Once our Express application is in production, it is crucial to have tools and strategies to monitor its status and ensure it functions correctly in the long term. Monitoring allows us to detect performance issues, failures, and errors before they affect users. In this chapter, we will learn how to implement an effective monitoring system and how to keep our application updated and secure.

Performance Monitoring

Monitoring the performance of an Express application is essential to identify bottlenecks and improve user experience. We can use tools like PM2 and New Relic to get real-time metrics on CPU usage, memory, response times, and more.

Using PM2 for Monitoring

PM2 is a process manager for Node.js that facilitates running applications in production and provides an integrated monitoring tool.

Installing PM2

First, we install PM2:

bash

Starting and Monitoring the Application with PM2

We can start our application with PM2 and enable real-time monitoring as follows:

bash

PM2 also allows logging, restarting the application in case of errors, and running in cluster mode to improve performance on multicore servers.

Viewing Logs with PM2

bash

External Monitoring with New Relic

New Relic is an external tool that offers advanced real-time application monitoring, including performance metrics, transaction monitoring, and automated alerts.

Integrating New Relic

To integrate New Relic into an Express application, we first install the New Relic package:

bash

Then, create a newrelic.js file in the root directory and configure our application with the license key provided by New Relic:

javascript

Error Monitoring

Error monitoring is key to identifying and resolving issues before they affect users. Tools like Sentry and Loggly allow us to capture, log, and analyze errors from our application.

Using Sentry for Error Monitoring

Sentry is a platform that captures exceptions and errors in real-time, allowing developers to resolve issues more quickly.

Installing Sentry

First, we install the Sentry package:

bash

Configuring Sentry

Then, set up Sentry in our Express application to capture errors:

javascript

Log Analysis with Loggly

Loggly is another tool that centralizes and analyzes the logs generated by our application. It allows us to search for error patterns and get real-time alerts when failures occur.

Integration with Loggly

We can integrate Loggly into our application using the winston-loggly-bulk library, which connects to Loggly to automatically log events.

bash

Then, configure Winston to use Loggly as a log destination:

javascript

Maintenance and Updates

Keeping our application updated and secure is essential to ensure it functions correctly in the long term. Below we will see some key strategies for maintaining and updating Express applications.

Updating Dependencies

Ensure to keep project dependencies updated to avoid security vulnerabilities and benefit from new features. You can use npm outdated to list dependencies that need updating:

bash

To update a specific dependency, use the following command:

bash

Monitoring Vulnerabilities

Tools like npm audit allow automatic verification of security vulnerabilities in project dependencies.

bash

If there are vulnerabilities, you can try to fix them automatically with:

bash

Backups and Restoration

Keeping regular backups of databases and configuration files is essential to ensure recovery in case of a serious system failure or attack.

Backup Strategies

1. Automate backups: Use automation tools to create periodic backups of the database and application files.
2. Secure storage: Ensure that backups are securely stored in a separate location, such as in the cloud.
3. Restoration tests: Regularly test the restoration of backups to ensure that the process works correctly.

Best Practices for Monitoring and Maintenance

1. Set up alerts: Set up alerts in tools like Sentry or New Relic to receive immediate notifications when errors or performance issues occur.
2. Document procedures: Ensure that the development and operations team has clear documentation on how to perform maintenance and troubleshoot in production.
3. Regular review: Regularly review performance metrics and logs to detect potential issues before they affect users.
4. Keep dependencies updated: Regularly update dependencies and conduct security audits to prevent vulnerabilities.

Conclusion

In this chapter, we explored how to monitor and maintain Express applications in production using tools like PM2, Sentry, Loggly, and New Relic. Constant monitoring and regular maintenance are essential to ensure that our applications remain stable, secure, and efficient over the long term.