[Security Solution] Support experimental features in timelines (#189028)

## Summary

Adding generic support for experimental features in timelines

---------

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

test/plugin_functional/test_suites/core_plugins/rendering.ts

@@ -336,6 +336,7 @@ export default function ({ getService }: PluginFunctionalProviderContext) {
         'xpack.stack_connectors.enableExperimental (array)',
         'xpack.trigger_actions_ui.enableExperimental (array)',
         'xpack.trigger_actions_ui.enableGeoTrackingThresholdAlert (boolean)',
+        'xpack.timelines.enableExperimental (array)',
         'xpack.alerting.rules.run.alerts.max (number)',
         'xpack.upgrade_assistant.featureSet.migrateSystemIndices (boolean)',
         'xpack.upgrade_assistant.featureSet.mlSnapshots (boolean)',

x-pack/plugins/security_solution/docs/openapi/ess/security_solution_endpoint_management_api_2023_10_31.bundled.schema.yaml

@@ -935,4 +935,3 @@ components:
       type: http
 security:
   - BasicAuth: []
-tags: !<tag:yaml.org,2002:js/undefined> ''

x-pack/plugins/security_solution/docs/openapi/serverless/security_solution_endpoint_management_api_2023_10_31.bundled.schema.yaml

@@ -863,4 +863,3 @@ components:
       type: http
 security:
   - BasicAuth: []
-tags: !<tag:yaml.org,2002:js/undefined> ''

x-pack/plugins/timelines/common/experimental_features.ts

@@ -0,0 +1,47 @@
+/*
+ * 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 allowedExperimentalValues = Object.freeze({
+  // NOTE: remove this after some actual flags are added, without it line 36 fails ts validation
+  sample: false,
+});
+
+export type ExperimentalFeatures = { [K in keyof typeof allowedExperimentalValues]: boolean };
+
+const allowedKeys = Object.keys(allowedExperimentalValues);
+
+type Mutable<T> = { -readonly [P in keyof T]: T[P] };
+
+/**
+ * Parses the string value used in `xpack.timelines.enableExperimental` kibana configuration,
+ * which should be a string of values delimited by a comma (`,`)
+ *
+ * @param configValue
+ * @throws SecuritySolutionInvalidExperimentalValue
+ */
+export const parseExperimentalConfigValue = (
+  configValue: string[]
+): { features: ExperimentalFeatures; invalid: string[] } => {
+  const enabledFeatures: Mutable<Partial<ExperimentalFeatures>> = {};
+  const invalidKeys: string[] = [];
+
+  for (const value of configValue) {
+    if (!allowedKeys.includes(value as keyof ExperimentalFeatures)) {
+      invalidKeys.push(value);
+    } else {
+      enabledFeatures[value as keyof ExperimentalFeatures] = true;
+    }
+  }
+
+  return {
+    features: {
+      ...allowedExperimentalValues,
+      ...enabledFeatures,
+    },
+    invalid: invalidKeys,
+  };
+};

x-pack/plugins/timelines/server/config.ts

@@ -0,0 +1,10 @@
+/*
+ * 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 interface ConfigSchema {
+  enableExperimental: string[];
+}

x-pack/plugins/timelines/server/index.ts

@@ -5,7 +5,9 @@
  * 2.0.
  */
 
-import { PluginInitializerContext } from '@kbn/core/server';
+import { PluginConfigDescriptor, PluginInitializerContext } from '@kbn/core/server';
+import { schema } from '@kbn/config-schema';
+import { ConfigSchema } from './config';
 
 export async function plugin(initializerContext: PluginInitializerContext) {
   const { TimelinesPlugin } = await import('./plugin');
@@ -13,3 +15,28 @@ export async function plugin(initializerContext: PluginInitializerContext) {
 }
 
 export type { TimelinesPluginUI, TimelinesPluginStart } from './types';
+
+const configSchema = schema.object({
+  /**
+   * For internal use. A list of string values (comma delimited) that will enable experimental
+   * type of functionality that is not yet released. Valid values for this settings need to
+   * be defined in:
+   * `x-pack/plugins/timelines/common/experimental_features.ts`
+   * under the `allowedExperimentalValues` object
+   *
+   * @example
+   * xpack.timelines.enableExperimental:
+   *   - someCrazyFeature
+   *   - someEvenCrazierFeature
+   */
+  enableExperimental: schema.arrayOf(schema.string(), {
+    defaultValue: () => [],
+  }),
+});
+
+export const config: PluginConfigDescriptor<ConfigSchema> = {
+  exposeToBrowser: {
+    enableExperimental: true,
+  },
+  schema: configSchema,
+};

x-pack/plugins/timelines/server/plugin.ts

@@ -12,6 +12,8 @@ import { SetupPlugins, StartPlugins, TimelinesPluginUI, TimelinesPluginStart } f
 import { timelineSearchStrategyProvider } from './search_strategy/timeline';
 import { timelineEqlSearchStrategyProvider } from './search_strategy/timeline/eql';
 import { indexFieldsProvider } from './search_strategy/index_fields';
+import { parseExperimentalConfigValue } from '../common/experimental_features';
+import { ConfigSchema } from './config';
 
 export class TimelinesPlugin
   implements Plugin<TimelinesPluginUI, TimelinesPluginStart, SetupPlugins, StartPlugins>
@@ -21,6 +23,11 @@ export class TimelinesPlugin
 
   constructor(initializerContext: PluginInitializerContext) {
     this.logger = initializerContext.logger.get();
+
+    // NOTE: underscored to skip lint warning, but it can be used to implement experimental features behind a flag
+    const { features: _experimentalFeatures } = parseExperimentalConfigValue(
+      initializerContext.config.get<ConfigSchema>().enableExperimental
+    );
   }
 
   public setup(core: CoreSetup<StartPlugins, TimelinesPluginStart>, plugins: SetupPlugins) {

x-pack/plugins/timelines/server/search_strategy/timeline/index.ts

@@ -17,6 +17,7 @@ import { ENHANCED_ES_SEARCH_STRATEGY } from '@kbn/data-plugin/common';
 import { SecurityPluginSetup } from '@kbn/security-plugin/server';
 import { Logger } from '@kbn/logging';
 import { z } from 'zod';
+
 import { searchStrategyRequestSchema } from '../../../common/api/search_strategy';
 import {
   TimelineFactoryQueryTypes,
@@ -30,7 +31,7 @@ import { isAggCardinalityAggregate } from './factory/helpers/is_agg_cardinality_
 export const timelineSearchStrategyProvider = (
   data: PluginStart,
   logger: Logger,
-  security?: SecurityPluginSetup
+  _security?: SecurityPluginSetup
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
 ): ISearchStrategy<z.input<typeof searchStrategyRequestSchema>, any> => {
   const es = data.search.getSearchStrategy(ENHANCED_ES_SEARCH_STRATEGY);

x-pack/plugins/timelines/tsconfig.json

@@ -37,7 +37,8 @@
     "@kbn/search-errors",
     "@kbn/search-types",
     "@kbn/react-kibana-mount",
-    "@kbn/field-formats-plugin"
+    "@kbn/field-formats-plugin",
+    "@kbn/config-schema"
   ],
   "exclude": [
     "target/**/*"