BC-6460 Remove redis-node package

package.json

@@ -223,7 +223,6 @@
 		"prom-client": "^13.1.0",
 		"qs": "^6.9.7",
 		"read-chunk": "^3.0.0",
-		"redis": "^4.6.13",
 		"reflect-metadata": "^0.1.13",
 		"request-promise-core": "^1.1.4",
 		"request-promise-native": "^1.0.3",

src/utils/redis.js

@@ -1,5 +1,5 @@
 const { promisify } = require('util');
-const redis = require('redis');
+const Redis = require('ioredis');
 const { Configuration } = require('@hpi-schul-cloud/commons');
 
 const { GeneralError } = require('../errors');
@@ -10,19 +10,13 @@ let redisClient = false;
 async function initializeRedisClient() {
 	if (Configuration.has('REDIS_URI')) {
 		try {
-			redisClient = redis.createClient({
-				url: Configuration.get('REDIS_URI'),
-				// Legacy mode is needed for compatibility with v4, see https://github.com/redis/node-redis/blob/HEAD/docs/v3-to-v4.md#legacy-mode
-				legacyMode: true,
-			});
+			redisClient = new Redis(Configuration.get('REDIS_URI'));
 
 			// The error event must be handled, otherwise the app crashes on redis connection errors.
 			// This is due to basic NodeJS behavior: https://nodejs.org/api/events.html#error-events
 			redisClient.on('error', (err) => {
 				logger.error('Redis client error', err);
 			});
-
-			await redisClient.connect();
 		} catch (err) {
 			throw new GeneralError('Redis connection failed!', err);
 		}