addressed review comments

nodejs/nodejs-backend-admin-feature-flag-launchdarkly/bootstrap.js

@@ -7,7 +7,7 @@ const PORT = 5000;
 const app = express();
 const simpleLogger = new Logger('SimpleLogging');
 
-const LD_SDK_KEY = 'sdk-d2432dc7-e56a-458b-9f93-0361af47d578';
+const LD_SDK_KEY = 'sdk-********-****-****-****-************';
 const LOG_LEVEL_FLAG_KEY = 'backend-log-level';
 const client = LaunchDarkly.init(LD_SDK_KEY);
 const asyncGetFlag = util.promisify(client.variation);

nodejs/nodejs-backend-admin-feature-flag-launchdarkly/cron_job.js

@@ -5,7 +5,7 @@ const CronJob = cron.CronJob;
 const CronTime = cron.CronTime;
 
 // Initiating LaunchDarkly Client
-const LD_SDK_KEY = 'sdk-d2432dc7-e56a-458b-9f93-0361af47d578';
+const LD_SDK_KEY = 'sdk-********-****-****-****-************';
 const userName = 'admin';
 const launchDarklyClient = LaunchDarkly.init( LD_SDK_KEY );
 

nodejs/nodejs-backend-admin-feature-flag-launchdarkly/dynamic_logger.js

@@ -0,0 +1,93 @@
+import { format } from 'date-fns';
+import padEnd from 'lodash/padEnd.js';
+import capitalize from 'lodash/capitalize.js';
+
+const LEVELS = { debug: 10, log: 20, warn: 30, error: 40 };
+let currentLogLevel = LEVELS['debug'];
+
+class DynamicLogger {
+  constructor( module, ldClient, flagKey, user ) {
+    this.module = module ? module : '';
+
+    this.debug = this.debug.bind(this);
+    this.info = this.info.bind(this);
+    this.warn = this.warn.bind(this);
+    this.error = this.error.bind(this);
+    this.writeToConsole = this.writeToConsole.bind(this);
+    this.ldClient = ldClient;
+	this.flagKey = flagKey;
+	this.user = user;
+	this.previousLevel = null; 
+  }
+
+  static setLogLevel(level) {
+    currentLogLevel = LEVELS[level];
+  }
+
+  static get(module) {
+    return new Logger(module);
+  }
+
+  writeToConsole(level, message) {
+    if (LEVELS[level] >= currentLogLevel) {
+      const dateTime = format(new Date(), 'MM-dd-yyyy HH:mm:ss:SSS');
+      const formattedLevel = padEnd(capitalize(level), 5);
+      const formattedMessage = `${dateTime} ${formattedLevel} [${
+        this.module
+      }] ${message}`;
+      console[level](formattedMessage, '');
+    }
+  }
+
+  async debug( message ) { 
+    if ( await this._presentLog( 'debug' ) ) {
+        this.writeToConsole('debug', message); 
+    } 
+  }
+
+  async error( message ) { 
+    if ( await this._presentLog( 'error' ) ) {
+        this.writeToConsole('error', message); 
+    } 
+  }
+
+  async info( message ) { 
+    if ( await this._presentLog( 'info' ) ) {
+        this.writeToConsole('info', message); 
+    } 
+  }
+
+  async warn( message ) { 
+    if ( await this._presentLog( 'warn' ) ) {
+        this.writeToConsole('warn', message); 
+    }
+  }
+
+  async _presentLog( level ) {
+
+    const minLogLevel = await this.ldClient.variation(
+        this.flagKey,
+        {
+           key: this.user
+        },
+        'debug' // Default / fall-back value if LaunchDarkly unavailable.
+    );
+
+    if ( minLogLevel !== this.previousLevel ) { 
+       console.log( `Switching to log-level: ${ minLogLevel }` ); 
+    }
+
+    switch ( this.previousLevel = minLogLevel ) {
+        case 'error':
+            return level === 'error';
+        case 'warn':
+            return level === 'error' ||	level === 'warn';
+        case 'info':
+            return level === 'error' || level === 'warn' || level === 'info';
+        default:
+            return true;
+        } 
+    }
+}
+
+export default DynamicLogger;

nodejs/nodejs-backend-admin-feature-flag-launchdarkly/dynamic_logging.js

@@ -1,41 +1,33 @@
 import chalk from 'chalk';
+import util from 'util';
 import LaunchDarkly from 'launchdarkly-node-server-sdk';
-import LdLogger from './ld_logger.js';
+import DynamicLogger from './dynamic_logger.js';
 
-const LD_SDK_KEY = 'sdk-d2432dc7-e56a-458b-9f93-0361af47d578';
+const LD_SDK_KEY = 'sdk-********-****-****-****-************';
 const flagKey = 'backend-log-level';
 const userName = 'admin';
 const launchDarklyClient = LaunchDarkly.init( LD_SDK_KEY );
-const logger = new LdLogger( launchDarklyClient, flagKey, userName );
+const asyncGetFlag = util.promisify(launchDarklyClient.variation);
+const user = {
+    user: userName
+};
+let logger;
 let loop = 0;
 
-launchDarklyClient.once('ready', async () => { 
+launchDarklyClient.once('ready', async () => {
 		setTimeout( executeLoop, 1000 ); 
 	}
 );
 
-//Fake node status reader randomized to throw errors.
-function readNodeStatus() { 
-	const nodeStatus = ( Math.random() * 100 ).toFixed( 1 ); 
-	if ( nodeStatus <= 30 ) { 
-		throw new Error( 'IOError' ); 
-	} 
-	return nodeStatus; 
-}
-
-function executeLoop () {
-		console.log( chalk.dim.italic( `Loop ${ ++loop }` ) ); 
-		logger.debug( 'Executing loop.' ); 
-		try { 
-			logger.debug( 'Checking number of nodes that are busy.' );
-			const nodeCount = readNodeStatus();
-			logger.info( `Number of Nodes that are busy: ${ nodeCount }%` ); 
-			if ( nodeCount >= 50 ) { 
-				logger.warn( 'More than half of the nodes are busy. We should'
-				+ ' think of adding more nodes to the cluster.' ); 
-			} 
-		} catch ( error ) { 
-			logger.error( `Node count could not be read: ${ error.message }` );
-		} 
-		setTimeout( executeLoop, 1000 ); 
+async function executeLoop () {	
+	const initialLogLevel = await asyncGetFlag(flagKey, user, 'debug');
+	logger = new DynamicLogger( 'DynamicLogging', launchDarklyClient, flagKey, userName );
+	DynamicLogger.setLogLevel(initialLogLevel);	
+	console.log( chalk.dim.italic( `Loop ${ ++loop }` ) ); 
+	logger.debug( 'Executing loop.' );
+	logger.debug('This is a debug log.');
+	logger.info('This is an info log.');
+	logger.warn('This is a warn log.');
+	logger.error('This is a error log.');
+	setTimeout( executeLoop, 1000 ); 
 }

nodejs/nodejs-backend-admin-feature-flag-launchdarkly/index.js

@@ -9,13 +9,13 @@ app.get("/", async (req, res) => {
 });
 app.listen(8080);
 
-const sdkKey = 'sdk-d2432dc7-e56a-458b-9f93-0361af47d578';
+const LD_SDK_KEY = 'sdk-********-****-****-****-************';
 const userName = 'admin';
 let client;
 
 async function init() {
   if (!client) {
-    client = LaunchDarkly.init(sdkKey);
+    client = LaunchDarkly.init(LD_SDK_KEY);
     await client.waitForInitialization();
   }
 

nodejs/nodejs-backend-admin-feature-flag-launchdarkly/logger.js

@@ -3,7 +3,7 @@ import padEnd from 'lodash/padEnd.js';
 import capitalize from 'lodash/capitalize.js';
 
 const LEVELS = { debug: 10, log: 20, warn: 30, error: 40 };
-let LD_LOG_LEVEL = LEVELS['debug'];
+let currentLogLevel = LEVELS['debug'];
 
 class Logger {
   constructor(module) {
@@ -13,19 +13,19 @@ class Logger {
     this.log = this.log.bind(this);
     this.warn = this.warn.bind(this);
     this.error = this.error.bind(this);
-    this.consoleWriter = this.consoleWriter.bind(this);
+    this.writeToConsole = this.writeToConsole.bind(this);
   }
 
   static setLogLevel(level) {
-    LD_LOG_LEVEL = LEVELS[level];
+    currentLogLevel = LEVELS[level];
   }
 
   static get(module) {
     return new Logger(module);
   }
 
-  consoleWriter(level, message, context = '') {
-    if (LEVELS[level] >= LD_LOG_LEVEL) {
+  writeToConsole(level, message, context = '') {
+    if (LEVELS[level] >= currentLogLevel) {
       const dateTime = format(new Date(), 'MM-dd-yyyy HH:mm:ss:SSS');
       const formattedLevel = padEnd(capitalize(level), 5);
       const formattedMessage = `${dateTime} ${formattedLevel} [${
@@ -36,19 +36,19 @@ class Logger {
   }
 
   debug(message, context) {
-    this.consoleWriter('debug', message, context);
+    this.writeToConsole('debug', message, context);
   }
 
   log(message, context) {
-    this.consoleWriter('log', message, context);
+    this.writeToConsole('log', message, context);
   }
 
   warn(message, context) {
-    this.consoleWriter('warn', message, context);
+    this.writeToConsole('warn', message, context);
   }
 
   error(message, context) {
-    this.consoleWriter('error', message, context);
+    this.writeToConsole('error', message, context);
   }
 }
 

nodejs/nodejs-backend-admin-feature-flag-launchdarkly/package.json

@@ -5,11 +5,11 @@
   "main": "index.js",
   "type": "module",
   "scripts": {
-    "start": "nodemon index.js",
-    "bootstrap": "nodemon bootstrap.js",
-    "dynamic": "nodemon dynamic_logging.js",
-    "rateLimiter": "nodemon rate_limiter.js",
-    "cron": "nodemon cron_job.js"
+    "start": "node index.js",
+    "bootstrap": "node bootstrap.js",
+    "dynamic": "node dynamic_logging.js",
+    "rateLimiter": "node rate_limiter.js",
+    "cron": "node cron_job.js"
   },
   "author": "Arpendu Kumar Garai",
   "license": "ISC",
@@ -21,7 +21,6 @@
     "express": "^4.18.1",
     "express-rate-limit": "^6.5.1",
     "launchdarkly-node-server-sdk": "^6.4.2",
-    "lodash": "^4.17.21",
-    "nodemon": "^2.0.19"
+    "lodash": "^4.17.21"
   }
 }