Fix: fix client sse tcp connection re-use by draining outstanding io

[bcain99]

Fix: fix client sse tcp connection re-use by draining outstanding io

This is a very targeted fix that does not introduce any additional functionality but fixes an issue with SSE TCP connection reuse from the mcp-go client.

Root cause: Go http client will not re-use connection if a close happens and outstanding io has not been drained

All tests pass

Note: It is hard to write a test case for this as you will need to track source port numbers to look for re-use

Summary by CodeRabbit

• Bug Fixes
  • Improved handling of server responses to ensure more reliable processing and error reporting.

[coderabbitai[bot]]

Walkthrough

The change updates the handling of HTTP response bodies in the SendRequest method within the SSE transport client. Instead of deferring the closure of the response body immediately after the request, the code now reads the entire response body into memory using io.ReadAll, closes the body right after reading, and uses the read content for error reporting. This prevents redundant reads and ensures the body is fully drained before closure.

Changes

Files	Change Summary
client/transport/sse.go	Modified SendRequest to read the entire HTTP response body before closing it and updated error reporting to use the read content, removing redundant body reads.

Possibly related PRs

• mark3labs/mcp-go#206: Addresses cleanup of the response channel to prevent resource leaks within the same SendRequest method, focusing on a different aspect of resource management.

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📜 Recent review details

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📥 Commits

Reviewing files that changed from the base of the PR and between 33c98f164515ab4185524c23015f9e4eb9499dcd and c3e3819ac738823d26be9e8ec0851eb0fa9ff491.

📒 Files selected for processing (1)

• client/transport/sse.go (1 hunks)

🔇 Additional comments (1)

client/transport/sse.go (1)

281-288: Great fix for TCP connection reuse!

This change correctly addresses the issue where TCP connections weren't being reused because of outstanding IO data. By explicitly reading the entire response body with io.ReadAll() and immediately closing it, you ensure that all data is drained from the connection before it's returned to the connection pool.

The fix aligns with Go's HTTP client behavior, which requires response bodies to be fully read and closed for connection reuse. This should result in better performance by reducing the number of TCP connections created over time.

✨ Finishing Touches

• [ ] 📝 Generate Docstrings

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