Save logs in log files

// app.js
var logger = require('morgan');
var fs = require('fs')
var logDirectory = path.join(__dirname, 'log')
fs.existsSync(logDirectory) || fs.mkdirSync(logDirectory)
var accesLogStream = FileStreamRotator.getStream({
  date_format: 'YYYYMMDD',
  filename: path.join(logDirectory, 'access-%DATE%.log'),
  frequency: 'daily',
  verbose: false
})
app.use(logger(logger.compile(`[joke] :req[User-Agent] :req[Referer]`), {stream: accesLogStream}))

// Run Results
// Request several times using postman
[joke] PostmanRuntime/7.15.2 -
[joke] PostmanRuntime/7.15.2 -
[joke] PostmanRuntime/7.15.2 -
[joke] PostmanRuntime/7.15.2 http://localhost:3000/dish

Save logs in mongodb

// models/log.js
let {Schame} = {require('mongoose')}
let Log = new Schema({
  userAgent: {
    type: String,
    default: ''
  },
  referrer: {
    type: String,
    default: ''
  }
})
modole.exports = mongoose.model('Log', Log)

// app.js
var logger = require('morgan');
var log = require('./models/log.js')
var writeToDB = {
  write: function (line) {
    var [, ua, re] = line.split(' ')
    var ele = new Log({
      userAgent: ua,
      referrer: re
    })
    ele.save(err => {
      if (err) {
        console.log('err', err)
      }
    })
  }
}
/*
morgan The source code for is written like this
stream.write(line + '\n')
So the write property of the stream property value specified for morgan is how the log is saved to the data
 */
app.use(logger(logger.compile(`[joke] :req[User-Agent] :req[Referer]`), {stream: writeToDB}))

Log a bug

The following error occurred when writing the log to mongodb:'E11000 duplicate key error collection: confusion.logs index: userAgent_1 DUP key: {: null}'
The solution I looked for online was db.addresses.createIndex ({"xmpp_id": 1}, {sparse: true}) which I didn't understand at the time.The problem was solved in a very violent way.The methods are as follows:

1. Open mongodb's compass and open the Indexes panel for the corresponding collection.Remove index from error message.
2. Open the Documents panel for the corresponding collection.Deleted index document without error message.(Don't have to stop using this method!!)