Feature: MDS client enhancement

opensearch_dashboards.json

@@ -7,7 +7,8 @@
   ],
   "requiredPlugins": [
     "navigation",
-    "opensearchDashboardsReact"
+    "opensearchDashboardsReact",
+    "dataSource"
   ],
   "optionalPlugins": [
     "managementOverview"

server/client/index.ts

@@ -0,0 +1,111 @@
+import { get } from "lodash";
+import {
+  IContextProvider,
+  ILegacyScopedClusterClient,
+  OpenSearchDashboardsRequest,
+  RequestHandler,
+  RequestHandlerContext,
+} from "opensearch-dashboards/server";
+import { IRequestHandlerContentWithDataSource, IGetClientProps, DashboardRequestEnhancedWithContext } from "./interface";
+
+export const getClientSupportMDS = (props: IGetClientProps) => {
+  const originalAsScoped = props.client.asScoped;
+  const handler: IContextProvider<RequestHandler<unknown, unknown, unknown>, "core"> = (
+    context: RequestHandlerContext,
+    request: OpenSearchDashboardsRequest
+  ) => {
+    (request as DashboardRequestEnhancedWithContext)[`${props.pluginId}_context`] = context as IRequestHandlerContentWithDataSource;
+    return {} as any;
+  };
+
+  /**
+   * asScoped can not get the request context,
+   * add _context to request
+   */
+  props.core.http.registerRouteHandlerContext(`${props.pluginId}_MDS_CTX_SUPPORT` as "core", handler);
+
+  /**
+   * it is not a good practice to rewrite the method like this
+   * but JS does not provide a method to copy a class instance
+   */
+  props.client.asScoped = function (request: DashboardRequestEnhancedWithContext): ILegacyScopedClusterClient {
+    const context = request[`${props.pluginId}_context`];
+
+    /**
+     * If the context can not be found
+     * reject the request and add a log
+     */
+    if (!context) {
+      const errorMessage = "There is some error between dashboards and your remote data source, please retry again.";
+      props.logger.error(errorMessage);
+      return {
+        callAsCurrentUser: () => Promise.reject(errorMessage),
+        callAsInternalUser: () => Promise.reject(errorMessage),
+      };
+    }
+
+    const dataSourceId = props.getDataSourceId?.(context, request);
+    /**
+     * If no dataSourceId provided
+     * use the original client
+     */
+    if (!dataSourceId) {
+      props.logger.debug("No dataSourceId, using original client");
+      return originalAsScoped.call(props.client, request);
+    }
+
+    const callApi: ILegacyScopedClusterClient["callAsCurrentUser"] = async (...args) => {
+      const [endpoint, clientParams, options] = args;
+      return new Promise(async (resolve, reject) => {
+        props.logger.debug(`Call api using the data source: ${dataSourceId}`);
+        try {
+          const dataSourceClient = await context.dataSource.opensearch.getClient(dataSourceId);
+
+          /**
+           * extend client if needed
+           **/
+          Object.assign(dataSourceClient, { ...props.onExtendClient?.(dataSourceClient) });
+
+          /**
+           * Call the endpoint by providing client
+           * The logic is much the same as what callAPI does in Dashboards
+           */
+          const clientPath = endpoint.split(".");
+          const api: any = get(dataSourceClient, clientPath);
+          let apiContext = clientPath.length === 1 ? dataSourceClient : get(dataSourceClient, clientPath.slice(0, -1));
+          const request = api.call(apiContext, clientParams);
+
+          /**
+           * In case the request is aborted
+           */
+          if (options?.signal) {
+            options.signal.addEventListener("abort", () => {
+              request.abort();
+              reject(new Error("Request was aborted"));
+            });
+          }
+          const result = await request;
+          resolve(result.body || result);
+        } catch (e: any) {
+          /**
+           * TODO
+           * ask dashboard team to add original error to DataSourceError
+           * so that we can make the client behave exactly the same as legacy client
+           */
+          reject(e);
+        }
+      });
+    };
+
+    /**
+     * Return a legacy-client-like client
+     * so that the callers no need to change their code.
+     */
+    const client: ILegacyScopedClusterClient = {
+      callAsCurrentUser: callApi,
+      callAsInternalUser: callApi,
+    };
+    return client;
+  };
+  return props.client;
+};

server/client/interface.ts

@@ -0,0 +1,41 @@
+import { OpenSearchDashboardsClient } from "@opensearch-project/opensearch/api/opensearch_dashboards";
+import {
+  CoreSetup,
+  ILegacyCustomClusterClient,
+  LegacyCallAPIOptions,
+  Logger,
+  OpenSearchDashboardsRequest,
+  RequestHandlerContext,
+} from "opensearch-dashboards/server";
+
+export interface IRequestHandlerContentWithDataSource extends RequestHandlerContext {
+  dataSource: {
+    opensearch: {
+      getClient: (dataSourceId: string) => OpenSearchDashboardsClient;
+      legacy: {
+        getClient: (
+          dataSourceId: string
+        ) => {
+          callAPI: (endpoint: string, clientParams?: Record<string, any>, options?: LegacyCallAPIOptions) => Promise<unknown>;
+        };
+      };
+    };
+  };
+}
+
+export interface IGetClientProps {
+  core: CoreSetup;
+  /**
+   * We will rewrite the asScoped method of your client
+   * It would be better that create a new client before you pass in one
+   */
+  client: ILegacyCustomClusterClient;
+  onExtendClient?: (client: OpenSearchDashboardsClient) => Record<string, any> | undefined;
+  getDataSourceId?: (context: RequestHandlerContext, request: OpenSearchDashboardsRequest) => string | undefined;
+  pluginId: string;
+  logger: Logger;
+}
+
+export type DashboardRequestEnhancedWithContext = OpenSearchDashboardsRequest & {
+  [contextKey: string]: IRequestHandlerContentWithDataSource;
+};