Implement retry logic with exponential backoff for OpenID discovery document fetching

[devin-ai-integration]

Implement retry logic with exponential backoff for OpenID discovery document fetching

Summary

This PR adds retry logic with exponential backoff to the get_discovery_doc() function to address intermittent SSL connection errors during AuthClient initialization. The specific error being addressed is:

HTTPSConnectionPool(host='developer.intuit.com', port=443): Max retries exceeded with url: /.well-known/openid_configuration/ (Caused by SSLError(SSLEOFError(8, '[SSL: UNEXPECTED_EOF_WHILE_READING] EOF occurred in violation of protocol (_ssl.c:1006)')))

Key Changes:

• Added retry strategy using HTTPAdapter and Retry from urllib3 with 3 max retries (configurable)
• Implemented exponential backoff with backoff_factor=1
• Configured retry for HTTP status codes [429, 500, 502, 503, 504]
• Modified session handling to always use requests.Session with mounted retry adapter
• Updated test mocking to properly handle session-based requests

Review & Testing Checklist for Human

• Test SSL connection resilience: Verify that the retry logic actually helps with intermittent SSL connection errors to Intuit's discovery endpoints
• Verify AuthClient initialization: Ensure AuthClient creation still works normally and doesn't introduce performance regressions
• Test error handling: Confirm that non-retryable errors (like 401, 404) still raise AuthClientError immediately without unnecessary retries
• Validate retry behavior: Test that the function properly retries on 5xx errors and rate limiting (429) but fails appropriately after max retries

Notes

• The retry strategy targets HTTP status codes but may not directly address SSL protocol errors - this should be tested in practice
• Default max_retries=3 with backoff_factor=1 means delays of ~1s, 2s, 4s between retries
• Session management has been modified to always use requests.Session - monitor for any unexpected side effects

Requested by: @abhay-codeium
Link to Devin run: https://app.devin.ai/sessions/e9482c54c5c44fe58afd4384cb2a6624

[devin-ai-integration]

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