Example of the difficulty in attaching a debugger to Node.js cluster forks if they're cycled (development environments)

app.js

var cluster = require("cluster");
var worker;

if (cluster.isMaster) {

  function spawnWorker(i) {
    var child;
    cluster.settings.execArgv || (cluster.settings.execArgv = []);
    // this has no effect
    cluster.settings.execArgv.push('--debug=' + 5859);
    child = cluster.fork();
    console.log('forked');
    cluster.settings.execArgv.pop();
    
    child.on('exit', function() {
      spawnWorker(i);
    });

    setTimeout(function() {
      child.kill();
    }, i * 2000);
    return child;

  }
  spawnWorker(1);
} else {
  console.log('im a fork');
  debugger
}

/*

output:

┌[josh@jarvice] [130]
└[~/code/clustertest]> node --debug=5000 app.js
Debugger listening on port 5000
forked
Debugger listening on port 5001
im a fork
forked
Debugger listening on port 5002
im a fork
forked
Debugger listening on port 5003
im a fork
forked
Debugger listening on port 5004
im a fork
forked
Debugger listening on port 5005
im a fork

master debug is reachable at 5000, but every fork gets a new port no matter what.

*/