From 42aa0582274b0263acdacdc3cf0f51a925af80df Mon Sep 17 00:00:00 2001
From: Vladyslav Dukhin <vladyslav.dukhin@gmail.com>
Date: Wed, 5 Apr 2017 02:08:39 +0300
Subject: [PATCH] Moved examples from cluster to child_process Closes
 HowProgrammingWorks/InterProcessCommunication#3

---
 workers/master.js    | 40 ----------------------------------------
 workers/multicore.js | 41 ++++++++++++++++++++++++++++++++++++-----
 workers/worker.js    | 24 ++++++++++--------------
 3 files changed, 46 insertions(+), 59 deletions(-)
 delete mode 100644 workers/master.js

diff --git a/workers/master.js b/workers/master.js
deleted file mode 100644
index 6e2f08e..0000000
--- a/workers/master.js
+++ /dev/null
@@ -1,40 +0,0 @@
-'use strict';
-
-module.exports = () => {
-
-  const cpuCount = api.os.cpus().length;
-
-  const workers = [];
-  for (let i = 0; i < cpuCount; i++) {
-    const worker = api.cluster.fork();
-    workers.push(worker);
-  }
-
-  const task = [2, 17, 3, 2, 5, 7, 15, 22, 1, 14, 15, 9, 0, 11];
-  const results = [];
-
-  workers.forEach((worker) => {
-
-    worker.send({ task });
-
-    worker.on('exit', (code) => {
-      console.log('exit ' + worker.process.pid + ' ' + code);
-    });
-
-    worker.on('message', (message) => {
-
-      console.log(
-        'message from worker ' + worker.process.pid + ': ' +
-        JSON.stringify(message)
-      );
-      results.push(message.result);
-
-      if (results.length === cpuCount) {
-        process.exit(1);
-      }
-
-    });
-
-  });
-
-};
diff --git a/workers/multicore.js b/workers/multicore.js
index c203bde..eb11325 100644
--- a/workers/multicore.js
+++ b/workers/multicore.js
@@ -1,11 +1,42 @@
 'use strict';
 
 global.api = {};
-api.cluster = require('cluster');
+api.cp = require('child_process');
 api.os = require('os');
 
-if (api.cluster.isMaster) {
-  require('./master.js')();
-} else {
-  require('./worker.js')();
+const cpuCount = api.os.cpus().length;
+console.log('Number of CPUs in computer: ' + cpuCount);
+console.log();
+
+const task = [2, 17, 3, 2, 5, 7, 15, 22, 1, 14, 15, 9, 0, 11];
+const results = [];
+
+const header = 'PID\tMESSAGE';
+const TAB_LENGTH = 4;
+console.log(header);
+console.log('-'.repeat(header.length + TAB_LENGTH));
+
+for (let i = 0; i < cpuCount; i++) {
+  const worker = api.cp.fork('./worker');
+
+  worker.on('message', (message) => {
+    console.log(
+      worker.pid + '\tFROM worker ' +
+      JSON.stringify(message)
+    );
+
+    results.push(message.result);
+
+    if (results.length === cpuCount) {
+      console.log();
+      console.log('Tasks done successfully by ' + cpuCount + ' workers.');
+      process.exit(0);
+    }
+  });
+
+  worker.on('exit', (code) => {
+    console.log('exit ' + worker.pid + ' ' + code);
+  });
+
+  worker.send({ task });
 }
diff --git a/workers/worker.js b/workers/worker.js
index a157232..85f08fb 100644
--- a/workers/worker.js
+++ b/workers/worker.js
@@ -1,22 +1,18 @@
 'use strict';
 
-module.exports = () => {
+console.log(process.pid + '\tHELLO');
 
-  console.log('Hello from worker ' + process.pid + ' ' + api.cluster.worker.id);
+const caltulations = item => item * 2;
 
-  const caltulations = item => item * 2;
+process.on('message', (message) => {
 
-  process.on('message', (message) => {
-
-    console.log(
-      'message to worker ' + process.pid +
-      ' from master: ' + JSON.stringify(message)
-    );
-
-    process.send({
-      result: message.task.map(caltulations)
-    });
+  console.log(
+    process.pid + '\t' +
+    'FROM master: ' + JSON.stringify(message)
+  );
 
+  process.send({
+    result: message.task.map(caltulations)
   });
 
-};
+});