cluster: support windowsHide option for workers

Fixes: #17370
PR-URL: #17412Fixes: #17370
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: toddwong

doc/api/cluster.md

@@ -756,6 +756,8 @@ changes:
  This can be a number, or a function that takes no arguments and returns a
  number. By default each worker gets its own port, incremented from the
  master's `process.debugPort`.
+*`windowsHide` {boolean} Hide the forked processes console window that would
+ normally be created on Windows systems. **Default:**`false`
 
 After calling `.setupMaster()` (or `.fork()`) this settings object will contain
 the settings, including the default values.

lib/internal/cluster/master.js

@@ -131,6 +131,7 @@ function createWorkerProcess(id, env) {
 returnfork(cluster.settings.exec,cluster.settings.args,{
 env: workerEnv,
 silent: cluster.settings.silent,
+windowsHide: cluster.settings.windowsHide,
 execArgv: execArgv,
 stdio: cluster.settings.stdio,
 gid: cluster.settings.gid,

test/parallel/test-cluster-fork-windowsHide.js

@@ -0,0 +1,76 @@
+'use strict';
+constcommon=require('../common');
+constassert=require('assert');
+constchild_process=require('child_process');
+constcluster=require('cluster');
+
+if(!process.argv[2]){
+/* It seems Windows only allocate new console window for
+ * attaching processes spawned by detached processes. i.e.
+ * - If process D is spawned by process C with `detached: true`,
+ * and process W is spawned by process D with `detached: false`,
+ * W will get a new black console window popped up.
+ * - If D is spawned by C with `detached: false` or W is spawned
+ * by D with `detached: true`, no console window will pop up for W.
+ *
+ * So, we have to spawn a detached process first to run the actual test.
+ */
+constmaster=child_process.spawn(
+process.argv[0],
+[process.argv[1],'--cluster'],
+{detached: true,stdio: ['ignore','ignore','ignore','ipc']});
+
+constmessageHandlers={
+workerOnline: common.mustCall((msg)=>{
+}),
+mainWindowHandle: common.mustCall((msg)=>{
+assert.ok(/0\s*/.test(msg.value));
+}),
+workerExit: common.mustCall((msg)=>{
+assert.strictEqual(msg.code,0);
+assert.strictEqual(msg.signal,null);
+})
+};
+
+master.on('message',(msg)=>{
+consthandler=messageHandlers[msg.type];
+assert.ok(handler);
+handler(msg);
+});
+
+master.on('exit',common.mustCall((code,signal)=>{
+assert.strictEqual(code,0);
+assert.strictEqual(signal,null);
+}));
+
+}elseif(cluster.isMaster){
+cluster.setupMaster({
+silient: true,
+windowsHide: true
+});
+
+constworker=cluster.fork();
+worker.on('exit',(code,signal)=>{
+process.send({type: 'workerExit',code: code,signal: signal});
+});
+
+worker.on('online',(msg)=>{
+process.send({type: 'workerOnline'});
+
+letoutput='0';
+if(process.platform==='win32'){
+output=child_process.execSync(
+'powershell -NoProfile -c '+
+`"(Get-Process -Id ${worker.process.pid}).MainWindowHandle"`,
+{windowsHide: true,encoding: 'utf8'});
+}
+
+process.send({type: 'mainWindowHandle',value: output});
+worker.send('shutdown');
+});
+
+}else{
+cluster.worker.on('message',(msg)=>{
+cluster.worker.disconnect();
+});
+}