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The Fix

Upgrade to version 0.30.0 or later.

Based on closed Kludex/uvicorn issue #611 · PR/commit linked

Production note: Most teams hit this during upgrades or environment changes. Roll out with a canary and smoke critical endpoints (health, OpenAPI/docs) before 100%.

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@@ -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. +
repro.py
class ShortLifeWorker(UvicornWorker): # --max-requests = 1 # --timeout = 15 # --workers=10 def notify(self): pass
verify
Re-run the minimal reproduction on your broken version, then apply the fix and re-run.
fix.md
Option A — Upgrade to fixed release\nUpgrade to version 0.30.0 or later.\nWhen NOT to use: Do not use if it changes public behavior or if the failure cannot be reproduced.\n\n

Why This Fix Works in Production

  • Trigger: Gunicorn with UvicornWorker is not respecting the timeout
  • Mechanism: Deprecates the `uvicorn.workers` module in favor of a new package, addressing the issue of timeout not being respected.
  • Why the fix works: Deprecates the `uvicorn.workers` module in favor of a new package, addressing the issue of timeout not being respected. (first fixed release: 0.30.0).
Production impact:
  • If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.

Why This Breaks in Prod

  • Shows up under Python 3.7 in real deployments (not just unit tests).
  • Production symptom (often without a traceback): Gunicorn with UvicornWorker is not respecting the timeout

Proof / Evidence

  • GitHub issue: #611
  • Fix PR: https://github.com/kludex/uvicorn/pull/2302
  • First fixed release: 0.30.0
  • Reproduced locally: No (not executed)
  • Last verified: 2026-02-09
  • Confidence: 0.95
  • Did this fix it?: Yes (upstream fix exists)
  • Own content ratio: 0.71

Discussion

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

“https://github.com/benoitc/gunicorn/issues/1493 is an interesting read”
@euri10 · 2020-04-07 · source
“for option 2 , untested and on top of my head, I think you can 1”
@euri10 · 2020-04-12 · source
“there's probably an error in the way the gunicorn config for the timeout is passed down to the UvicornWorker ie "timeout_notify": self.timeout should certainly be…”
@euri10 · 2020-04-06 · source
“@euri10 I am stuck testing to get a timeout , can you please give me your test example, or point me if I have something…”
@assem-ch · 2020-04-07 · source

Failure Signature (Search String)

  • Gunicorn with UvicornWorker is not respecting the timeout
  • I am setting up a timeout check so I made and endpoint:
Copy-friendly signature
signature.txt
Failure Signature ----------------- Gunicorn with UvicornWorker is not respecting the timeout I am setting up a timeout check so I made and endpoint:

Error Message

Signature-only (no traceback captured)
error.txt
Error Message ------------- Gunicorn with UvicornWorker is not respecting the timeout I am setting up a timeout check so I made and endpoint:

Minimal Reproduction

repro.py
class ShortLifeWorker(UvicornWorker): # --max-requests = 1 # --timeout = 15 # --workers=10 def notify(self): pass

Environment

  • Python: 3.7

What Broke

Timeouts are not enforced, leading to long-running requests without termination.

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

Upgrade to version 0.30.0 or later.

When NOT to use: Do not use if it changes public behavior or if the failure cannot be reproduced.

Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.

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

First fixed release: 0.30.0

Last verified: 2026-02-09. Validate in your environment.

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When NOT to Use This Fix

  • Do not use if it changes public behavior or if the failure cannot be reproduced.

Verify Fix

verify
Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

Did This Fix Work in Your Case?

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

Prevention

  • Add a TLS smoke test that performs a real handshake in CI (include CA bundle validation and hostname checks).
  • Alert on handshake failures by error string and endpoint to catch cert/CA changes quickly.
  • Make timeouts explicit and test them (unit + integration) to avoid silent behavior changes.
  • Instrument retries (attempt count + reason) and alert on spikes to catch dependency slowdowns.

Version Compatibility Table

VersionStatus
0.30.0 Fixed

Related Issues

No related fixes found.

Sources

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