Node.js Logging

Solution 1:

Winston is a pretty good logging library. You can write logs out to a file using it.

Code would look something like:

var winston = require('winston');

var logger = new (winston.Logger)({
  transports: [
    new (winston.transports.Console)({ json: false, timestamp: true }),
    new winston.transports.File({ filename: __dirname + '/debug.log', json: false })
  ],
  exceptionHandlers: [
    new (winston.transports.Console)({ json: false, timestamp: true }),
    new winston.transports.File({ filename: __dirname + '/exceptions.log', json: false })
  ],
  exitOnError: false
});

module.exports = logger;

You can then use this like:

var logger = require('./log');

logger.info('log to file');

Solution 2:

Scribe.JS Lightweight Logger

I have looked through many loggers, and I wasn't able to find a lightweight solution - so I decided to make a simple solution that is posted on github.

• Saves the file which are organized by user, date, and level
• Gives you a pretty output (we all love that)
• Easy-to-use HTML interface

I hope this helps you out.

Online Demo

http://bluejamesbond.github.io/Scribe.js/

Secure Web Access to Logs

Prints Pretty Text to Console Too!

Web Access

Github

https://github.com/bluejamesbond/Scribe.js

Solution 3:

Log4js is one of the most popular logging library for nodejs application.

It supports many cool features:

1. Coloured console logging
2. Replacement of node's console.log functions (optional)
3. File appender, with log rolling based on file size
4. SMTP, GELF, hook.io, Loggly appender
5. Multiprocess appender (useful when you've got worker processes)
6. A logger for connect/express servers
7. Configurable log message layout/patterns
8. Different log levels for different log categories (make some parts of your app log as DEBUG, others only ERRORS, etc.)

Example:

1. Installation: npm install log4js

2. Configuration (./config/log4js.json):

   {"appenders": [
       {
           "type": "console",
           "layout": {
               "type": "pattern",
               "pattern": "%m"
           },
           "category": "app"
       },{
           "category": "test-file-appender",
           "type": "file",
           "filename": "log_file.log",
           "maxLogSize": 10240,
           "backups": 3,
           "layout": {
               "type": "pattern",
               "pattern": "%d{dd/MM hh:mm} %-5p %m"
           }
       }
   ],
   "replaceConsole": true }
   

3. Usage:

   var log4js = require( "log4js" );
   log4js.configure( "./config/log4js.json" );
   var logger = log4js.getLogger( "test-file-appender" );
   // log4js.getLogger("app") will return logger that prints log to the console
   logger.debug("Hello log4js");// store log in file