backend-app-api,backend-test-api: hook up shutdown hook to stop method

Co-authored-by: Johan Haals <johan.haals@gmail.com>
Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/backend-app-api/api-report.md

@@ -26,6 +26,8 @@ export interface Backend {
   add(feature: BackendFeature): void;
   // (undocumented)
   start(): Promise<void>;
+  // (undocumented)
+  stop(): Promise<void>;
 }
 
 // @public (undocumented)

packages/backend-app-api/src/wiring/BackendInitializer.ts

@@ -17,8 +17,10 @@
 import {
   BackendFeature,
   ExtensionPoint,
+  lifecycleServiceRef,
   ServiceRef,
 } from '@backstage/backend-plugin-api';
+import { BackendLifecycleImpl } from '../services/implementations/lifecycleService';
 import {
   BackendRegisterInit,
   ServiceHolder,
@@ -165,4 +167,24 @@ export class BackendInitializer {
 
     return orderedRegisterInits;
   }
+
+  async stop(): Promise<void> {
+    if (!this.#started) {
+      throw new Error('Backend has not started');
+    }
+    this.#started = false;
+
+    const lifecycleService = await this.#serviceHolder.get(
+      lifecycleServiceRef,
+      'root',
+    );
+
+    // TODO(Rugvip): :D
+    const lifecycle = (lifecycleService as any)?.lifecycle;
+    if (lifecycle instanceof BackendLifecycleImpl) {
+      await lifecycle.shutdown();
+    } else {
+      throw new Error('Unexpected lifecycle service implementation');
+    }
+  }
 }

packages/backend-app-api/src/wiring/BackstageBackend.ts

@@ -36,7 +36,7 @@ export class BackstageBackend implements Backend {
     await this.#initializer.start();
   }
 
-  // async stop(): Promise<void> {
-  //   await this.#initializer.stop();
-  // }
+  async stop(): Promise<void> {
+    await this.#initializer.stop();
+  }
 }

packages/backend-app-api/src/wiring/types.ts

@@ -28,6 +28,7 @@ import { BackstageBackend } from './BackstageBackend';
 export interface Backend {
   add(feature: BackendFeature): void;
   start(): Promise<void>;
+  stop(): Promise<void>;
 }
 
 export interface BackendRegisterInit {