Backend Plugins: add a common implementation (#21408)

* add common backend

* use const for range

* likely not differnt

* send the right orgId

* Add DataSourceWithBackend to @grafana/runtime mock in root reducer test

Co-authored-by: Dominik Prokop <dominik.prokop@grafana.com>

packages/grafana-runtime/src/index.ts

@@ -3,3 +3,5 @@ export * from './config';
 export * from './types';
 export { loadPluginCss, SystemJS } from './utils/plugin';
 export { reportMetaAnalytics } from './utils/analytics';
+
+export { DataSourceWithBackend } from './utils/DataSourceWithBackend';

packages/grafana-runtime/src/utils/DataSourceWithBackend.ts

+import {
+  DataSourceApi,
+  DataQueryRequest,
+  DataQueryResponse,
+  DataSourceInstanceSettings,
+  DataQuery,
+  DataSourceJsonData,
+} from '@grafana/data';
+import { Observable, from } from 'rxjs';
+import { config } from '..';
+import { getBackendSrv } from '../services';
+
+// Ideally internal (exported for consistency)
+const ExpressionDatasourceID = '__expr__';
+
+export class DataSourceWithBackend<
+  TQuery extends DataQuery = DataQuery,
+  TOptions extends DataSourceJsonData = DataSourceJsonData
+> extends DataSourceApi<TQuery, TOptions> {
+  constructor(instanceSettings: DataSourceInstanceSettings<TOptions>) {
+    super(instanceSettings);
+  }
+
+  /**
+   * Ideally final -- any other implementation would be wrong!
+   */
+  query(request: DataQueryRequest): Observable<DataQueryResponse> {
+    const { targets, intervalMs, maxDataPoints, range } = request;
+
+    let expressionCount = 0;
+    const orgId = config.bootData.user.orgId;
+    const queries = targets.map(q => {
+      if (q.datasource === ExpressionDatasourceID) {
+        expressionCount++;
+        return {
+          ...q,
+          datasourceId: this.id,
+          orgId,
+        };
+      }
+      const dsName = q.datasource && q.datasource !== 'default' ? q.datasource : config.defaultDatasource;
+      const ds = config.datasources[dsName];
+      if (!ds) {
+        throw new Error('Unknown Datasource: ' + q.datasource);
+      }
+      return {
+        ...q,
+        datasourceId: ds.id,
+        intervalMs,
+        maxDataPoints,
+        orgId,
+      };
+    });
+
+    const body: any = {
+      expressionCount,
+      queries,
+    };
+    if (range) {
+      body.range = range;
+      body.from = range.from.valueOf().toString();
+      body.to = range.to.valueOf().toString();
+    }
+
+    const req: Promise<DataQueryResponse> = getBackendSrv()
+      .post('/api/ds/query', body)
+      .then((rsp: any) => {
+        return this.toDataQueryResponse(rsp);
+      });
+    return from(req);
+  }
+
+  /**
+   * This makes the arrow libary loading async.
+   */
+  async toDataQueryResponse(rsp: any): Promise<DataQueryResponse> {
+    const { resultsToDataFrames } = await import(
+      /* webpackChunkName: "apache-arrow-util" */ '@grafana/data/src/dataframe/ArrowDataFrame'
+    );
+    return { data: resultsToDataFrames(rsp) };
+  }
+
+  testDatasource() {
+    // TODO, this will call the backend healthcheck endpoint
+    return Promise.resolve({});
+  }
+}

public/app/core/reducers/root.test.ts

@@ -14,6 +14,7 @@ jest.mock('@grafana/runtime', () => ({
       user: {},
     },
   },
+  DataSourceWithBackend: jest.fn(),
 }));
 
 describe('recursiveCleanState', () => {

public/app/features/expressions/ExpressionDatasource.ts

-import {
-  DataSourceApi,
-  DataQueryRequest,
-  DataQueryResponse,
-  DataSourceInstanceSettings,
-  DataSourcePluginMeta,
-} from '@grafana/data';
+import { DataSourceInstanceSettings, DataSourcePluginMeta } from '@grafana/data';
 import { ExpressionQuery, GELQueryType } from './types';
 import { ExpressionQueryEditor } from './ExpressionQueryEditor';
-import { Observable, from } from 'rxjs';
-import { config } from '@grafana/runtime';
-import { getBackendSrv } from 'app/core/services/backend_srv';
+import { DataSourceWithBackend } from '@grafana/runtime';
 
 /**
  * This is a singleton instance that just pretends to be a DataSource
  */
-export class ExpressionDatasourceApi extends DataSourceApi<ExpressionQuery> {
+export class ExpressionDatasourceApi extends DataSourceWithBackend<ExpressionQuery> {
   constructor(instanceSettings: DataSourceInstanceSettings) {
     super(instanceSettings);
   }
@@ -23,61 +15,6 @@ export class ExpressionDatasourceApi extends DataSourceApi<ExpressionQuery> {
     return `Expression: ${query.type}`;
   }
 
-  query(request: DataQueryRequest): Observable<DataQueryResponse> {
-    const { targets, intervalMs, maxDataPoints, range } = request;
-
-    let expressionCount = 0;
-    const orgId = (window as any).grafanaBootData.user.orgId;
-    const queries = targets.map(q => {
-      if (q.datasource === ExpressionDatasourceID) {
-        expressionCount++;
-        return {
-          ...q,
-          datasourceId: this.id,
-          orgId,
-        };
-      }
-      const dsName = q.datasource && q.datasource !== 'default' ? q.datasource : config.defaultDatasource;
-      const ds = config.datasources[dsName];
-      if (!ds) {
-        throw new Error('Unknown Datasource: ' + q.datasource);
-      }
-      return {
-        ...q,
-        datasourceId: ds.id,
-        intervalMs,
-        maxDataPoints,
-        orgId,
-      };
-    });
-    const req: Promise<DataQueryResponse> = getBackendSrv()
-      .post('/api/ds/query', {
-        from: range.from.valueOf().toString(),
-        to: range.to.valueOf().toString(),
-        queries: queries,
-        range,
-        expressionCount,
-      })
-      .then((rsp: any) => {
-        return this.toDataQueryResponse(rsp);
-      });
-    return from(req);
-  }
-
-  /**
-   * This makes the arrow libary loading async.
-   */
-  async toDataQueryResponse(rsp: any): Promise<DataQueryResponse> {
-    const { resultsToDataFrames } = await import(
-      /* webpackChunkName: "apache-arrow-util" */ '@grafana/data/src/dataframe/ArrowDataFrame'
-    );
-    return { data: resultsToDataFrames(rsp) };
-  }
-
-  testDatasource() {
-    return Promise.resolve({});
-  }
-
   newQuery(): ExpressionQuery {
     return {
       refId: '--', // Replaced with query
@@ -87,7 +24,9 @@ export class ExpressionDatasourceApi extends DataSourceApi<ExpressionQuery> {
   }
 }
 
+// MATCHES the constant in DataSourceWithBackend
 export const ExpressionDatasourceID = '__expr__';
+
 export const expressionDatasource = new ExpressionDatasourceApi({
   id: -100,
   name: ExpressionDatasourceID,