[SLO] Add burn rate windows to SLO detail page (#159750)

## Summary

This PR adds a burn rate visualization to the overview tab of the SLO
Detail page. This PR also includes a fix for fetching the index pattern
fields hook; it uses the DataViews service to fetch the fields instead
of the internal API.

<img width="1170" alt="image"
src="https://github.com/elastic/kibana/assets/41702/41057791-880e-4cc8-a0c7-02a0f18aaeca">

### All good

<img width="1141" alt="image"
src="https://github.com/elastic/kibana/assets/41702/3ec07efa-e35a-4251-87f3-7ddc836171b7">

### Degrading

<img width="1141" alt="image"
src="https://github.com/elastic/kibana/assets/41702/a6d347be-7b55-404e-99a1-14ad4a38ad36">

### EVERYTHING IS BURNING 🔥

<img width="1141" alt="image"
src="https://github.com/elastic/kibana/assets/41702/9ed05875-b907-4a57-8387-a094876dd35e">


### Recovering in the dark

<img width="1151" alt="image"
src="https://github.com/elastic/kibana/assets/41702/f2999c7a-f97b-474c-8146-4565445df892">

### No data

<img width="1141" alt="image"
src="https://github.com/elastic/kibana/assets/41702/675a65a4-91b1-4de3-9f51-b65760efbb66">

x-pack/packages/kbn-slo-schema/src/rest_specs/slo.ts

@@ -22,6 +22,9 @@ import {
   summarySchema,
   tagsSchema,
   timeWindowSchema,
+  apmTransactionErrorRateIndicatorSchema,
+  apmTransactionDurationIndicatorSchema,
+  durationType,
   timeWindowTypeSchema,
 } from '../schema';
 
@@ -141,6 +144,28 @@ const getSLODiagnosisParamsSchema = t.type({
   path: t.type({ id: t.string }),
 });
 
+const getSLOBurnRatesResponseSchema = t.type({
+  burnRates: t.array(
+    t.type({
+      name: t.string,
+      burnRate: t.number,
+      sli: t.number,
+    })
+  ),
+});
+
+const getSLOBurnRatesParamsSchema = t.type({
+  path: t.type({ id: t.string }),
+  body: t.type({
+    windows: t.array(
+      t.type({
+        name: t.string,
+        duration: durationType,
+      })
+    ),
+  }),
+});
+
 type SLOResponse = t.OutputOf<typeof sloResponseSchema>;
 type SLOWithSummaryResponse = t.OutputOf<typeof sloWithSummaryResponseSchema>;
 
@@ -166,6 +191,11 @@ type HistoricalSummaryResponse = t.OutputOf<typeof historicalSummarySchema>;
 type GetPreviewDataParams = t.TypeOf<typeof getPreviewDataParamsSchema.props.body>;
 type GetPreviewDataResponse = t.TypeOf<typeof getPreviewDataResponseSchema>;
 
+type APMTransactionErrorRateIndicatorSchema = t.TypeOf<
+  typeof apmTransactionErrorRateIndicatorSchema
+>;
+type APMTransactionDurationIndicatorSchema = t.TypeOf<typeof apmTransactionDurationIndicatorSchema>;
+type GetSLOBurnRatesResponse = t.OutputOf<typeof getSLOBurnRatesResponseSchema>;
 type BudgetingMethod = t.TypeOf<typeof budgetingMethodSchema>;
 type TimeWindow = t.TypeOf<typeof timeWindowTypeSchema>;
 
@@ -190,6 +220,8 @@ export {
   sloWithSummaryResponseSchema,
   updateSLOParamsSchema,
   updateSLOResponseSchema,
+  getSLOBurnRatesParamsSchema,
+  getSLOBurnRatesResponseSchema,
 };
 export type {
   BudgetingMethod,
@@ -210,6 +242,9 @@ export type {
   UpdateSLOInput,
   UpdateSLOParams,
   UpdateSLOResponse,
+  APMTransactionDurationIndicatorSchema,
+  APMTransactionErrorRateIndicatorSchema,
+  GetSLOBurnRatesResponse,
   Indicator,
   MetricCustomIndicator,
   KQLCustomIndicator,

x-pack/plugins/observability/public/hooks/slo/query_key_factory.ts

@@ -33,6 +33,7 @@ export const sloKeys = {
   historicalSummaries: () => [...sloKeys.all, 'historicalSummary'] as const,
   historicalSummary: (sloIds: string[]) => [...sloKeys.historicalSummaries(), sloIds] as const,
   globalDiagnosis: () => [...sloKeys.all, 'globalDiagnosis'] as const,
+  burnRates: (sloId: string) => [...sloKeys.all, 'burnRates', sloId] as const,
   preview: (indicator?: Indicator) => [...sloKeys.all, 'preview', indicator] as const,
 };
 

x-pack/plugins/observability/public/hooks/slo/use_fetch_slo_burn_rates.ts

@@ -0,0 +1,76 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+import {
+  QueryObserverResult,
+  RefetchOptions,
+  RefetchQueryFilters,
+  useQuery,
+} from '@tanstack/react-query';
+import { GetSLOBurnRatesResponse } from '@kbn/slo-schema';
+import { useKibana } from '../../utils/kibana_react';
+import { sloKeys } from './query_key_factory';
+
+export interface UseFetchSloBurnRatesResponse {
+  isInitialLoading: boolean;
+  isLoading: boolean;
+  isRefetching: boolean;
+  isSuccess: boolean;
+  isError: boolean;
+  data: GetSLOBurnRatesResponse | undefined;
+  refetch: <TPageData>(
+    options?: (RefetchOptions & RefetchQueryFilters<TPageData>) | undefined
+  ) => Promise<QueryObserverResult<GetSLOBurnRatesResponse | undefined, unknown>>;
+}
+
+const LONG_REFETCH_INTERVAL = 1000 * 60; // 1 minute
+
+interface UseFetchSloBurnRatesParams {
+  sloId: string;
+  windows: Array<{ name: string; duration: string }>;
+  shouldRefetch?: boolean;
+}
+
+export function useFetchSloBurnRates({
+  sloId,
+  windows,
+  shouldRefetch,
+}: UseFetchSloBurnRatesParams): UseFetchSloBurnRatesResponse {
+  const { http } = useKibana().services;
+  const { isInitialLoading, isLoading, isError, isSuccess, isRefetching, data, refetch } = useQuery(
+    {
+      queryKey: sloKeys.burnRates(sloId),
+      queryFn: async ({ signal }) => {
+        try {
+          const response = await http.post<GetSLOBurnRatesResponse>(
+            `/internal/observability/slos/${sloId}/_burn_rates`,
+            {
+              body: JSON.stringify({ windows }),
+              signal,
+            }
+          );
+
+          return response;
+        } catch (error) {
+          // ignore error
+        }
+      },
+      refetchInterval: shouldRefetch ? LONG_REFETCH_INTERVAL : undefined,
+      refetchOnWindowFocus: false,
+      keepPreviousData: true,
+    }
+  );
+
+  return {
+    data,
+    refetch,
+    isLoading,
+    isRefetching,
+    isInitialLoading,
+    isSuccess,
+    isError,
+  };
+}

x-pack/plugins/observability/public/pages/slo_details/components/burn_rate_window.tsx

@@ -0,0 +1,127 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import React from 'react';
+import {
+  EuiSpacer,
+  EuiFlexGroup,
+  EuiPanel,
+  EuiFlexItem,
+  EuiStat,
+  EuiTextColor,
+  EuiText,
+  EuiIconTip,
+} from '@elastic/eui';
+import numeral from '@elastic/numeral';
+import { i18n } from '@kbn/i18n';
+
+export interface BurnRateWindowParams {
+  title: string;
+  target: number;
+  longWindow: {
+    label: string;
+    burnRate: number | null;
+    sli: number | null;
+  };
+  shortWindow: {
+    label: string;
+    burnRate: number | null;
+    sli: number | null;
+  };
+  isLoading?: boolean;
+  size?: 'xxxs' | 'xxs' | 'xs' | 's' | 'm' | 'l';
+}
+
+const SUBDUED = 'subdued';
+const DANGER = 'danger';
+const SUCCESS = 'success';
+const WARNING = 'warning';
+
+function getColorBasedOnBurnRate(target: number, burnRate: number | null, sli: number | null) {
+  if (burnRate === null || sli === null || sli < 0) {
+    return SUBDUED;
+  }
+  if (burnRate > target) {
+    return DANGER;
+  }
+  return SUCCESS;
+}
+
+export function BurnRateWindow({
+  title,
+  target,
+  longWindow,
+  shortWindow,
+  isLoading,
+  size = 's',
+}: BurnRateWindowParams) {
+  const longWindowColor = getColorBasedOnBurnRate(target, longWindow.burnRate, longWindow.sli);
+  const shortWindowColor = getColorBasedOnBurnRate(target, shortWindow.burnRate, shortWindow.sli);
+
+  const overallColor =
+    longWindowColor === DANGER && shortWindowColor === DANGER
+      ? DANGER
+      : [longWindowColor, shortWindowColor].includes(DANGER)
+      ? WARNING
+      : longWindowColor === SUBDUED && shortWindowColor === SUBDUED
+      ? SUBDUED
+      : SUCCESS;
+
+  const isLongWindowValid =
+    longWindow.burnRate != null && longWindow.sli != null && longWindow.sli >= 0;
+
+  const isShortWindowValid =
+    shortWindow.burnRate != null && shortWindow.sli != null && shortWindow.sli >= 0;
+
+  return (
+    <EuiPanel color={overallColor}>
+      <EuiText color={overallColor}>
+        <h5>
+          {title}
+          <EuiIconTip
+            content={i18n.translate('xpack.observability.slo.burnRateWindow.thresholdTip', {
+              defaultMessage: 'Threshold is {target}x',
+              values: { target },
+            })}
+            position="top"
+          />
+        </h5>
+      </EuiText>
+      <EuiSpacer size="xs" />
+      <EuiFlexGroup>
+        <EuiFlexItem>
+          <EuiStat
+            title={isLongWindowValid ? `${numeral(longWindow.burnRate).format('0.[00]')}x` : '--'}
+            titleColor={longWindowColor}
+            titleSize={size}
+            textAlign="left"
+            isLoading={isLoading}
+            description={
+              <EuiTextColor color={longWindowColor}>
+                <span>{longWindow.label}</span>
+              </EuiTextColor>
+            }
+          />
+        </EuiFlexItem>
+        <EuiFlexItem>
+          <EuiStat
+            title={isShortWindowValid ? `${numeral(shortWindow.burnRate).format('0.[00]')}x` : '--'}
+            titleColor={shortWindowColor}
+            titleSize={size}
+            textAlign="left"
+            isLoading={isLoading}
+            description={
+              <EuiTextColor color={shortWindowColor}>
+                <span>{shortWindow.label}</span>
+              </EuiTextColor>
+            }
+          />
+        </EuiFlexItem>
+      </EuiFlexGroup>
+    </EuiPanel>
+  );
+}