A Comprehensive Guide On NodeJS Logging (Detailed Tutorial)

NodeJS logging is crucial for any application. Imagine finding yourself in a scenario where you need to track down a bug or understand how your application is performing in real time. NodeJS logging becomes invaluable, providing the necessary insights into your application's behavior. This blog will uncover NodeJS logging's importance, helping you understand how it can improve your NodeJS application.

Alerty's NodeJS logging, an innovative solution that will help you master this critical aspect of application development.

Table of Contents

• What Is Logging?
• Why Is Logging Important?
• What Data Should Be Logged?
• 3 Basic NodeJS Logging Techniques
• Advanced Logging With Third-Party Libraries
• 7 NodeJS Logging Best Practices
• Integrating Logging With Monitoring Tools
• Catch Issues Before They Affect Your Users With Alerty's NodeJS Logging Tool 

What Is Logging?

Logging records information about a program's execution to track its behavior and performance. 

Importance of Logs in Software Development

• Diagnose and troubleshoot issues
• Monitor system performance
• Gain insights into user interactions with an application

Logs can capture a wide range of data, from simple messages indicating the program's flow to detailed error reports with stack traces and contextual information.

Categorizing Log Entries with Log Levels

• Debug
• Info
• Warn
• Error

Developers use these log levels to categorize the importance and severity of log entries. By analyzing logs, teams can identify patterns, spot anomalies, and understand the root causes of problems, leading to more reliable and efficient software.

Why Is Logging Important?

Performance

Performance is vital in the realm of NodeJS logging. Both you and your users value performance, and tracking it is essential. Logging is one way to achieve this, enabling you to monitor your application's behavior in real-time. 

Log data can help you identify bottlenecks and areas for optimization, leading to a more optimized and efficient application. APM tools that automatically track and monitor performance are even more beneficial, allowing you to gain valuable insights without the effort of manual logging.

Debugging

Mistakes are inevitable in development processes. We're not perfect, and errors are bound to happen. When these issues arise, the first step in rectifying them is analyzing logs to pinpoint where the error transpired and under what circumstances. Logging various events within your application allows you to debug and resolve issues swiftly.

Error Tracking

Error tracking is another vital aspect of NodeJS logging. 

Benefits of Error Tracking

• Understand when errors began
• Track the frequency of occurrences
• Identify affected users
• Determine if errors have been resolved
• Monitor for reoccurrence of errors

You can identify patterns, trends, and recurring issues by tracking errors. This information is crucial for improving your application's overall stability and reliability.

Analyzing Logs

Logs contain a wealth of information that can be incredibly valuable for your application.

Valuable Insights from Logs

• Gain insights into usage patterns
• Understand user behaviors
• Monitor performance metrics
• Access a wealth of valuable information for your application

Log data is valuable for troubleshooting, optimizing, and enhancing your application. By leveraging log data, you can make decisions and drive continuous improvement within your NodeJS application.

Related Reading

• Node Problem Detector
• NodeJS Performance
• Node Js Error Handling

What Data Should Be Logged?

When setting up logging for your Node.js application, it's crucial to log data that provides meaningful insights while avoiding information overload. 

Effective Node.js Logging Setup

• Log meaningful data to avoid information overload
• Capture basic metadata: timestamps, log levels, and module names
• Track when and where events occur
• Include event details: error messages, user actions, and system states

To help diagnose issues, include information on the event, such as: 

• Error messages
• User actions
• System states

For errors, log stack traces and any relevant context to facilitate troubleshooting. Monitor critical application metrics like request durations, response statuses, and resource usage.

Keep sensitive information like passwords or personal data out of your logs to maintain security and comply with privacy regulations. Logging the correct data can turn a confusing troubleshooting session into a straightforward and efficient process.

Simplify Your Development Workflow With Alerty

Alerty is a cloud monitoring service for developers and early-stage startups. It offers application performance monitoring, database monitoring, and incident management. It supports technologies like NextJS, React, Vue, and Node.js, helping developers identify and fix issues. 

Comprehensive Monitoring with Alerty

• Monitors databases: Supabase, PostgreSQL, and RDS
• Tracks key metrics: CPU usage and memory consumption
• Features quick incident management
• Real User Monitoring (RUM) to optimize user experience
• Universal Service Monitoring for dependencies: Stripe API, OpenAI, and Vercel

Alerty uses AI to simplify setup, providing a cost-effective solution compared to competitors. It is designed for ease of use, allowing quick setup, and integrates with tools like Sentry, making it ideal for developers and small teams needing efficient, affordable monitoring. 

Prevent issues from impacting your users with Alerty's NodeJS logging tool today!

3 Basic NodeJS Logging Techniques

1. Console.log

The original method of logging is console.log. It has variants like: 

• Console.error
• Console.info
• Console.warn 

Those are convenience methods over the base function, console.log (level, message). You can write to console.log but have little control over where things log from outside the code. So, we have the next best thing.

2. Debug Module

With so many packages using debug, it’s tempting to think we should hook directly into its power. Sure, we can enable it and get output to the console. The trouble is, this is the most we can do with it. We can redirect stdout and stderr to a file.

The benefit of using debug is that many packages use it. You can turn it on to get additional info on what’s happening in web middleware like Express and Koa when your back-end gets a web request. The good frameworks will allow you to hook up logging middleware, but you might not get all the details sent to it.

3. Middleware

Middleware is a versatile tool that can be incorporated into the request pipeline. Requests and responses traverse through middleware, allowing you to set up logging middleware in various frameworks. 

Express, a popular API framework, offers several ways to establish logging middleware:

• Application Level: Implement logging middleware at the application level by creating an instance of Express and incorporating the logging middleware. 
• Router Level: To control logging more granularly, you can set up logging middleware at the router level within Express.
• Error Handling: Error handling is critical, and it's beneficial to set up error-logging middleware to intercept and log mistakes efficiently.
  
  

Avoid directly writing middleware functions within your application code, which can lead to code entanglement when enhancing your application. Instead, encapsulate logging within utility code to centralize behavior changes. 

This approach ensures a seamless process for future enhancements and modifications to your logging mechanism.

Advanced Logging With Third-Party Libraries

Logging libraries help developers create and manage log events, which can increase your application's overall efficiency and functionality. Some of Node's most popular logging libraries are: 

Winston

Winston is one of the most popular logging utilities. The cool thing is it can take more than one output transport. Unfortunately, because Node.js works as it does, you still can’t pipe the " debug " output into a different transport. Otherwise, it would be great to do that and send all the debug logs to whatever you want! Here’s how you set Winston up in Express:

const express = require("express");

const { createLogger, transports } = require("winston");

const app = express();

const logger = createLogger({

transports: [new transports.Console

});

function logRequest(req, res, next) {

    logger.info(req.url)

    next()

}

app.use(logRequest)

function logError(err, req, res, next) {

    logger.error(err)

    next()

}

app.use(logError)

Incorporating Winston is easy because it is highly configurable. You can set up multiple modes of transport with filtering, set custom formatters, and use more than one logger instance. In the code above, I’m only logging the requested URL.

You can set a formatter on your request logger that prepares the request and response for logging. Here are sample snippets:

'use strict'

const winston = require('winston')

const remoteLog = new winston.transports.Http({

    host: "localhost",

    port: 3001,

    path: "/errors"

})

const consoleLog = new winston.transports.Console()

module.exports = {

    requestLogger: createRequestLogger([consoleLog]),

    errorLogger: createErrorLogger([remoteLog, consoleLog])

}

function createRequestLogger(transports) {

    const requestLogger = winston.createLogger({

        format: getRequestLogFormatter(),

        transports: transports

    })

    return function logRequest(req, res, next) {

        requestLogger.info({req, res})

        next()

    }

}

function createErrorLogger(transports) {

    const errLogger = winston.createLogger({

        level: 'error',

        transports: transports

    })

    return function logError(err, req, res, next) {

        errLogger.error({err, req, res})

        next()

    }

}

function getRequestLogFormatter() {

    const {combine, timestamp, printf} = winston.format;

    return combine(

        timestamp(),

        printf(info => {

            const {req, res} = info.message;

            return ${info.timestamp} ${info.level}: ${req.hostname}${req.port || ''}${req.originalUrl};

        })

    );

}

This setup will create logging middleware using Winston. The middleware plugs into the Express request pipeline. Keep in mind the patterns you’re seeing here. The middleware is reusable. You can apply this pattern to any framework you’re using. If you want to hook in the debug module, change this file to include it.

Pino

This logging library is very popular for its low overhead and minimalism. It uses fewer resources for logging by using a worker thread for processing.

const pino = require('pino');

// Create a logging instance

const logger = pino({

level: process.env.NODE_ENV === 'production' ? 'info' : 'debug',

});

logger.info('Application started!');

Bunyan

Bunyan is another fast JSON logging library that supports multiple transports and uses a CLI to filter the logs. Its refined method produces what it should do. One of Bunyan's best features is log snooping, which helps in debugging failures in production.

const bunyan = require('bunyan');

const log = bunyan.createLogger({name: 'myapp'});

log.info('My App');

{"name":"myapp","hostname":"banana.local","pid":40161,"level":30,"msg":"My App","time":"2022-04-04T18:24:23.851Z","v":0}

Other cool features of Bunyan are a stream system for controlling where logs are located, support for environments other than Node.js, and the fact that JSON objects are serialized by default.

Related Reading

• • Node Js Security
  • NodeJS Profiling
  • NodeJS Metrics
  • Node Js Performance Testing
  • NodeJS Server Monitoring
    

7 NodeJS Logging Best Practices

1. Use a Logging Library

When logging in to Node.js, it's best to avoid relying solely on `console.log()`. Dedicated logging libraries such as Winston, Pino, and Bunyan offer advanced features like:

• Log levels
• Formatting
• Transport options

2. Define Log Levels

Appropriate log levels can help categorize and filter log messages based on severity. Common log levels include:

• Error
• Warn
• Info
• Debug
• Trace

Avoiding logging sensitive information, such as passwords or personal data, is crucial to protecting user privacy and complying with regulations.

3. Implement Structured Logging

Structured logging enhances the readability and analysis of log data. It typically involves storing logs in JSON format and relevant metadata like:

• Timestamps
• Log levels
• Module names

4. Write Descriptive Messages

Descriptive log messages provide context, aiding in debugging and troubleshooting. Avoiding generic messages like "Error occurred" without additional details is essential. Including specific information about the issue and its context can make debugging easier.

5. Centralize and Monitor Logs

Aggregating logs from various sources into a centralized platform enables efficient monitoring and analysis. Tools like Alerty offer real-time log management, search capabilities, and alerting features that help identify and resolve issues promptly.

6. Rotate and Retain Logs

Log rotation helps manage log file size, preventing excessive disk space consumption. Configuring log retention policies ensures that logs are retained for an appropriate period based on storage requirements and compliance needs.

7. Integrate with Monitoring Tools

Integrating logs with monitoring tools allows for proactive error tracking and performance monitoring. Alerty can provide insights into application health, helping quickly identify and resolve issues.

Integrating Logging With Monitoring Tools

Combining log management systems and error tracking with a powerful solution like Alerty can ensure real-time monitoring and swift issue resolution, keeping your applications running smoothly.

Centralized Logging With Alerty

Alerty allows you to aggregate logs from various sources into a centralized platform, providing real-time monitoring and in-depth analysis. This centralized approach enables you to identify and address potential issues quickly. With Alerty's intuitive interface and powerful features, managing and analyzing your logs becomes flawless, offering insights that help you optimize your application's performance.

Error Tracking

Error tracking is another critical aspect of integrating logging with monitoring tools. You can facilitate faster debugging and issue resolution by setting up error tracking alongside your logging system. Combining error tracking with your logging mechanism allows you to respond rapidly to issues and maintain a high level of application performance.

Swift Issue Resolution

Logging with monitoring tools helps identify potential issues and dramatically speeds up the issue resolution process. A centralized platform that combines logging data and monitoring statistics allows you to quickly pinpoint the root causes of problems and resolve them efficiently. 

This approach ensures that your system remains reliable and high-performing, preventing any downtime that affects user experience.

Related Reading

• Datadog NodeJS
• Node PM2
• Prometheus NodeJS
• Clinic.Js
• Node.Js Monitoring
• Kubernetes Node Status
• Node.js Application Monitoring
  
• Node Logs
• Node Monitor
  
• Node Performance
• Node Throw Error
• Node Observability
  
• Node Errors
• Node JS Performance Monitoring

Catch Issues Before They Affect Your Users With Alerty's NodeJS Logging Tool

Alerty is a game-changer in cloud monitoring services, especially for developers and early-stage startups diving into the complexities of NodeJS logging. Offering a comprehensive suite of monitoring tools, Alerty provides application performance monitoring, database monitoring, and incident management that are vital for any developer's toolkit. 

Benefits of Using Alerty

• Easily navigate modern technologies like NextJS, React, Vue, and Node.js
• Efficiently identify and fix issues, saving time and resources
• Support for databases such as Supabase, PostgreSQL, and RDS
• Monitor key metrics like CPU usage and memory consumption
• Gain valuable insights for optimization

Key Features

• Quick incident management
• Real User Monitoring (RUM) for a smooth user experience
• Universal service monitoring covering dependencies like Stripe API, OpenAI, and Vercel
• Comprehensive coverage to catch issues before they affect users
• Commitment to top-notch monitoring solutions for NodeJS applications

Advantages of Using Alerty

• Leverages AI to simplify setup processes
• Cost-effective compared to competitors
• Efficient integration with platforms like Sentry
• Designed for ease of use with quick and hassle-free setup
• Reliable and affordable monitoring solution that delivers on promises

Alerty's NodeJS logging tool is necessary for any developer or small team looking to enhance their monitoring capabilities. By leveraging Alerty, developers can take their NodeJS logging to the next level, ensuring their applications run smoothly and efficiently.

Get started with Alerty today and revolutionize your NodeJS logging and cloud monitoring experience!