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;

lib/log4js.js

@@ -248,13 +248,13 @@ function getDefaultLogger () {
     return getLogger(DEFAULT_CATEGORY);
 }
 
-function findConfiguration() {
+function findConfiguration(filename) {
     var path;
     try {
-        path = require.resolve('log4js.json');
+        path = require.resolve(filename || 'log4js.json');
     } catch (e) {
         //file not found. default to the one in the log4js module.
-        path = __dirname + '/log4js.json';
+        path = filename || __dirname + '/log4js.json';
     }
 
     return path;
@@ -263,7 +263,7 @@ function findConfiguration() {
 var configState = {};
 
 function loadConfigurationFile(filename) {
-    filename = filename || findConfiguration();
+    filename = findConfiguration(filename);
     if (filename && (!configState.lastFilename || filename !== configState.lastFilename ||
                      !configState.lastMTime || fs.statSync(filename).mtime !== configState.lastMTime)) {
         configState.lastFilename = filename;
@@ -285,7 +285,7 @@ function configureOnceOff(config) {
 }
 
 function reloadConfiguration() {
-    var filename = configState.filename || findConfiguration(),
+    var filename = findConfiguration(configState.filename),
     mtime;
     if (!filename) {
         // can't find anything to reload
@@ -371,6 +371,7 @@ module.exports = {
 
     layouts: layouts,
     appenders: {},
+    appenderMakers: appenderMakers,
     connectLogger: require('./connect-logger').connectLogger
 };
 

package.json

@@ -21,6 +21,9 @@
        "test": "test",
        "lib": "lib"
    },
+   "dependencies": {
+     "hook.io": "0.7.7"
+   },
    "devDependencies": {
        "vows": ">=0.5.2",
        "sandboxed-module": ">= 0.1.1"