生产环境配置与调优

生产环境配置与调优

Express作为Node.js最流行的Web框架之一，在生产环境中需要特别关注性能、安全性和稳定性。合理的配置和调优能显著提升应用吞吐量，降低响应延迟，同时保障系统安全。

环境变量管理

生产环境必须使用环境变量存储敏感配置，避免硬编码。推荐使用dotenv库管理环境变量：

require('dotenv').config();

const express = require('express');
const app = express();

const PORT = process.env.PORT || 3000;
const DB_URI = process.env.MONGODB_URI;

app.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
});

.env文件示例：

PORT=8080
MONGODB_URI=mongodb://user:pass@host:port/db
NODE_ENV=production

性能优化中间件

启用Gzip压缩

使用compression中间件减少传输数据量：

const compression = require('compression');

app.use(compression({
  level: 6, // 压缩级别1-9
  threshold: 10 * 1024 // 大于10KB才压缩
}));

静态资源缓存

设置长期缓存策略减少重复请求：

const expressStaticGzip = require("express-static-gzip");

app.use("/static", expressStaticGzip("public", {
  enableBrotli: true,
  orderPreference: ["br", "gzip"],
  setHeaders: (res) => {
    res.setHeader("Cache-Control", "public, max-age=31536000");
  }
}));

集群模式部署

利用多核CPU启动集群：

const cluster = require('cluster');
const numCPUs = require('os').cpus().length;

if (cluster.isMaster) {
  for (let i = 0; i < numCPUs; i++) {
    cluster.fork();
  }
} else {
  const app = require('./app');
  app.listen(3000);
}

日志记录优化

生产环境需要结构化日志：

const winston = require('winston');
const expressWinston = require('express-winston');

app.use(expressWinston.logger({
  transports: [
    new winston.transports.File({
      filename: 'logs/request.log',
      level: 'info',
      format: winston.format.combine(
        winston.format.timestamp(),
        winston.format.json()
      )
    })
  ],
  meta: true,
  msg: "HTTP {{req.method}} {{req.url}}",
  expressFormat: true
}));

安全加固配置

设置安全头部

使用helmet中间件增强安全性：

const helmet = require('helmet');

app.use(helmet({
  contentSecurityPolicy: {
    directives: {
      defaultSrc: ["'self'"],
      scriptSrc: ["'self'", "trusted.cdn.com"]
    }
  },
  hsts: {
    maxAge: 63072000,
    includeSubDomains: true,
    preload: true
  }
}));

请求频率限制

防止暴力攻击：

const rateLimit = require('express-rate-limit');

const apiLimiter = rateLimit({
  windowMs: 15 * 60 * 1000,
  max: 100,
  message: 'Too many requests from this IP'
});

app.use('/api/', apiLimiter);

数据库连接优化

使用连接池提高数据库访问效率：

const { Pool } = require('pg');

const pool = new Pool({
  connectionString: process.env.DATABASE_URL,
  max: 20,
  idleTimeoutMillis: 30000,
  connectionTimeoutMillis: 2000
});

app.get('/data', async (req, res) => {
  const client = await pool.connect();
  try {
    const result = await client.query('SELECT * FROM large_table');
    res.json(result.rows);
  } finally {
    client.release();
  }
});

错误处理机制

生产环境需要完善的错误处理：

app.use((err, req, res, next) => {
  console.error(err.stack);
  
  if (req.accepts('json')) {
    res.status(500).json({
      error: 'Internal Server Error',
      requestId: req.id
    });
  } else {
    res.type('txt').send('Internal Server Error');
  }
});

process.on('unhandledRejection', (reason, promise) => {
  console.error('Unhandled Rejection at:', promise, 'reason:', reason);
});

process.on('uncaughtException', (err) => {
  console.error('Uncaught Exception:', err);
  process.exit(1);
});

性能监控与分析

集成APM工具监控应用性能：

const apm = require('elastic-apm-node').start({
  serviceName: 'express-app',
  serverUrl: 'http://apm-server:8200',
  captureExceptions: true,
  metricsInterval: '30s'
});

app.use(apm.middleware.connect());

模板引擎优化

如果使用模板引擎，启用缓存：

app.set('view engine', 'pug');
app.set('view cache', true);
app.enable('view cache');

负载均衡配置

Nginx反向代理示例配置：

upstream nodejs_backend {
  server 127.0.0.1:3000;
  server 127.0.0.1:3001;
  keepalive 64;
}

server {
  listen 80;
  server_name example.com;
  
  location / {
    proxy_pass http://nodejs_backend;
    proxy_http_version 1.1;
    proxy_set_header Connection "";
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
  }
}

内存泄漏排查

使用heapdump捕获内存快照：

const heapdump = require('heapdump');

setInterval(() => {
  if (process.memoryUsage().heapUsed > 500 * 1024 * 1024) {
    heapdump.writeSnapshot(`heap-${Date.now()}.heapsnapshot`);
  }
}, 60 * 1000);

持续集成部署

.github/workflows/deploy.yml示例：

name: Node.js CI

on:
  push:
    branches: [ main ]

jobs:
  build:
    runs-on: ubuntu-latest
    
    steps:
    - uses: actions/checkout@v2
    - name: Use Node.js
      uses: actions/setup-node@v2
      with:
        node-version: '16'
    - run: npm ci
    - run: npm test
    - run: npm run build
    
  deploy:
    needs: build
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - name: Deploy to Production
      uses: appleboy/ssh-action@master
      with:
        host: ${{ secrets.PRODUCTION_HOST }}
        username: ${{ secrets.PRODUCTION_USER }}
        key: ${{ secrets.PRODUCTION_SSH_KEY }}
        script: |
          cd /var/www/express-app
          git pull origin main
          npm install --production
          pm2 restart app