http: add optional logging for socket timeouts

[rohit-chouhan]

What does this PR do?

This PR adds optional debug logging to the socketOnTimeout function in lib/_http_server.js. The logging is enabled only when the environment variable NODE_DEBUG_TIMEOUTS is set (e.g., NODE_DEBUG_TIMEOUTS=1 node app.js). It outputs details like whether the timeout affected the request, response, or server, helping debug issues like unexpected connection drops.

Example log output:
Socket timeout: req=true, res=false, server=false

This change is non-breaking, has no performance impact in production (since it's gated by an env var), and aligns with Node.js's debuglog patterns.

Why is this useful?

• Improves debuggability for common timeout issues (e.g., servers stopping responses after inactivity, as discussed in HTTP Server Stops Responding to Any/All Requests #40724 and test: add OS X to module loading error test #3901).
• No existing logging exists for these specifics in _http_server.js, making it harder to trace without external tools.
• Inspired by community feedback on better HTTP diagnostics.

Changes

• Updated lib/_http_server.js: Added conditional logging in socketOnTimeout.
• Added new test: test/parallel/test-http-timeout-logging.js to verify logging under forced timeouts.

Diff summary (full diff in commits):

function socketOnTimeout() {
    // Existing code...
    if (process.env.NODE_DEBUG_TIMEOUTS) {
		console.log(Socket timeout: req=${!!req}, res=${!!res}, server=${!!serverTimeout});
    }
    // Existing code...
}

Testing

• Ran make test on [your OS, e.g., Ubuntu 22.04] – all tests pass.
• Manually tested with a simple HTTP server: Logging appears only when NODE_DEBUG_TIMEOUTS is set, and timeouts are triggered correctly.
• No regressions in benchmark/http/ (ran benchmark/http/simple.js – performance unchanged).

References

• Related issues: HTTP Server Stops Responding to Any/All Requests #40724 (HTTP server stops responding), test: add OS X to module loading error test #3901 (5-minute timeout errors).
• Docs: No changes needed, but could extend if maintainers suggest.

I signed the CLA. Let me know if any adjustments are needed!

[nodejs-github-bot]

Review requested:

• @nodejs/http
• @nodejs/net

[mcollina]

Thanks for sending this PR. Instead of introducing a new env variable and a console.log, please use the debuglog and NODE_DEBUG facilities.

[mcollina]

move this to the top of the file

[mcollina]

This file is redundant and not testing anything, you can remove it

[rohit-chouhan]

@mcollina

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It will be automatically closed in 30 days if no further activity occurs. If this is still relevant, please leave a comment or update it to keep it open.

[github-actions]

This pull request has been marked as stale due to 90 days of inactivity.
It will be automatically closed in 30 days if no further activity occurs. If this is still relevant, please leave a comment or update it to keep it open.