PM2与Babel踩坑

PM2与Babel踩坑

PM2是node进程管理工具，可以利用它来简化很多node应用管理的繁琐任务，如性能监控、自动重启、负载均衡等，而且使用非常简单。官方文档 中文快速入门

Babel 是一个工具链，主要用于将 ECMAScript 2015+ 版本的代码转换为向后兼容的 JavaScript 语法，以便能够运行在当前和旧版本的浏览器或其他环境中。官方文档 中文

项目背景

node服务，采用es6语法，import模块导入、async/await语法糖、箭头函数等等,以及koa-swagger-decorator自动生成swagger.json(api接口的注解,通过注解在swagger页面展现出每个api接口的详细描述)
项目部署采用pm2，集群　+ 环境区分（开发、测试、生产）

babel

如果使用koa-swagger-decorator,在github仓库中说明了使用时依赖babel-plugin-transform-decorators-legacy这个babel插件,但是This plugin is specifically for Babel 6.x. If you're using Babel 7, this plugin is not for you.(npm原话),如果你使用Babel7的话,你可以使用@babel/plugin-proposal-decorators, 但是在.babelrc中必须如下设置

"plugins": [
    ["@babel/plugin-proposal-decorators", { "legacy": true }],
  ]

好, 我们用babel-7.4.0试一下 安装babel依赖

"dependencies": {
    "@babel/cli": "^7.4.4",
    "@babel/core": "^7.4.5",
    "@babel/plugin-proposal-decorators": "^7.4.4",
    "@babel/plugin-transform-runtime": "^7.4.4",
    "@babel/preset-env": "^7.4.5",
    "@babel/runtime": "^7.4.5",
    "@babel/runtime-corejs3": "^7.4.5",
    ...你的其他依赖
}

完整的.babelrc配置

{
    "presets": [
        ["@babel/preset-env", {
            "targets": {"node": true},
            } 
        ]
    ],
    "plugins": [
    // 可以做到最小化加载babel-polyfill减小项目体积,虽然在node环境中无所谓
        ["@babel/plugin-transform-runtime", {
            "corejs": 3 // 可选 false | 2 | 3
        }],
        ["@babel/plugin-proposal-decorators", { "legacy": true }],
    ]
}

ok 通过上述的babel安装及.babelrc设置试一试转码

• 入口文件app.js

import config from './config'
import eurekaServer from './eureka'
import {connectDB} from './db'
import Koa from 'koa';
import router from './swagger/index'
import responseHandler from './middleware/response_handle'
import mqServer from './mq/MQServer'
import cron from './cron'

const koaCors = require('koa-cors');
const koaBody = require('koa-body');
const app = new Koa();
async function initApp (){
    //连接mysql
    await connectDB();
    //连接mq
    await mqServer.connect();
    //启动Eureka
    await eurekaServer.start();
    //Eureka心跳
    app.use(eurekaServer.info()); 
    //启动定时拉取微信公众号图文及统计任务
    await cron();
    app.use(async function (ctx, next) {
        ctx.response.get("Access-Control-Allow-Origin", "*");
        ctx.response.set("Access-Control-Allow-Headers", "Content-Type,Content-Length,Accept,X-Requested-With,token");
        ctx.response.set("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");
        if (ctx.request.method == "OPTIONS") ctx.response.status = 200;
        await next();
    })         
            
    //restful 中间件
    app.use(responseHandler.restify());
    app.use(koaCors());
    app.use(koaBody({ multipart: true }));
    app.use(router.routes());
    app.use(router.allowedMethods());
    app.listen(config.port, _ =>  console.log(`app started at port ${config.port}`));
    return app;
}

initApp()
.catch(err => `未知服务错误：${err.message}`)

• 项目目录

src/
 'app.js',
 'config/',
 'controllers/',
 'cron/',
 'dao/',
 'db/',
 'domain/',
 'eureka/',
 'middleware/',
 'model/',
 'mq/',
 'repository/',
 'swagger/',
 'util/' 
 

• 下一步 在package.json 中build

"scripts": {
  "build": "babel src -d dist"
},

• 启动 node dist/app.js

pan@ubuntu18:~/disk/panyanan/project/website_node$ node dist/app.js 
加载local环境的配置文件成功
sequelize deprecated The logging-option should be either a function or false. Default: console.log node_modules/sequelize/lib/sequelize.js:193:13
Executing (default): SELECT 1+1 AS result
connect MQ queues: {"queueNames":["q.upa_logs_node"],"connectOption":{"vhost":"OuterHost","hostname":"192.168.10.200","port":5672,"username":"admin","password":"123456"}}
registered with eureka:  NTDWebsit/192.168.10.49:8989
eureka注册成功
koa deprecated Support for generators will be removed in v3. See the documentation for examples of how to convert old middleware https://github.com/koajs/koa/blob/master/docs/migration.md dist/app.js:47:7
app started at port 8989

用babel-6.0+试一下 安装依赖

 "dependencies": {
   "babel-cli": "^6.26.0",
   "babel-core": "^6.26.3",
   "babel-preset-env": "^1.7.0",
   "babel-plugin-transform-decorators-legacy": "^1.3.5",
   "babel-polyfill": "^6.26.0",
   ...其它依赖
   }
   

.babelrc

{
   "presets": [
       ["env", {
               "targets": {"node": true},
               //会加载所有polyfill
               "useBuiltIns":true
           }
       ]
   ],
   "plugins": [
       "transform-decorators-legacy"
   ]
}

转码

"scripts": {
"build": "babel src -d dist"
  },
  

bable6中转码过程会显示所有被转码的文件

> selected@1.0.0 build /home/pan/disk/panyanan/project/website_node
> babel src -d dist

src/app.js -> dist/app.js
src/config/config.dev.js -> dist/config/config.dev.js
src/config/config.local.js -> dist/config/config.local.js
src/config/config.pred.js -> dist/config/config.pred.js
src/config/config.prod.js -> dist/config/config.prod.js
src/config/index.js -> dist/config/index.js
src/controllers/article_controller.js -> dist/controllers/article_controller.js
src/controllers/category_controller.js -> dist/controllers/category_controller.js
src/cron/articleTask.js -> dist/cron/articleTask.js
src/cron/index.js -> dist/cron/index.js
src/dao/article_dao.js -> dist/dao/article_dao.js
src/dao/article_day_summary_dao.js -> dist/dao/article_day_summary_dao.js
src/dao/category_dao.js -> dist/dao/category_dao.js
src/db/index.js -> dist/db/index.js
src/domain/article_domain.js -> dist/domain/article_domain.js
src/domain/category_domain.js -> dist/domain/category_domain.js
src/eureka/index.js -> dist/eureka/index.js
src/middleware/response_handle.js -> dist/middleware/response_handle.js
src/model/article_day_summary_model.js -> dist/model/article_day_summary_model.js
src/model/article_model.js -> dist/model/article_model.js
src/model/category_model.js -> dist/model/category_model.js
src/mq/MQServer.js -> dist/mq/MQServer.js
src/mq/UpalogsSendMsg.js -> dist/mq/UpalogsSendMsg.js
src/repository/article_day_summary_repository.js -> dist/repository/article_day_summary_repository.js
src/repository/article_repository.js -> dist/repository/article_repository.js
src/repository/category_repository.js -> dist/repository/category_repository.js
src/swagger/api.js -> dist/swagger/api.js
src/swagger/index.js -> dist/swagger/index.js
src/util/index.js -> dist/util/index.js

启动 node dist/app.js

pan@ubuntu18:~/disk/panyanan/project/website_node$ node dist/app.js 
加载local环境的配置文件成功
sequelize deprecated The logging-option should be either a function or false. Default: console.log node_modules/sequelize/lib/sequelize.js:193:13
Executing (default): SELECT 1+1 AS result
connect MQ queues: {"queueNames":["q.upa_logs_node"],"connectOption":{"vhost":"OuterHost","hostname":"192.168.10.200","port":5672,"username":"admin","password":"123456"}}
registered with eureka:  NTDWebsit/192.168.10.49:8989
eureka注册成功
koa deprecated Support for generators will be removed in v3. See the documentation for examples of how to convert old middleware https://github.com/koajs/koa/blob/master/docs/migration.md dist/app.js:59:9
app started at port 8989

ok 以上就是在node服务中使用babel转码的尝试,babel中的配置及插件很多.设置起来也很麻烦,需要耐心的阅读官方文档,及前辈们的博客,总结一下基本概念.

• babel-core 是babel的核心
• babel-preset-env 是针对环境设置不同的转码规则
• babel-polyfill,用于转码es6的api,比如Iterator、Generator、Set、Maps、Proxy、Reflect、Symbol、Promise等全局对象，以及一些定义在全局对象上的方法（比如Object.assign）都不会转码。babel 默认只转换语法 如() => {}
• babe-runtime可以做到按需转码,减少转码后的代码体积
• 利用useBuiltIns选项,可以不必在代码中require(bable-polyfill)
• 通过提前build的方式可以提高性能,相比之下 babel-node则很重,内存使用率很高
• babel6/bable7的使用有很大不同,无论是.babelrc配置还是插件

PM2

pm2 基础命令可以看看官方文档
这里说一下与babel相关的小坑,如果采用上面的build的方式是没有任何问题的,只需要修改配置文件的目录为转码之后的启动文件 apps.config.js

pm2 start apps.config.js 启动
如果设置env 则需要加上参数如 pm2 start apps.config.js --env prod
则process.env.NODE_ENV == 'production'

module.exports = {
  apps : [{
    name: 'websit_node',
    script: './dist/app.js',
    args: 'one two',
    instances: 1,
    autorestart: true,
    watch: false,
    max_memory_restart: '1G',
    env: {
      NODE_ENV: 'local'
    },
    env_dev: {
      NODE_ENV: 'development'
    },
    env_pred: {
      NODE_ENV: 'pred'
    },
    env_prod: {
      NODE_ENV: 'production'
    }
  }],
};

如果采用babel-node方式启动,则需要增加解释器配置

module.exports = {
  apps : [{
    name: 'websit_node',
    script: './src/app.js',
    args: 'one two',
    instances: 1,
    autorestart: true,
    watch: false,
    max_memory_restart: '1G',
    interpreter: 'node_modules/babel-cli/bin/babel-node.js',
    env: {
      NODE_ENV: 'local'
    },
    env_dev: {
      NODE_ENV: 'development'
    },
    env_pred: {
      NODE_ENV: 'pred'
    },
    env_prod: {
      NODE_ENV: 'production'
    }
  }],
};

注意:

• script字段则是未转码的项目入口文件,
• interpreter字段,使用babe-node作为编译器执行script指定的入口文件,
• babel-node启动的方式在pm2中不支持集群模式,就是说instances字段只能写1,而提前build的方式则没有这个限制.