nodejs 服务器实现负载均衡

server.js

const express = require('express');
const { createProxyMiddleware } = require('http-proxy-middleware');
const axios = require('axios');const app = express();// 定义后端服务列表
const services = [{ target: 'http://localhost:3001' },{ target: 'http://localhost:3002' }
];// 检查服务存活性
async function isServiceAlive(target) {try {const response = await axios.get(target, { timeout: 2000 });return response.status === 200;} catch (error) {console.error(`Service at ${target} is not alive:`, error.message);return false;}
}// 获取活跃的服务
async function getActiveServices() {const checkPromises = services.map(async (service) => {const isAlive = await isServiceAlive(service.target);return isAlive ? service : null;});const results = await Promise.all(checkPromises);return results.filter(service => service);
}// 使用负载均衡中间件
app.use(async (req, res, next) => {const activeServices = await getActiveServices();if (activeServices.length > 0) {const randomService = activeServices[Math.floor(Math.random() * activeServices.length)];createProxyMiddleware({target: randomService.target,changeOrigin: true,onError: (err, req, res) => {console.error(`Proxy error: ${err.message}`);res.status(502).send('Bad Gateway');}})(req, res, next);} else {res.status(503).send('No available services');}
});// 启动负载均衡服务器
const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {console.log(`Load balancer is running on http://localhost:${PORT}`);
});

server1.js

const express = require('express');
const app = express();
const path = require("path")
app.use(express.static(path.join(__dirname, 'public')));const PORT = 3001;
app.listen(PORT, () => {console.log(`Server 1 is running on http://localhost:${PORT}`);
});

 server2.js

const express = require('express');
const app = express();
const path = require("path")
app.use(express.static(path.join(__dirname, 'public')));const PORT = 3002;
app.listen(PORT, () => {console.log(`Server 2 is running on http://localhost:${PORT}`);
});