splog/lib/index.js

A NodeJS library which provides a syslog-like remote logging interface

var exec = require('child_process').exec;
var net = require('net');
var util = require('util');

var hostname = null;
function _hostname(error, stdout, stderr) {
  if (stdout) {
    hostname = stdout.trim();
  } else {
    hostname = 'localhost';
  }
  onHostnameReady();
}
exec('hostname', _hostname);

function _pad(what, howFar, withWhat) {
  var padded = what.toString();
  if (withWhat === undefined) {
    if (typeof what === 'number') {
      withWhat = '0';
    } else {
      withWhat = ' ';
    }
  }
  for (var index = padded.length; index < howFar; index = index + 1) {
    padded = withWhat + padded;
  }
  return padded;
}

function _timestamp() {
  var now = new Date();
  return [
    [
      [now.getFullYear(), _pad(now.getMonth() + 1, 2), _pad(now.getDate(), 2)].join('-'),
      [_pad(now.getHours(), 2), _pad(now.getMinutes(), 2), _pad(now.getSeconds(), 2)].join(':'),
    ].join(' '), _pad(now.getMilliseconds(), 3)].join(',');
}

var FACILITIES = {
  'user': 1,
};

var LEVELS = {
  'debug': 7,
  'info': 6,
  'warning': 4,
  'error': 3,
  'critical': 2,
};

var configuration = {
  'hostnameBacklog': [],
  'socketBacklog': [],
  'hostnameReady': false,
  'socketReady': false,
};

function onSocketError(line) {
  configuration['socketReady'] = false;
  if (line) {
    if(line instanceof Error){
      log('warning',line.toString());
      console.log(line);
    } else {
      configuration['socketBacklog'].push(line);
    }
  }
  _reconnectSocket();
}

function onHostnameReady() {
  configuration['hostnameReady'] = true;
  var backlog = configuration['hostnameBacklog'];
  configuration['hostnameBacklog'] = [];
  for (var index in backlog) {
    backlog[index]['hostname'] = hostname;
    _format(backlog[index]);
  }
}

function onSocketReady() {
  configuration['socketReady'] = true;
  var backlog = configuration['socketBacklog'];
  configuration['socketBacklog'] = [];
  if (backlog.length > 0) {
    _send(backlog.join(''));
  }
}

function _reconnectSocket() {
  if (configuration['socket']) {
    configuration['socket'].destroy();
  }
  var socket = new net.Socket({type: 'tcp'});
  socket.setNoDelay(true);
  socket.setKeepAlive(true);

  socket.on('error', onSocketError);
  socket.on('connect', onSocketReady);
  configuration['socketReady'] = false;
  configuration['socket'] = socket;
  socket.connect(configuration['port'] || 514, configuration['host']);
}

function configure(settings) {
  if (settings) {
    if (settings['port']) {
      configuration['port'] = settings['port'];
    } else {
      delete configuration['port'];
    }
    if (settings['host']) {
      configuration['host'] = settings['host'];
    } else {
      delete configuration['host'];
    }
    if (settings['app']) {
      configuration['app'] = settings['app'];
    } else {
      delete configuration['app'];
    }
    if (settings['instance']) {
      configuration['instance'] = settings['instance'];
    } else {
      delete configuration['instance'];
    }
    if (settings['minLevel']) {
      configuration['minLevel'] = parseInt(settings['minLevel']);
      if(isNaN(configuration['minLevel'])){
        configuration['minLevel'] = LEVELS[settings['minLevel'].trim().toLowerCase()];
      }
    }
  }
  if (configuration['host']) {
    _reconnectSocket();
  }
}
module.exports.configure = configure;

function _format(data) {
  if (configuration['hostnameReady']) {
    var message = (data['msg'] || '').toString();
    if (message[message.length - 1] === '\n'){
      message = message.slice(0, -1);
    }
    var lines = message.split('\n');
    for (var index in lines) {
      var line = data['hostname'] + ' ' + data['app'] + ' ' + data['timestamp']+ ' ' + data['instance'] + ' ' + data['level'].toUpperCase() + ' ' + lines[index];
      if (configuration['host']) {
        line = '<' + 8 * FACILITIES[data['facility']] + LEVELS[data['level'].toLowerCase()] + '>' + line;
        if (line[line.length - 1] !== '\n') {
          line += '\n';
        }
      } else {
        // This is destined for console.log which will throw in a newline.
        if (line[line.length - 1] === '\n') {
          line = line.slice(0, -1);
        }
      }
      _send(line);
    }
  } else {
    configuration['hostnameBacklog'].push(data);
  }
}

function _send(line) {
  if (configuration['host']) {
    if (configuration['socketReady']) {
      configuration['socket'].write(line,function(err){
        if(err){
          onSocketError(line);
        }
      });
    } else {
      configuration['socketBacklog'].push(line);
    }
  } else {
    console.log(line);
  }
}

function log(level, msg) {
  if(configuration.minLevel && LEVELS[level.trim().toLowerCase()] > configuration.minLevel){
    return;
  }
  var data = {
    'facility': configuration['facility'] || 'user',
    'level': level,
    'hostname': hostname,
    'app': configuration['app'] || process.argv[0],
    'timestamp': _timestamp(),
    'instance': configuration['instance'] || process.pid,
    'msg': msg,
  };
  _format(data);
}
module.exports.log = log

module.exports.debug = function(msg) { log('debug', msg); }
module.exports.info = function(msg) { log('info', msg); }
module.exports.warning = function(msg) { log('warning', msg); }
module.exports.error = function(msg) { log('error', msg); }
module.exports.critical = function(msg) { log('critical', msg); }

//module.exports.configure = configure