Javascript Modules

2022-11-03 · process

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const { workerData, parentPort }	= require('worker_threads')

console.log('Technical Articles on ' + workerData);

parentPort.postMessage(
	{ fileName: workerData, status: 'Done' })

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const { Worker } = require('worker_threads')

function runService(workerData) {
	return new Promise((resolve, reject) => {
		const worker = new Worker(
				'./worker.js', { workerData });
		worker.on('message', resolve);
		worker.on('error', reject);
		worker.on('exit', (code) => {
			if (code !== 0)
				reject(new Error(
`Stopped the Worker Thread with the exit code: ${code}`));
		})
	})
}

async function run() {
	const result = await runService('GeeksForGeeks')
	console.log(result);
}

run().catch(err => console.error(err))

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const http = require('http');
const longComputation = () => {
  let sum = 0;
  for (let i = 0; i < 1e10; i++) {
    sum += i;
  };
  return sum;
};
const server = http.createServer();
server.on('request', (req, res) => {
  if (req.url === '/compute') {
    console.info('计算开始',new Date());
    const sum = longComputation();
    console.info('计算结束',new Date());
    return res.end(`Sum is ${sum}`);
  } else {
    res.end('Ok')
  }
});

server.listen(3000);

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const http = require('http');
const fork = require('child_process').fork;

const server = http.createServer((req, res) => {
    if(req.url == '/compute'){
        const compute = fork('./compute.js');
        compute.send('开启一个新的子进程');

        // 当一个子进程使用 process.send() 发送消息时会触发 'message' 事件
        compute.on('message', sum => {
            res.end(`Sum is ${sum}`);
            compute.kill();
        });

        // 子进程监听到一些错误消息退出
        compute.on('close', (code, signal) => {
            console.log(`收到close事件，子进程收到信号 ${signal} 而终止，退出码 ${code}`);
            compute.kill();
        })
    }else{
        res.end(`ok`);
    }
});
server.listen(3000, '127.0.0.1', () => {
    console.log(`server started at http://127.0.0.1:3000`);
});

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const computation = () => {
    let sum = 0;
    console.info('计算开始');
    console.time('计算耗时');

    for (let i = 0; i < 1e10; i++) {
        sum += i
    };

    console.info('计算结束');
    console.timeEnd('计算耗时');
    return sum;
};

process.on('message', msg => {
    console.log(msg, 'process.pid', process.pid); // 子进程id
    const sum = computation();

    // 如果Node.js进程是通过进程间通信产生的，那么，process.send()方法可以用来给父进程发送消息
    process.send(sum);
})

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const http = require('http');
const numCPUs = require('os').cpus().length;
const cluster = require('cluster');
if(cluster.isMaster){
    console.log(`Master process id is ${process.pid}, cpu number ${numCPUs}`);
    // fork workers
    for(let i= 0;i<numCPUs;i++){
        cluster.fork();
    }
    cluster.on('exit',function(worker,code,signal){
        console.log('worker process died,id',worker.process.pid)
    })
}else{
    // Worker can share the same TCP connection
    // It's an http server here
    console.log(`created worker pid ${process.pid}`)
    http.createServer(function(req,res){
        res.writeHead(200);
        res.end(String(process.pid));
    }).listen(8000);

}

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Master process id is 18428, cpu number 4
created slave pid 16672
created slave pid 9896
created slave pid 14676
created slave pid 1460

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worker process died,id 1460

Refs

What is a Javascript Module ?

Refs

What is OAuth 2.0 ?

Refs

What is a memory leak ?

Refs

What is typescript ?

Refs

Why Koa ?

Refs

What is Vuetify ?

Install

Refs

Components

Config Provider

Refs

Multithreading: Worker thread

What and why

How-to

Multiprocess: Fork and Cluster

An example to address the problem of single-threaded node.js

Pros and cons of single-threaded node.js

Fork

Cluster

Multithreading vs multiprocess

How it happened

Debugging

Reasoning

Solution

Links

Categories

Recents

Archives

Tags