Version: 4.x

与 PM2 一起使用

PM2 是 Node.js 应用的生产进程管理器，具有内置负载均衡器。它允许你使应用永远保持活动状态，无需停机即可重新加载它们，并简化常见的系统管理任务。

¥PM2 is a production process manager for Node.js applications with a built-in load balancer. It allows you to keep applications alive forever, to reload them without downtime and to facilitate common system admin tasks.

你可以在这里找到它的文档：https://pm2.keymetrics.io/docs/usage/pm2-doc-single-page/

¥You can find its documentation here: https://pm2.keymetrics.io/docs/usage/pm2-doc-single-page/

要使用 PM2 扩展 Socket.IO 服务器，有以下三种解决方案：

¥To scale a Socket.IO server with PM2, there are three solutions:

在客户端禁用 HTTP 长轮询
¥disable HTTP long-polling on the client-side

const socket = io({
  transports: ["websocket"]
});

但在这种情况下，如果无法建立 WebSocket 连接，则不会回退到 HTTP 长轮询。

¥Though in that case, there will be no fallback to HTTP long-polling if the WebSocket connection cannot be established.

为每个工作进程使用不同的端口，并在它们前面使用像 nginx 这样的负载均衡器
¥use a distinct port for each worker, and a load-balancer like nginx in front of them
使用 @socket.io/pm2
¥use @socket.io/pm2

安装

¥Installation

npm install -g @socket.io/pm2

如果 pm2 已安装，则必须先将其删除：

¥If pm2 is already installed, you will have to remove it first:

npm remove -g pm2

@socket.io/pm2 可用作 pm2 的直接替代品，并支持 pm2 类实用程序的所有命令。

¥@socket.io/pm2 can be used as a drop-in replacement for pm2, and supports all the commands of the class pm2 utility.

唯一的区别来自这次提交。

¥The only difference comes from this commit.

用法

¥Usage

worker.js

const { createServer } = require("http");
const { Server } = require("socket.io");
const { createAdapter } = require("@socket.io/cluster-adapter");
const { setupWorker } = require("@socket.io/sticky");

const httpServer = createServer();
const io = new Server(httpServer);

io.adapter(createAdapter());

setupWorker(io);

io.on("connection", (socket) => {
  console.log(`connect ${socket.id}`);
});

ecosystem.config.js

module.exports = {
  apps : [{
    script    : "worker.js",
    instances : "max",
    exec_mode : "cluster"
  }]
}

然后运行 pm2 start ecosystem.config.js（或 pm2 start worker.js -i 0）。就是这样！你现在可以通过端口 8080 访问 Socket.IO 集群。

¥And then run pm2 start ecosystem.config.js (or pm2 start worker.js -i 0). That's it! You can now reach the Socket.IO cluster on port 8080.

工作原理

¥How it works

当扩展到多个节点时，有两件事要做：

¥When scaling to multiple nodes, there are two things to do:

启用粘性会话，以便 Socket.IO 会话的 HTTP 请求路由到同一个工作线程
¥enable sticky sessions, so that the HTTP requests of a Socket.IO session are routed to the same worker
使用自定义适配器，以便数据包广播到所有客户端，即使它们连接到另一个工作线程
¥use a custom adapter, so that the packets are broadcast to all clients, even if they are connected to another worker

为了实现这一目标，@socket.io/pm2 包含两个附加软件包：

¥In order to achieve this, @socket.io/pm2 includes two additional packages:

与 pm2 的唯一区别来自这次提交：

¥The only difference with pm2 comes from this commit:

God 进程现在创建自己的 HTTP 服务器并将 HTTP 请求路由到正确的工作进程
¥the God process now creates its own HTTP server and routes the HTTP requests to the right worker
God 进程还在 worker 之间中继数据包，以便 io.emit() 正确到达所有客户端
¥the God process also relays the packets between the workers, so that io.emit() correctly reaches all clients

请注意，如果你有多个主机，每个主机都运行 PM2 集群，则必须使用另一个适配器，例如 Redis 适配器。

¥Please note that if you have several hosts each running a PM2 cluster, you will have to use another adapter, like the Redis adapter.

复刻的源代码可以在此处找到。我们将尽力密切关注 pm2 软件包的发布。

¥The source code of the fork can be found here. We will try to closely follow the releases of the pm2 package.

安装​

用法​

工作原理​

安装

用法

工作原理