Loki: Run instant query only when doing metric query (#28325)

* Run instant query only when doing metric query

* Update public/app/plugins/datasource/loki/datasource.ts

Co-authored-by: Ivana Huckova <30407135+ivanahuckova@users.noreply.github.com>

Co-authored-by: Ivana Huckova <30407135+ivanahuckova@users.noreply.github.com>

public/app/plugins/datasource/loki/datasource.test.ts

@@ -36,11 +36,7 @@ const timeSrvStub = {
   }),
 };
 
-describe('LokiDatasource', () => {
-  let fetchStream: Subject<FetchResponse>;
-  const fetchMock = jest.spyOn(backendSrv, 'fetch');
-
-  const testResponse: FetchResponse<LokiResponse> = {
+const testResponse: FetchResponse<LokiResponse> = {
   data: {
     data: {
       resultType: LokiResultType.Stream,
@@ -61,7 +57,11 @@ describe('LokiDatasource', () => {
   type: 'default',
   url: '',
   config: ({} as unknown) as BackendSrvRequest,
-  };
+};
+
+describe('LokiDatasource', () => {
+  let fetchStream: Subject<FetchResponse>;
+  const fetchMock = jest.spyOn(backendSrv, 'fetch');
 
   beforeEach(() => {
     jest.clearAllMocks();
@@ -178,48 +178,42 @@ describe('LokiDatasource', () => {
   });
 
   describe('when querying', () => {
-    it('should run range and instant query in Explore', done => {
+    function setup(expr: string, app: CoreApp) {
       const ds = createLokiDSForTests();
       const options = getQueryOptions<LokiQuery>({
-        targets: [{ expr: '{job="grafana"}', refId: 'B' }],
-        app: CoreApp.Explore,
+        targets: [{ expr, refId: 'B' }],
+        app,
       });
-
       ds.runInstantQuery = jest.fn(() => of({ data: [] }));
       ds.runRangeQuery = jest.fn(() => of({ data: [] }));
+      return { ds, options };
+    }
 
-      observableTester().subscribeAndExpectOnComplete<DataQueryResponse>({
-        observable: ds.query(options),
-        expect: () => {
+    it('should run range and instant query in Explore if running metric query', async () => {
+      const { ds, options } = setup('rate({job="grafana"}[10m])', CoreApp.Explore);
+      await ds.query(options).toPromise();
       expect(ds.runInstantQuery).toBeCalled();
       expect(ds.runRangeQuery).toBeCalled();
-        },
-        done,
-      });
     });
 
-    it('should run only range query in Dashboard', done => {
-      const ds = createLokiDSForTests();
-      const options = getQueryOptions<LokiQuery>({
-        targets: [{ expr: '{job="grafana"}', refId: 'B' }],
+    it('should run only range query in Explore if running logs query', async () => {
+      const { ds, options } = setup('{job="grafana"}', CoreApp.Explore);
+      await ds.query(options).toPromise();
+      expect(ds.runInstantQuery).not.toBeCalled();
+      expect(ds.runRangeQuery).toBeCalled();
     });
 
-      ds.runInstantQuery = jest.fn(() => of({ data: [] }));
-      ds.runRangeQuery = jest.fn(() => of({ data: [] }));
-
-      observableTester().subscribeAndExpectOnComplete<DataQueryResponse>({
-        observable: ds.query(options),
-        expect: () => {
+    it('should run only range query in Dashboard', async () => {
+      const { ds, options } = setup('rate({job="grafana"}[10m])', CoreApp.Dashboard);
+      await ds.query(options).toPromise();
+      expect(ds.runInstantQuery).not.toBeCalled();
       expect(ds.runRangeQuery).toBeCalled();
-        },
-        done,
-      });
     });
 
-    it('should return series data for both queries in Explore', done => {
+    it('should return series data for both queries in Explore if metrics query', done => {
       const ds = createLokiDSForTests();
       const options = getQueryOptions<LokiQuery>({
-        targets: [{ expr: '{job="grafana"} |= "foo"', refId: 'B' }],
+        targets: [{ expr: 'rate({job="grafana"} |= "foo" [10m])', refId: 'B' }],
         app: CoreApp.Explore,
       });
 

public/app/plugins/datasource/loki/datasource.ts

@@ -99,7 +99,9 @@ export class LokiDatasource extends DataSourceApi<LokiQuery, LokiOptions> {
       }));
 
     for (const target of filteredTargets) {
-      if (options.app === CoreApp.Explore) {
+      // In explore we want to show result of metrics instant query in a table under the graph panel to mimic behaviour of prometheus.
+      // We don't want to do that in dashboards though as user would have to pick the correct data frame.
+      if (options.app === CoreApp.Explore && isMetricsQuery(target.expr)) {
         subQueries.push(this.runInstantQuery(target, options, filteredTargets.length));
       }
       subQueries.push(this.runRangeQuery(target, options, filteredTargets.length));