[SLO] Migrate composite SLO to Kibana feature flags (elastic#271130)

## Summary

- Replace `xpack.slo.experimental.compositeSlo.enabled` with
`slo.compositeSloEnabled` (Kibana Feature Flags).
- Keep composite SO/routes/resources unconditional; gate API handlers,
UI, and summary task at runtime.
- Update Scout configs and unit tests for FF gating.

Requires companion PR in `kibana-feature-flags` for
`slo.compositeSloEnabled`.

Closes elastic#270358

## Test plan

- [ ] `node scripts/jest x-pack/solutions/observability/plugins/slo`
- [ ] Scout (stateful): `node scripts/scout run-tests --arch stateful
--domain classic --serverConfigSet composite_slo --config
x-pack/solutions/observability/plugins/slo/test/scout_composite_slo/api/playwright.config.ts`
- [ ] Scout (serverless): same with `--arch serverless --domain
observability_complete`


Made with [Cursor](https://cursor.com)

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

Author: miguelmartin-elastic

src/platform/packages/shared/kbn-scout/src/servers/configs/config_sets/composite_slo/serverless/observability_complete.serverless.config.ts

@@ -16,7 +16,7 @@ export const servers: ScoutServerConfig = {
     ...obltServerlessConfig.kbnTestServer,
     serverArgs: [
       ...obltServerlessConfig.kbnTestServer.serverArgs,
-      '--xpack.slo.experimental.compositeSlo.enabled=true',
+      '--feature_flags.overrides.slo.compositeSloEnabled=true',
     ],
   },
 };

src/platform/packages/shared/kbn-scout/src/servers/configs/config_sets/composite_slo/stateful/classic.stateful.config.ts

@@ -16,7 +16,7 @@ export const servers: ScoutServerConfig = {
     ...defaultConfig.kbnTestServer,
     serverArgs: [
       ...defaultConfig.kbnTestServer.serverArgs,
-      '--xpack.slo.experimental.compositeSlo.enabled=true',
+      '--feature_flags.overrides.slo.compositeSloEnabled=true',
     ],
   },
 };

x-pack/solutions/observability/plugins/slo/common/config.ts

@@ -13,16 +13,13 @@ export const configSchema = schema.object({
   tempSummaryCleanupTaskEnabled: schema.boolean({ defaultValue: true }),
   healthScanTaskEnabled: schema.boolean({ defaultValue: true }),
   staleInstancesCleanupTaskEnabled: schema.boolean({ defaultValue: false }),
-  compositeSloSummaryTaskEnabled: schema.boolean({ defaultValue: false }),
+  compositeSloSummaryTaskEnabled: schema.boolean({ defaultValue: true }),
   enabled: schema.boolean({ defaultValue: true }),
   experimental: schema.maybe(
     schema.object({
       ruleFormV2: schema.object({
         enabled: schema.boolean({ defaultValue: false }),
       }),
-      compositeSlo: schema.object({
-        enabled: schema.boolean({ defaultValue: false }),
-      }),
     })
   ),
 });

x-pack/solutions/observability/plugins/slo/common/feature_flags.ts

@@ -0,0 +1,8 @@
+/*
+ * 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.
+ */
+
+export const SLO_COMPOSITE_ENABLED = 'slo.compositeSloEnabled';

x-pack/solutions/observability/plugins/slo/moon.yml

@@ -136,6 +136,7 @@ dependsOn:
   - '@kbn/agent-builder-browser'
   - '@kbn/core-analytics-browser'
   - '@kbn/inspector-plugin'
+  - '@kbn/core-feature-flags-server'
 tags:
   - plugin
   - prod

x-pack/solutions/observability/plugins/slo/public/application.tsx

@@ -24,7 +24,7 @@ import ReactDOM from 'react-dom';
 import type { ExperimentalFeatures } from '../common/config';
 import { PluginContext } from './context/plugin_context';
 import { InspectedSloClientProvider } from './components/inspect/inspected_slo_client_provider';
-import { usePluginContext } from './hooks/use_plugin_context';
+import { useCompositeSloEnabled } from './hooks/use_composite_slo_enabled';
 import { getRoutes } from './routes/routes';
 import type { SLOPublicPluginsStart, SLORepositoryClient } from './types';
 import type { ISloTelemetryClient } from './services/telemetry';
@@ -151,8 +151,8 @@ export const renderApp = ({
 };
 
 function App() {
-  const { experimentalFeatures } = usePluginContext();
-  const routes = getRoutes(experimentalFeatures);
+  const isCompositeSloEnabled = useCompositeSloEnabled();
+  const routes = getRoutes(isCompositeSloEnabled);
 
   return (
     <Routes enableExecutionContextTracking={true}>

x-pack/solutions/observability/plugins/slo/public/hooks/use_composite_slo_enabled.ts

@@ -0,0 +1,17 @@
+/*
+ * 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 { SLO_COMPOSITE_ENABLED } from '../../common/feature_flags';
+import { useKibana } from './use_kibana';
+
+export function useCompositeSloEnabled(): boolean {
+  const {
+    services: { featureFlags },
+  } = useKibana();
+
+  return featureFlags.getBooleanValue(SLO_COMPOSITE_ENABLED, false);
+}

x-pack/solutions/observability/plugins/slo/public/pages/composite_slo_edit/composite_slo_edit.tsx

@@ -12,6 +12,7 @@ import { paths } from '@kbn/slo-shared-plugin/common/locators/paths';
 import React, { useEffect } from 'react';
 import { useParams } from 'react-router-dom';
 import { HeaderMenu } from '../../components/header_menu/header_menu';
+import { useCompositeSloEnabled } from '../../hooks/use_composite_slo_enabled';
 import { useKibana } from '../../hooks/use_kibana';
 import { useLicense } from '../../hooks/use_license';
 import { usePermissions } from '../../hooks/use_permissions';
@@ -33,23 +34,24 @@ export function CompositeSloEditPage() {
     useFetchCompositeSlo(compositeSloId);
 
   const { data: permissions } = usePermissions();
-  const { ObservabilityPageTemplate, experimentalFeatures } = usePluginContext();
+  const { ObservabilityPageTemplate } = usePluginContext();
   const { hasAtLeast } = useLicense();
   const hasRightLicense = hasAtLeast('platinum');
+  const isCompositeSloEnabled = useCompositeSloEnabled();
 
   useEffect(() => {
     if (
       hasRightLicense === false ||
       permissions?.hasAllReadRequested === false ||
-      !experimentalFeatures?.compositeSlo?.enabled
+      !isCompositeSloEnabled
     ) {
       navigateToUrl(basePath.prepend(paths.slos));
     }
 
     if (permissions?.hasAllWriteRequested === false) {
       navigateToUrl(basePath.prepend(paths.slos));
     }
-  }, [hasRightLicense, permissions, navigateToUrl, basePath, experimentalFeatures]);
+  }, [hasRightLicense, permissions, navigateToUrl, basePath, isCompositeSloEnabled]);
 
   useBreadcrumbs(
     [

x-pack/solutions/observability/plugins/slo/public/pages/slos/components/common/create_slo_btn.test.tsx

@@ -19,6 +19,9 @@ jest.mock('../../../../hooks/use_kibana');
 jest.mock('../../../../hooks/use_permissions');
 jest.mock('../../../../hooks/use_fetch_slo_templates');
 jest.mock('../../../../hooks/use_fetch_slo_template_tags');
+jest.mock('../../../../hooks/use_composite_slo_enabled', () => ({
+  useCompositeSloEnabled: jest.fn().mockReturnValue(false),
+}));
 
 const mockNavigateToUrl = jest.fn();
 const useKibanaMock = useKibana as jest.Mock;

x-pack/solutions/observability/plugins/slo/public/pages/slos/components/common/create_slo_btn.tsx

@@ -9,9 +9,9 @@ import { EuiButton, EuiContextMenuItem, EuiContextMenuPanel, EuiPopover } from '
 import { i18n } from '@kbn/i18n';
 import { paths } from '@kbn/slo-shared-plugin/common/locators/paths';
 import React, { useCallback, useMemo, useState } from 'react';
+import { useCompositeSloEnabled } from '../../../../hooks/use_composite_slo_enabled';
 import { useKibana } from '../../../../hooks/use_kibana';
 import { usePermissions } from '../../../../hooks/use_permissions';
-import { usePluginContext } from '../../../../hooks/use_plugin_context';
 import { SloTemplatesFlyout } from '../../../../components/slo/slo_templates/slo_templates_flyout';
 
 export function CreateSloBtn() {
@@ -20,13 +20,12 @@ export function CreateSloBtn() {
     http: { basePath },
   } = useKibana().services;
 
-  const { experimentalFeatures } = usePluginContext();
   const { data: permissions } = usePermissions();
   const [isPopoverOpen, setIsPopoverOpen] = useState(false);
   const [isFlyoutOpen, setIsFlyoutOpen] = useState(false);
 
   const isDisabled = !permissions?.hasAllWriteRequested;
-  const isCompositeSloEnabled = experimentalFeatures?.compositeSlo?.enabled === true;
+  const isCompositeSloEnabled = useCompositeSloEnabled();
 
   const handleClickCreateSlo = useCallback(() => {
     setIsPopoverOpen(false);