现在开始接手node端测试，有好多知识点，比如启动进程的命令，查看进程的命令都不是很清晰，现在具体来学习下～

前端最大的社区是GitHub，大家在这里分享代码，讨论问题，收集学习资源。大家需要依赖什么安装包从以前的去官网下载到去GitHub下载，还是很麻烦。这时候一个拥有三大美德的程序员 Isaac Z. Schlueter （以下简称 Isaaz）给出一个解决方案：用一个工具把这些代码集中到一起来管理吧！

这个工具就是他用 JavaScript （运行在 Node.js 上）写的 npm，全称是 Node Package Manager

NPM 的实现思路大概是这样的：

1. 买个服务器作为代码仓库（registry），在里面放所有需要被共享的代码
2. 发邮件通知 jQuery、Bootstrap、Underscore 作者使用 npm publish 把代码提交到 registry 上，分别取名 jquery、bootstrap 和 underscore（注意大小写）
3. 社区里的其他人如果想使用这些代码，就把 jquery、bootstrap 和 underscore 写到 package.json 里，然后运行 npm install jquery，npm 就会帮他们下载代码
4. 下载完的代码出现在 node_modules 目录里，可以随意使用了。

这些可以被使用的代码被叫做「包」（package），这就是 NPM 名字的由来：Node Package(包) Manager(管理器)。node包管理器。

新版的nodejs 已经集成了npm，所以安装nodejs的时候，npm也一并安装好了。

常用命令：

安装模块：npm install

卸载模块：npm uninstall 

更新模块：npm update 

在 NodeJS 项目中，会看到一个package.json，这个文件用来声明项目中使用的模块，这样在新的环境部署时，只要在 package.json 文件所在的目录执行npm install命令即可安装所需要的模块。

还有一些scripts脚本,可以执行一些命令，比如启动npm start

{
"name": "maimai_node",
"version": "0.0.0",
"private": true,
"scripts": {
"start": "DEBUG='app,body,rpc' gulp watch",
"pc": "DEBUG='app,body,rpc' gulp watch_pc",
"test": "DEBUG='app' mocha test/main.js --harmony -t 200000",
"dev": "DEBUG='' gulp watch",
"reload": "DEBUG='app,body,rpc' node --harmony --inspect app.js",
"dev:allocatememory": "DEBUG='app,body,rpc' gulp --max_old_space_size=4098 watch",
"growth": "DEBUG='app,body,rpc' gulp --gulpfile gulpfile.growth.js --max_old_space_size=4098 watch",
"build-lib": "node-gyp rebuild --directory native_lib",
"build-bundle": "webpack --config webpack.config.js --progress --display-optimization-bailout",
"lint": "CHANGED_LIST=`git diff-index --name-only HEAD | grep .js$`; if [[ $CHANGED_LIST ]]; then ./node_modules/.bin/eslint --fix `echo $CHANGED_LIST | xargs`; fi",
"precommit": "#npm run lint",
"watchNoBundle": "DEBUG='app,body' DEV_PATH=dev gulp --max_old_space_size=4098 watchNoBundle"
},
"dependencies": {
"autoprefixer": "6.0.3",
"autoprefixer-core": "6.0.1",
"babel": "6.5.2",
"babel-eslint": "^8.0.3",
"babel-plugin-transform-async-to-generator": "6.8.0",
"babel-polyfill": "6.9.1",
"babel-preset-es2015": "6.9.0",
"babel-preset-react": "6.11.1",
"babel-preset-stage-0": "6.5.0",
"babel-register": "6.9.0",
"babelify": "6.4.0",
"baobab": "2.0.1",
"base62": "1.1.0",
"bindings": "1.2.1",
"blob-util": "2.0.2",
"bluebird": "3.0.5",
"brfs": "1.4.1",
"bunyan": "1.8.2",
"canvas": "1.6.5",
"classnames": "^2.1.3",
"co": "4.6.0",
"co-child-process": "0.0.3",
"co-mocha": "1.1.2",
"co-request": "1.0.0",
"co-wechat-api": "3.8.2",
"co-wechat-oauth": "2.0.1",
"commander": "2.9.0",
"crc-32": "1.0.1",
"crypto-js": "^3.1.9-1",
"cssmin": "0.4.3",
"cuint": "0.2.0",
"date-utils": "1.2.17",
"debug": "2.2.0",
"detect-browser": "1.1.1",
"dtrace-provider": "0.8.5",
"echarts": "^4.0.4",
"echarts-for-react": "^2.0.8",
"email-validation": "0.1.2",
"emoji-strip": "^1.0.1",
"envify": "3.4.0",
"es6-promise": "3.0.2",
"event-stream": "3.3.2",
"eventemitter3": "^3.1.0",
"exenv": "^1.2.2",
"fastclick": "^1.0.6",
"find-remove": "1.0.1",
"form-data": "1.0.1",
"generic-pool": "2.2.0",
"gulp": "3.9.1",
"gulp-cssmin": "0.1.7",
"gulp-download": "0.0.1",
"gulp-imacss": "1.0.0",
"gulp-jade": "1.1.0",
"gulp-less": "3.0.3",
"gulp-nodemon": "2.0.4",
"gulp-postcss": "6.0.1",
"gulp-rename": "1.2.2",
"gulp-replace": "0.5.4",
"gulp-streamify": "1.0.2",
"gulp-uglify": "1.4.2",
"gulp-util": "3.0.6",
"gulp-watch": "4.3.5",
"gulp-zip": "3.1.0",
"heapdump": "0.3.7",
"highcharts": "^6.0.7",
"hls.js": "0.8.6",
"html2canvas": "^1.0.0-alpha.12",
"http-shutdown": "1.2.0",
"idcard": "4.1.0",
"imacss": "1.0.0",
"immutability-helper": "^2.9.0",
"in-view": "0.6.0",
"ioredis": "2.3.0",
"iscroll": "5.2.0",
"jade": "1.11.0",
"jade-loader": "0.8.0",
"jquery": "^3.3.1",
"js-base64": "2.3.2",
"json-loader": "0.5.4",
"jsonfile-promised": "0.0.1",
"jsonwebtoken": "5.4.0",
"klass": "1.4.1",
"koa": "1.2.4",
"koa-body": "1.4.0",
"koa-compose": "2.4.0",
"koa-cors": "0.0.16",
"koa-csrf": "2.3.0",
"koa-gzip": "0.1.0",
"koa-jade": "2.0.0",
"koa-mount": "1.3.0",
"koa-proxy": "0.4.1",
"koa-qs": "2.0.0",
"koa-rewrite": "1.1.0",
"koa-router": "5.2.3",
"koa-send": "3.1.0",
"koa-session": "3.3.1",
"koa-static": "1.4.9",
"koa-swig": "2.1.0",
"koa-views": "3.1.0",
"lodash": "^4.17.10",
"md5": "^2.2.1",
"md5-file-promise": "1.0.2",
"mobile-detect": "1.3.1",
"mocha": "2.3.3",
"modern-syslog": "^1.1.4",
"moment": "2.10.6",
"moment-mini": "2.18.1",
"mongoose": "4.4.12",
"mongoose-auto-increment": "5.0.1",
"mongoose-multitenant": "0.8.2",
"ms": "0.7.1",
"mysql": "2.14.1",
"nan": "2.6.2",
"nconf": "0.8.2",
"node-canvas-text": "1.0.2",
"node-fetch": "1.7.1",
"node-jsx": "0.13.3",
"node-rsa": "0.2.26",
"node-xml-lite": "0.0.5",
"nsqjs": "0.8.4",
"opentype.js": "0.7.1",
"pako": "0.2.8",
"platform": "^1.3.4",
"preload-js": "^0.6.3",
"prop-types": "15.6.0",
"protobufjs": "6.8.0",
"qiniu": "7.2.1",
"qrcode.react": "^0.8.0",
"qs": "6.5.1",
"radium": "^0.14.2",
"rapscallion": "^2.1.14",
"ratelimiter": "2.0.1",
"raven": "2.2.1",
"raw-body": "2.1.4",
"raw-loader": "0.5.1",
"react": "^15.6.1",
"react-addons-linked-state-mixin": "15.6.0",
"react-addons-pure-render-mixin": "15.6.0",
"react-autosuggest": "^9.3.4",
"react-bootstrap": "0.31.0",
"react-clipboard.js": "^1.1.3",
"react-countup": "^3.0.3",
"react-distpicker": "^1.0.1",
"react-dom": "15.6.1",
"react-fastclick": "^3.0.2",
"react-fullpage": "^0.1.18",
"react-helmet": "2.1.1",
"react-highcharts": "^16.0.2",
"react-id-swiper": "^1.6.8",
"react-infinite": "0.11.0",
"react-infinite-scroller": "1.0.13",
"react-iscroll": "2.0.3",
"react-lazyload": "^2.3.0",
"react-motion": "0.5.0",
"react-radio-group": "^3.0.3",
"react-scroll": "^1.7.10",
"react-side-effect": "1.0.2",
"react-slick": "^0.22.3",
"react-sticky": "5.0.0",
"react-swipe": "3.0.0",
"react-swipeable-views": "^0.12.4",
"react-swipeable-views-core": "^0.12.11",
"react-swipeable-views-utils": "^0.12.13",
"react-tap-event-plugin": "^2.0.1",
"react-tappable": "^1.0.4",
"react-timer-mixin": "0.13.3",
"react-transition-group": "^2.3.1",
"redis": "2.7.1",
"request": "2.65.0",
"retry": "0.8.0",
"rmc-picker": "^5.0.5",
"rmc-pull-to-refresh": "^1.0.11",
"routes": "2.1.0",
"save": "^2.3.2",
"semver": "5.0.3",
"simditor": "2.3.6",
"sphinxapi": "1.1.1",
"style-loader": "0.13.1",
"styled-components": "^3.4.10",
"superagent": "3.5.2",
"swig": "1.4.2",
"swipe-js-iso": "2.0.1",
"tiny-cookie": "0.5.4",
"truncate": "2.0.0",
"underscore": "1.8.3",
"underscore.string": "3.2.2",
"unicode": "^0.6.1",
"url-loader": "^1.1.2",
"urlsafe-base64": "1.0.0",
"uuid": "2.0.1",
"vinyl-source-stream": "1.1.0",
"watchify": "3.6.1",
"webpack-stream": "3.2.0",
"weixin-js-sdk": "1.2.0",
"weixin-pay": "1.1.6",
"whatwg-fetch": "0.10.0",
"zepto-webpack": "1.2.1"
},
"devDependencies": {
"aliasify": "2.0.0",
"babel-core": "6.26.0",
"babel-loader": "7.1.2",
"babel-preset-env": "1.6.1",
"colors": "^1.2.1",
"css-loader": "0.28.4",
"eslint": "^4.13.0",
"eslint-plugin-react": "^7.5.1",
"gulp-imagemin": "^4.1.0",
"gulp-plumber": "^1.2.0",
"happypack": "^4.0.0",
"hard-source-webpack-plugin": "0.11.1",
"husky": "^0.14.3",
"less": "^2.5.3",
"less-loader": "^4.1.0",
"react-tappable": "^1.0.4",
"stylelint": "^9.9.0",
"webpack": "3.10.0",
"webpack-bundle-analyzer": "2.8.2",
"webpack-livereload-plugin": "^1.2.0",
"webpack-merge": "4.1.1"
}
}

package.json

启动：npm start    就是执行 DEBUG='app,body,rpc' gulp watch

重启：npm restart

停止：npm stop

有时候采用上面的方式启动node服务时，会报out of memory的错。那么我们可以用下面的命令。

npm run dev:allocatememory  就如package.json所写，最大化内存。

我们还经常看见cnpm，这个是淘宝镜像。

由于国内连npm服务是比较慢的，所以淘宝就自己出了一个镜像，同步频率是10分钟一次，保证package跟npm一致。

$ npm install -g cnpm --registry=https://registry.npm.taobao.org

安装后就可以cnpm代替npm了。比如：cnpm install

PM2(process manager)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

常见命令：

$ npm install pm2 -g # 命令行安装 pm2

$ pm2 start app.js -i 4 #后台运行pm2，启动4个app.js

# 也可以把'max' 参数传递给 start

# 正确的进程数目依赖于Cpu的核心数目

$ pm2 start app.js --name my-api # 命名进程

$ pm2 list # 显示所有进程状态

$ pm2 monit # 监视所有进程

$ pm2 logs # 显示所有进程日志

$ pm2 stop all # 停止所有进程

$ pm2 restart all # 重启所有进程

$ pm2 reload all # 0秒停机重载进程 (用于 NETWORKED 进程)

$ pm2 stop 0 # 停止指定的进程

$ pm2 restart 0 # 重启指定的进程

$ pm2 startup # 产生 init 脚本 保持进程活着

$ pm2 web # 运行健壮的 computer API endpoint (http://localhost:9615)

$ pm2 delete 0 # 杀死指定的进程

$ pm2 delete all # 杀死全部进程

运行进程的不同方式：

$ pm2 start app.js -i max # 根据有效CPU数目启动最大进程数目

$ pm2 start app.js -i 3 # 启动3个进程

$ pm2 start app.js -x #用fork模式启动 app.js 而不是使用 cluster

$ pm2 start app.js -x -- -a 23 # 用fork模式启动 app.js 并且传递参数 (-a 23)

$ pm2 start app.js --name serverone # 启动一个进程并把它命名为 serverone

$ pm2 stop serverone # 停止 serverone 进程

$ pm2 start app.json # 启动进程, 在 app.json里设置选项

$ pm2 start app.js -i max -- -a 23 #在--之后给 app.js 传递参数

$ pm2 start app.js -i max -e err.log -o out.log # 启动 并 生成一个配置文件

你也可以执行用其他语言编写的app ( fork 模式):

$ pm2 start my-bash-script.sh -x --interpreter bash

$ pm2 start my-python-script.py -x --interpreter python