Celery task args and kwargs in LOG_RECEIVED and LOG

The Fix

pip install celery==5.3.4

Based on closed celery/celery issue #8288 · PR/commit linked

Production note: This usually shows up under retries/timeouts. Treat it as a side-effect risk until you can verify behavior with a canary + real traffic.

Jump to Verify Open PR/Commit

@@ -250,8 +250,8 @@ def _log_error(self, task, req, einfo):
             safe_str(einfo.traceback),
             einfo.exc_info,
-            safe_repr(req.args),
-            safe_repr(req.kwargs),
+            req.get('argsrepr') or safe_repr(req.args),

repro

this bug.

verify

Follow the reproduction steps, confirm the failure, apply the fix, and repeat the same steps to verify the behavior changes.

fix.md

Option A — Upgrade to fixed release\npip install celery==5.3.4\nWhen NOT to use: This fix should not be applied if the logging format needs to remain unchanged.\n\n

Why This Fix Works in Production

Trigger: - [x] I have included all related issues and possible duplicate issues
Mechanism: The logging of task arguments in LOG_RECEIVED and LOG_SUCCESS did not use argsrepr and kwargsrepr
Why the fix works: Updates the logging of task arguments in LOG_RECEIVED and LOG_SUCCESS to use argsrepr and kwargsrepr for better representation. (first fixed release: 5.3.4).

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

The logging of task arguments in LOG_RECEIVED and LOG_SUCCESS did not use argsrepr and kwargsrepr
Production symptom (often without a traceback): - [x] I have included all related issues and possible duplicate issues

Proof / Evidence

GitHub issue: #8288
Fix PR: https://github.com/celery/celery/pull/8301
First fixed release: 5.3.4
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.76

Discussion

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

Jump to Sources Open on GitHub

“Hey @zhu :wave:, Thank you for opening an issue”

@open-collective-bot · 2023-06-02 · source

“can you contribute the fix with appropriate test?”

@auvipy · 2023-06-04 · source

“> can you contribute the fix with appropriate test? I cannot get argsrepr and kwargsrepr in celery.app.trace.”

@zhu · 2023-06-07 · source

Failure Signature (Search String)

- [x] I have included all related issues and possible duplicate issues
or possible duplicates to this issue as requested by the checklist above.

Copy-friendly signature

signature.txt

Failure Signature
-----------------
- [x] I have included all related issues and possible duplicate issues
or possible duplicates to this issue as requested by the checklist above.

Error Message

Signature-only (no traceback captured)

error.txt

Error Message
-------------
- [x] I have included all related issues and possible duplicate issues
or possible duplicates to this issue as requested by the checklist above.

Minimal Reproduction

this bug.

What Broke

Task logs did not accurately represent arguments, leading to confusion in debugging.

Why It Broke

The logging of task arguments in LOG_RECEIVED and LOG_SUCCESS did not use argsrepr and kwargsrepr

Fix Options (Details)

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

pip install celery==5.3.4

When NOT to use: This fix should not be applied if the logging format needs to remain unchanged.

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

Option D — Guard side-effects with OnceOnly Guardrail for side-effects

Mitigate duplicate external side-effects under retries/timeouts/agent loops by gating the operation before calling external systems.

Place OnceOnly between your code/agent and real side-effects (Stripe, emails, CRM, APIs).
Use a stable key per side-effect (e.g., customer_id + action + idempotency_key).
Fail-safe: configure fail-open vs fail-closed based on blast radius and spend risk.

Show example snippet (optional)

onceonly.py

from onceonly import OnceOnly
import os

once = OnceOnly(api_key=os.environ["ONCEONLY_API_KEY"], fail_open=True)

# Stable idempotency key per real side-effect.
# Use a request id / job id / webhook delivery id / Stripe event id, etc.
event_id = "evt_..."  # replace
key = f"stripe:webhook:{event_id}"

res = once.check_lock(key=key, ttl=3600)
if res.duplicate:
    return {"status": "already_processed"}

# Safe to execute the side-effect exactly once.
handle_event(event_id)

See OnceOnly SDK

When NOT to use: Do not use this to hide logic bugs or data corruption. Use it to block duplicate external side-effects and enforce tool permissions/spend caps.

Fix reference: https://github.com/celery/celery/pull/8301

First fixed release: 5.3.4

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

When NOT to Use This Fix

This fix should not be applied if the logging format needs to remain unchanged.
Do not use this to hide logic bugs or data corruption. Use it to block duplicate external side-effects and enforce tool permissions/spend caps.

Verify Fix

verify

Follow the reproduction steps, confirm the failure, apply the fix, and repeat the same steps to verify the behavior changes.

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.

Version Compatibility Table

Version	Status
5.3.4	Fixed

Related Issues

No related fixes found.

Cluster: celery:configuration-error Celery hub Celery best practices All hubs All clusters

Related clusters: Data consistency Duplicates Duplicate processing

Sources

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

Celery task args and kwargs in LOG_RECEIVED and LOG_SUCCESS should use argsrepr and kwargsrepr (Fix)