init data source service

Signed-off-by: Zhongnan Su <szhongna@amazon.com>

src/plugins/data_source/server/client/data_source_client.ts

@@ -4,6 +4,7 @@
  */
 
 import { Logger, OpenSearchClient, SavedObjectsClientContract } from 'src/core/server';
+import { DataSourceService } from '../data_source_service';
 
 /**
  * Represents an OpenSearch cluster API client created by the platform.
@@ -31,16 +32,24 @@ export interface ICustomDataSourceClient extends IDataSourceClient {
   close: () => Promise<void>;
 }
 
+interface DataSourceClientCtorParams {
+  dataSourceService: DataSourceService;
+  logger: Logger;
+  scopedSavedObjectsClient: SavedObjectsClientContract;
+}
 // TODO: This needs further implementation. See https://github.com/opensearch-project/OpenSearch-Dashboards/issues/1981
 export class DataSourceClient implements ICustomDataSourceClient {
-  private scopedSavedObjectsClient?: SavedObjectsClientContract;
-
-  constructor(logger: Logger) {}
-  asDataSource!: (dataSourceId: string) => Promise<OpenSearchClient>;
+  private dataSourceService: DataSourceService;
+  private log: Logger;
+  private scopedSavedObjectClient;
 
-  public attachScopedSavedObjectsClient(scopedSavedObjectsClient: SavedObjectsClientContract) {
-    this.scopedSavedObjectsClient = scopedSavedObjectsClient;
+  constructor(ctorParams: DataSourceClientCtorParams) {
+    this.dataSourceService = ctorParams.dataSourceService;
+    this.log = ctorParams.logger;
+    this.scopedSavedObjectClient = ctorParams.scopedSavedObjectsClient;
   }
 
+  asDataSource!: (dataSourceId: string) => Promise<OpenSearchClient>;
+
   public async close() {}
 }

src/plugins/data_source/server/data_source_service.ts

@@ -0,0 +1,35 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { Logger, OpenSearchClient, SavedObjectsClientContract } from 'src/core/server';
+import { DataSourceClient } from './client';
+import { IDataSourceService } from './types';
+
+export class DataSourceService implements IDataSourceService {
+  private openSearchClientsPool: Map<string, OpenSearchClient>;
+  constructor() {
+    this.openSearchClientsPool = new Map<string, OpenSearchClient>();
+  }
+  // TODO: placeholders, need implement when adding global config
+  isEnabled(): boolean {
+    throw new Error('Method not implemented.');
+  }
+
+  getDataSourceClient(logger: Logger, savedObjectClient: SavedObjectsClientContract) {
+    return new DataSourceClient({
+      logger,
+      dataSourceService: this,
+      scopedSavedObjectsClient: savedObjectClient,
+    });
+  }
+  // TODO: placeholders, need implement client pooling strategy
+  addOpenSearchClient() {}
+  getOpenSearchClient(): OpenSearchClient {
+    throw new Error('Method not implemented.');
+  }
+
+  // TODO: close all data source clients in the clients pool
+  stop() {}
+}

src/plugins/data_source/server/plugin.ts

@@ -14,17 +14,17 @@ import {
 } from '../../../../src/core/server';
 import { DataSourceClient } from './client/data_source_client';
 import { DataSourceRouteHandlerContext } from './data_source_route_handler_context';
+import { DataSourceService } from './data_source_service';
 import { dataSource, credential } from './saved_objects';
 
 import { DataSourcePluginSetup, DataSourcePluginStart } from './types';
 
 export class DataSourcePlugin implements Plugin<DataSourcePluginSetup, DataSourcePluginStart> {
   private readonly logger: Logger;
-  private readonly dataSourceClient: DataSourceClient;
+  private dataSourceService?: DataSourceService;
 
   constructor(initializerContext: PluginInitializerContext) {
     this.logger = initializerContext.logger.get();
-    this.dataSourceClient = new DataSourceClient(this.logger);
   }
 
   public setup(core: CoreSetup) {
@@ -36,6 +36,8 @@ export class DataSourcePlugin implements Plugin<DataSourcePluginSetup, DataSourc
     // Register data source saved object type
     core.savedObjects.registerType(dataSource);
 
+    this.dataSourceService = new DataSourceService();
+
     // Register plugin context to route handler context
     core.http.registerRouteHandlerContext('data_source', this.createRouteHandlerContext(core));
 
@@ -48,16 +50,19 @@ export class DataSourcePlugin implements Plugin<DataSourcePluginSetup, DataSourc
   }
 
   public stop() {
-    this.dataSourceClient.close();
+    this.dataSourceService!.stop();
   }
 
   private createRouteHandlerContext = (
     core: CoreSetup
   ): IContextProvider<RequestHandler<unknown, unknown, unknown>, 'data_source'> => {
     return async (context, req) => {
       const [{ savedObjects }] = await core.getStartServices();
-      this.dataSourceClient.attachScopedSavedObjectsClient(savedObjects.getScopedClient(req));
-      return new DataSourceRouteHandlerContext(this.dataSourceClient, this.logger);
+      const dataSourceClient = this.dataSourceService!.getDataSourceClient(
+        this.logger,
+        savedObjects.getScopedClient(req)
+      );
+      return new DataSourceRouteHandlerContext(dataSourceClient, this.logger);
     };
   };
 }

src/plugins/data_source/server/types.ts

@@ -3,8 +3,19 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { OpenSearchClient } from 'src/core/server';
+import { Logger, OpenSearchClient, SavedObjectsClientContract } from 'src/core/server';
+import { DataSourceClient } from './client';
 
+export interface IDataSourceService {
+  isEnabled(): boolean;
+  getDataSourceClient(
+    logger: Logger,
+    savedObjectClient: SavedObjectsClientContract
+  ): DataSourceClient;
+  addOpenSearchClient(): void;
+  getOpenSearchClient(): OpenSearchClient;
+  stop(): void;
+}
 export interface DataSourcePluginRequestContext {
   opensearch: {
     getClient: (dataSourceId: string) => Promise<OpenSearchClient>;