Split search index service startup into a build and start phase

Fixes #24794. The build process takes place synchronously to the plugin
initialization rather than at startup so that the HTTP router has the
relevant types available to validate incoming requests.

Signed-off-by: Brian Phillips <28457+brianphillips@users.noreply.github.com>

plugins/search-backend-node/src/alpha.ts

@@ -34,7 +34,7 @@ import {
  * @alpha
  * Options for build method on {@link SearchIndexService}.
  */
-export type SearchIndexServiceStartOptions = {
+export type SearchIndexServiceBuildOptions = {
   searchEngine: SearchEngine;
   collators: RegisterCollatorParameters[];
   decorators: RegisterDecoratorParameters[];
@@ -45,15 +45,21 @@ export type SearchIndexServiceStartOptions = {
  * Interface for implementation of index service.
  */
 export interface SearchIndexService {
+  /**
+   * Initializes state in preparation for starting the search index service
+   */
+  build(options: SearchIndexServiceBuildOptions): void;
+
   /**
    * Starts indexing process
    */
-  start(options: SearchIndexServiceStartOptions): Promise<void>;
+  start(): Promise<void>;
 
   /**
    * Stops indexing process
    */
   stop(): Promise<void>;
+
   /**
    * Returns an index types list.
    */
@@ -83,7 +89,7 @@ type DefaultSearchIndexServiceOptions = {
 
 /**
  * @alpha
- * Reponsible for register the indexing task and start the schedule.
+ * Responsible for register the indexing task and start the schedule.
  */
 class DefaultSearchIndexService implements SearchIndexService {
   private readonly logger: LoggerService;
@@ -98,7 +104,7 @@ class DefaultSearchIndexService implements SearchIndexService {
     return new DefaultSearchIndexService(options);
   }
 
-  async start(options: SearchIndexServiceStartOptions): Promise<void> {
+  build(options: SearchIndexServiceBuildOptions): void {
     this.indexBuilder = new IndexBuilder({
       logger: this.logger,
       searchEngine: options.searchEngine,
@@ -111,8 +117,13 @@ class DefaultSearchIndexService implements SearchIndexService {
     options.decorators.forEach(decorator =>
       this.indexBuilder?.addDecorator(decorator),
     );
+  }
 
-    const { scheduler } = await this.indexBuilder?.build();
+  async start(): Promise<void> {
+    if (!this.indexBuilder) {
+      throw new Error('IndexBuilder is not initialized, call build first');
+    }
+    const { scheduler } = await this.indexBuilder.build();
     this.scheduler = scheduler;
     this.scheduler!.start();
   }