From 49fe8c20005c8a09780a044f917bf388b096ff33 Mon Sep 17 00:00:00 2001
From: Emma Indal <emma.indahl@gmail.com>
Date: Tue, 28 Feb 2023 14:34:34 +0100
Subject: [PATCH] define interfaces for extension points and services

Signed-off-by: Emma Indal <emma.indahl@gmail.com>
Co-authored-by: Camila Loiola <camilaibs@gmail.com>
---
 .../search-backend-node/src/IndexBuilder.ts   |  7 ++-
 plugins/search-backend-node/src/index.ts      |  2 +-
 plugins/search-backend-node/src/types.ts      | 26 ++++++++
 plugins/search-backend/src/plugin.ts          | 59 +++++++++++++++++++
 4 files changed, 92 insertions(+), 2 deletions(-)
 create mode 100644 plugins/search-backend/src/plugin.ts

diff --git a/plugins/search-backend-node/src/IndexBuilder.ts b/plugins/search-backend-node/src/IndexBuilder.ts
index 907519f289..9397c098aa 100644
--- a/plugins/search-backend-node/src/IndexBuilder.ts
+++ b/plugins/search-backend-node/src/IndexBuilder.ts
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import { createServiceRef } from '@backstage/backend-plugin-api';
 import {
   DocumentDecoratorFactory,
   DocumentTypeInfo,
@@ -23,16 +24,20 @@ import { Transform, pipeline } from 'stream';
 import { Logger } from 'winston';
 import { Scheduler } from './Scheduler';
 import {
+  IndexBuilderService,
   IndexBuilderOptions,
   RegisterCollatorParameters,
   RegisterDecoratorParameters,
 } from './types';
 
+export const searchIndexBuilderRef = createServiceRef<IndexBuilderService>({
+  id: 'search.index-node',
+});
 /**
  * Used for adding collators, decorators and compile them into tasks which are added to a scheduler returned to the caller.
  * @public
  */
-export class IndexBuilder {
+export class IndexBuilder implements IndexBuilderService {
   private collators: Record<string, RegisterCollatorParameters>;
   private decorators: Record<string, DocumentDecoratorFactory[]>;
   private documentTypes: Record<string, DocumentTypeInfo>;
diff --git a/plugins/search-backend-node/src/index.ts b/plugins/search-backend-node/src/index.ts
index a188509c1c..1bcd31de93 100644
--- a/plugins/search-backend-node/src/index.ts
+++ b/plugins/search-backend-node/src/index.ts
@@ -20,7 +20,7 @@
  * @packageDocumentation
  */
 
-export { IndexBuilder } from './IndexBuilder';
+export { IndexBuilder, searchIndexBuilderRef } from './IndexBuilder';
 export { Scheduler } from './Scheduler';
 export * from './collators';
 export { LunrSearchEngine } from './engines';
diff --git a/plugins/search-backend-node/src/types.ts b/plugins/search-backend-node/src/types.ts
index dfcf4d12ce..94b21cceec 100644
--- a/plugins/search-backend-node/src/types.ts
+++ b/plugins/search-backend-node/src/types.ts
@@ -18,9 +18,11 @@ import { TaskRunner } from '@backstage/backend-tasks';
 import {
   DocumentCollatorFactory,
   DocumentDecoratorFactory,
+  DocumentTypeInfo,
   SearchEngine,
 } from '@backstage/plugin-search-common';
 import { Logger } from 'winston';
+import { Scheduler } from './Scheduler';
 
 /**
  * Options required to instantiate the index builder.
@@ -57,3 +59,27 @@ export interface RegisterDecoratorParameters {
    */
   factory: DocumentDecoratorFactory;
 }
+
+export type IndexBuilderServiceBuildOptions = {
+  searchEngine: SearchEngine;
+  collators: RegisterCollatorParameters[];
+  decorators: RegisterDecoratorParameters[];
+};
+export interface IndexBuilderService {
+  build(options: IndexBuilderServiceBuildOptions): Promise<{
+    scheduler: Scheduler;
+  }>;
+  getDocumentTypes(): Record<string, DocumentTypeInfo>;
+}
+
+export interface SearchIndexRegistryExtensionPoint {
+  addCollator(options: RegisterCollatorParameters): void;
+  addDecorator(options: RegisterDecoratorParameters): void;
+  getCollators(): RegisterCollatorParameters[];
+  getDecorators(): RegisterDecoratorParameters[];
+}
+
+export interface SearchEngineRegistryExtensionPoint {
+  setSearchEngine(searchEngine: SearchEngine): void;
+  getSearchEngine(): SearchEngine;
+}
diff --git a/plugins/search-backend/src/plugin.ts b/plugins/search-backend/src/plugin.ts
new file mode 100644
index 0000000000..5d7c7935a8
--- /dev/null
+++ b/plugins/search-backend/src/plugin.ts
@@ -0,0 +1,59 @@
+import {
+  coreServices,
+  createBackendPlugin,
+} from '@backstage/backend-plugin-api';
+import { loggerToWinstonLogger } from '@backstage/backend-common';
+import {
+  searchIndexBuilderRef,
+  searchEngineExtensionPoint,
+  searchIndexExtensionPoint,
+} from '@backstage/plugin-search-backend-node';
+
+import { createRouter } from './service/router';
+
+export const searchPlugin = createBackendPlugin({
+  pluginId: 'search',
+  register(env) {
+    env.registerInit({
+      deps: {
+        logger: coreServices.logger,
+        config: coreServices.config,
+        permissions: coreServices.permissions,
+        http: coreServices.httpRouter,
+        searchIndexBuilder: searchIndexBuilderRef,
+        searchEngineRegistry: searchEngineExtensionPoint,
+        searchIndexRegistry: searchIndexExtensionPoint,
+      },
+      async init({
+        config,
+        logger,
+        permissions,
+        http,
+        searchEngineRegistry,
+        searchIndexRegistry,
+        searchIndexBuilder,
+      }) {
+        const searchEngine = searchEngineRegistry.getSearchEngine();
+        const collators = searchIndexRegistry.getCollators();
+        const decorators = searchIndexRegistry.getDecorators();
+
+        const { scheduler } = searchIndexBuilder.build({
+          searchEngine,
+          collators,
+          decorators,
+        });
+        scheduler.start();
+
+        const router = await createRouter({
+          config,
+          permissions,
+          logger: loggerToWinstonLogger(logger),
+          engine: searchEngine,
+          types: searchIndexBuilder.getDocumentTypes(),
+        });
+        // We register the router with the http service.
+        http.use(router);
+      },
+    });
+  },
+});