500 Internal Server Error on login related to Redis auth

[umamidot]

I am using SimpleChat with a "custom" Azure_Environment. The start page appears and when I click Login I get an HTTP 500 error, Internal Server Error, on https://appsc.appservice.customdomain/getAToken.

I am using Managed Identity with Redis.

The App Service Log Stream shows no errors.

App Insights has the error:
ClientAuthenticationError
Exception on /robots933456.txt [GET]
Traceback (most recent call last):
File "/app/venv/lib/python3.13/site-packages/flask/app.py", line 2529, in wsgi_app
response = self.full_dispatch_request()
File "/app/venv/lib/python3.13/site-packages/flask/app.py", line 1815, in full_dispatch_request
self.ensure_sync(func)()
File "/app/app.py", line 89, in before_first_request
token = credential.get_token(f"https://{redis_hostname}.{REDIS_URL_VALUE}:10225/appid")
15 more lines...

I am using custom endpoints, where REDIS_URL_VALUE equals the App Service environment variable CUSTOM_REDIS_URL_VALUE. I've tried these variations on CUSTOM_REDIS_URL_VALUE to no avail:

1. cacheinfra.windows.net
2. cacheinfra.customdomain
3. cacheinfra.cloudapi.customdomain

At this point, the SimpleChat UI doesn't come up so I can change the Redis auth back to keys.

[paullizer]

you can change the key values from Cosmos in the settings container.

I will need more info on this, we have only tested using Azure Cache for Redis service. I can get more debug logging into the upcoming release on Dec 18th so we can see more details on the redis cache execution to help troubleshoot your use case.

[Bionic711]

To add to Paul, only Azure Commercial supports using managed identity with Azure Cache for Redis. MAG and other custom environments do not support this scenario. I recently spoke with the PG about this (about a month ago now) and confirmed this to be true.

We have not tested Azure Managed Redis.

As far as config to try and get it working: config.py currently creates and uses:
CUSTOM_REDIS_CACHE_INFRASTRUCTURE_URL_VALUE = os.getenv("CUSTOM_REDIS_CACHE_INFRASTRUCTURE_URL_VALUE", "")
for the URL to connect using a custom environment (maybe we have out of date docs?)

If you switch back to key, make sure to update the redis_auth_type and redis_key keys. auth_type should either be managed_identity or key.