Monitoring NodeJS APIs is an essential part of developing and maintaining robust and reliable applications. One of the most popular tools for this task is PM2, a production process manager for Node.js applications that has a built-in load balancer. It lets you keep your applications active forever, reload them without downtime, helps you create an application cluster, and much more.
Why PM2?
PM2 is a powerful tool that helps manage and maintain Node.js applications in production. It provides an easy way to manage applications, monitor their status and resources, and automatically restart applications if they fail. Furthermore, PM2 can also be configured to automatically launch your applications at system startup.
Installing PM2
To start using PM2, you need to install it on your system. This can easily be done with npm, the Node.js package manager, using the following command:
npm install pm2 -g
This command installs PM2 globally on your system so you can use it with any application.
Using PM2 to start your application
Once PM2 is installed, you can use it to start your Node.js application with the following command:
pm2 start app.js
Where 'app.js' is your application's input file. When you start your application with PM2, it automatically keeps it active and restarts the application if it fails.
Monitoring your application
One of the key features of PM2 is the ability to monitor your application in real time. This includes monitoring CPU usage, memory, and other key metrics. You can access this information using the following command:
pm2 monitor
This command opens a real-time monitoring interface where you can see the status of your applications and system resources.
Managing applications with PM2
PM2 provides a number of useful commands for managing your applications. For example, you can stop an application with the following command:
pm2 stop app
Where 'app' is the name of your application. Similarly, you can restart an application with the following command:
pm2 restart app
Also, you can reload an application (i.e., safely restart without downtime) with the following command:
pm2 reload app
PM2 also allows you to exclude an application from the list of managed applications with the following command:
pm2 delete app
Conclusion
PM2 is a powerful tool for managing and monitoring Node.js applications. It provides a number of useful features that make it easier to keep your applications active, monitor their status and resources, and manage your applications in an efficient manner. If you are developing Node.js applications, you should definitely consider using PM2.
I hope this chapter has given you a good overview of monitoring NodeJS APIs with PM2. In the next chapter, we'll explore more about optimizing the performance of your NodeJS API.
