How to reconnect to the database in case of a connection break without restarting the application?

Question

MongoDB

At the moment, everything is quite trivial for me:

// Модуль бд
var mongoose = require('mongoose')

module.exports.connect = () => {
  mongoose.connect('mongodb://....', 
  { 
    useNewUrlParser: true, 
    useUnifiedTopology: true
  }
  )
  var db = mongoose.connection
  db.on('error', console.error.bind(console, 'connection error'))
  db.once('open', () => {
    console.log('Connection Succeeded')
  })
  return db
}

// app.js
const mongodb_conn_module = require('./config/mongoConnection')
const db = mongodb_conn_module.connect()

The code is frankly crappy, but I wrote it a year ago, when I just sat down to master the node and js in general) The
question is how to handle the error event correctly? It happens stably when the connection breaks. Since the base is in the cloud, the probability of a gap is extremely high. Mongoose, it seems, has the keepAlive: true parameter by default, but it does not save something.

Answer 1

Add options to mongoose.connect

reconnectTries: 2, // попытки реконнекта
reconnectInterval: 1000, //каждую секунду
connectTimeoutMS: 2000, // после 2 секунд ожидания соединения пытаться снова или сбрасывать

Then catch events through

db.on('reconnected', function(){ console.log('reconnected successfully'});
db.on('reconnectFailed', function (error){
//Что делать если все попытки реконнекта провалились
});