node.js 利用所有的 CPU 内核

node-koa-cluster.js

const Koa = require('koa');
const os = require('os');
const cluster = require('cluster');

const app = new Koa();
const PORT = process.env.PORT || 5000;
const clusterWorkerSize = os.cpus().length;

if (clusterWorkerSize > 1) {
  if (cluster.isMaster) {
    for (let i = 0; i < clusterWorkerSize; i++) {
      cluster.fork();
    }
    cluster.on('exit', (worker, code, signal) => {
      console.log('Worker', worker.id, ' has exitted.');
    });
  } else {    
    app.listen(PORT, () => {
      console.log(
        `Koa server listening on port ${PORT} and worker ${process.pid}`
      );
    });
  }
} else {
  app.listen(PORT, () => {
    console.log(
      `Koa server listening on port ${PORT} with the single worker ${process.pid}`
    );
  });
}