Managing Connections with the MongoDB Node.js Driver

Managing Connections with the MongoDB Node.js Driver

Managing Connections with the MongoDB Node.js Driver - The MongoDB Node.js driver is very good about handling connection issues automatically. If you lose a node in your replica set or you restart your single server, the driver will usually recover on its own with no external help needed.

Too often, MongoDB REST API developers don't think about handling database outages until they have an outage in production. Usually you can get away with this because version 2.x of the MongoDB Node.js driver does most of the work for you: it handles attempting to reconnect and can buffer operations for you so you don't get errors during a temporary outage. However, the MongoDB Node.js driver has a lot of tunable options and corresponding subtleties that you need to be aware of. In this article, I'll cover the basics of what happens when your backend MongoDB topology goes down for single server and replica sets, so you can configure the driver to do the right thing for your use case.

Handling Single Server Outages

The  mongodb-topology-manager npm package is indispensible for testing MongoDB connection logic. This lib can stop and start MongoDB servers, replica sets, and sharded clusters from Node.js. The  MongoDB driver Node.js uses it for testing internally.

First, let's see what happens when the MongoDB server that the driver is connected to shuts down. The db  handle the driver gives you emits several events, including 'close' when it loses connection and 'reconnect' when it reconnects. The driver attempts to reconnect by default, but this is a tuneable option. Note that these events only get fired for a single server or mongos, not when you're connected to a replica set (more on that later). Here's a script that uses the topology manager to stop/start a MongoDB instance so you can see these events actually fire:

const { Server } = require('mongodb-topology-manager');
const mongodb = require('mongodb');

run().catch(error => console.error(error));

async function run() {
  // Start a single server on port 27000 whose `dbpath` is in the
  // data directory in the current directory
  // Note that this requires a `mongod` executable in your PATH variable
  const server = new Server('mongod', {
    dbpath: `${__dirname}/data/db/27000`,
    port: 27000
  await server.start();
  console.log('Server started...');

node.js node

What is Geek Coin

What is GeekCash, Geek Token

Best Visual Studio Code Themes of 2021

Bootstrap 5 Tutorial - Bootstrap 5 Crash Course for Beginners

Nest.JS Tutorial for Beginners

Hello Vue 3: A First Look at Vue 3 and the Composition API

Hire Top Node JS Developers | Best Node.js Development Company India

Hire dedicated Node JS developers & programmers in India for custom full-stack NodeJS web development projects on hourly/full-time basis. Strict NDA, 16+ years exp & 2500+ clients|450+ Experts

Hire Dedicated Node.js Developers - Hire Node.js Developers

Get business-centric Node.Js development services from expert Node.JS developers. We have expertise in developing & maintaining Node JS apps as per the business requirements.

Node JS Development Company| Node JS Web Developers-SISGAIN

SISGAIN is the top rated node js development company providing professional services on node js web and mobile development.

Why use Node.js for Web Development? Benefits and Examples of Apps

Get Node.js developers & programmers, and dedicated Node coders in India with average 5 years of experience. 15+ Yrs Exp, 500+ Staff, 13800+ Projects, 6800+ Clients.

Node JS Development Company | Hire Node.js Developers

Looking to hire Node js developers? One of the top Node js development companies in India & USA offers cost-effective Node js web development services.