用NodeJS實現叢集計算

Node的單個例項執行在單個的執行緒中，要充分利用多核系統，我們可以執行Node程式叢集來處理負載。

也就是說，如果系統有8核，單個Node例項只能使用其中1核，可以利用cluster包的workers概念來充分利用所有的核。有趣的是，它們可以共享同一個埠。

該模組還處於實驗階段。

CODE:

var cluster = require('cluster');
var http = require('http');
var numCPUs = require('os').cpus().length;

if (cluster.isMaster) {
  // Fork workers.
  require('os').cpus().forEach(function(){
    cluster.fork();
  });
  // In case the worker dies!
  cluster.on('exit', function(worker, code, signal) {
    console.log('worker ' + worker.process.pid + ' died');
  });
  // As workers come up.
  cluster.on('listening', function(worker, address) {
    console.log("A worker with #"+worker.id+" is now connected to " +\
     address.address +\
    ":" + address.port);
  });
  // When the master gets a msg from the worker increment the request count.
  var reqCount = 0;
  Object.keys(cluster.workers).forEach(function(id) {
    cluster.workers[id].on('message',function(msg){
      if(msg.info && msg.info == 'ReqServMaster'){
        reqCount += 1;
      }
    });
  });
  // Track the number of request served.
  setInterval(function() {
    console.log("Number of request served = ",reqCount);
  }, 1000);

} else {
  // Workers can share the same port!
  require('http').Server(function(req, res) {
    res.writeHead(200);
    res.end("Hello from Cluster!");
    // Notify the master about the request.
    process.send({ info : 'ReqServMaster' });
  }).listen(8000);
}在一個4核的計算機上，輸出如下：

CODE:

Number of request served =  0
A worker with #2 is now connected to 0.0.0.0:8000
A worker with #4 is now connected to 0.0.0.0:8000
A worker with #1 is now connected to 0.0.0.0:8000
A worker with #3 is now connected to 0.0.0.0:8000
Number of request served =  0
...
Number of request served =  2
..
Number of request served =  4
...
Number of request served =  6

來自 “ ITPUB部落格 ” ，連結：http://blog.itpub.net/301743/viewspace-746038/，如需轉載，請註明出處，否則將追究法律責任。