Merge pull request #31691 from backstage/sennyeya/make-instance-metadata-root

fix: explicitly mark instance metadata as a root service

.changeset/odd-states-melt.md

@@ -0,0 +1,5 @@
+---
+'@backstage/backend-plugin-api': minor
+---
+
+Explicitly mark `coreServices.rootInstanceMetadata` as a root service.

packages/backend-defaults/src/alpha/entrypoints/instanceMetadata/instanceMetadataServiceFactory.test.ts

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  coreServices,
+  createBackendPlugin,
+} from '@backstage/backend-plugin-api';
+import { instanceMetadataServiceFactory } from './instanceMetadataServiceFactory';
+import { startTestBackend } from '@backstage/backend-test-utils';
+import { instanceMetadataServiceRef } from '@backstage/backend-plugin-api/alpha';
+import Router from 'express-promise-router';
+import request from 'supertest';
+
+describe('instanceMetadataServiceFactory', () => {
+  it('should create an instance metadata service', async () => {
+    const pluginSubject = createBackendPlugin({
+      pluginId: 'my-plugin',
+      register(reg) {
+        reg.registerInit({
+          deps: {
+            instanceMetadata: instanceMetadataServiceRef,
+            httpRouter: coreServices.httpRouter,
+          },
+          async init({ instanceMetadata, httpRouter }) {
+            const router = Router();
+            router.get('/instance-metadata', async (_, res) => {
+              const metadata = await instanceMetadata.getInstalledFeatures();
+              res.json(metadata);
+            });
+            httpRouter.use(router);
+          },
+        });
+      },
+    });
+
+    const { server } = await startTestBackend({
+      features: [pluginSubject, instanceMetadataServiceFactory],
+    });
+
+    const response = await request(server)
+      .get('/api/my-plugin/instance-metadata')
+      .expect(200);
+    expect(response.body).toEqual([{ pluginId: 'my-plugin', type: 'plugin' }]);
+  });
+});

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

@@ -234,7 +234,7 @@ export namespace coreServices {
   const urlReader: ServiceRef<UrlReaderService, 'plugin', 'singleton'>;
   const rootInstanceMetadata: ServiceRef<
     RootInstanceMetadataService,
-    'plugin',
+    'root',
     'singleton'
   >;
 }

packages/backend-plugin-api/src/services/definitions/coreServices.ts

@@ -287,5 +287,6 @@ export namespace coreServices {
     import('./RootInstanceMetadataService').RootInstanceMetadataService
   >({
     id: 'core.rootInstanceMetadata',
+    scope: 'root',
   });
 }

packages/backend-test-utils/report.api.md

@@ -355,7 +355,7 @@ export namespace mockServices {
     const // (undocumented)
       factory: () => ServiceFactory<
         RootInstanceMetadataService,
-        'plugin',
+        'root',
         'singleton' | 'multiton'
       >;
   }