[Serve] [Bug] Redeploying function causes "AttributeError: 'function' object has no attribute '__del__'"

[architkulkarni]

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• I searched the issues and found no similar issues.

Ray Component

Ray Serve

What happened + What you expected to happen

Deploying a function twice gives the following traceback:

2021-09-20 15:59:17,902 INFO api.py:243 -- Updating deployment 'f'. component=serve deployment=f
(pid=87851) 2021-09-20 15:59:17,906     INFO backend_state.py:854 -- Stopping 1 replicas of deployment 'f' with outdated versions. component=serve deployment=f OLD VERSION: wLDnZI  NEW VERSION: nVoLLY
(pid=87853) 2021-09-20 15:59:19,909     ERROR backend_worker.py:360 -- Exception during graceful shutdown of replica. component=serve deployment=f replica=f#DrtNqg
(pid=87853) Traceback (most recent call last):
(pid=87853)   File "/Users/archit/ray/python/ray/serve/backend_worker.py", line 358, in prepare_for_shutdown
(pid=87853)     self.callable.__del__()
(pid=87853) AttributeError: 'function' object has no attribute '__del__'
(pid=87851) 2021-09-20 15:59:20,072     INFO backend_state.py:898 -- Adding 1 replicas to deployment 'f'. component=serve deployment=f
2021-09-20 15:59:20,400 INFO api.py:251 -- Deployment 'f' is ready at `http://127.0.0.1:8000/f`. component=serve deployment=f

Reproduction script

from ray import serve
@serve.deployment
def f(request):
    return "Hi"
serve.start()
f.deploy()
f.deploy()

Anything else

Occurs on master
No response

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

[simon-mo]

nice catch. can you make a quick fix? you can just gate that line with hasattr(self, callable, "__del__")