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你会不会有这么一种场景, 比如创建一个TCP连接并且监听一个configserver的配置变动, 当变动的时候同时调整配置, 当你的应用运行在cluster模式下这个TCP连接就会是N个, 但是你并不需要N个因为浪费系统和你的服务方资源, 你只需要有一个TCP连接就够了.
这个模块就是解决这个问题诞生的.
他用了这样一个进程模型
``
Master -> fork Library
| |
| Agent
Cluster |
Wokrer, Wokrer, Woker....
你可以把需要复用的资源放在Library进程中, Agent来负责跨进程的调用
js
$ npm i cluster-dispatch --save
``Example
$ git clone$ npm i
$ npm run example
API
Master
master作为守护进程也是应用的入口, 负责启动appWokrer和libraryWorker
js
const Master = require('cluster-dispatch').Master;/*
* @param {Object} options
* - {String} baseDir - 工程根路径
* - {String} appPath - app进程入口文件, 可以是一个相对路径
* - {String} libraryPath - 第三方库入口文件, 具体参照exmaple/lib/index.js, 可以是一个相对路径
* - {Number} appWorkerCount - 需要启动的app进程数
* - {Funcion} logging - log
* - {Boolean} needLibrary - 是否需要启动library进程
* - {Boolean} needAgent - 是否需要自动启动代理
*/
const master = new Master({
baseDir: __dirname,
logging: debug,
appWorkerCount,
});
(async function initMaster() {
await master.init(); // 初始化
master.on('error', error => debug(error));
})().catch(debug)
``Agent
agent负责跨进程的调度, 这个agent实例每个appWorker都有, 默认会在appWorker初始化时创建好在appWorker中通过Agent.getAgent()就可以拿到agent实例
js
// agent/index.js
'use strict';const Agent = require('cluster-dispatch').Agent;
module.exports = Agent.getAgent();
``
通过agent调用和正常调用是一样的, 只是得通过agent对象调用eg
js
// agent/lib/demo.js
module.exports = {
getName() {
return new Promise((resolve) => {
resolve('get name')
});
}
}// index.js
const agent = require('./agent')
(async function eg() {
const name = await agent.demo.getName()
console.log(name) // "get name"
})().catch(console.error)
``
不过因为是跨进程的所以任何调用都是异步的, 即使你调用的原本是个同步方法启动流程
1. 启动master进程
2. master fork 出 library worker
3. library worker 根据实例化master传递的libraryPath参数拿到下面对象签名, 然后触发ready事件给master
4. master接到ready事件后开始已cluster模式启动app worker
5. app worker初始化完成后会向library worker请求对象签名, 拿到对象签名后开始初始化agent
6. agent遍历对象签名, 并且把对象的每个key重写, 类似这样的逻辑
js
agent.invoke = function(objName, methodName, ...rest) {
return client.setTo('Library').send({
objName,
methodName,
args: rest,
})
}
```7. done