Chris' basic node logger

SimpleLogger.js

/*
 * Copyright 1999-2012 TeaLeaf Technology, Inc.
 * All rights reserved.
 *
 */

var fs = require('fs');

function SimpleLogger(logName, logDir, rollDays, consoleOutput) {
  if(logDir == undefined || logDir == '')
    logDir = './';
  else if(logDir.substr(logDir.length-1) != '/')
    logDir += '/';

  this.logName = logName == 'undefined' ? 'Unknown' : logName;
  this.logDir = logDir;
  this.rollDays = rollDays;
  this.consoleOutput = consoleOutput;
  this.logWriters = [];

  initRollTimer(this);
}

SimpleLogger.prototype.trace = function (source, message) {
  writeLog(this, 'TRACE', source, message);
}

SimpleLogger.prototype.info = function(source, message) {
  writeLog(this, 'INFO', source, message);
}
 
SimpleLogger.prototype.error = function(source, message) {
  writeLog(this, 'ERROR', source, message);
}

SimpleLogger.prototype.log = function(type, source, message) {
  writeLog(this, type, source, message);
}

function writeLog (log, type, source, message) {
  var now = new Date();

  var todaysLog = logFilename(log, now);
  var logWriter;
  if(log.logWriters[todaysLog] == undefined) {
    log.logWriters = [];
    logWriter = log.logWriters[todaysLog] = fs.createWriteStream(todaysLog, {'flags': 'a'});
  }
  else
    logWriter = log.logWriters[todaysLog];

  var logMsg = '  ' + type + '  ' + source + '\t' + message;

  if(log.consoleOutput)
    console.log(formatDate(now, false, '', true, ':') + logMsg);
  logWriter.write(formatDate(now, true, '-',  true, ':') + logMsg + '\n');
}

function padNumber(input) {   
     return input < 10 ? '0' + input : input;
}

function logFilename(log, input) {
  return log.logDir + log.logName 
    + '_' + formatDate(input, true, '', false, '') + '.log';
}

//[CF] Using a custom date format function to eliminate the need for an additional module
function formatDate(input, includeDate, dateSeparator, includeTime, timeSeparator) {
  var retString = '';

  if(input == undefined) return retString;

  if(includeDate) {
    retString = input.getFullYear() + dateSeparator + padNumber(input.getMonth()+1)
      + dateSeparator + padNumber(input.getDate());
  }

  if(includeTime) {
    if(includeDate)
      retString += 'T';

      retString += padNumber(input.getHours()) + timeSeparator + padNumber(input.getMinutes()) + timeSeparator 
        + padNumber(input.getSeconds());
  }

  return retString;
}

 //Roll logs at 1am every day
function initRollTimer(log) {
  var hourToRoll = 1;

  var now = new Date();
  var rollTime = new Date(now.getFullYear(), now.getMonth(), now.getDate(), 
    hourToRoll, 0, 0, 0);
  rollTime.setDate(rollTime.getDate()+1);

  var timerDelay = rollTime.getTime() - now.getTime();
  setTimeout(rollLogs, timerDelay);
}

//[CF] Current roll logic only deletes a single day, it will not go back any further
function rollLogs(log) {
  var curDate = new Date();
  curDate.setDate(curDate.getDate()-log.rollDays);

  var fileToDelete = logFilename(log, curDate);
  fs.unlink(fileToDelete);

  initRollTimer(log);
}

module.exports = SimpleLogger;