Datasource: Fix - apply default query also to queries in new panels (#59625)

* apply default query also to new panels

* add comment

* add tests

public/app/core/utils/query.test.ts

@@ -1,6 +1,10 @@
 import { DataQuery } from '@grafana/data';
 
-import { getNextRefIdChar } from './query';
+import { getNextRefIdChar, queryIsEmpty } from './query';
+
+export interface TestQuery extends DataQuery {
+  name?: string;
+}
 
 function dataQueryHelper(ids: string[]): DataQuery[] {
   return ids.map((letter) => {
@@ -29,3 +33,20 @@ describe('Get next refId char', () => {
     expect(getNextRefIdChar(singleExtendedDataQuery)).toEqual('AA');
   });
 });
+
+describe('queryIsEmpty', () => {
+  it('should return true if query only includes props that are defined in the DataQuery interface', () => {
+    const testQuery: DataQuery = { refId: 'A' };
+    expect(queryIsEmpty(testQuery)).toEqual(true);
+  });
+
+  it('should return true if query only includes props that are defined in the DataQuery interface and a label prop', () => {
+    const testQuery: DataQuery & { label: string } = { refId: 'A', label: '' };
+    expect(queryIsEmpty(testQuery)).toEqual(true);
+  });
+
+  it('should return false if query only includes props that are not defined in the DataQuery interface', () => {
+    const testQuery: TestQuery = { refId: 'A', name: 'test' };
+    expect(queryIsEmpty(testQuery)).toEqual(false);
+  });
+});

public/app/core/utils/query.ts

@@ -9,6 +9,23 @@ export const getNextRefIdChar = (queries: DataQuery[]): string => {
   }
 };
 
+// This function checks if the query has defined properties beyond those defined in the DataQuery interface.
+export function queryIsEmpty(query: DataQuery): boolean {
+  const dataQueryProps = ['refId', 'hide', 'key', 'queryType', 'datasource'];
+
+  for (const key in query) {
+    // label is not a DataQuery prop, but it's defined in the query when called from the QueryRunner.
+    if (key === 'label') {
+      continue;
+    }
+    if (!dataQueryProps.includes(key)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
 export function addQuery(queries: DataQuery[], query?: Partial<DataQuery>, datasource?: DataSourceRef): DataQuery[] {
   const q = query || {};
   q.refId = getNextRefIdChar(queries);

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

@@ -17,7 +17,7 @@ import { Button, CustomScrollbar, HorizontalGroup, InlineFormLabel, Modal, style
 import { PluginHelp } from 'app/core/components/PluginHelp/PluginHelp';
 import config from 'app/core/config';
 import { backendSrv } from 'app/core/services/backend_srv';
-import { addQuery } from 'app/core/utils/query';
+import { addQuery, queryIsEmpty } from 'app/core/utils/query';
 import { dataSource as expressionDatasource } from 'app/features/expressions/ExpressionDatasource';
 import { DashboardQueryEditor, isSharedDashboardQuery } from 'app/plugins/datasource/dashboard';
 import { QueryGroupDataSource, QueryGroupOptions } from 'app/types';
@@ -96,7 +96,11 @@ 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 }));
+      const queries = options.queries.map((q) => ({
+        ...(queryIsEmpty(q) && ds?.getDefaultQuery?.(CoreApp.PanelEditor)),
+        datasource,
+        ...q,
+      }));
       this.setState({
         queries,
         dataSource: ds,

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

@@ -6,6 +6,7 @@ import { catchError, map, mapTo, share, takeUntil, tap } from 'rxjs/operators';
 // Utils & Services
 // Types
 import {
+  CoreApp,
   DataFrame,
   DataQueryError,
   DataQueryRequest,
@@ -23,6 +24,7 @@ import {
 import { toDataQueryError } from '@grafana/runtime';
 import { isExpressionReference } from '@grafana/runtime/src/utils/DataSourceWithBackend';
 import { backendSrv } from 'app/core/services/backend_srv';
+import { queryIsEmpty } from 'app/core/utils/query';
 import { dataSource as expressionDatasource } from 'app/features/expressions/ExpressionDatasource';
 import { ExpressionQuery } from 'app/features/expressions/types';
 
@@ -174,6 +176,11 @@ export function callQueryMethod(
   request: DataQueryRequest,
   queryFunction?: typeof datasource.query
 ) {
+  // If the datasource has defined a default query, make sure it's applied if the query is empty
+  request.targets = request.targets.map((t) =>
+    queryIsEmpty(t) ? { ...datasource?.getDefaultQuery?.(CoreApp.PanelEditor), ...t } : t
+  );
+
   // If its a public datasource, just return the result. Expressions will be handled on the backend.
   if (datasource.type === 'public-ds') {
     return from(datasource.query(request));

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

@@ -5,6 +5,7 @@ import {
   DataSourceWithQueryImportSupport,
 } from '@grafana/data';
 import { ExpressionDatasourceRef } from '@grafana/runtime/src/utils/DataSourceWithBackend';
+import { TestQuery } from 'app/core/utils/query.test';
 
 import { updateQueries } from './updateQueries';
 
@@ -41,6 +42,9 @@ const newUidSameTypeDS = {
 } as DataSourceApi;
 
 describe('updateQueries', () => {
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
   it('Should update all queries except expression query when changing data source with same type', async () => {
     const updated = await updateQueries(
       newUidSameTypeDS,
@@ -111,6 +115,53 @@ describe('updateQueries', () => {
     expect(updated[0].datasource).toEqual({ type: 'new-type', uid: 'new-uid' });
   });
 
+  it('Should clear queries and get default query from ds when changing type', async () => {
+    newUidDS.getDefaultQuery = jest.fn().mockReturnValue({ test: 'default-query1' } as Partial<TestQuery>);
+    const updated = await updateQueries(
+      newUidDS,
+      'new-uid',
+      [
+        {
+          refId: 'A',
+          datasource: {
+            uid: 'old-uid',
+            type: 'old-type',
+          },
+        },
+        {
+          refId: 'B',
+          datasource: {
+            uid: 'old-uid',
+            type: 'old-type',
+          },
+        },
+      ],
+      oldUidDS
+    );
+
+    expect(newUidDS.getDefaultQuery).toHaveBeenCalled();
+    expect(updated as TestQuery[]).toEqual([
+      {
+        datasource: { type: 'new-type', uid: 'new-uid' },
+        refId: 'A',
+        test: 'default-query1',
+      },
+    ]);
+  });
+
+  it('Should return default query from ds when changing type and no new queries exist', async () => {
+    newUidDS.getDefaultQuery = jest.fn().mockReturnValue({ test: 'default-query2' } as Partial<TestQuery>);
+    const updated = await updateQueries(newUidDS, 'new-uid', [], oldUidDS);
+    expect(newUidDS.getDefaultQuery).toHaveBeenCalled();
+    expect(updated as TestQuery[]).toEqual([
+      {
+        datasource: { type: 'new-type', uid: 'new-uid' },
+        refId: 'A',
+        test: 'default-query2',
+      },
+    ]);
+  });
+
   it('Should preserve query data source when changing to mixed', async () => {
     const updated = await updateQueries(
       mixedDS,

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

@@ -1,4 +1,4 @@
-import { DataQuery, DataSourceApi, hasQueryExportSupport, hasQueryImportSupport } from '@grafana/data';
+import { CoreApp, DataQuery, DataSourceApi, hasQueryExportSupport, hasQueryImportSupport } from '@grafana/data';
 import { isExpressionReference } from '@grafana/runtime/src/utils/DataSourceWithBackend';
 
 export async function updateQueries(
@@ -9,6 +9,7 @@ export async function updateQueries(
 ): Promise<DataQuery[]> {
   let nextQueries = queries;
   const datasource = { type: nextDS.type, uid: nextDSUidOrVariableExpression };
+  const DEFAULT_QUERY = { ...nextDS?.getDefaultQuery?.(CoreApp.PanelEditor), datasource, refId: 'A' };
 
   // we are changing data source type
   if (currentDS?.meta.id !== nextDS.meta.id) {
@@ -27,12 +28,12 @@ export async function updateQueries(
     }
     // Otherwise clear queries
     else {
-      return [{ refId: 'A', datasource }];
+      return [DEFAULT_QUERY];
     }
   }
 
   if (nextQueries.length === 0) {
-    return [{ refId: 'A', datasource }];
+    return [DEFAULT_QUERY];
   }
 
   // Set data source on all queries except expression queries