feat: add support for new backend to notifications

Signed-off-by: Heikki Hellgren <heikki.hellgren@op.fi>

plugins/notifications-node/src/index.ts

@@ -22,3 +22,4 @@
 
 export * from './database';
 export * from './service';
+export * from './lib';

plugins/notifications-node/src/lib.ts

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2023 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,
+  createServiceFactory,
+  createServiceRef,
+} from '@backstage/backend-plugin-api';
+import { NotificationService } from './service';
+
+/** @public */
+export const notificationService = createServiceRef<NotificationService>({
+  id: 'notifications.service',
+  scope: 'plugin',
+  defaultFactory: async service =>
+    createServiceFactory({
+      service,
+      deps: {
+        discovery: coreServices.discovery,
+        database: coreServices.database,
+        // TODO: Signals
+      },
+      factory({ discovery, database }) {
+        return NotificationService.create({ discovery, database });
+      },
+    }),
+});