cluster.js

function History(options) {
  this.timestamp = options.timestamp || new Date();
  this.time      = options.time || new Date().getTime();
}
 
function Server(options) {
  this.port = options.port || null;
  this.alias = options.alias || null;
  this.queue = [];
  this.history = options.history || [];
  this.numOpenRequests = 0;
  this.lastTime = null;
}
 
Server.prototype.addHistory = function(history) {
  this.history.push(history);
};
 
function Cluster() {
  this.previous = null;
  this.servers  = [];
}
 
Cluster.prototype.addServer = function(options) {
  this.servers.push(new Server(options));
};
 
// Algorithm:
Cluster.prototype.next = function() {
  // Find any server that doesn't have any open connections or any queues:
  var points = {};
  var last_time = {index: null, time: 0};
  var self = this;
  var processedFirst = false;
  this.servers.forEach(function(s, index) {
    if (!points[index]) points[index] = 0;
    // Add 50 points for this process:
    if (s.queue.length === 0 && s.numOpenRequests === 0) {
      points[index] += 50;
    } else {
      points[index] -= 30; 
    }
    
    // Now process the completion time from the last request:
    if (last_time.index === null) {
       last_time.index = index;
       last_time.time  = self.servers[index].lastTime;
    }
    
    if (last_time.time < self.servers[index].lastTime) {
      // Increase points by 18
      points[index] += 18;
      // Decrease the last index by 18:
      points[index-1] -= 18;
    }
    
  });
  
  var bigger = 0;
  var index = 0;
  for (var i = 0; i< Object.keys(points).length; i++) {
    var p = points[i];
    if (p > bigger) {
      bigger = p;
      index = i;
    } else if (p === bigger) {
      var random = Math.floor(Math.random() * (i - 0 + 1)) + 0;
      bigger = points[random];
      index = random;
    }
  }
 
  return this.servers[index];
};
 
 
// Testing:
var cluster = new Cluster();

cluster.addServer({
  port: 9999,
  alias: 'server#113'
});

cluster.addServer({
  port: 1111,
  alias: 'server#11'
});
 
//console.log(cluster);
 
 
function HTTPServer() {
        
}
 
HTTPServer.prototype.request = function(req, res) {
    console.log("Accepting a request");
    // Find the next server responsible for this request:
    var next = cluster.next();
    console.log("Responsible Server: ", next, " with a port of: #" + next.port);
};
 
window.http = new HTTPServer();

cluster.next();