Merge pull request #189 from jengler/add-support-for-prerequired-appender-styles

Add support for prerequired appender styles

lib/log4js.js

@@ -298,13 +298,42 @@ function restoreConsole() {
   });
 }
 
-function loadAppender(appender) {
+/**
+ * Load an appenderModule based on the provided appender filepath. Will first
+ * check if the appender path is a subpath of the log4js "lib/appenders" directory.
+ * If not, it will attempt to load the the appender as complete path.
+ *
+ * @param {string} appender The filepath for the appender.
+ * @returns {Object|null} The required appender or null if appender could not be loaded.
+ * @private
+ */
+function requireAppender(appender) {
   var appenderModule;
   try {
     appenderModule = require('./appenders/' + appender);
   } catch (e) {
     appenderModule = require(appender);
   }
+  return appenderModule;
+}
+
+/**
+ * Load an appender. Provided the appender path to be loaded. If appenderModule is defined,
+ * it will be used in place of requiring the appender module.
+ *
+ * @param {string} appender The path to the appender module.
+ * @param {Object|void} [appenderModule] The pre-required appender module. When provided,
+ * instead of requiring the appender by its path, this object will be used.
+ * @returns {void}
+ * @private
+ */
+function loadAppender(appender, appenderModule) {
+  appenderModule = appenderModule || requireAppender(appender);
+
+  if (!appenderModule) {
+    throw new Error("Invalid log4js appender: " + util.inspect(appender));
+  }
+
   module.exports.appenders[appender] = appenderModule.appender.bind(appenderModule);
   if (appenderModule.shutdown) {
     appenderShutdowns[appender] = appenderModule.shutdown.bind(appenderModule);

test/configuration-test.js

@@ -86,6 +86,21 @@ vows.describe('log4js configure').addBatch({
         assert.isFunction(log4js.appenderMakers['some/other/external']);
       }
     },
+    'when appender object loaded via loadAppender': {
+      topic: function() {
+        var testAppender = makeTestAppender(),
+            log4js = sandbox.require('../lib/log4js');
+
+        log4js.loadAppender('some/other/external', testAppender);
+        return log4js;
+      },
+      'should load appender with provided object': function(log4js) {
+        assert.ok(log4js.appenders['some/other/external']);
+      },
+      'should add appender configure function to appenderMakers': function(log4js) {
+        assert.isFunction(log4js.appenderMakers['some/other/external']);
+      }
+    },
     'when configuration file loaded via LOG4JS_CONFIG environment variable': {
       topic: function() {
         process.env.LOG4JS_CONFIG = 'some/path/to/mylog4js.json';