sw-node-logger

An easy to use logger for node js

Quick start

let Logger = require('sw-node-logger')

// Instantiate a Logger
let logger = new Logger([
  // Instantiate the driver(s) you want to use
  new Logger.DRIVERS.CONSOLE(),
  new Logger.DRIVERS.FILEROLLING({ logDirectory: './log' })
])

logger.Log('This is info')

Documentation

How to log

When the logger is instantiated, you simply need to call the Log method. This will Log on all defined Drivers. By default the log type is INFO but you can either change the default log type or specify it for a specific log

// Default log type is INFO
logger.Log('This is info')

// Set default to WARNING
logger.SetType(Logger.TYPES.WARN)
logger.Log('This is warn')

// Specify the type for this log
logger.Log('This is error', Logger.TYPES.ERROR)

What is logged

The log types are organized by priority

• DEBUG
• INFO
• WARN
• ERROR
• FATAL

By default the lvl is set to INFO. It means that everything above will be logged but not what is below. You can change the default lvl with this command.

// Set the minimum log lvl to display to WARNING
logger.SetLvl(Logger.TYPES.WARN)

The drivers

This library use drivers. You can specify one or many.

// How to set options
let options = {
  useColors: false
}

let drv = new Logger.DRIVERS.CONSOLE(options)

// Give that driver to the main Logger object
let logger = new Logger(drv)

Console Driver

This will simply log into the console

Option	Type	Default	Description
timestampFormat	string	'YYYY-MM-DD HH:mm:ss'	DateTime format for the log line
useColors	boolean	true	Use colors in the console

File rolling Driver

This will log into a file. A new file everyday

Option	Type	Default	Description
timestampFormat	string	'YYYY-MM-DD HH:mm:ss'	DateTime format for the log line
logDirectory	string	'./'	The directory where to store the logs
fileNamePattern	string	'log-<DATE>.log'	The filename format. <DATE> will be automatically replaced by the date of the day
keepLast	integer	10	How many log file to keep. If it set to 0, all the files will be kept

Syslog Driver

This will log into a syslog server

Option	Type	Default	Description
timestampFormat	string	'YYYY-MM-DD HH:mm:ss'	DateTime format for the log line
srvAddress	string	'localhost'	The address of the server
port	integer	514	The server port number
transport	'TCP' or 'UDP'	'UDP'	The transport type
hostName	string	computer hostname	The hostname of your machine displayed on the syslog
appName	string	'MyApp'	The application name

Custom Driver

How to build your custom driver

The minimum required is to use a constructor with options and a Log method which get message and type

let Logger = require('sw-node-logger')

class MyDriver extends Logger.LoggerDriverInterface {
  constructor (options) {
    super(options)
  }

  Log (message, type) {
    console.log(message, type)
    // You can use the common formatting method
    // to get a clean line
    console.log(this.Format(message, type))
  }
}

let logger = new Logger([
  new MyDriver()
])

logger.Log('Voilà', Logger.TYPES.ERROR)