StateTimeline: insert trailing null value at +interval (#45997)

packages/grafana-ui/src/components/GraphNG/GraphNG.tsx

@@ -116,7 +116,8 @@ export class GraphNG extends React.Component<GraphNGProps, GraphNGState> {
       fields || {
         x: fieldMatchers.get(FieldMatcherID.firstTimeField).get({}),
         y: fieldMatchers.get(FieldMatcherID.numeric).get({}),
-      }
+      },
+      props.timeRange
     );
     pluginLog('GraphNG', false, 'data aligned', alignedFrame);
 

packages/grafana-ui/src/components/GraphNG/nullInsertThreshold.test.ts

@@ -97,6 +97,23 @@ describe('nullInsertThreshold Transformer', () => {
     expect(result.fields[2].values.toArray()).toStrictEqual(['a', null, 'b', null, 'c']);
   });
 
+  test('should insert trailing null at end +interval when timeRange.to.valueOf() exceeds threshold', () => {
+    const df = new MutableDataFrame({
+      refId: 'A',
+      fields: [
+        { name: 'Time', type: FieldType.time, config: { interval: 1 }, values: [1, 3, 10] },
+        { name: 'One', type: FieldType.number, values: [4, 6, 8] },
+        { name: 'Two', type: FieldType.string, values: ['a', 'b', 'c'] },
+      ],
+    });
+
+    const result = applyNullInsertThreshold(df, null, 13);
+
+    expect(result.fields[0].values.toArray()).toStrictEqual([1, 2, 3, 4, 10, 11]);
+    expect(result.fields[1].values.toArray()).toStrictEqual([4, null, 6, null, 8, null]);
+    expect(result.fields[2].values.toArray()).toStrictEqual(['a', null, 'b', null, 'c', null]);
+  });
+
   // TODO: make this work
   test.skip('should insert nulls at +threshold (when defined) instead of +interval', () => {
     const df = new MutableDataFrame({
@@ -115,23 +132,6 @@ describe('nullInsertThreshold Transformer', () => {
     expect(result.fields[2].values.toArray()).toStrictEqual(['a', null, 'b', null, 'c']);
   });
 
-  test('should insert nulls at midpoints between adjacent > interval: 2', () => {
-    const df = new MutableDataFrame({
-      refId: 'A',
-      fields: [
-        { name: 'Time', type: FieldType.time, config: { interval: 2 }, values: [5, 7, 11] },
-        { name: 'One', type: FieldType.number, values: [4, 6, 8] },
-        { name: 'Two', type: FieldType.string, values: ['a', 'b', 'c'] },
-      ],
-    });
-
-    const result = applyNullInsertThreshold(df);
-
-    expect(result.fields[0].values.toArray()).toStrictEqual([5, 7, 9, 11]);
-    expect(result.fields[1].values.toArray()).toStrictEqual([4, 6, null, 8]);
-    expect(result.fields[2].values.toArray()).toStrictEqual(['a', 'b', null, 'c']);
-  });
-
   test('should noop on fewer than two values', () => {
     const df = new MutableDataFrame({
       refId: 'A',

packages/grafana-ui/src/components/GraphNG/nullInsertThreshold.ts

@@ -12,6 +12,7 @@ const INSERT_MODES = {
 export function applyNullInsertThreshold(
   frame: DataFrame,
   refFieldName?: string | null,
+  refFieldPseudoMax: number | null = null,
   insertMode: InsertMode = INSERT_MODES.threshold
 ): DataFrame {
   if (frame.length < 2) {
@@ -48,7 +49,7 @@ export function applyNullInsertThreshold(
 
     const frameValues = frame.fields.map((field) => field.values.toArray());
 
-    const filledFieldValues = nullInsertThreshold(refValues, frameValues, threshold, insertMode);
+    const filledFieldValues = nullInsertThreshold(refValues, frameValues, threshold, refFieldPseudoMax, insertMode);
 
     if (filledFieldValues === frameValues) {
       return frame;
@@ -70,7 +71,14 @@ export function applyNullInsertThreshold(
   return frame;
 }
 
-function nullInsertThreshold(refValues: number[], frameValues: any[][], threshold: number, getInsertValue: InsertMode) {
+function nullInsertThreshold(
+  refValues: number[],
+  frameValues: any[][],
+  threshold: number,
+  // will insert a trailing null when refFieldPseudoMax > last datapoint + threshold
+  refFieldPseudoMax: number | null = null,
+  getInsertValue: InsertMode
+) {
   const len = refValues.length;
   let prevValue: number = refValues[0];
   const refValuesNew: number[] = [prevValue];
@@ -87,6 +95,10 @@ function nullInsertThreshold(refValues: number[], frameValues: any[][], threshol
     prevValue = curValue;
   }
 
+  if (refFieldPseudoMax != null && prevValue + threshold <= refFieldPseudoMax) {
+    refValuesNew.push(getInsertValue(prevValue, refFieldPseudoMax, threshold));
+  }
+
   const filledLen = refValuesNew.length;
 
   if (filledLen === len) {

packages/grafana-ui/src/components/GraphNG/utils.ts

@@ -1,5 +1,5 @@
 import { XYFieldMatchers } from './types';
-import { ArrayVector, DataFrame, FieldConfig, FieldType, outerJoinDataFrames } from '@grafana/data';
+import { ArrayVector, DataFrame, FieldConfig, FieldType, outerJoinDataFrames, TimeRange } from '@grafana/data';
 import { nullToUndefThreshold } from './nullToUndefThreshold';
 import { applyNullInsertThreshold } from './nullInsertThreshold';
 import { AxisPlacement, GraphFieldConfig, ScaleDistribution, ScaleDistributionConfig } from '@grafana/schema';
@@ -29,9 +29,9 @@ function applySpanNullsThresholds(frame: DataFrame) {
   return frame;
 }
 
-export function preparePlotFrame(frames: DataFrame[], dimFields: XYFieldMatchers) {
+export function preparePlotFrame(frames: DataFrame[], dimFields: XYFieldMatchers, timeRange?: TimeRange | null) {
   let alignedFrame = outerJoinDataFrames({
-    frames: frames.map((frame) => applyNullInsertThreshold(frame)),
+    frames: frames.map((frame) => applyNullInsertThreshold(frame, null, timeRange?.to.valueOf())),
     joinBy: dimFields.x,
     keep: dimFields.y,
     keepOriginIndices: true,

public/app/plugins/panel/state-timeline/utils.ts

@@ -1,5 +1,4 @@
 import React from 'react';
-import { XYFieldMatchers } from '@grafana/ui/src/components/GraphNG/types';
 import {
   ArrayVector,
   DataFrame,
@@ -19,7 +18,6 @@ import {
   getActiveThreshold,
   Threshold,
   getFieldConfigWithMinMax,
-  outerJoinDataFrames,
   ThresholdsMode,
 } from '@grafana/data';
 import {
@@ -48,15 +46,6 @@ export function mapMouseEventToMode(event: React.MouseEvent): SeriesVisibilityCh
   return SeriesVisibilityChangeMode.ToggleSelection;
 }
 
-export function preparePlotFrame(data: DataFrame[], dimFields: XYFieldMatchers) {
-  return outerJoinDataFrames({
-    frames: data,
-    joinBy: dimFields.x,
-    keep: dimFields.y,
-    keepOriginIndices: true,
-  });
-}
-
 export const preparePlotConfigBuilder: UPlotConfigPrepFn<TimelineOptions> = ({
   frame,
   theme,