uvicorn Test Gunicorn Worker (Fix)

The Fix

Deprecates the `uvicorn.workers` module in favor of the `uvicorn-worker` package, addressing issue #1834.

Based on closed Kludex/uvicorn issue #1834 · PR/commit linked

Production note: Watch p95/p99 latency and retry volume; timeouts can turn into retry storms and duplicate side-effects.

Open PR/Commit

@@ -182,6 +182,15 @@ Uvicorn provides a lightweight way to run multiple worker processes, for example
 ### Gunicorn
 
+!!! warning
+    The `uvicorn.workers` module is deprecated and will be removed in a future release.
+

fix.md

Option A — Apply the official fix\nDeprecates the `uvicorn.workers` module in favor of the `uvicorn-worker` package, addressing issue #1834.\nWhen NOT to use: This fix is not applicable if the `uvicorn-worker` package is not used.\n\n

Why This Fix Works in Production

Trigger: When doing this, please change those lines: https://github.com/encode/uvicorn/blob/eec7d22ecc0c8926feb365ac7708918e32725f4f/setup.cfg#L39-L43
Mechanism: Deprecates the `uvicorn.workers` module in favor of the `uvicorn-worker` package, addressing issue #1834.

Production impact:

If left unfixed, tail latency can spike under load and surface as timeouts/retries (amplifying incident impact).

Why This Breaks in Prod

Production symptom (often without a traceback): When doing this, please change those lines: https://github.com/encode/uvicorn/blob/eec7d22ecc0c8926feb365ac7708918e32725f4f/setup.cfg#L39-L43

Proof / Evidence

GitHub issue: #1834
Fix PR: https://github.com/kludex/uvicorn/pull/2302
Reproduced locally: No (not executed)
Last verified: 2026-02-11
Confidence: 0.80
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.61

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“> Am I missing something? Or will I need to do a PR that resolves wemake-services/coverage-conditional-plugin#2 in order to unblock this? PR submitted (wemake-services/coverage-conditional-plugin#221)”

@br3ndonland · 2023-04-22 · confirmation · source

“Coding for this is done, and we now have a nice way to omit the worker code from test coverage measurement on Windows, thanks to…”

@br3ndonland · 2023-06-03 · source

“I can take this on”

@br3ndonland · 2023-01-05 · source

“- The workers are moved to the Uvicorn Worker package. I'll deprecate the workers within Uvicorn.”

@Kludex · 2024-03-30 · source

Failure Signature (Search String)

When doing this, please change those lines: https://github.com/encode/uvicorn/blob/eec7d22ecc0c8926feb365ac7708918e32725f4f/setup.cfg#L39-L43
[Coverage.py has an `--omit` flag](https://coverage.readthedocs.io/en/latest/source.html), but I don't think this flag can handle platform-specific conditionals like we need here.

Copy-friendly signature

signature.txt

Failure Signature
-----------------
When doing this, please change those lines: https://github.com/encode/uvicorn/blob/eec7d22ecc0c8926feb365ac7708918e32725f4f/setup.cfg#L39-L43
[Coverage.py has an `--omit` flag](https://coverage.readthedocs.io/en/latest/source.html), but I don't think this flag can handle platform-specific conditionals like we need here.

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
When doing this, please change those lines: https://github.com/encode/uvicorn/blob/eec7d22ecc0c8926feb365ac7708918e32725f4f/setup.cfg#L39-L43
[Coverage.py has an `--omit` flag](https://coverage.readthedocs.io/en/latest/source.html), but I don't think this flag can handle platform-specific conditionals like we need here.

Fix Options (Details)

Option A — Apply the official fix

Deprecates the `uvicorn.workers` module in favor of the `uvicorn-worker` package, addressing issue #1834.

When NOT to use: This fix is not applicable if the `uvicorn-worker` package is not used.

Fix reference: https://github.com/kludex/uvicorn/pull/2302

Last verified: 2026-02-11. Validate in your environment.

When NOT to Use This Fix

This fix is not applicable if the `uvicorn-worker` package is not used.

Did This Fix Work in Your Case?

Quick signal helps us prioritize which fixes to verify and improve.

Prevention

Capture the exact failing error string in logs and tests so you can reproduce via a minimal script.
Pin production dependencies and upgrade only with a reproducible test that hits the failing path.

Related Issues

No related fixes found.

Cluster: uvicorn:latency All hubs All clusters

Related clusters: Configuration error Data consistency Race condition

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.