https://discuss.ray.io/t/ray-serve-no-attribute-add-done-callback/10697/1 "2023-05-17T12:03:00Z")
I try the basic HTTP ingress example of Ray Serve ([Key Concepts — Ray 2.8.0](https://docs.ray.io/en/latest/serve/key-concepts.html#ingress-deployment-http-handling)), but whenever I launch a post request, I get a `AttributeError: ‘ray._raylet.ObjectRef’ object has no attribute ‘add_done_callback’` error (complete stack trace below). This happens in the FastAPI ingress example. In the raw starlette Request example, I get the error: > TypeError: ‘coroutine’ object is not subscriptable On this line: > name = await request.json()[“name”] I use a poetry project in which I have installed the following: > [tool.poetry.dependencies] > python = “^3.11” > flask = “^2.3.2” > pyopenssl = “^23.1.1” > gunicorn = “^20.1.0” > ray = {extras = [“serve”], version = “^2.4.0”} > requests = “^2.30.0” > fastapi = “^0.95.2” The Ray server is launched using the command > poetry run serve run --port 4444 --host 0.0.0.0 src.project.model.serve:basic\_ingress Complete stack trace: > (HTTPProxyActor pid=1781699) ERROR: Exception in ASGI application > (HTTPProxyActor pid=1781699) Traceback (most recent call last): > (HTTPProxyActor pid=1781699) File “/.venv/lib/python3.11/site-packages/uvicorn/protocols/http/h11\_impl.py”, line 428, in run\_asgi > (HTTPProxyActor pid=1781699) result = await app( # type: ignore[func-returns-value] > (HTTPProxyActor pid=1781699) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > (HTTPProxyActor pid=1781699) File “/.venv/lib/python3.11/site-packages/uvicorn/middleware/proxy\_headers.py”, line 78, in **call** > (HTTPProxyActor pid=1781699) return await self.app(scope, receive, send) > (HTTPProxyActor pid=1781699) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > (HTTPProxyActor pid=1781699) File “/.venv/lib/python3.11/site-packages/ray/serve/\_private/http\_proxy.py”, line 404, in **call** > (HTTPProxyActor pid=1781699) status\_code = await \_send\_request\_to\_handle(handle, scope, receive, send) > (HTTPProxyActor pid=1781699) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > (HTTPProxyActor pid=1781699) File “/.venv/lib/python3.11/site-packages/ray/serve/\_private/http\_proxy.py”, line 117, in \_send\_request\_to\_handle > (HTTPProxyActor pid=1781699) \_, request\_timed\_out = await asyncio.wait( > (HTTPProxyActor pid=1781699) ^^^^^^^^^^^^^^^^^^^ > (HTTPProxyActor pid=1781699) File “/.conda/envs/python3.11/lib/python3.11/asyncio/tasks.py”, line 418, in wait > (HTTPProxyActor pid=1781699) return await \_wait(fs, timeout, return\_when, loop) > (HTTPProxyActor pid=1781699) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > (HTTPProxyActor pid=1781699) File “/.conda/envs/python3.11/lib/python3.11/asyncio/tasks.py”, line 522, in \_wait > (HTTPProxyActor pid=1781699) f.add\_done\_callback(\_on\_completion) > (HTTPProxyActor pid=1781699) ^^^^^^^^^^^^^^^^^^^ > (HTTPProxyActor pid=1781699) AttributeError: ‘ray.\_raylet.ObjectRef’ object has no attribute ‘add\_done\_callback’ ---
**Author:** ![cedricdeboom](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/cedricdeboom/32/4447_2.png) [@cedricdeboom](https://discuss.ray.io/u/cedricdeboom)\ **Post date:** [May 19, 2023, 11:05am UTC](https://discuss.ray.io/t/ray-serve-no-attribute-add-done-callback/10697/2 "2023-05-19T11:05:56Z")
FYI: I solved it by using Python 3.10 instead of Python 3.11… ---
**Author:** ![joso](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/joso/32/3745_2.png) [@joso](https://discuss.ray.io/u/joso)\ **Post date:** [June 9, 2023, 1:21pm UTC](https://discuss.ray.io/t/ray-serve-no-attribute-add-done-callback/10697/3 "2023-06-09T13:21:03Z")
Thank you for posting a solution to your problem as well. Is there maybe a potential solution which supports use of Python 3.11 as well? 🙂 ---
**Author:** ![Oblynx](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/oblynx/32/6471_2.png) [@Oblynx](https://discuss.ray.io/u/Oblynx)\ **Post date:** [November 18, 2024, 6:37pm UTC](https://discuss.ray.io/t/ray-serve-no-attribute-add-done-callback/10697/4 "2024-11-18T18:37:34Z")
I see a very similar issue after upgrading to python 3.11. - ray: 2.38.0 - fastapi: 0.94.1 ```auto AttributeError: 'DeploymentResponse' object has no attribute 'add_done_callback' ``` I’m looking more into FastAPI – maybe it’s solved in later versions? ---
**Author:** ![cindy\_zhang](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/cindy_zhang/32/3559_2.png) [@cindy\_zhang](https://discuss.ray.io/u/cindy_zhang)\ **Post date:** [November 18, 2024, 11:41pm UTC](https://discuss.ray.io/t/ray-serve-no-attribute-add-done-callback/10697/5 "2024-11-18T23:41:49Z")
Hi @Oblynx could you post more info on what code you ran, and where you saw this error? ---
**Author:** ![Oblynx](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/oblynx/32/6471_2.png) [@Oblynx](https://discuss.ray.io/u/Oblynx)\ **Post date:** [November 27, 2024, 3:00pm UTC](https://discuss.ray.io/t/ray-serve-no-attribute-add-done-callback/10697/6 "2024-11-27T15:00:11Z")
Hey, coming back to this with some extra info. The object is `ray.serve.handle.DeploymentResponse`. It ends up raising: ```auto > f.add_done_callback(_on_completion) E AttributeError: 'DeploymentResponse' object has no attribute 'add_done_callback' /usr/lib/python3.11/asyncio/tasks.py:532: AttributeError ``` Why are we trying to use it this way? The user code does: - `await asyncio.wait([coro], timeout=timeout)` - where `coro: ray.serve.handle.DeploymentResponse = model_handle.preprocess.remote(...)` - where `model_handle: ray.serve.handle.DeploymentHandle` ---
**Author:** ![Oblynx](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/oblynx/32/6471_2.png) [@Oblynx](https://discuss.ray.io/u/Oblynx)\ **Post date:** [November 27, 2024, 5:56pm UTC](https://discuss.ray.io/t/ray-serve-no-attribute-add-done-callback/10697/7 "2024-11-27T17:56:11Z")
Essentially what happens in Python 3.11 is that `asyncio.wait` calls the method `add_done_callback` that is defined in the stdlib [Task](https://docs.python.org/3.11/library/asyncio-task.html#asyncio.Task.add_done_callback) and [Future](https://docs.python.org/3.11/library/asyncio-future.html#asyncio.Future.add_done_callback) interface. I currently use this workaround: ```auto if isinstance(coro, DeploymentResponse): coro = asyncio.ensure_future(coro) await asyncio.wait([coro], timeout=timeout) ```