Added logic to serialize Error objects correctly

This should fix #97.

lib/appenders/clustered.js

@@ -7,6 +7,14 @@ var log4js = require('../log4js');
  * Takes a loggingEvent object, returns string representation of it.
  */
 function serializeLoggingEvent(loggingEvent) {
+	// JSON.stringify(new Error('test')) returns {}, which is not really useful for us.
+	// The following allows us to serialize errors correctly.
+	for (var i = 0; i < loggingEvent.data.length; i++) {
+		var item = loggingEvent.data[i];
+		if (item && item.stack && JSON.stringify(item) === '{}') { // Validate that we really are in this case
+			loggingEvent.data[i] = {stack : item.stack};
+		}
+	}
 	return JSON.stringify(loggingEvent);
 }
 
@@ -115,4 +123,4 @@ function configure(config, options) {
 }
 
 exports.appender = createAppender;
-exports.configure = configure; 
+exports.configure = configure; 

lib/appenders/multiprocess.js

@@ -94,6 +94,11 @@ function workerAppender(config) {
   }
   
   function write(loggingEvent) {
+	// JSON.stringify(new Error('test')) returns {}, which is not really useful for us.
+	// The following allows us to serialize errors correctly.
+	if (loggingEvent && loggingEvent.stack && JSON.stringify(loggingEvent) === '{}') { // Validate that we really are in this case
+		loggingEvent = {stack : loggingEvent.stack};
+	}
     socket.write(JSON.stringify(loggingEvent), 'utf8');
     socket.write(END_MSG, 'utf8');
   }

test/clusteredAppender-test.js

@@ -97,6 +97,7 @@ vows.describe('log4js cluster appender').addBatch({
 
 			// Actual test - log message using masterAppender
 			workerAppender(new LoggingEvent('wovs', 'Info', ['workerAppender test']));
+			workerAppender(new LoggingEvent('wovs', 'Info', [new Error('Error test')]));
 			
 			var returnValue = {
 				registeredProcessEvents: registeredProcessEvents,
@@ -109,6 +110,12 @@ vows.describe('log4js cluster appender').addBatch({
 		"worker appender should call process.send" : function(topic) {
 			assert.equal(topic.registeredProcessEvents[0].type, '::log-message');
 			assert.equal(JSON.parse(topic.registeredProcessEvents[0].event).data[0], "workerAppender test");
+		},
+		
+		"worker should serialize an Error correctly" : function(topic) {
+			var expected = { stack: 'Error: Error test\n    at Object.vows.describe.addBatch.when in worker mode.topic (/home/vagrant/log4js-node/test/clusteredAppender-test.js:100:53)\n    at run (/home/vagrant/log4js-node/node_modules/vows/lib/vows/suite.js:134:35)\n    at EventEmitter.Suite.runBatch.callback (/home/vagrant/log4js-node/node_modules/vows/lib/vows/suite.js:234:40)\n    at EventEmitter.emit (events.js:126:20)\n    at EventEmitter.vows.describe.options.Emitter.emit (/home/vagrant/log4js-node/node_modules/vows/lib/vows.js:237:24)\n    at Suite.runBatch.topic (/home/vagrant/log4js-node/node_modules/vows/lib/vows/suite.js:169:45)\n    at process.startup.processNextTick.process._tickCallback (node.js:245:9)' };
+			assert.equal(topic.registeredProcessEvents[1].type, '::log-message');
+			assert.equal(JSON.stringify(JSON.parse(topic.registeredProcessEvents[1].event).data[0]), JSON.stringify(expected));
 		}
 		
 	}

test/multiprocess-test.js

@@ -75,6 +75,7 @@ vows.describe('Multiprocess Appender').addBatch({
       appender('after error, before connect');
       fakeNet.cbs.connect();
       appender('after error, after connect');
+	  appender(new Error('Error test'));
       
       return fakeNet;
     },
@@ -98,6 +99,10 @@ vows.describe('Multiprocess Appender').addBatch({
       assert.equal(net.data[6], JSON.stringify('after error, after connect'));
       assert.equal(net.data[7], '__LOG4JS__');
       assert.equal(net.createConnectionCalled, 2);
+    },
+    'should serialize an Error correctly': function(net) {
+      var expected = { stack: 'Error: Error test\n    at Object.vows.describe.addBatch.worker.topic (/home/vagrant/log4js-node/test/multiprocess-test.js:78:13)\n    at run (/home/vagrant/log4js-node/node_modules/vows/lib/vows/suite.js:134:35)\n    at EventEmitter.Suite.runBatch.callback (/home/vagrant/log4js-node/node_modules/vows/lib/vows/suite.js:234:40)\n    at EventEmitter.emit (events.js:126:20)\n    at EventEmitter.vows.describe.options.Emitter.emit (/home/vagrant/log4js-node/node_modules/vows/lib/vows.js:237:24)\n    at Suite.runBatch.topic (/home/vagrant/log4js-node/node_modules/vows/lib/vows/suite.js:169:45)\n    at process.startup.processNextTick.process._tickCallback (node.js:245:9)' };
+	  assert.equal(net.data[8], JSON.stringify(expected));
     }
   },
   'worker with timeout': {