Azure / Azure/azure-functions-host

Did not find any initialized language workers

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#11,152 4 comments 0 reactions 0 assignees View on GitHub
Needs: Triage (Functions)
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Description

We have a consumption plan function app that has started producing spikes of this exception in both our production and UAT environments. I believe this is related to #10580 and/or #11119 . The function appears to be well behaved but then the language worker is killed. I've seen this proceeded by a trace like either "Language Worker Process exited. Pid=144." or "python exited with code 137" (indicative of a sigkill). For some reason the runtime(?) appears to continue pick up triggers and create invocations which are then almost immediately failed with the above exception. During this time the memory usage of the function worker usually spikes. This can continue for several minutes and chew through a lot of messages, causing some to be moved to poison.

Questions:
1. Why is the language worker being killed?
2. Is this the same underlying bug as #10580 or something else?
3. What can I do to prevent this?

#### Investigative information

Please provide the following:

- Timestamp: 6/23/2025, 4:42:16.8650252 AM
- Function App version: 4
- Function App name:
- Function name(s) (as appropriate):
- Invocation ID: 74e03d42-321e-49e4-92cf-1d6b179afc23
- Region: West Europe

#### Related information

Provide any related information

* Programming language used = Python 3.12

Contributor guide

Open the contributing guide

Research direction

No source file, test, or entry point is named. Start by reviewing the supplied timestamp, invocation ID, worker-exit traces, memory spike, and related issues #10580 and #11119; done means establishing whether the worker termination and subsequent failed invocations share a cause and documenting a supported prevention or mitigation.

Written by the indexing model from the issue text.

Assessment

Tech stack
azure, python
Domain
backend, cloud
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
30/100

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