loglevel-debug

Loglevel Debug Plugin

Plugin for JS logger loglevel which allows enable/disable debug output dynamically and draws inspiration from TJ Hollowaychuk's debug.

Features

• Ability to change logging levels of specific modules.
• Ability to turn on/off debug output for specific modules in development.
• Production logging would be all modules with warn, info, error levels,

Installation

npm install loglevel-debug

bower install loglevel-debug

Usage

This plugin is deigned to be used standalone.

var log = require('loglevel-debug')('http')
  , http = require('http')
  , name = 'My App';
 
// fake app
 
log('booting %s', name);
 
http.createServer(function(req, res){
  log(req.method + ' ' + req.url);
  res.end('hello\n');
}).listen(3000, function(){
  log.info('listening');
});
 
// fake worker of some kind
 
require('./worker');

Example worker.js:

var log = require('loglevel-debug')('worker');
 
setInterval(function(){
  log('doing some work');
}, 1000);

Use DEBUG environment variable to control debug output.

$ DEBUG=http,worker:* node example/app
[DEBUG] http booting %s
[DEBUG] worker:a doing lots of uninteresting work
[DEBUG] worker:b doing some work
[INFO] http listening
[DEBUG] worker:a doing lots of uninteresting work
[DEBUG] worker:a doing lots of uninteresting work
[DEBUG] worker:b doing some work
[DEBUG] worker:a doing lots of uninteresting work
[DEBUG] worker:a doing lots of uninteresting work

Logging Methods

loglevel methods are all supported.

# creates a logger for Module1.
var log = require('loglevel-debug')('Module1');
 
log('this is a debug message');
log.debug('this is a debug message');
log.info('this is a info message');
log.warn('this is a warring message');
log.error('this is a errror message');
log.trace('this is a trace message');

you can dynamic change specific logger's logging level.

log.setLevel(log.levels.INFO)

Browser support

This plugin works on browser as well. To enable debug output, you can use its enable public api,

loglevelDebug.enable('worker:*');

As a loglevel plugin

var loglevel = require('loglevel');
var loglevelDebug = require('loglevel');
 
loglevelDebug(loglevel);
 
log.debug('Test');