Added a hookio appender, this allows you to run a 'master' log4js instance and 'worker' so only one process writes to file

lib/appenders/hookio.js

@@ -0,0 +1,55 @@
+var log4js = require('../log4js');
+var layouts = require('../layouts');
+var Hook = require('hook.io').Hook;
+var util = require('util');
+
+var Logger = function createLogger(options) {
+  var self = this;
+  var actualAppender = options.actualAppender;
+  Hook.call(self, options);
+  self.on('hook::ready', function hookReady() {
+    self.on('*::' + options.name + '::log', function log(loggingEvent) {
+      deserializeLoggingEvent(loggingEvent);
+      actualAppender(loggingEvent);
+    });
+  });
+}
+util.inherits(Logger, Hook);
+
+function deserializeLoggingEvent(loggingEvent) {
+  loggingEvent.startTime = new Date(loggingEvent.startTime);
+  loggingEvent.level.toString = function levelToString() {
+    return loggingEvent.level.levelStr;
+  };
+}
+
+function createAppender(hookioOptions, actualAppender) {
+  var loggerHook;
+  if (hookioOptions.mode === 'master') {
+    // Start the master hook, handling the actual logging
+    loggerHook = new Logger({ name: hookioOptions.name, debug: hookioOptions.debug, actualAppender: actualAppender });
+  } else {
+    // Start a worker, just emitting events for a master
+    loggerHook = new Hook({ name: hookioOptions.name, debug: hookioOptions.debug });
+  }
+  loggerHook.start();
+
+  var loggerEvent = hookioOptions.name + '::log';
+  return function log(loggingEvent) {
+    loggerHook.emit(loggerEvent, loggingEvent);
+  };
+}
+
+function configure(config) {
+  var actualAppender;
+  if (config.appender && config.mode === 'master') {
+    actualAppender = log4js.appenderMakers[config.appender.type](config.appender);
+  }
+  delete config.appender;
+  delete config.type;
+  return createAppender(config, actualAppender);
+}
+
+exports.name = 'hookio';
+exports.appender = createAppender;
+exports.configure = configure;