Merge branch 'master' of https://github.com/nomiddlename/log4js-node

Conflicts:
	test/gelfAppender-test.js

lib/appenders/gelf.js

@@ -35,21 +35,67 @@ levelMapping[levels.FATAL] = LOG_CRIT;
  * @param facility - facility to log to (default:nodejs-server)
  */
 function gelfAppender (layout, host, port, hostname, facility) {
+  var config, customFields;
+  if (typeof(host) === 'object') {
+    config = host;
+    host = config.host;
+    port = config.port;
+    hostname = config.hostname;
+    facility = config.facility;
+    customFields = config.customFields;
+  }
   
   host = host || 'localhost';
   port = port || 12201;
   hostname = hostname || require('os').hostname();
   facility = facility || 'nodejs-server';
   layout = layout || layouts.messagePassThroughLayout;
+
+  var defaultCustomFields = customFields || {};
   
   var client = dgram.createSocket("udp4");
   
   process.on('exit', function() {
     if (client) client.close();
   });
-  
+
+  /**
+   * Add custom fields (start with underscore ) 
+   * - if the first object passed to the logger contains 'GELF' field, 
+   *   copy the underscore fields to the message
+   * @param loggingEvent
+   * @param msg
+   */
+  function addCustomFields(loggingEvent, msg){
+
+    /* append defaultCustomFields firsts */
+    Object.keys(defaultCustomFields).forEach(function(key) {
+      // skip _id field for graylog2, skip keys not starts with UNDERSCORE
+      if (key.match(/^_/) && key !== "_id") { 
+        msg[key] = defaultCustomFields[key];
+      }
+    });
+
+    /* append custom fields per message */
+    var data = loggingEvent.data;
+    if (!Array.isArray(data) || data.length === 0) return;
+    var firstData = data[0];
+    
+    if (!firstData.GELF) return; // identify with GELF field defined
+    Object.keys(firstData).forEach(function(key) {
+      // skip _id field for graylog2, skip keys not starts with UNDERSCORE
+      if (key.match(/^_/) || key !== "_id") { 
+        msg[key] = firstData[key];
+      }
+    });
+    
+    /* the custom field object should be removed, so it will not be looged by the later appenders */
+    loggingEvent.data.shift(); 
+  }
+ 
   function preparePacket(loggingEvent) {
     var msg = {};
+    addCustomFields(loggingEvent, msg);
     msg.full_message = layout(loggingEvent);
     msg.short_message = msg.full_message;
     
@@ -88,7 +134,7 @@ function configure(config) {
   if (config.layout) {
     layout = layouts.layout(config.layout.type, config.layout);
   }
-  return gelfAppender(layout, config.host, config.port, config.hostname, config.facility);
+  return gelfAppender(layout, config);
 }
 
 exports.appender = gelfAppender;