added shutdown to datefile

lib/appenders/dateFile.js

@@ -1,6 +1,7 @@
 "use strict";
 var streams = require('../streams')
 , layouts = require('../layouts')
+, async = require('async')
 , path = require('path')
 , os = require('os')
 , eol = os.EOL || '\n'
@@ -24,12 +25,12 @@ function appender(filename, pattern, alwaysIncludePattern, layout) {
   layout = layout || layouts.basicLayout;
 
   var logFile = new streams.DateRollingFileStream(
-    filename, 
-    pattern, 
+    filename,
+    pattern,
     { alwaysIncludePattern: alwaysIncludePattern }
   );
   openFiles.push(logFile);
-  
+
   return function(logEvent) {
     logFile.write(layout(logEvent) + eol, "utf8");
   };
@@ -38,15 +39,15 @@ function appender(filename, pattern, alwaysIncludePattern, layout) {
 
 function configure(config, options) {
   var layout;
-  
+
   if (config.layout) {
     layout = layouts.layout(config.layout.type, config.layout);
   }
-  
+
   if (!config.alwaysIncludePattern) {
     config.alwaysIncludePattern = false;
   }
-  
+
   if (options && options.cwd && !config.absolute) {
     config.filename = path.join(options.cwd, config.filename);
   }
@@ -54,5 +55,18 @@ function configure(config, options) {
   return appender(config.filename, config.pattern, config.alwaysIncludePattern, layout);
 }
 
+function shutdown(cb) {
+  async.forEach(openFiles, function(file, done) {
+    if (!file.write(eol, "utf-8")) {
+      file.once('drain', function() {
+        file.end(done);
+      });
+    } else {
+      file.end(done);
+    }
+  }, cb);
+}
+
 exports.appender = appender;
 exports.configure = configure;
+exports.shutdown = shutdown;