refactor to not use net-cluster and underscore

lib/getRandomPort.js

@@ -0,0 +1,69 @@
+var net = require('net');
+
+var DEFAULT_MIN = 1025;
+var DEFAULT_MAX = 65535;
+var DEFAULT_MAX_ATTEMPTS = 50;
+
+function getRandomPort (opts, cb) {
+	var min = DEFAULT_MIN;
+	var max = DEFAULT_MAX;
+	var maxAttempts = DEFAULT_MAX_ATTEMPTS;
+	var options = opts || {};
+	var host;
+	var port;
+	var server;
+
+	if (options.min != null) {
+		min = options.min;
+	}
+
+	if (options.max != null) {
+		max = options.max;
+	}
+
+	if (options.maxAttempts != null) {
+		maxAttempts = options.maxAttempts;
+	}
+
+	if (options.host != null) {
+		host = options.host;
+	}
+
+	port = getRandomNumber(min, max);
+
+	server = net.createServer();
+
+	server.listen(port, host, function () {
+    server.once('close', function () { cb(null, port) });
+    server.close();
+  });
+
+	server.on('error', function () {
+    if (--maxAttempts) {
+      return getRandomPort({
+				min: min,
+				max: max,
+				maxAttempts: maxAttempts
+			}, cb);
+    }
+
+    cb(new Error('Could not find an available port'));
+  });
+}
+
+function getRandomNumber (minimum, maximum) {
+  if (maximum === undefined) {
+	  maximum = minimum;
+		minimum = 0;
+	}
+
+	if (typeof minimum !== 'number' || typeof maximum !== 'number') {
+		throw new TypeError('Expected all arguments to be numbers');
+	}
+
+	return Math.floor(
+		(Math.random() * (maximum - minimum + 1)) + minimum
+	);
+}
+
+module.exports = getRandomPort;

lib/phantomManager.js

@@ -5,11 +5,10 @@
  * and distributing pdf rendering tasks to them.
  */
 
-var events = require("events"),
-    util = require("util"),
-    _ = require("underscore"),
+var events = require('events'),
+    util = require('util'),
+    find = require('lodash.find'),
     numCPUs = require('os').cpus().length,
-    cluster = require("cluster"),
     PhantomWorker = require("./phantomWorker.js");
 
 var PhantomManager = module.exports = function (options) {
@@ -86,7 +85,7 @@ PhantomManager.prototype.kill = function() {
 PhantomManager.prototype.execute = function (options, cb) {
     var self = this;
 
-    var freePhantomInstance = _.findWhere(this._phantomInstances, {
+    var freePhantomInstance = find(this._phantomInstances, {
         isBusy: false
     });
 
@@ -146,7 +145,7 @@ PhantomManager.prototype.tryFlushQueue = function () {
     if (this.tasksQueue.length === 0)
         return;
 
-    var freePhantomInstance = _.findWhere(this._phantomInstances, {
+    var freePhantomInstance = find(this._phantomInstances, {
         isBusy: false
     });
 

lib/phantomWorker.js

@@ -1,35 +1,22 @@
 var childProcess = require('child_process'),
-    cluster = require("cluster"),
+    cluster = require('cluster'),
     http = require('http'),
-    netCluster = require("net-cluster"),
-    checkPortStatus = require("./checkPortStatus.js"),
-    portScanner = require('portscanner'),
+    checkPortStatus = require('./checkPortStatus'),
+    getRandomPort = require('./getRandomPort'),
     objectAssign = require('object-assign');
 
-
 var findFreePort = function (host, cb) {
-    var server = netCluster.createServer();
-    var port = 0;
-    server.on('listening', function () {
-        port = server.address().port;
-        server.close();
-    });
-    server.on('close', function () {
-        cb(null, port);
-    });
-    server.listen(0, host);
+    getRandomPort({
+        host: host
+    }, cb);
 };
 
 var findFreePortInRange = function (host, portLeftBoundary, portRightBoundary, cb) {
-
-    //in cluster we don't want ports to collide, so we make a special space for every worker assuming max number of cluster workers is 5
-    if (cluster.worker) {
-        portLeftBoundary = portLeftBoundary + (((portRightBoundary - portLeftBoundary) / 5) * (cluster.worker.id - 1));
-    }
-
-    portScanner.findAPortNotInUse(portLeftBoundary, portRightBoundary, host, function(error, port) {
-        cb(error, port);
-    })
+    getRandomPort({
+        min: portLeftBoundary,
+        max: portRightBoundary,
+        host: host
+    }, cb);
 };
 
 
@@ -175,13 +162,13 @@ PhantomWorker.prototype.execute = function (options, cb) {
             result += chunk;
         });
         res.on("end", function () {
-            self.isBusy = false;            
+            self.isBusy = false;
             try {
                 var parsedResult = result ? JSON.parse(result) : null
                 cb(null, parsedResult)
             } catch (e) {
                 cb(new Error('Unparsable response from the phantomjs ' + result))
-            }            
+            }
         });
     });
 
@@ -190,17 +177,17 @@ PhantomWorker.prototype.execute = function (options, cb) {
     req.setHeader('Content-Length', Buffer.byteLength(json));
     req.write(json);
 
-    req.on("error", function (e) {   
+    req.on("error", function (e) {
         // recycle phantomjs if it cannot accept connections to avoid getting it freezed in the invalid state
         if (e.code === 'ECONNREFUSED' || e.code === 'ECONNRESET') {
             return self.recycle(function (recycleError) {
                 self.isBusy = false;
                 cb(recycleError || e);
             });
-        } 
+        }
 
         self.isBusy = false;
-        cb(e);       
+        cb(e);
     });
 
     req.end();