Datasources: Propagate TestDataDB default selection to PanelModel

e2e/various-suite/explore.spec.ts

@@ -46,6 +46,20 @@ e2e.scenario({
 
     // Both queries above should have been run and be shown in the query history
     e2e.components.QueryTab.queryHistoryButton().should('be.visible').click();
-    e2e.components.QueryHistory.queryText().should('have.length', 2).should('contain', 'csv_metric_values');
+    e2e.components.QueryHistory.queryText()
+      .should('have.length.gte', 3)
+      .should('contain', 'csv_metric_values')
+      .should('contain', 'random_walk');
+    // Latest three queries should be [csv_metric_values, csv_metric_values, random_walk]
+    e2e.components.QueryHistory.queryText().each(($el, i) => {
+      if (i === 0 || i === 1) {
+        expect($el.text()).to.equal('csv_metric_values');
+      } else if (i === 2) {
+        expect($el.text()).to.equal('random_walk');
+      } else {
+        return false;
+      }
+      return true;
+    });
   },
 });

public/app/features/query/components/QueryGroup.tsx

@@ -82,8 +82,25 @@ export class QueryGroup extends PureComponent<Props, State> {
       const dsSettings = this.dataSourceSrv.getInstanceSettings(options.dataSource);
       const defaultDataSource = await this.dataSourceSrv.get();
       const datasource = ds.getRef();
-      const queries = options.queries.map((q) => (q.datasource ? q : { ...q, datasource }));
+      let changedQueries = false;
+      const queries = await Promise.all(options.queries.map(async (q) => {
+        if (!q.datasource) {
+          q = { ...q, datasource };
+          changedQueries = true;
+        }
+        if (Object.keys(q).length === 2) {
+          // If query has only refId and datasource, try to set the default query for its datasource
+          q = {...this.newQuery(await this.dataSourceSrv.get(q.datasource), dsSettings), ...q};
+          changedQueries = true;
+        }
+        return q;
+      }));
       this.setState({ queries, dataSource: ds, dsSettings, defaultDataSource });
+      if (changedQueries) {
+        this.onChange({
+          queries
+        });
+      }
     } catch (error) {
       console.log('failed to load data source', error);
     }
@@ -107,6 +124,9 @@ export class QueryGroup extends PureComponent<Props, State> {
 
     // We need to pass in newSettings.uid as well here as that can be a variable expression and we want to store that in the query model not the current ds variable value
     const queries = await updateQueries(nextDS, newSettings.uid, this.state.queries, currentDS);
+    if (queries.length === 0) {
+      queries.push(this.newQuery(nextDS, newSettings) as DataQuery);
+    }
 
     const dataSource = await this.dataSourceSrv.get(newSettings.name);
     this.onChange({
@@ -132,13 +152,18 @@ export class QueryGroup extends PureComponent<Props, State> {
     this.onScrollBottom();
   };
 
-  newQuery(): Partial<DataQuery> {
-    const { dsSettings, defaultDataSource } = this.state;
+  newQuery(newDs?: DataSourceApi, newSettings?: DataSourceInstanceSettings): Partial<DataQuery> {
+    const { defaultDataSource } = this.state;
+    const dsSettings = newSettings || this.state.dsSettings;
 
     const ds = !dsSettings?.meta.mixed ? dsSettings : defaultDataSource;
 
+    let defaultQuery = (newDs || this.state.dataSource)?.getDefaultQuery?.(CoreApp.PanelEditor);
+    if (!defaultQuery) {
+      defaultQuery = { refId: 'A' };
+    }
     return {
-      ...this.state.dataSource?.getDefaultQuery?.(CoreApp.PanelEditor),
+      ...defaultQuery,
       datasource: { uid: ds?.uid, type: ds?.type },
     };
   }

public/app/features/query/state/updateQueries.ts

@@ -27,12 +27,12 @@ export async function updateQueries(
     }
     // Otherwise clear queries
     else {
-      return [{ refId: 'A', datasource }];
+      return [];
     }
   }
 
   if (nextQueries.length === 0) {
-    return [{ refId: 'A', datasource }];
+    return [];
   }
 
   // Set data source on all queries except expression queries

public/app/plugins/datasource/testdata/datasource.ts

@@ -4,6 +4,7 @@ import { delay } from 'rxjs/operators';
 import {
   AnnotationEvent,
   ArrayDataFrame,
+  CoreApp,
   DataFrame,
   DataQueryRequest,
   DataQueryResponse,
@@ -18,6 +19,7 @@ import {
 import { DataSourceWithBackend, getBackendSrv, getGrafanaLiveSrv, getTemplateSrv, TemplateSrv } from '@grafana/runtime';
 import { getSearchFilterScopedVar } from 'app/features/variables/utils';
 
+import { defaultQuery } from './constants';
 import { queryMetricTree } from './metricTree';
 import { generateRandomNodes, savedNodesResponse } from './nodeGraphUtils';
 import { runStream } from './runStreams';
@@ -258,6 +260,21 @@ export class TestDataDataSource extends DataSourceWithBackend<TestDataQuery> {
 
     return null;
   }
+
+  getDefaultQuery(app: CoreApp): TestDataQuery {
+    switch (app) {
+      // Ignore the app input for now, always use the same default query
+      case CoreApp.CloudAlerting:
+      case CoreApp.UnifiedAlerting:
+      case CoreApp.Dashboard:
+      case CoreApp.Explore:
+      case CoreApp.PanelEditor:
+      case CoreApp.PanelViewer:
+      case CoreApp.Unknown:
+      default:
+        return defaultQuery;
+    }
+  }
 }
 
 function runGrafanaAPI(target: TestDataQuery, req: DataQueryRequest<TestDataQuery>): Observable<DataQueryResponse> {