chore(slo): simplify error budget calculations (#158941)

x-pack/plugins/observability/server/assets/constants.ts

@@ -11,6 +11,7 @@ export const SLO_INDEX_TEMPLATE_NAME = '.slo-observability.sli';
 export const SLO_RESOURCES_VERSION = 1;
 export const SLO_INGEST_PIPELINE_NAME = `${SLO_INDEX_TEMPLATE_NAME}.monthly`;
 export const SLO_DESTINATION_INDEX_NAME = `${SLO_INDEX_TEMPLATE_NAME}-v${SLO_RESOURCES_VERSION}`;
+export const SLO_DESTINATION_INDEX_PATTERN = `${SLO_DESTINATION_INDEX_NAME}*`;
 
 export const getSLOTransformId = (sloId: string, sloRevision: number) =>
   `slo-${sloId}-${sloRevision}`;

x-pack/plugins/observability/server/domain/services/compute_sli.test.ts

@@ -9,18 +9,18 @@ import { computeSLI } from './compute_sli';
 
 describe('computeSLI', () => {
   it('returns -1 when no total events', () => {
-    expect(computeSLI({ good: 100, total: 0 })).toEqual(-1);
+    expect(computeSLI(100, 0)).toEqual(-1);
   });
 
   it('returns the sli value', () => {
-    expect(computeSLI({ good: 100, total: 1000 })).toEqual(0.1);
+    expect(computeSLI(100, 1000)).toEqual(0.1);
   });
 
   it('returns 1 when good is greater than total events', () => {
-    expect(computeSLI({ good: 9999, total: 9 })).toEqual(1);
+    expect(computeSLI(9999, 9)).toEqual(1);
   });
 
   it('returns rounds the value to 6 digits', () => {
-    expect(computeSLI({ good: 33, total: 90 })).toEqual(0.366667);
+    expect(computeSLI(33, 90)).toEqual(0.366667);
   });
 });

x-pack/plugins/observability/server/domain/services/compute_sli.ts

@@ -5,13 +5,11 @@
  * 2.0.
  */
 
-import { IndicatorData } from '../models';
 import { toHighPrecision } from '../../utils/number';
 
 const NO_DATA = -1;
 
-export function computeSLI(sliData: Pick<IndicatorData, 'good' | 'total'>): number {
-  const { good, total } = sliData;
+export function computeSLI(good: number, total: number): number {
   if (total === 0) {
     return NO_DATA;
   }

x-pack/plugins/observability/server/domain/services/compute_summary_status.ts

@@ -12,7 +12,7 @@ export function computeSummaryStatus(slo: SLO, sliValue: number, errorBudget: Er
     return 'NO_DATA';
   }
 
-  if (slo.objective.target <= sliValue) {
+  if (sliValue >= slo.objective.target) {
     return 'HEALTHY';
   } else {
     return errorBudget.remaining > 0 ? 'DEGRADING' : 'VIOLATED';

x-pack/plugins/observability/server/domain/services/error_budget.ts

@@ -0,0 +1,22 @@
+/*
+ * 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 { toHighPrecision } from '../../utils/number';
+import { ErrorBudget } from '../models';
+
+export function toErrorBudget(
+  initial: number,
+  consumed: number,
+  isEstimated: boolean = false
+): ErrorBudget {
+  return {
+    initial: toHighPrecision(initial),
+    consumed: toHighPrecision(consumed),
+    remaining: toHighPrecision(1 - consumed),
+    isEstimated,
+  };
+}

x-pack/plugins/observability/server/domain/services/index.ts

@@ -6,7 +6,7 @@
  */
 
 export * from './compute_burn_rate';
-export * from './compute_error_budget';
+export * from './error_budget';
 export * from './compute_sli';
 export * from './compute_summary_status';
 export * from './date_range';