From d582731f204b77ffad4ac427229d0544a531f8e9 Mon Sep 17 00:00:00 2001
From: Radek Adamus <adamus.r@gmail.com>
Date: Mon, 3 Mar 2014 11:56:12 +0100
Subject: [PATCH] turns into a demon

---
 app.js                           | 14 ------
 bin/node-awslab-http-daemon      | 79 ++++++++++++++++++++++++++++++++
 lib/app.js                       | 23 ++++++++++
 example_1.js => lib/example_1.js |  0
 helpers.js => lib/helpers.js     |  0
 index.html => lib/index.html     |  0
 lab1_1.js => lib/lab1_1.js       |  0
 service.js => lib/service.js     |  0
 package.json                     |  3 ++
 9 files changed, 105 insertions(+), 14 deletions(-)
 delete mode 100644 app.js
 create mode 100644 bin/node-awslab-http-daemon
 create mode 100644 lib/app.js
 rename example_1.js => lib/example_1.js (100%)
 rename helpers.js => lib/helpers.js (100%)
 rename index.html => lib/index.html (100%)
 rename lab1_1.js => lib/lab1_1.js (100%)
 rename service.js => lib/service.js (100%)

diff --git a/app.js b/app.js
deleted file mode 100644
index b64c946..0000000
--- a/app.js
+++ /dev/null
@@ -1,14 +0,0 @@
-var lab1_1 = require("./lab1_1").lab
-
-var example_1 = require("./example_1").lab
-
-
-var urlMap = [
-	{path: "/", action:__dirname + "/index.html"},	 
-	{path: "/digest", action: lab1_1},	
-	{path: "/example_1", action: example_1}, 
-	];
-
-var service = require("./service").http(urlMap);
-
-service(8080);
\ No newline at end of file
diff --git a/bin/node-awslab-http-daemon b/bin/node-awslab-http-daemon
new file mode 100644
index 0000000..222294b
--- /dev/null
+++ b/bin/node-awslab-http-daemon
@@ -0,0 +1,79 @@
+#!/usr/bin/env node
+
+/**
+ * bin/node-awslab-http-daemon
+ */
+
+ require('daemon')();
+
+ var cluster = require('cluster');
+
+// Number of CPUs
+var numCPUs = require('os').cpus().length;
+
+/**
+ * Creates a new worker when running as cluster master.
+ * Runs the HTTP server otherwise.
+ */
+function createWorker() {
+  if (cluster.isMaster) {
+    // Fork a worker if running as cluster master
+    var child = cluster.fork();
+
+    // Respawn the child process after exit
+    // (ex. in case of an uncaught exception)
+    child.on('exit', function (code, signal) {
+      createWorker();
+    });
+  } else {
+    // Run the HTTP server if running as worker
+    require('../lib/app');
+  }
+}
+
+/**
+ * Creates the specified number of workers.
+ * @param  {Number} n Number of workers to create.
+ */
+function createWorkers(n) {
+  while (n-- > 0) {
+    createWorker();
+  }
+}
+
+/**
+ * Kills all workers with the given signal.
+ * Also removes all event listeners from workers before sending the signal
+ * to prevent respawning.
+ * @param  {Number} signal
+ */
+function killAllWorkers(signal) {
+  var uniqueID,
+      worker;
+
+  for (uniqueID in cluster.workers) {
+    if (cluster.workers.hasOwnProperty(uniqueID)) {
+      worker = cluster.workers[uniqueID];
+      worker.removeAllListeners();
+      worker.process.kill(signal);
+    }
+  }
+}
+
+/**
+ * Restarts the workers.
+ */
+process.on('SIGHUP', function () {
+  killAllWorkers('SIGTERM');
+  createWorkers(numCPUs * 2);
+});
+
+/**
+ * Gracefully Shuts down the workers.
+ */
+process.on('SIGTERM', function () {
+  killAllWorkers('SIGTERM');
+});
+
+// Create two children for each CPU
+createWorkers(numCPUs * 2);
\ No newline at end of file
diff --git a/lib/app.js b/lib/app.js
new file mode 100644
index 0000000..2ead3dc
--- /dev/null
+++ b/lib/app.js
@@ -0,0 +1,23 @@
+var lab1_1 = require("./lab1_1").lab
+var example_1 = require("./example_1").lab;
+
+var PORT = 8080;
+
+
+var urlMap = [
+	{path: "/", action:__dirname + "/index.html"},	 
+	{path: "/digest", action: lab1_1},	
+	{path: "/example_1", action: example_1}, 
+	];
+
+var service = require("./service").http(urlMap);
+
+service(PORT);
+
+process.on('SIGTERM', function () {
+  if (server === undefined) return;
+  server.close(function () {
+    // Disconnect from cluster master
+    process.disconnect && process.disconnect();
+  });
+});
\ No newline at end of file
diff --git a/example_1.js b/lib/example_1.js
similarity index 100%
rename from example_1.js
rename to lib/example_1.js
diff --git a/helpers.js b/lib/helpers.js
similarity index 100%
rename from helpers.js
rename to lib/helpers.js
diff --git a/index.html b/lib/index.html
similarity index 100%
rename from index.html
rename to lib/index.html
diff --git a/lab1_1.js b/lib/lab1_1.js
similarity index 100%
rename from lab1_1.js
rename to lib/lab1_1.js
diff --git a/service.js b/lib/service.js
similarity index 100%
rename from service.js
rename to lib/service.js
diff --git a/package.json b/package.json
index 931c340..bedc271 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,9 @@
 {
   "name": "aws_lab",
   "version": "0.0.1",
+  "scripts": {    
+    "start": "node app.js"
+  },
   "dependencies": {
     "express": "~3.4.8",
     "aws-sdk": "~2.0.0-rc9"