fix: Enhance error handling for closed and broken resources in retry …

[utkarshkingh]

Description #2769 resolved

This PR enhances the error handling in the MCPSessionManager to make it more resilient to connection failures. The changes focus on handling anyio.BrokenResourceError in addition to anyio.ClosedResourceError, ensuring the session manager can gracefully recover from a wider range of network-related issues.

Changelog

• Improved retry_on_closed_resource decorator:

  • The decorator now catches anyio.BrokenResourceError alongside anyio.ClosedResourceError.
  • This ensures that actions are automatically retried if the connection is either closed or broken, improving the reliability of session operations.

• Enhanced exception handling in create_session:

  • The error cleanup logic within the create_session method has been updated to specifically catch anyio.BrokenResourceError and anyio.ClosedResourceError if session creation fails.
  • This prevents a secondary error during cleanup from masking the original exception, making it easier to diagnose connection problems.

How to Test

1. Simulate a anyio.BrokenResourceError during an MCP session operation.
2. Verify that the retry_on_closed_resource decorator catches the exception and retries the operation.
3. Induce a failure during create_session and confirm that the original exception is raised without being obscured by a cleanup error.

[gemini-code-assist]

Summary of Changes

Hello @utkarshkingh, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly improves the robustness of the MCPSessionManager by enhancing its error handling capabilities. It ensures that the system can more effectively recover from various network-related disruptions, specifically by treating broken resources similarly to closed ones, leading to more reliable session management and clearer error diagnostics.

Highlights

• Enhanced Retry Mechanism: The retry_on_closed_resource decorator now handles anyio.BrokenResourceError in addition to anyio.ClosedResourceError, ensuring operations are retried for a wider range of connection issues.
• Improved Session Creation Error Handling: The create_session method's cleanup logic has been updated to gracefully handle anyio.BrokenResourceError and anyio.ClosedResourceError during exit_stack closure, preventing secondary errors from obscuring the primary connection failure.

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[adk-bot]

Response from ADK Triaging Agent

Hello @utkarshkingh, thank you for your contribution!

It's great to see that you've included a "How to Test" section. To help reviewers verify the fix, could you please also provide the logs or screenshots from your manual tests, as suggested in our contribution guidelines?

This will help speed up the review process. Thanks!

[gemini-code-assist]

Code Review

This pull request enhances error handling in the MCPSessionManager by also catching anyio.BrokenResourceError in the retry decorator and during session creation cleanup. The changes are generally good and improve the resilience of the session manager. However, I've identified a significant issue with the simple retry logic in the retry_on_closed_resource decorator. When applied to non-idempotent operations, such as the generic call_tool method, it can lead to unintended side effects. I've left a detailed comment explaining the risk and suggesting ways to mitigate it.