refactor: stop using the legacy standalone server

Signed-off-by: Camila Belo <camilaibs@gmail.com>

plugins/app-backend/README.md

@@ -13,7 +13,19 @@ yarn --cwd packages/backend add @backstage/plugin-app-backend app
 
 By adding the app package as a dependency we ensure that it is built as part of the backend, and that it can be resolved at runtime.
 
-Now add the plugin router to your app, creating it for example like this:
+Now add the plugin to your app, creating it for example like this:
+
+### New Backend
+
+```ts
+import { createBackend } from '@backstage/backend-defaults';
+
+const backend = createBackend();
+backend.add(import('@backstage/plugin-app-backend/alpha'));
+backend.start();
+```
+
+### Old Backend
 
 ```ts
 const router = await createRouter({

plugins/app-backend/dev/index.ts

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2024 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 { createBackend } from '@backstage/backend-defaults';
+
+const backend = createBackend();
+backend.add(import('../src/alpha'));
+backend.start();

plugins/app-backend/package.json

@@ -66,6 +66,7 @@
   },
   "devDependencies": {
     "@backstage/backend-app-api": "workspace:^",
+    "@backstage/backend-defaults": "workspace:^",
     "@backstage/backend-test-utils": "workspace:^",
     "@backstage/cli": "workspace:^",
     "@backstage/types": "workspace:^",

plugins/app-backend/src/service/standaloneServer.ts

@@ -1,51 +0,0 @@
-/*
- * Copyright 2020 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 { Server } from 'http';
-import { createServiceBuilder } from '@backstage/backend-common';
-import { Config } from '@backstage/config';
-import { createRouter } from './router';
-import { LoggerService } from '@backstage/backend-plugin-api';
-
-export interface ServerOptions {
-  port: number;
-  enableCors: boolean;
-  config: Config;
-  logger: LoggerService;
-}
-
-export async function startStandaloneServer(
-  options: ServerOptions,
-): Promise<Server> {
-  const logger = options.logger.child({ service: 'app-backend' });
-  logger.debug('Starting application server...');
-  const router = await createRouter({
-    logger,
-    config: options.config,
-    appPackageName: 'example-app',
-  });
-
-  const service = createServiceBuilder(module)
-    .setPort(options.port)
-    .addRouter('', router);
-
-  return await service.start().catch(err => {
-    logger.error(err);
-    process.exit(1);
-  });
-}
-
-module.hot?.accept();