OCPBUGS-81521: Adapt dashboard Prometheus polling interval based on query response time

frontend/public/actions/__tests__/dashboards.spec.ts

@@ -9,6 +9,7 @@ import {
 } from '../dashboards';
 import { defaults } from '../../reducers/dashboards';
 import { RESULTS_TYPE } from '../../reducers/dashboard-results';
+import { MIN_POLL_DELAY } from '../../components/utils/adaptive-polling';
 
 const testStopWatch = (stopAction, type: RESULTS_TYPE, key: string) => {
   expect(stopAction(key)).toEqual({
@@ -102,4 +103,73 @@ describe('dashboards-actions', () => {
 
   it('stopWatchPrometheusQuery stops watching Prometheus', () =>
     testStopWatch(stopWatchPrometheusQuery, RESULTS_TYPE.PROMETHEUS, 'fooQuery'));
+
+  describe('adaptive polling', () => {
+    let setTimeoutSpy: jest.SpyInstance;
+
+    beforeEach(() => {
+      setTimeoutSpy = jest.spyOn(global, 'setTimeout');
+    });
+
+    afterEach(() => {
+      setTimeoutSpy.mockRestore();
+      jest.restoreAllMocks();
+    });
+
+    const flushPromises = () => new Promise(process.nextTick);
+
+    const setupWatchURL = (fetchMock: jest.Mock) => {
+      const activeState = ImmutableMap(defaults).setIn([RESULTS_TYPE.URL, 'testURL', 'active'], 1);
+      const getState = jest
+        .fn()
+        .mockReturnValueOnce({ dashboards: ImmutableMap(defaults) })
+        .mockReturnValue({ dashboards: activeState });
+      const dispatch = jest.fn();
+
+      watchURL('testURL', fetchMock)(dispatch, getState);
+      return { dispatch, getState };
+    };
+
+    it('uses MIN_POLL_DELAY for fast responses', async () => {
+      const now = 1000;
+      jest
+        .spyOn(Date, 'now')
+        .mockReturnValueOnce(now)
+        .mockReturnValueOnce(now + 100);
+
+      const fetchMock = jest.fn().mockResolvedValueOnce({ data: 'test' });
+      setupWatchURL(fetchMock);
+
+      await flushPromises();
+
+      const lastSetTimeout = setTimeoutSpy.mock.calls[setTimeoutSpy.mock.calls.length - 1];
+      expect(lastSetTimeout[1]).toBe(MIN_POLL_DELAY);
+    });
+
+    it('increases delay for slow responses', async () => {
+      const now = 1000;
+      jest
+        .spyOn(Date, 'now')
+        .mockReturnValueOnce(now)
+        .mockReturnValueOnce(now + 3000);
+
+      const fetchMock = jest.fn().mockResolvedValueOnce({ data: 'test' });
+      setupWatchURL(fetchMock);
+
+      await flushPromises();
+
+      const lastSetTimeout = setTimeoutSpy.mock.calls[setTimeoutSpy.mock.calls.length - 1];
+      expect(lastSetTimeout[1]).toBe(30000);
+    });
+
+    it('does not jump to MAX_POLL_DELAY on first fetch error', async () => {
+      const fetchMock = jest.fn().mockRejectedValueOnce(new Error('network error'));
+      setupWatchURL(fetchMock);
+
+      await flushPromises();
+
+      const lastSetTimeout = setTimeoutSpy.mock.calls[setTimeoutSpy.mock.calls.length - 1];
+      expect(lastSetTimeout[1]).toBe(MIN_POLL_DELAY);
+    });
+  });
 });

frontend/public/actions/dashboards.ts

@@ -7,7 +7,13 @@ import { isWatchActive, RESULTS_TYPE } from '../reducers/dashboard-results';
 import type { RootState } from '../redux';
 import { getPrometheusURL, PrometheusEndpoint } from '../components/graphs/helpers';
 import { PrometheusResponse } from '../components/graphs';
-import { URL_POLL_DEFAULT_DELAY } from '../components/utils/url-poll-hook';
+import {
+  computeAdaptiveDelay,
+  emaToDelay,
+  MIN_POLL_DELAY,
+  MAX_POLL_DELAY,
+  SCALE_FACTOR,
+} from '../components/utils/adaptive-polling';
 import { Fetch, RequestMap } from '@console/dynamic-plugin-sdk/src/api/internal-types';
 
 export enum ActionType {
@@ -63,23 +69,32 @@ const fetchPeriodically: FetchPeriodically = async (
   getURL,
   getState,
   fetch,
+  responseTimeEma = 0,
 ) => {
   if (!isWatchActive(getState().dashboards, type, key)) {
     return;
   }
+  let nextEma = responseTimeEma;
   try {
     dispatch(updateWatchInFlight(type, key, true));
+    const startTime = Date.now();
     const data = await fetch(getURL());
+    const elapsed = Date.now() - startTime;
+    [, nextEma] = computeAdaptiveDelay(elapsed, responseTimeEma);
     dispatch(setData(type, key, data));
     dispatch(setError(type, key, null));
   } catch (error) {
+    // Feed a synthetic slow response into the EMA to gradually back off without jumping to max
+    const errorSeed =
+      responseTimeEma === 0 ? MIN_POLL_DELAY / SCALE_FACTOR : MAX_POLL_DELAY / SCALE_FACTOR;
+    [, nextEma] = computeAdaptiveDelay(errorSeed, responseTimeEma);
     dispatch(setError(type, key, error));
     dispatch(setData(type, key, null));
   } finally {
     dispatch(updateWatchInFlight(type, key, false));
     const timeout = setTimeout(
-      () => fetchPeriodically(dispatch, type, key, getURL, getState, fetch),
-      URL_POLL_DEFAULT_DELAY,
+      () => fetchPeriodically(dispatch, type, key, getURL, getState, fetch, nextEma),
+      emaToDelay(nextEma),
     );
     dispatch(updateWatchTimeout(type, key, timeout));
   }
@@ -147,6 +162,7 @@ type FetchPeriodically = (
   getURL: () => string,
   getState: () => RootState,
   fetch: Fetch,
+  responseTimeEma?: number,
 ) => void;
 
 export type DashboardsAction = Action<typeof dashboardsActions>;

frontend/public/components/utils/__tests__/adaptive-polling.spec.ts

@@ -0,0 +1,98 @@
+import {
+  computeAdaptiveDelay,
+  emaToDelay,
+  MIN_POLL_DELAY,
+  MAX_POLL_DELAY,
+  EMA_ALPHA,
+  SCALE_FACTOR,
+} from '../adaptive-polling';
+
+describe('emaToDelay', () => {
+  it('clamps to MIN_POLL_DELAY for small EMA values', () => {
+    expect(emaToDelay(0)).toBe(MIN_POLL_DELAY);
+    expect(emaToDelay(500)).toBe(MIN_POLL_DELAY);
+    expect(emaToDelay(1499)).toBe(MIN_POLL_DELAY);
+  });
+
+  it('scales proportionally for mid-range EMA values', () => {
+    expect(emaToDelay(2000)).toBe(20000);
+    expect(emaToDelay(3000)).toBe(30000);
+    expect(emaToDelay(4500)).toBe(45000);
+  });
+
+  it('clamps to MAX_POLL_DELAY for large EMA values', () => {
+    expect(emaToDelay(6000)).toBe(MAX_POLL_DELAY);
+    expect(emaToDelay(10000)).toBe(MAX_POLL_DELAY);
+  });
+
+  it('falls back to MIN_POLL_DELAY for non-finite values', () => {
+    expect(emaToDelay(NaN)).toBe(MIN_POLL_DELAY);
+    expect(emaToDelay(Infinity)).toBe(MIN_POLL_DELAY);
+    expect(emaToDelay(-Infinity)).toBe(MIN_POLL_DELAY);
+  });
+});
+
+describe('computeAdaptiveDelay', () => {
+  it('uses elapsed directly as EMA on first call (previousEma = 0)', () => {
+    const [delay, ema] = computeAdaptiveDelay(500, 0);
+    expect(ema).toBe(500);
+    expect(delay).toBe(MIN_POLL_DELAY);
+  });
+
+  it('applies EMA smoothing with previous value', () => {
+    const [, ema] = computeAdaptiveDelay(4000, 3000);
+    const expected = EMA_ALPHA * 4000 + (1 - EMA_ALPHA) * 3000;
+    expect(ema).toBe(expected);
+  });
+
+  it('returns MIN_POLL_DELAY for fast responses', () => {
+    const [delay] = computeAdaptiveDelay(200, 300);
+    expect(delay).toBe(MIN_POLL_DELAY);
+  });
+
+  it('returns proportional delay for moderate responses', () => {
+    const [delay, ema] = computeAdaptiveDelay(3000, 3000);
+    expect(ema).toBe(3000);
+    expect(delay).toBe(30000);
+  });
+
+  it('returns MAX_POLL_DELAY for very slow responses', () => {
+    const [delay] = computeAdaptiveDelay(10000, 8000);
+    expect(delay).toBe(MAX_POLL_DELAY);
+  });
+
+  it('dampens a single outlier spike via EMA smoothing', () => {
+    // Stable at 1s, then a 10s spike
+    const [, ema1] = computeAdaptiveDelay(1000, 1000);
+    expect(ema1).toBe(1000);
+
+    const [delay, ema2] = computeAdaptiveDelay(10000, ema1);
+    const expected = EMA_ALPHA * 10000 + (1 - EMA_ALPHA) * 1000;
+    expect(ema2).toBe(expected);
+    // Should not jump to MAX_POLL_DELAY from a single spike
+    expect(delay).toBeLessThan(MAX_POLL_DELAY);
+  });
+
+  it('recovers gradually after error backoff', () => {
+    const errorInput = MAX_POLL_DELAY / SCALE_FACTOR;
+    // Start from stable fast state
+    const [, emaAfterError] = computeAdaptiveDelay(errorInput, 500);
+    expect(emaAfterError).toBeGreaterThan(500);
+
+    // Follow up with a fast response — EMA should decrease
+    const [, emaRecovery] = computeAdaptiveDelay(500, emaAfterError);
+    expect(emaRecovery).toBeLessThan(emaAfterError);
+  });
+
+  it('defaults previousEma to 0 when omitted', () => {
+    const [delay, ema] = computeAdaptiveDelay(2000);
+    expect(ema).toBe(2000);
+    expect(delay).toBe(20000);
+  });
+
+  it('falls back safely for non-finite or negative elapsedMs', () => {
+    expect(computeAdaptiveDelay(NaN, 1000)).toEqual([MIN_POLL_DELAY, 1000]);
+    expect(computeAdaptiveDelay(Infinity, 1000)).toEqual([MIN_POLL_DELAY, 1000]);
+    expect(computeAdaptiveDelay(-1, 1000)).toEqual([MIN_POLL_DELAY, 1000]);
+  });
+});

frontend/public/components/utils/adaptive-polling.ts

@@ -0,0 +1,34 @@
+export const MIN_POLL_DELAY = 15000;
+export const MAX_POLL_DELAY = 60000;
+export const EMA_ALPHA = 0.3;
+export const SCALE_FACTOR = 10;
+
+/** Converts a smoothed response time (EMA) to a clamped polling delay in ms. */
+export const emaToDelay = (ema: number): number =>
+  Number.isFinite(ema)
+    ? Math.max(MIN_POLL_DELAY, Math.min(MAX_POLL_DELAY, Math.round(ema * SCALE_FACTOR)))
+    : MIN_POLL_DELAY;
+
+/**
+ * Computes the next adaptive polling delay using an Exponential Moving Average
+ * of response times. Returns `[nextDelay, updatedEma]`.
+ *
+ * On first call pass `previousEma` as 0 (or omit) to seed the EMA with `elapsedMs`.
+ *
+ * With current parameters (alpha=0.3, scale=10x, 15s–60s clamp):
+ *   ~500ms response = 15s poll (floor)
+ *   ~2s    response = 20s poll
+ *   ~3s    response = 30s poll
+ *   ~5s    response = 50s poll
+ *   ~6s+   response = 60s poll (ceiling)
+ */
+export const computeAdaptiveDelay = (
+  elapsedMs: number,
+  previousEma: number = 0,
+): [number, number] => {
+  if (!Number.isFinite(elapsedMs) || elapsedMs < 0) {
+    return [MIN_POLL_DELAY, previousEma];
+  }
+  const ema = previousEma === 0 ? elapsedMs : EMA_ALPHA * elapsedMs + (1 - EMA_ALPHA) * previousEma;
+  return [emaToDelay(ema), ema];
+};