chore: cache the database calls and return the cached one if available

Signed-off-by: blam <ben@blam.sh>

packages/backend-common/src/database/DatabaseManager.test.ts

@@ -113,7 +113,11 @@ describe('DatabaseManager', () => {
         },
       },
     };
-    const manager = DatabaseManager.fromConfig(new ConfigReader(config));
+    let manager: DatabaseManager;
+
+    beforeEach(() => {
+      manager = DatabaseManager.fromConfig(new ConfigReader(config));
+    });
 
     it('connects to a plugin database using default config', async () => {
       const pluginId = 'pluginwithoutconfig';
@@ -340,6 +344,15 @@ describe('DatabaseManager', () => {
       );
     });
 
+    it('returns the same client for the same pluginId', async () => {
+      const client1 = await manager.forPlugin('plugin1').getClient();
+      const client2 = await manager.forPlugin('plugin1').getClient();
+
+      expect(mocked(createDatabaseClient)).toHaveBeenCalledTimes(1);
+
+      expect(client1).toBe(client2);
+    });
+
     it('uses plugin connection as base if default client is different from plugin client', async () => {
       const pluginId = 'differentclient';
       await manager.forPlugin(pluginId).getClient();

packages/backend-common/src/database/DatabaseManager.ts

@@ -84,6 +84,7 @@ export class DatabaseManager {
     private readonly config: Config,
     private readonly prefix: string = 'backstage_plugin_',
     private readonly options?: DatabaseManagerOptions,
+    private readonly databaseCache: Map<string, Knex> = new Map(),
   ) {}
 
   /**
@@ -307,6 +308,9 @@ export class DatabaseManager {
    *          plugin
    */
   private async getDatabase(pluginId: string): Promise<Knex> {
+    if (this.databaseCache.has(pluginId)) {
+      return this.databaseCache.get(pluginId)!;
+    }
     const pluginConfig = new ConfigReader(
       this.getConfigForPlugin(pluginId) as JsonObject,
     );
@@ -344,7 +348,7 @@ export class DatabaseManager {
 
     const client = createDatabaseClient(pluginConfig, databaseClientOverrides);
     this.startKeepaliveLoop(pluginId, client);
-
+    this.databaseCache.set(pluginId, client);
     return client;
   }