Implement basic functionalities for workflow control.
- Manage join/leave of clients
- All clients communicate via socket.io
- Probes emit events
- Managers register workflows (by using a workflow essence)
- Send kickstart request to Managers to launch workflows
- Route events to workflow runs
- Queue events to not lose events between workflow tasks
- Fixed some issues found while working on testcases
- Set to perform coverage and unittest and generate outputs to files

Change-Id: I678723edc20df9247d63a4bf6380785ab8b2b221
diff --git a/src/config/logger.js b/src/config/logger.js
new file mode 100644
index 0000000..0a70904
--- /dev/null
+++ b/src/config/logger.js
@@ -0,0 +1,49 @@
+/*
+ * Copyright 2019-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+(function () {
+    'use strict';
+    
+    const winston = require('winston');
+    const fs = require('fs');
+    const path = require('path');
+    const level = process.env.LOG_LEVEL || 'debug';
+    winston.level = level;
+  
+    const logFile = path.join(__dirname, '../../logs/cord-workflow-control-service');
+  
+    // clear old logs
+    ['error', 'debug'].forEach(l => {
+        try {
+            fs.statSync(`${logFile}.${l}.log`)
+            fs.unlinkSync(`${logFile}.${l}.log`);
+        }
+        catch(e) {
+            // log does not exist
+        }
+    });
+  
+    // create a custom logger with colorized console and persistance to file
+    const logger = winston.createLogger({
+        transports: [
+            new (winston.transports.Console)({level: level, colorize: true}),
+            new (winston.transports.File)({name: 'error-log', level: 'error', filename: `${logFile}.error.log`}),
+            new (winston.transports.File)({name: 'debug-log', level: 'debug', filename: `${logFile}.debug.log`})
+        ]
+    });
+  
+    module.exports = logger;  
+})();
\ No newline at end of file