Feature/improve cache verification in health check endpoint (#4868)

* Improve implementation of isHealthy() without using getKeys()

* Update changelog

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Renamed the asset profile icon component to entity logo component and moved to `@ghostfolio/ui`
 - Renamed `Account` to `accounts` in the `User` database schema
+- Improved the cache verification in the health check endpoint (experimental)
 - Improved the language localization for Catalan (`ca`)
 - Improved the language localization for French (`fr`)
 - Improved the language localization for Polish (`pl`)

apps/api/src/app/redis-cache/redis-cache.service.ts

@@ -79,12 +79,22 @@ export class RedisCacheService {
   }
 
   public async isHealthy() {
+    const testKey = '__health_check__';
+    const testValue = Date.now().toString();
+
     try {
       await Promise.race([
-        this.getKeys(),
+        (async () => {
+          await this.set(testKey, testValue, ms('1 second'));
+          const result = await this.get(testKey);
+
+          if (result !== testValue) {
+            throw new Error('Redis health check failed: value mismatch');
+          }
+        })(),
         new Promise((_, reject) =>
           setTimeout(
-            () => reject(new Error('Redis health check timeout')),
+            () => reject(new Error('Redis health check failed: timeout')),
             ms('2 seconds')
           )
         )
@@ -92,7 +102,13 @@ export class RedisCacheService {
 
       return true;
     } catch (error) {
+      Logger.error(error?.message, 'RedisCacheService');
+
       return false;
+    } finally {
+      try {
+        await this.remove(testKey);
+      } catch {}
     }
   }