fix(cluster): respect the backlog from workers

[oyyd]

Encounter the same issue of #4056.

Currently, the master process would ignore backlog passed from worker processes and use the default value instead. This commit will respect the first backlog passed to the master process for a specific handle.

It seems hard to test backlog in a Node.js script. I use the script below and ss to check backlog. It's correct on my Linux(Ubuntu):

const net = require('net');
const cluster = require('cluster');
const path = require('path');

if (cluster.isMaster) {
  const workers = [];

  for (let i = 0; i < 2; i += 1) {
    const worker = cluster.fork();
    workers.push(worker);
  }
} else {
  net.createServer().listen(9230, 7); // ss -l
  net.createServer().listen(path.resolve(__dirname, './test.sock'), 7); // ss -x -l
}

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• documentation is changed or added
• commit message follows commit guidelines

[addaleax]

@oyyd Could you add a test for this?

[oyyd]

@addaleax Have added a test monkey-patching the net module to ensure it works as expected.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/32826/

[oyyd]

The included test failed on a windows environment of CI as both net.Server.prototype.listen and net.Server.prototype._listen2 don't get called. Need more investigation.

[mcollina]

lgtm

[mcollina]

@oyyd do you plan to keep working on this?

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/34304/

[aduh95]

@oyyd Test is consistently failing on Windows. Can you take a look?

[github-actions]

This issue/PR was marked as stalled, it will be automatically closed in 30 days. If it should remain open, please leave a comment explaining why it should remain open.

[oyyd]

I can't fix the failure on windows.. so that I'm going to close this PR.