Why not use Nodemon for production Node.js apps?

Introduction

Nodemon has become a staple in the toolset of Node.js developers for its ability to watch the filesystem for changes and automatically restart the application during the development process. However, when it comes to production environments, it is important to understand that the benefits it offers for development do not translate effectively. This article explores the reasons why Nodemon should not be employed in production for Node.js applications and provides code examples outlining best practices for running your Node.js app in a production environment.

Nodemon Basics

The tool is designed to simplify the development process by watching for any changes made in the source code and subsequently restarting the Node.js app automatically. Here’s a basic usage example:

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  res.send('Hello world!');
});

app.listen(3000, () => {
  console.log('Server is listening on port 3000');
});

To start this script with Nodemon: install Nodemon as a development dependency and run it through your Node.js script:

npm install --save-dev nodemon
npx nodemon app.js

Environmental Considerations

In a production environment, stability, uptime, monitoring, and security take precedence. Let’s dissect the factors that lead developers to avoid Nodemon in production.

Reliability and Risks

Using Nodemon in production might create unwanted risks. The primary function of Nodemon is to restart the server upon file changes. This feature is unnecessary in production, where stability is far more crucial, and frequent restarts can lead to unscheduled downtime and degraded user experience.

Monitoring

Applications in production should implement robust monitoring tools. While Nodemon can display console logs effectively, it lacks advanced monitoring capabilities that are essential to maintain the health and performance of a production system.

Memory Leaks and Performance

Restarts via Nodemon do not handle potential memory leaks or optimization concerns inherit to your production application. Each time your Node.js process restarts, it doesn’t signify releasing all the system resources properly, potentially leading to performance degradation.

Production Alternatives

Tools like PM2, forever, or monitored installations using Docker and Kubernetes offer a more stable and robust solution, fit for production, over what Nodemon can provide. Here’s how we might use PM2:

npm install pm2 -g
pm2 start app.js --name my-app
pm2 status

Through additional modules, PM2 can provide critical features for production workloads:

• load balancing
• monitoring memory and CPU usage
• cluster mode for horizontal scaling
• graceful start and shutdown

Although not as straightforward, using container orchestrators like Kubernetes can provide excellent control over your deployment, scaling, and operations strategies:

kubectl run my-app --image=your-image --replicas=3
kubectl get pods

Advanced Production Patterns

Employing other advanced strategies while deploying to production includes:

• Zero-downtime deployments
• Canary releases
• Blue-green deployment
• Autoscaling

Implementation Best Practices

Including coding patterns and best practices in your Node.js application can improve your overall stability and performance.

Utilizing async/await:

app.get('/async', async (req, res) => {
  const data = await fetchSomeData();
  res.send(data);
});

Implement module level caching or smartly setting reuse connections can minimize performance bottlenecks due to process reloads:

let myCachedModule;

function loadModule() {
  if (!myCachedModule) {
    myCachedModule = computeHeavyResource();
  }
  return myCachedModule;
}

Incorporate environment variables for finer control of different production and development settings:

const DATABASE_URL = process.env.DATABASE_URL || 'mongodb://localhost/myapp';

Summary

The context surrounding the production deployment of Node.js applications is significantly different from the developer’s environment, where tools like Nodemon shine. For robust, scalable, and reliable production operations, it’s preferable to utilize tailor-made solutions such as PM2, Docker, or Kubernetes over Nodemon. Building your application with production in mind, right from the start, ensures a seamless transition when taking your project to the next level.

While Nodemon remains an invaluable tool for development, its purpose and application are rightly confined to the development stage. This understanding is key to maintaining the much sought-after stability and high performance of your production Node.js applications.