关于自定义Egg.js的请求级别日志详解

//config.default.js
exports.customLogger = {
 log: {
  file: 'appname.log',
  formatter: (message)=>{
   return `${message.time}${message.processid}` 
  }
 }
}

[ 'error', 'warn', 'info', 'debug' ].forEach(level => {
 const LEVEL = level.toUpperCase();
 ContextLogger.prototype[level] = function() {
 const meta = {
  formatter: contextFormatter,
  paddingMessage: this.paddingMessage,
 };
 this._logger.log(LEVEL, arguments, meta);
 };
});

module.exports = ContextLogger;

function contextFormatter(meta) {
 return meta.date + ' ' + meta.level + ' ' + meta.pid + ' ' + meta.paddingMessage + ' ' + meta.message;
}

//CoustomTransport.js
const FileTransport = require('egg-logger').FileTransport;
const moment = require('moment');

class CoustomTransport extends FileTransport {
 constructor(options, ctx) {
  super(options);
  this.ctx = ctx;
 }

 log(level, args, meta) {
  const prefixStr = this.buildFormat(level);
  for (let i in args) {
   if (args.hasOwnProperty(i)) {
    if (parseInt(i, 10) === 0) {
     args[i] = `${prefixStr}${args[i]}`;
    }
    if (parseInt(i, 10) === args.length - 1) {
     args[i] += '\n';
    }
   }
  }

  super.log(level, args, meta);
 }

 buildFormat(level) {
  const timeStr = `[${moment().format('YYYY-MM-DD HH:mm:ss.SSS')}]`;
  const threadNameStr = `[${process.pid}]`;
  const urlStr = `[${this.ctx.request.url}]`
  return `${timeStr}${threadNameStr}${urlStr}`;
 }

 setUserId(userId) {
  this.userId = userId;
 }
}

module.exports = CoustomTransport;

//CustomLogger.js
const Logger = require('egg-logger').Logger;
const CoustomTransport = require('./CoustomTransport.js');

module.exports = function(ctx){
 const logger = new Logger();
 logger.set('file', new CoustomTransport({
  level: 'INFO',
  file: 'app.log'
 }, ctx));
 return logger;
};

// app/extend/context.js
/*
* Context对象扩展
* */
const Logger = require('egg-logger').Logger;
const CoustomTransport = require('./CoustomTransport');
const CustomLogger = require('./CustomLogger');
module.exports = {
 get swLog() {
  return CustomLogger(this);
 }
};

// app/controller/home.js
module.exports = app => {
 class HomeController extends app.Controller {
  async index() {
   this.ctx.swLog.info('Hello World');
  }
 }
 return HomeController;
};