Celery Celery does not consider authMechanism on mongodb

The Fix

pip install celery==4.4.0rc5

Based on closed celery/celery issue #5734 · 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

@@ -157,6 +157,10 @@ def _get_connection(self):
             conf = dict(self.options)
             conf['host'] = host
+            if self.user:
+                conf['username'] = self.user
+            if self.password:

repro.py

software -> celery:4.3.0 (rhubarb) kombu:4.6.4 py:3.7.4
            billiard:3.6.1.0 py-amqp:2.5.1
platform -> system:Windows arch:64bit, WindowsPE
            kernel version:10 imp:CPython
loader   -> celery.loaders.default.Loader
settings -> transport:amqp results:disabled

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\npip install celery==4.4.0rc5\nWhen NOT to use: Do not use this fix if the MongoDB connection does not require authentication.\n\n

Why This Fix Works in Production

Trigger: return obj.__dict__[self.__name__]
Mechanism: Username must be provided if 'authMechanism' is used while connecting to MongoDB
Why the fix works: Fixes issue #5734 by ensuring that the username and password are included when connecting to MongoDB with an authMechanism. (first fixed release: 4.4.0rc5).

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

Username must be provided if 'authMechanism' is used while connecting to MongoDB
Surfaces as: Traceback (most recent call last):

Proof / Evidence

GitHub issue: #5734
Fix PR: https://github.com/celery/celery/pull/5795
First fixed release: 4.4.0rc5
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.34

Discussion

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

Jump to Sources Open on GitHub

“raise ConfigurationError("%s requires a username." % (mech,)) pymongo.errors.ConfigurationError: SCRAM-SHA-256 requires a username. did you provide the username?”

@auvipy · 2019-10-24 · source

“@auvipy, thanks for your reply”

@spengjie · 2019-10-24 · source

Failure Signature (Search String)

return obj.__dict__[self.__name__]

Error Message

Stack trace

error.txt

Error Message
-------------
Traceback (most recent call last):
  File "D:\GitHub\org\dev\.venv\lib\site-packages\kombu\utils\objects.py", line 42, in __get__
    return obj.__dict__[self.__name__]
KeyError: 'collection'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "D:\GitHub\org\dev\.venv\lib\site-packages\kombu\utils\objects.py", line 42, in __get__
    return obj.__dict__[self.__name__]
KeyError: 'database'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\Users\user\.vscode\extensions\ms-python.python-2019.9.34911\pythonFiles\ptvsd_launcher.py", line 43, in <module>
    main(ptvsdArgs)
  File "c:\Users\user\.vscode\extensions\ms-python.python-2019.9.34911\pythonFiles\lib\python\ptvsd\__main__.py", line 432, in main
    run()
  File "c:\Users\user\.vscode\extensions\ms-python.python-2019.9.34911\pythonFiles\lib\python\ptvsd\__main__.py", line 316, in run_file
    runpy.run_path(target, run_name='__main__')
  File "C:\Program Files\Python37\lib\runpy.py", line 263, in run_path
    pkg_name=pkg_name, script_name=fname)
  File "C:\Program Files\Python37\lib\runpy.py", line 96, in _run_module_code
    mod_name, mod_spec, pkg_name, script_name)
  File "C:\Program Files\Python37\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "d:\GitHub\org\dev\backend\te
... (truncated) ...

Minimal Reproduction

repro.py

software -> celery:4.3.0 (rhubarb) kombu:4.6.4 py:3.7.4
            billiard:3.6.1.0 py-amqp:2.5.1
platform -> system:Windows arch:64bit, WindowsPE
            kernel version:10 imp:CPython
loader   -> celery.loaders.default.Loader
settings -> transport:amqp results:disabled

What Broke

Connection attempts fail with a configuration error due to missing username.

Why It Broke

Username must be provided if 'authMechanism' is used while connecting to MongoDB

Fix Options (Details)

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

pip install celery==4.4.0rc5

When NOT to use: Do not use this fix if the MongoDB connection does not require authentication.

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

Fix reference: https://github.com/celery/celery/pull/5795

First fixed release: 4.4.0rc5

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

When NOT to Use This Fix

Do not use this fix if the MongoDB connection does not require authentication.

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

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
4.4.0rc5	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 Celery does not consider authMechanism on mongodb backend URLs (Fix)