support legacy client for data source

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

src/core/server/opensearch/legacy/cluster_client.ts

@@ -65,7 +65,7 @@ const noop = () => undefined;
  * OpenSearch JS client.
  * @param options Options that affect the way we call the API and process the result.
  */
-const callAPI = async (
+export const callAPI = async (
   client: Client,
   endpoint: string,
   clientParams: Record<string, any> = {},

src/plugins/data/server/index_patterns/fetcher/index_patterns_fetcher.ts

@@ -28,7 +28,7 @@
  * under the License.
  */
 
-import { LegacyAPICaller, OpenSearchClient } from 'opensearch-dashboards/server';
+import { LegacyAPICaller } from 'opensearch-dashboards/server';
 
 import { getFieldCapabilities, resolveTimePattern, createNoMatchingIndicesError } from './lib';
 
@@ -48,9 +48,9 @@ interface FieldSubType {
 }
 
 export class IndexPatternsFetcher {
-  private _callDataCluster: LegacyAPICaller | OpenSearchClient;
+  private _callDataCluster: LegacyAPICaller;
 
-  constructor(callDataCluster: LegacyAPICaller | OpenSearchClient) {
+  constructor(callDataCluster: LegacyAPICaller) {
     this._callDataCluster = callDataCluster;
   }
 

src/plugins/data/server/index_patterns/fetcher/lib/field_capabilities/field_capabilities.ts

@@ -30,7 +30,7 @@
 
 import { defaults, keyBy, sortBy } from 'lodash';
 
-import { LegacyAPICaller, OpenSearchClient } from 'opensearch-dashboards/server';
+import { LegacyAPICaller } from 'opensearch-dashboards/server';
 import { callFieldCapsApi } from '../opensearch_api';
 import { FieldCapsResponse, readFieldCapsResponse } from './field_caps_response';
 import { mergeOverrides } from './overrides';
@@ -47,7 +47,7 @@ import { FieldDescriptor } from '../../index_patterns_fetcher';
  *  @return {Promise<Array<FieldDescriptor>>}
  */
 export async function getFieldCapabilities(
-  callCluster: LegacyAPICaller | OpenSearchClient,
+  callCluster: LegacyAPICaller,
   indices: string | string[] = [],
   metaFields: string[] = [],
   fieldCapsOptions?: { allowNoIndices: boolean }

src/plugins/data/server/index_patterns/fetcher/lib/opensearch_api.ts

@@ -94,22 +94,11 @@ export async function callIndexAliasApi(
  *  @return {Promise<FieldCapsResponse>}
  */
 export async function callFieldCapsApi(
-  callCluster: LegacyAPICaller | OpenSearchClient,
+  callCluster: LegacyAPICaller,
   indices: string[] | string,
   fieldCapsOptions: { allowNoIndices: boolean } = { allowNoIndices: false }
 ) {
   try {
-    if ('transport' in callCluster) {
-      return (
-        await callCluster.fieldCaps({
-          index: indices,
-          fields: '*',
-          ignore_unavailable: true,
-          allow_no_indices: fieldCapsOptions.allowNoIndices,
-        })
-      ).body as FieldCapsResponse;
-    }
-
     return (await callCluster('fieldCaps', {
       index: indices,
       fields: '*',

src/plugins/data/server/index_patterns/routes.ts

@@ -29,7 +29,11 @@
  */
 
 import { schema } from '@osd/config-schema';
-import { HttpServiceSetup, RequestHandlerContext } from 'opensearch-dashboards/server';
+import {
+  HttpServiceSetup,
+  LegacyAPICaller,
+  RequestHandlerContext,
+} from 'opensearch-dashboards/server';
 import { IndexPatternsFetcher } from './fetcher';
 
 export function registerRoutes(http: HttpServiceSetup) {
@@ -153,9 +157,8 @@ export function registerRoutes(http: HttpServiceSetup) {
 
 const decideClient = async (context: RequestHandlerContext, request: any) => {
   const dataSourceId = request.query.data_source;
-  if (dataSourceId) {
-    return await context.dataSource.opensearch.getClient(dataSourceId);
-  }
-
-  return context.core.opensearch.legacy.client.callAsCurrentUser;
+  return dataSourceId
+    ? ((await context.dataSource.opensearch.legacy.getClient(dataSourceId)
+        .callAPI) as LegacyAPICaller)
+    : context.core.opensearch.legacy.client.callAsCurrentUser;
 };

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

@@ -4,13 +4,14 @@
  */
 
 import { Client } from '@opensearch-project/opensearch';
+import { Client as LegacyClient } from 'elasticsearch';
 import LRUCache from 'lru-cache';
 import { Logger } from 'src/core/server';
 import { DataSourcePluginConfigType } from '../../config';
 
 export interface OpenSearchClientPoolSetup {
-  getClientFromPool: (id: string) => Client | undefined;
-  addClientToPool: (endpoint: string, client: Client) => void;
+  getClientFromPool: (id: string) => Client | LegacyClient | undefined;
+  addClientToPool: (endpoint: string, client: Client | LegacyClient) => void;
 }
 
 /**
@@ -21,14 +22,14 @@ export interface OpenSearchClientPoolSetup {
  */
 export class OpenSearchClientPool {
   // LRU cache
-  //   key: data source endpoint url
-  //   value: OpenSearch client object
-  private cache?: LRUCache<string, Client>;
+  //   key: data source endpoint, prefixed with identifier for legacy
+  //   value: OpenSearch client object | Legacy client object
+  private cache?: LRUCache<string, Client | LegacyClient>;
   private isClosed = false;
 
   constructor(private logger: Logger) {}
 
-  public async setup(config: DataSourcePluginConfigType) {
+  public async setup(config: DataSourcePluginConfigType): Promise<OpenSearchClientPoolSetup> {
     const logger = this.logger;
     const { size } = config.clientPool;
 
@@ -53,7 +54,7 @@ export class OpenSearchClientPool {
       return this.cache!.get(endpoint);
     };
 
-    const addClientToPool = (endpoint: string, client: Client) => {
+    const addClientToPool = (endpoint: string, client: Client | LegacyClient) => {
       this.cache!.set(endpoint, client);
     };
 

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

@@ -5,7 +5,7 @@
 
 import { Client } from '@opensearch-project/opensearch';
 import {
-  Logger,
+  LegacyAPICaller,
   SavedObject,
   SavedObjectsClientContract,
   SavedObjectsErrorHelpers,
@@ -18,17 +18,18 @@ import {
 import { DataSourceAttributes } from '../../common/data_sources';
 import { DataSourcePluginConfigType } from '../../config';
 import { CryptographyClient } from '../cryptography';
+import { DataSourceClientParams } from '../types';
 import { parseClientOptions } from './client_config';
 import { OpenSearchClientPoolSetup } from './client_pool';
 
-export const configureClient = async (
-  dataSourceId: string,
-  savedObjects: SavedObjectsClientContract,
-  cryptographyClient: CryptographyClient,
-  openSearchClientPoolSetup: OpenSearchClientPoolSetup,
-  config: DataSourcePluginConfigType,
-  logger: Logger
-): Promise<Client> => {
+export const configureClient = async ({
+  dataSourceId,
+  savedObjects,
+  config,
+  logger,
+  cryptographyClient,
+  openSearchClientPoolSetup,
+}: DataSourceClientParams): Promise<Client> => {
   const dataSource = await getDataSource(dataSourceId, savedObjects);
   const rootClient = getRootClient(dataSource.attributes, config, openSearchClientPoolSetup);
 
@@ -120,7 +121,7 @@ const getRootClient = (
   const endpoint = dataSourceAttr.endpoint;
   const cachedClient = getClientFromPool(endpoint);
   if (cachedClient) {
-    return cachedClient;
+    return cachedClient as Client;
   } else {
     const clientOptions = parseClientOptions(config, endpoint);
 
@@ -147,3 +148,36 @@ const getBasicAuthClient = (
     headers: { authorization: null },
   });
 };
+
+// const getLegacyClient = (client: Client, isLegacy: boolean, logger: Logger): Client => {
+//   if (isLegacy) {
+//     logger.warn(
+//       'Legacy OpenSearch client is used. Please migrate your code to use the new OpenSearch client.'
+//     );
+//     return new LegacyScopedClusterClient(callAsCurrentUser, callAsCurrentUser);
+//   } else {
+//     return client;
+//   }
+// };
+
+/**
+ * Calls specified endpoint with provided clientParams on behalf of the
+ * user initiated request to the OpenSearch Dashboards server (via HTTP request headers).
+ * See {@link LegacyAPICaller}.
+ *
+ * @param endpoint - String descriptor of the endpoint e.g. `cluster.getSettings` or `ping`.
+ * @param clientParams - A dictionary of parameters that will be passed directly to the OpenSearch JS client.
+ * @param options - Options that affect the way we call the API and process the result.
+ */
+// const callAsCurrentUser: LegacyAPICaller = async (
+//   client: Client,
+//   endpoint: string,
+//   clientParams: Record<string, any> = {},
+//   options?: LegacyCallAPIOptions
+// ) => {
+//   return await (callAPI.bind(null, client as EsClient) as LegacyAPICaller)(
+//     endpoint,
+//     clientParams,
+//     options
+//   );
+// };

src/plugins/data_source/server/data_source_service.ts

@@ -3,17 +3,42 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { Logger, OpenSearchClient, SavedObjectsClientContract } from '../../../../src/core/server';
+import {
+  LegacyCallAPIOptions,
+  Logger,
+  OpenSearchClient,
+  SavedObjectsClientContract,
+} from '../../../../src/core/server';
 import { DataSourcePluginConfigType } from '../config';
 import { OpenSearchClientPool, configureClient } from './client';
 import { CryptographyClient } from './cryptography';
+import { configureLegacyClient } from './legacy';
+
+export interface LegacyClientCallAPIParams {
+  endpoint: string;
+  clientParams?: Record<string, any>;
+  options?: LegacyCallAPIOptions;
+}
+
+export interface DataSourceClientParams {
+  dataSourceId: string;
+  // this saved objects client is used to fetch data source on behalf of users, caller should pass scoped saved objects client
+  savedObjects: SavedObjectsClientContract;
+  cryptographyClient: CryptographyClient;
+}
+
 export interface DataSourceServiceSetup {
-  getDataSourceClient: (
-    dataSourceId: string,
-    // this saved objects client is used to fetch data source on behalf of users, caller should pass scoped saved objects client
-    savedObjects: SavedObjectsClientContract,
-    cryptographyClient: CryptographyClient
-  ) => Promise<OpenSearchClient>;
+  getDataSourceClient: (params: DataSourceClientParams) => Promise<OpenSearchClient>;
+
+  getDataSourceLegacyClient: (
+    params: DataSourceClientParams
+  ) => {
+    callAPI: (
+      endpoint: string,
+      clientParams?: Record<string, any>,
+      options?: LegacyCallAPIOptions
+    ) => Promise<any>;
+  };
 }
 export class DataSourceService {
   private readonly openSearchClientPool: OpenSearchClientPool;
@@ -22,25 +47,40 @@ export class DataSourceService {
     this.openSearchClientPool = new OpenSearchClientPool(logger);
   }
 
-  async setup(config: DataSourcePluginConfigType) {
-    const openSearchClientPoolSetup = await this.openSearchClientPool.setup(config);
+  async setup(config: DataSourcePluginConfigType): Promise<DataSourceServiceSetup> {
+    const basicParams = {
+      openSearchClientPoolSetup: await this.openSearchClientPool.setup(config),
+      config,
+      logger: this.logger,
+    };
 
     const getDataSourceClient = async (
-      dataSourceId: string,
-      savedObjects: SavedObjectsClientContract,
-      cryptographyClient: CryptographyClient
+      dataSourceClientParams: DataSourceClientParams
     ): Promise<OpenSearchClient> => {
-      return configureClient(
-        dataSourceId,
-        savedObjects,
-        cryptographyClient,
-        openSearchClientPoolSetup,
-        config,
-        this.logger
-      );
+      return configureClient({
+        ...basicParams,
+        ...dataSourceClientParams,
+      });
+    };
+
+    const getDataSourceLegacyClient = (dataSourceClientParams: DataSourceClientParams) => {
+      return {
+        callAPI: (
+          endpoint: string,
+          clientParams?: Record<string, any>,
+          options?: LegacyCallAPIOptions
+        ) =>
+          configureLegacyClient(
+            {
+              ...basicParams,
+              ...dataSourceClientParams,
+            },
+            { endpoint, clientParams, options }
+          ),
+      };
     };
 
-    return { getDataSourceClient };
+    return { getDataSourceClient, getDataSourceLegacyClient };
   }
 
   start() {}

src/plugins/data_source/server/legacy/client_config.ts

@@ -0,0 +1,28 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { ConfigOptions } from 'elasticsearch';
+import { DataSourcePluginConfigType } from '../../config';
+
+/**
+ * Parse the client options from given data source config and endpoint
+ *
+ * @param config The config to generate the client options from.
+ * @param endpoint endpoint url of data source
+ */
+export function parseClientOptions(
+  // TODO: will use client configs, that comes from a merge result of user config and default legacy client config,
+  config: DataSourcePluginConfigType,
+  endpoint: string
+): ConfigOptions {
+  const configOptions: ConfigOptions = {
+    host: endpoint,
+    ssl: {
+      rejectUnauthorized: true,
+    },
+  };
+
+  return configOptions;
+}