[SECURITY SOLUTION] add enableExperimental plugin configuration setting (#94944)

* Added new setting (enableExperimental) to plugin configuration
* Remove plugin config setting `fleetServerEnabled` and use instead `enableExperimental`

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

@@ -0,0 +1,52 @@
+/*
+ * 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 type ExperimentalFeatures = typeof allowedExperimentalValues;
+
+/**
+ * A list of allowed values that can be used in `xpack.securitySolution.enableExperimental`.
+ * This object is then used to validate and parse the value entered.
+ */
+const allowedExperimentalValues = Object.freeze({
+  fleetServerEnabled: false,
+});
+
+type ExperimentalConfigKeys = Array<keyof ExperimentalFeatures>;
+type Mutable<T> = { -readonly [P in keyof T]: T[P] };
+
+const SecuritySolutionInvalidExperimentalValue = class extends Error {};
+const allowedKeys = Object.keys(allowedExperimentalValues) as Readonly<ExperimentalConfigKeys>;
+
+/**
+ * Parses the string value used in `xpack.securitySolution.enableExperimental` kibana configuration,
+ * which should be a string of values delimited by a comma (`,`)
+ *
+ * @param configValue
+ * @throws SecuritySolutionInvalidExperimentalValue
+ */
+export const parseExperimentalConfigValue = (configValue: string[]): ExperimentalFeatures => {
+  const enabledFeatures: Mutable<Partial<ExperimentalFeatures>> = {};
+
+  for (const value of configValue) {
+    if (!isValidExperimentalValue(value)) {
+      throw new SecuritySolutionInvalidExperimentalValue(`[${value}] is not valid.`);
+    }
+
+    enabledFeatures[value as keyof ExperimentalFeatures] = true;
+  }
+
+  return {
+    ...allowedExperimentalValues,
+    ...enabledFeatures,
+  };
+};
+
+export const isValidExperimentalValue = (value: string): boolean => {
+  return allowedKeys.includes(value as keyof ExperimentalFeatures);
+};
+
+export const getExperimentalAllowedValues = (): string[] => [...allowedKeys];

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

@@ -8,6 +8,12 @@
 import { schema, TypeOf } from '@kbn/config-schema';
 import { PluginInitializerContext } from '../../../../src/core/server';
 import { SIGNALS_INDEX_KEY, DEFAULT_SIGNALS_INDEX } from '../common/constants';
+import {
+  getExperimentalAllowedValues,
+  isValidExperimentalValue,
+} from '../common/experimental_features';
+
+const allowedExperimentalValues = getExperimentalAllowedValues();
 
 export const configSchema = schema.object({
   enabled: schema.boolean({ defaultValue: true }),
@@ -17,8 +23,30 @@ export const configSchema = schema.object({
   maxTimelineImportPayloadBytes: schema.number({ defaultValue: 10485760 }),
   [SIGNALS_INDEX_KEY]: schema.string({ defaultValue: DEFAULT_SIGNALS_INDEX }),
 
-  /** Fleet server integration */
-  fleetServerEnabled: schema.boolean({ defaultValue: false }),
+  /**
+   * 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/security_solution/common/experimental_features.ts`
+   * under the `allowedExperimentalValues` object
+   *
+   * @example
+   * xpack.securitySolution.enableExperimental:
+   *   - fleetServerEnabled
+   *   - trustedAppsByPolicyEnabled
+   */
+  enableExperimental: schema.arrayOf(schema.string(), {
+    defaultValue: () => [],
+    validate(list) {
+      for (const key of list) {
+        if (!isValidExperimentalValue(key)) {
+          return `[${key}] is not allowed. Allowed values are: ${allowedExperimentalValues.join(
+            ', '
+          )}`;
+        }
+      }
+    },
+  }),
 
   /**
    * Host Endpoint Configuration

x-pack/plugins/security_solution/server/lib/detection_engine/routes/__mocks__/index.ts

@@ -21,7 +21,7 @@ export const createMockConfig = (): ConfigType => ({
   maxRuleImportPayloadBytes: 10485760,
   maxTimelineImportExportSize: 10000,
   maxTimelineImportPayloadBytes: 10485760,
-  fleetServerEnabled: true,
+  enableExperimental: [],
   endpointResultListDefaultFirstPageIndex: 0,
   endpointResultListDefaultPageSize: 10,
   alertResultListDefaultDateRange: {

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

@@ -77,6 +77,7 @@ import {
 import { licenseService } from './lib/license/license';
 import { PolicyWatcher } from './endpoint/lib/policy/license_watch';
 import { securitySolutionTimelineEqlSearchStrategyProvider } from './search_strategy/timeline/eql';
+import { parseExperimentalConfigValue } from '../common/experimental_features';
 
 export interface SetupPlugins {
   alerting: AlertingSetup;
@@ -357,7 +358,7 @@ export class Plugin implements IPlugin<PluginSetup, PluginStart, SetupPlugins, S
           logger: this.logger,
           cache: this.artifactsCache,
         },
-        this.config.fleetServerEnabled
+        parseExperimentalConfigValue(this.config.enableExperimental).fleetServerEnabled
       );
 
       if (this.manifestTask) {