Logful

Logging everywhere, made simple and still configurable

About

Logful is a logging module. It can write your log messages to multiple destinations at once. It provides you with a client whose methods are named in accordance with the Syslog's severity levels specification.

The following logging handlers are currently supported:

• console - send messages to the console (STDERR), and with colours!
• file - log messages to a log file
• syslog - send messages to Syslog

... and you can easily implement your own if needed.

Installation Instructions

Install the module via npm: npm install logful [--save]

Unless you plan on removing your logging statements make sure you install the module as production dependency.

Usage

The most powerful feature of Logful is the possibility to use multiple logging destinations at the same time:

// Load the module's main "class"
var Logful = require('logful')

// This needs to be done only once - tell Logful where to write
// your log messages
Logful
  // Name your app - some handlers may use this information to
  // distinguish your app's entries from others (i.e. Syslog does this)
  .application('MyApp')
  .use('console')
  .use('syslog')

// somewhere where you actually need to log something...

// Each instance accepts an optional 'name' argument that further helps
// identifying from where the message is coming
var logger = new Logful('my-module')
logger.info('this will be logged to console and Syslog!')

All logging methods also accept Error objects as input - the err.message will then be logged. Also, you may use printf-like syntax:

var str = 'test string'
logger.info('Value of str: %s', str) // -> Value of str: test string

logger.info(new Error('Just FYI, Something bad happened'))

Available logging methods

Here is the list of all the methods you can use in your code to log your messages at various severity levels.

logger
  .debug()
  .info()
  .notice()
  .warn()   // or .warning()
  .error()
  .alert()
  .crit()   // or .critical()
  .emerg()  // or .emergency() or .panic()

Note for Mac OS X users

The native Console app by default shows only messages with severity level of warn and above.

API Documentation

Logful tries to provide reasonable defaults, but if you like, you can customise almost all aspects of its behaviour.

Logful.application()

Logful uses the application name to distinguish your application from others, i.e. in Syslog.

Default: node

Logful.application('MyApp') // Set a new application's name

Logful.level()

Specify the minimum severity level at which messages should start being logged.

Default: info

Logful.level('warn') // debug, info and notice will be ignored

Logful.use()

Tell Logful where to send your messages.

By default, messages are ignored if you do not specify a destination

Logful.use('file', { path: './logfile' })

new Logful()

Create a new instance and start logging! Optionally, you can provide a module name to this instance so that each of you modules' entries will be easily recognisable.

var logger = new Logful('MyModule')

Customising Logful

To be documented. For now, please take a look at GenericHandler's constructor.

Performance

All the built-in handlers are implemented using Streams, so sending a message to all available log handlers will not slow your code execution. If you wish to see how fast you can go, run the included benchmarks:

• git checkout https://github.com/Dreamscapes/Logful.git
• npm install --dev
• npm run bench

Generating detailed API documentation

You can generate the API docs using [Grunt][grunt-url]:

git checkout https://github.com/Dreamscapes/Logful.git
npm install --dev
[sudo] npm install -g grunt-cli
grunt docs

Documentation is now available at docs/index.html.

License

This software is licensed under the BSD-3-Clause License. See the LICENSE file for more information.