Validate the OpenAI API key format

[gunnarku]

Increase the amount of internal validation for OpenAI API keys. The intent is to shorten the debugging loop in case of invalid keys and typos. The changes do not add validation for Azure OpenAI API keys.

• Add the validation in __init__ of OpenAIClient.

• Introduce the MOCK_OPEN_AI_API_KEY constant for testing.

• Add unit test coverage for the is_valid_api_key function.

Why are these changes needed?

The intent is to shorten the debugging loop in case of invalid keys and typos. In addition, we increase the correctness guarantees for OpenAIClient, i.e., the OpenAIClient instance will be created only with the API key in a valid format.

If anyone has a definition of constraints for Azure OpenAI API keys, then that will be a next step to increase the validation.

Topics for discussion:

• Could logger.warning be more appropriate than raise ValueError(...)?
• Currently there is no output of self._oai_client.api_key by design to avoid leaking API keys. Is this overly paranoid?

Related issue number

Checks

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• [ X] I've added tests (if relevant) corresponding to the changes introduced in this PR.
• [ X] I've made sure all auto checks have passed.

[gunnarku]

@microsoft-github-policy-service agree

[sonichi]

To help with debugging when a config_list is provided, we can add some info in the error message about the index of the config in the list which causes this error, by catching the error at line 359 of client.py.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (ad9e5cf) 37.80% compared to head (f6a0ab3) 57.42%.
Report is 2 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #1635       +/-   ##
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+ Coverage   37.80%   57.42%   +19.61%     
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  Files          50       50               
  Lines        5726     5733        +7     
  Branches     1296     1406      +110     
===========================================
+ Hits         2165     3292     +1127     
+ Misses       3390     2179     -1211     
- Partials      171      262       +91     

Flag	Coverage Δ
unittests	57.40% <100.00%> (+19.59%)	⬆️

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[gunnarku]

To help with debugging when a config_list is provided, we can add some info in the error message about the index of the config in the list which causes this error, by catching the error at line 359 of client.py.

@sonichi: Thank you for guidance! I will make two updates to the current set of changes:

• Fix the root cause (missing api_key update in test_llava.py that I didn't catch locally. Output from the test log(s) was helpful.
• Add a warning in client.py as you proposed.

Updates en route.