Logs: Issue queries in forward or backward direction depending on the selected sorting option

src/Components/ServiceScene/LogsPanelScene.tsx

@@ -5,6 +5,7 @@ import {
   sceneGraph,
   SceneObjectBase,
   SceneObjectState,
+  SceneQueryRunner,
   VizPanel,
 } from '@grafana/scenes';
 import { DataFrame, getValueFormat, LogRowModel } from '@grafana/data';
@@ -104,6 +105,14 @@ export class LogsPanelScene extends SceneObjectBase<LogsPanelSceneState> {
     if (!this.state.body) {
       return;
     }
+    if ('sortOrder' in options) {
+      const $data = sceneGraph.getData(this);
+      const queryRunner =
+        $data instanceof SceneQueryRunner ? $data : sceneGraph.findDescendents($data, SceneQueryRunner)[0];
+      if (queryRunner) {
+        queryRunner.runQueries();
+      }
+    }
     this.state.body.onOptionsChange(options);
   }
 

src/services/datasource.ts

@@ -10,7 +10,7 @@ import {
 } from '@grafana/data';
 import { config, DataSourceWithBackend, getDataSourceSrv } from '@grafana/runtime';
 import { RuntimeDataSource, sceneUtils } from '@grafana/scenes';
-import { DataQuery } from '@grafana/schema';
+import { DataQuery, LogsSortOrder } from '@grafana/schema';
 import { Observable, Subscriber } from 'rxjs';
 import { getDataSource } from './scenes';
 import { getPrimaryLabelFromUrl } from './routing';
@@ -19,11 +19,13 @@ import { FIELDS_TO_REMOVE, LABELS_TO_REMOVE, sortLabelsByCardinality } from './f
 import { SERVICE_NAME } from './variables';
 import { runShardSplitQuery } from './shardQuerySplitting';
 import { requestSupportsSharding } from './logql';
-import { LokiDatasource, LokiQuery } from './lokiQuery';
+import { LokiDatasource, LokiQuery, LokiQueryDirection } from './lokiQuery';
 import { SceneDataQueryRequest, SceneDataQueryResourceRequest, VolumeRequestProps } from './datasourceTypes';
 import { logger } from './logger';
 import { PLUGIN_ID } from './plugin';
 import { sanitizeStreamSelector } from './query';
+import { LOGS_PANEL_QUERY_REFID } from 'Components/ServiceScene/ServiceScene';
+import { getLogsPanelSortOrder } from 'Components/ServiceScene/LogOptionsScene';
 
 export const WRAPPED_LOKI_DS_UID = 'wrapped-loki-ds-uid';
 
@@ -141,11 +143,13 @@ export class WrappedLokiDatasource extends RuntimeDataSource<DataQuery> {
 
     const updatedRequest = {
       ...request,
-      targets: ds.interpolateVariablesInQueries(request.targets, request.scopedVars).map((target) => ({
-        ...target,
-        resource: undefined,
-        expr: sanitizeStreamSelector(target.expr),
-      })),
+      targets: this.applyQueryDirection(
+        ds.interpolateVariablesInQueries(request.targets, request.scopedVars).map((target) => ({
+          ...target,
+          resource: undefined,
+          expr: sanitizeStreamSelector(target.expr),
+        }))
+      ),
     };
 
     // Query the datasource and return either observable or promise
@@ -266,6 +270,18 @@ export class WrappedLokiDatasource extends RuntimeDataSource<DataQuery> {
     return { interpolatedTarget, expression };
   }
 
+  private applyQueryDirection(targets: LokiQuery[]) {
+    const sortOrder = getLogsPanelSortOrder();
+    return targets.map((target) => {
+      if (target.refId !== LOGS_PANEL_QUERY_REFID) {
+        return target;
+      }
+      target.direction =
+        sortOrder === LogsSortOrder.Descending ? LokiQueryDirection.Backward : LokiQueryDirection.Forward;
+      return target;
+    });
+  }
+
   private async getDetectedLabels(
     request: DataQueryRequest<LokiQuery & SceneDataQueryResourceRequest>,
     ds: LokiDatasource,

src/services/lokiQuery.ts

@@ -3,6 +3,12 @@ import { DataSourceRef } from '@grafana/schema';
 import { DataSourceWithBackend } from '@grafana/runtime';
 import { DataSourceJsonData } from '@grafana/data';
 
+export enum LokiQueryDirection {
+  Backward = 'backward',
+  Forward = 'forward',
+  Scan = 'scan',
+}
+
 export type LokiQuery = {
   refId: string;
   queryType?: LokiQueryType;
@@ -13,6 +19,7 @@ export type LokiQuery = {
   splitDuration?: string;
   datasource?: DataSourceRef;
   maxLines?: number;
+  direction?: LokiQueryDirection;
 };
 
 export type LokiQueryType = 'instant' | 'range' | 'stream' | string;

tests/exploreServicesBreakDown.spec.ts

@@ -1092,10 +1092,6 @@ test.describe('explore services breakdown page', () => {
     // Scroll the whole page to the bottom so the whole logs panel is visible
     await explorePage.scrollToBottom();
 
-    // The logs panel keeps the lines in the viewport the same, but will scroll us down
-    await expect(firstRow).not.toBeInViewport();
-    await expect(page.getByText(newestLogContent)).toBeInViewport();
-
     // assert timestamps are ASC (oldest first)
     expect(new Date(await firstRowTimeCell.textContent()).valueOf()).toBeLessThanOrEqual(
       new Date(await secondRowTimeCell.textContent()).valueOf()