Logging Best Practices For Your Node.js App

As a Node.js developer, logging is pretty much everything when it comes to debugging, monitoring, and maintaining your applications. But are you using the logging best practices? Let's explore some logging techniques that can take your Node.js apps to the next level.

To learn more, you can check out the full blog post.

1. Winston: The Swiss Army Knife of Logging

🔧 Tool: Winston
📝 Description: A versatile logging library for Node.js
🌟 Key Features:

• Multiple transport options (console, file, database)
• Customizable log levels
• Supports logging in various formats (JSON, plain text)

javascriptCopyconst winston = require('winston');

const logger = winston.createLogger({
  level: 'info',
  format: winston.format.json(),
  transports: [
    new winston.transports.File({ filename: 'error.log', level: 'error' }),
    new winston.transports.File({ filename: 'combined.log' })
  ]
});

2. Morgan: HTTP Request Logger Middleware

🔧 Tool: Morgan
📝 Description: Simplifies HTTP request logging in Express.js
🌟 Key Features:

• Pre-defined logging formats
• Custom token support
• Easy integration with Express.js

javascriptCopyconst express = require('express');
const morgan = require('morgan');

const app = express();
app.use(morgan('combined'));

3. Bunyan: JSON Logging for Node.js

🔧 Tool: Bunyan
📝 Description: Structured JSON logging for Node.js applications
🌟 Key Features:

• JSON log format by default
• Supports child loggers
• Built-in CLI for viewing logs

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

log.info("Hi");
log.warn({lang: 'fr'}, "Au revoir");

4. Pino: Super Fast Node.js Logger

🔧 Tool: Pino
📝 Description: Low overhead logging with JSON output
🌟 Key Features:

• Extremely fast performance
• Automatic log rotation
• Supports child loggers

javascriptCopyconst pino = require('pino');
const logger = pino();

logger.info('hello world');
logger.error('this is at error level');

5. debug: Tiny Debugging Utility

🔧 Tool: debug
📝 Description: Small debugging utility for Node.js
🌟 Key Features:

• Lightweight and simple to use
• Selective debugging with namespaces
• Browser support

javascriptCopyconst debug = require('debug')('http');

debug('booting %o', name);

6. Log4js: Flexible Logging for JavaScript

🔧 Tool: Log4js
📝 Description: A conversion of the log4j framework to JavaScript
🌟 Key Features:

• Hierarchical logging levels
• Multiple output appenders
• Configurable layouts

javascriptCopyconst log4js = require("log4js");
log4js.configure({
  appenders: { cheese: { type: "file", filename: "cheese.log" } },
  categories: { default: { appenders: ["cheese"], level: "error" } }
});

const logger = log4js.getLogger("cheese");
logger.error("Cheese is too ripe!");

7. Elasticsearch, Logstash, and Kibana (ELK Stack)

🔧 Tool: ELK Stack
📝 Description: A powerful combination for log management and analysis
🌟 Key Features:

• Centralized logging
• Real-time log analysis
• Visualizations and dashboards

javascriptCopyconst winston = require('winston');
const Elasticsearch = require('winston-elasticsearch');

const esTransportOpts = {
  level: 'info',
  clientOpts: { node: 'http://localhost:9200' }
};
const logger = winston.createLogger({
  transports: [
    new Elasticsearch(esTransportOpts)
  ]
});

8. Sentry: Error Tracking and Performance Monitoring

🔧 Tool: Sentry
📝 Description: Real-time error tracking and performance monitoring
🌟 Key Features:

• Automatic error capturing
• Release tracking
• Performance monitoring

javascriptCopyconst Sentry = require("@sentry/node");

Sentry.init({ dsn: "https://examplePublicKey@o0.ingest.sentry.io/0" });

try {
  someFunction();
} catch (e) {
  Sentry.captureException(e);
}

9. New Relic: Application Performance Monitoring

🔧 Tool: New Relic
📝 Description: Comprehensive application performance monitoring
🌟 Key Features:

• Real-time performance metrics
• Error analytics
• Custom instrumentation

javascriptCopyconst newrelic = require('newrelic');

newrelic.setTransactionName('myCustomTransaction');
// Your application code here

10. Loggly: Cloud-based Log Management

🔧 Tool: Loggly
📝 Description: Cloud-based log management and analytics service
🌟 Key Features:

• Centralized log management
• Real-time log search and analysis
• Custom dashboards and alerts

javascriptCopyconst winston = require('winston');
const { Loggly } = require('winston-loggly-bulk');

winston.add(new Loggly({
    token: "YOUR-TOKEN",
    subdomain: "YOUR-SUBDOMAIN",
    tags: ["Winston-NodeJS"],
    json: true
}));

winston.log('info', "Hello World from Node.js!");

Bonus Tip: Structured Logging

Regardless of the tool you choose, implementing structured logging can greatly improve your log analysis capabilities:

javascriptCopylogger.info({
  event: 'user_login',
  userId: user.id,
  timestamp: new Date().toISOString(),
  ipAddress: req.ip
});

By using these additional tools and practices, you'll have a comprehensive logging strategy that covers everything from basic debugging to advanced application performance monitoring. Remember, the key to effective logging is choosing the right tools for your specific needs and consistently applying best practices throughout your codebase.

If you need help debugging your web app, check out Alerty to learn more about easy frontend monitoring.

Happy logging, and may your Node.js apps run smoothly! 🚀🔍