etc.rsyslog.conf

[node@li79-228 ~]$ cat /etc/rsyslog.conf 
# rsyslog v5 configuration file

# enable logger command
$ModLoad imuxsock

$ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat

*.emerg * 

local0.* /var/log/nodejs.log

gistfile1.sh

[node@li79-228 ~]$ node syslog.js 

Message from syslogd@li79-228 at Mar 24 16:16:24 ...
 web[28634]: emerg: a message
[node@li79-228 ~]$ cat /var/log/nodejs.log 
Mar 24 16:16:24 li79-228 web[28634]: alert: a message
Mar 24 16:16:24 li79-228 web[28634]: crit: a message
Mar 24 16:16:24 li79-228 web[28634]: debug: a message
Mar 24 16:16:24 li79-228 web[28634]: emerg: a message
Mar 24 16:16:24 li79-228 web[28634]: err: a message
Mar 24 16:16:24 li79-228 web[28634]: info: a message
Mar 24 16:16:24 li79-228 web[28634]: warning: a message
[node@li79-228 ~]$ 

syslog.js

// 
// async logs with node.js
// 
// Setup rsyslog:
//
// forward local0 facility messages to nodejs.log
// echo "local0.* /var/log/nodejs.log" >> /etc/rsyslog.conf
//
// forward local0 facility messages to 192.168.0.1 with UDP
// echo "local0.* @192.168.0.1 " > /etc/rsyslog.conf
//
// forward local0 facility messages to 192.168.0.1 with TCP
// echo "local0.* @@192.168.0.1:514 " > /etc/rsyslog.conf
//
// forward all messaged to 192.168.0.1
// echo "*.* @192.168.0.1 " > /etc/rsyslog.conf
//
// service rsyslog restart
//

;(function (exports) {

  var spawn = require('child_process').spawn

  ;['alert'
  , 'crit'
  , 'debug'
  , 'emerg'
  , 'err'
  , 'info'
  , 'notice'
  , 'warning'
  ].forEach(function (level) {

    console[level] = function (str, next) {

      var log = spawn('logger', [
        '-t'
        , process.title +'[' + process.pid +']'
        , '-p'
        , process.facility +'.' + level
        , level + ': ' + str
      ])

      if (next) log.on('exit', next)

    }

  })

})(this)

// example
;(function () {
  'use strict'

  process.title = 'web'
  process.facility = 'local0'

for (var i=0; i<1000; i++) {
  console.info('a message')
  console.alert('a message', function (code, sig) { })
  console.crit('a message', function (code, sig) { })
  console.debug('a message', function (code, sig) { })
  console.emerg('a message', function (code, sig) { })
  console.err('a message', function (code, sig) { })
  console.info('a message', function (code, sig) { })
  console.warning('a message', function (code, sig) { })
}

})()