avoid panic on client disconnect

[ask-elad]

What type of PR is this?
/kind bug

What this PR does / why we need it:
This PR fixes a router panic that occurs when a client disconnects during a long running agent invocation.
The router uses httputil.ReverseProxy to forward requests, and when the client times out or disconnects, the standard library panics with http.ErrAbortHandler. This panic was previously unhandled, causing the router to crash and Gin to emit recovery warnings.

The change treats client disconnects as a normal early exit by catching http.ErrAbortHandler at the proxy boundary, preventing the router from panicking while preserving existing behavior for all other error cases.

Which issue(s) this PR fixes:
Fixes #78

Special notes for your reviewer:
Additionally tests can be written for this in a new pr if this is fine

Does this PR introduce a user-facing change?:
NONE

NONE

[volcano-sh-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign yaozengzeng for approval. For more information see the Kubernetes Code Review Process.

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Details

Needs approval from an approver in each of these files:

• pkg/router/OWNERS

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[volcano-sh-bot]

Welcome @ask-elad! It looks like this is your first PR to volcano-sh/agentcube 🎉

[gemini-code-assist]

Summary of Changes

Hello @ask-elad, 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 addresses a critical bug where the router would experience a panic and subsequent crash when a client disconnected during a long-running agent invocation. By introducing a targeted recovery mechanism for http.ErrAbortHandler, the system now gracefully handles these client disconnects, preventing router instability and ensuring continuous service without altering the handling of other error conditions.

Highlights

• Panic Prevention: Implemented a defer and recover block around the proxy.ServeHTTP call to gracefully handle http.ErrAbortHandler. This prevents the router from panicking and crashing when a client disconnects prematurely during a proxied request.
• Error Handling: The change specifically catches http.ErrAbortHandler to treat client disconnects as a normal early exit, while re-panicking for any other recovered errors to preserve existing error handling behavior.
• Logging: A log message is now emitted at verbosity level 2 when a client disconnects, indicating that the proxy is stopping for the specific session.

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[gemini-code-assist]

Code Review

This pull request addresses a panic that occurs when a client disconnects during a long-running operation by recovering from http.ErrAbortHandler. The approach is sound and correctly handles the specific panic from httputil.ReverseProxy. My review includes one high-severity comment regarding a potential nil pointer dereference within the new recover block, which could lead to a panic within a panic. I've recommended adding a defensive nil check to improve robustness.

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

❌ Patch coverage is 30.76923% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 35.67%. Comparing base (845b798) to head (e8f3cad).
⚠️ Report is 20 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/router/handlers.go	30.76%	8 Missing and 1 partial ⚠️
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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #176      +/-   ##
==========================================
+ Coverage   35.60%   35.67%   +0.06%     
==========================================
  Files          29       29              
  Lines        2533     2562      +29     
==========================================
+ Hits          902      914      +12     
- Misses       1505     1521      +16     
- Partials      126      127       +1     

Flag	Coverage Δ
unittests	35.67% <30.76%> (+0.06%)	⬆️

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[hzxuzhonghu]

why do you call panic, this is not recommended in production

[hzxuzhonghu]

BTW, donot we have recovery middleware

	v1.Use(gin.Recovery())