Support for disabling log writes on shutdown.

Updated logger.js to support disabling all log writes.
Updated log4js.js shutdown function to disable log writes.
Added tests.
Update gitignore to ignore rolling date stream's test output.

lib/log4js.js

@@ -50,8 +50,9 @@ var events = require('events')
 , util = require('util')
 , layouts = require('./layouts')
 , levels = require('./levels')
-, LoggingEvent = require('./logger').LoggingEvent
-, Logger = require('./logger').Logger
+, loggerModule = require('./logger')
+, LoggingEvent = loggerModule.LoggingEvent
+, Logger = loggerModule.Logger
 , ALL_CATEGORIES = '[all]'
 , appenders = {}
 , loggers = {}
@@ -306,11 +307,27 @@ function loadAppender(appender) {
   appenderMakers[appender] = appenderModule.configure.bind(appenderModule);
 }
 
+/**
+ * Shutdown all log appenders. This will first disable all writing to appenders
+ * and then call the shutdown function each appender.
+ *
+ * @params {Function} cb - The callback to be invoked once all appenders have
+ *  shutdown. If an error occurs, the callback will be given the error object
+ *  as the first argument.
+ * @returns {void}
+ */
 function shutdown(cb) {
+  // First, disable all writing to appenders. This prevents appenders from
+  // not being able to be drained because of run-away log writes.
+  loggerModule.disableAllLogWrites();
+
+  // Next, get all the shutdown functions for appenders as an array.
   var shutdownFunctions = Object.keys(appenderShutdowns).reduce(
     function(accum, category) {
       return accum.concat(appenderShutdowns[category]);
     }, []);
+
+  // Call each of the shutdown functions.
   async.forEach(
     shutdownFunctions,
     function(shutdownFn, done) {

lib/logger.js

@@ -4,6 +4,8 @@ var levels = require('./levels')
 , events = require('events')
 , DEFAULT_CATEGORY = '[default]';
 
+var logWritesEnabled = true;
+
 /**
  * Models a logging event.
  * @constructor
@@ -66,7 +68,7 @@ Logger.prototype.isLevelEnabled = function(otherLevel) {
     };
     
     Logger.prototype[levelString.toLowerCase()] = function () {
-      if (this.isLevelEnabled(level)) {
+      if (logWritesEnabled && this.isLevelEnabled(level)) {
         var args = Array.prototype.slice.call(arguments);
         args.unshift(level);
         Logger.prototype.log.apply(this, args);
@@ -75,6 +77,23 @@ Logger.prototype.isLevelEnabled = function(otherLevel) {
   }
 );
 
+/**
+ * Disable all log writes.
+ * @returns {void}
+ */
+function disableAllLogWrites() {
+  logWritesEnabled = false;
+}
+
+/**
+ * Enable log writes.
+ * @returns {void}
+ */
+function enableAllLogWrites() {
+  logWritesEnabled = true;
+}
 
 exports.LoggingEvent = LoggingEvent;
 exports.Logger = Logger;
+exports.disableAllLogWrites = disableAllLogWrites;
+exports.enableAllLogWrites = enableAllLogWrites;