node.js使用cluster实现多进程

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

if (cluster.isMaster) {
  console.log('[master] ' + "start master...");

  for (var i = 0; i < numCPUs; i++) {
    cluster.fork();
  }

  cluster.on('listening', function (worker, address) {
    console.log('[master] ' + 'listening: worker' + worker.id + ',pid:' + worker.process.pid + ', Address:' + address.address + ":" + address.port);
  });

  cluster.on('exit', function () {
    console.log('A worker process died, restarting...');
    cluster.fork();
  });

} else if (cluster.isWorker) {
  console.log('[worker] ' + "start worker ..." + cluster.worker.id);

  http.createServer(function (req, res) {
    console.log('worker' + cluster.worker.id);

    let data = []
    req.on('data', chunk => {
      data.push(chunk.toString()) 
    })
    req.on('end', () => {
      console.log(data)
    })

    try {
      if (req.url === '/') {
        res.end('worker' + cluster.worker.id + ',PID:' + process.pid);
      } else if (req.url === '/test') {
        a(111)
      } else if (req.url === '/a') {
        res.end(" xxxxx");
      }
    } catch (e) {
      res.end(" error");
    }
  })
}