Client invalid sdk key error using automatic config profile

[simonkotwicz]

Describe the bug
If you rotate an environment's SDK key and start the relay proxy, clients started with the old SDK key get a 401 invalid SDK key error.

To reproduce

• Start the relay proxy using an automatic configuration profile (eg. docker run --rm -p 8030:8030 --name ld-relay -e AUTO_CONFIG_KEY="***" launchdarkly/ld-relay)
• Start an ld client that talks to the relay proxy
• Rotate an environment's sdk key so that there are two valid sdk keys (new and old)
• At this point, the relay proxy is notified of the change in the sdk key and everything still works
• Restart the relay proxy (you should see a log message like Old SDK key ending in *** for environment *** (*** ***) will expire at *** when the relay proxy starts)
• The client gets an error ERROR: Error in stream connection (giving up permanently): HTTP error 401 (invalid SDK key)

Relay version
launchdarkly/ld-relay@sha256:2a3bdc8d8adf774a1631d7f13bacac5a8e9e89cdb2ce84f662104a3bb4be11fa

[eli-darkly]

Could I ask you to submit this as a support request instead of a GitHub issue? It's not for sure that this is a bug in the Relay Proxy code (as opposed to an issue with how the LaunchDarkly service sends data to the Relay Proxy), and in order to diagnose this problem we might need to ask you for account information or log data that shouldn't be posted publicly on GitHub, so it would be better to have a support ticket.

[eli-darkly]

Actually, never mind that; I was originally unable to reproduce the problem so I thought we might have to investigate further through support, but then I identified a mistake in my test procedure and proved that this is indeed a problem in the Relay Proxy code— one that unfortunately we had a gap in test coverage for. It should be a straightforward fix. Thanks for reporting this!

[eli-darkly]

We've released version 6.1.1, which should fix this. Sorry for the inconvenience and thanks for pointing out the problem.