Deprecate kibana.index setting (#83988)

* Deprecating `kibana.index` setting

* Using ela.st service so this can be changed to the blog in the future

* Adding unit tests

* Revising deprecation log message

* Changing the deprecation log message to be more consistent with others

* Updating kibana.index docs also

* Using rename deprecation as the "standard" for the deprecation messages

* /s/'/`

docs/setup/settings.asciidoc

@@ -214,10 +214,12 @@ Please use the `defaultRoute` advanced setting instead.
 The default application to load. *Default: `"home"`*
 
 |[[kibana-index]] `kibana.index:`
- | {kib} uses an index in {es} to store saved searches, visualizations, and
+ | *deprecated* This setting is deprecated and will be removed in 8.0. Multitenancy by changing
+`kibana.index` will not be supported starting in 8.0. See https://ela.st/kbn-remove-legacy-multitenancy[8.0 Breaking Changes]
+for more details. {kib} uses an index in {es} to store saved searches, visualizations, and
 dashboards. {kib} creates a new index if the index doesn’t already exist.
 If you configure a custom index, the name must be lowercase, and conform to the
-{es} {ref}/indices-create-index.html[index name limitations].
+{es} {ref}/indices-create-index.html[index name limitations]. 
 *Default: `".kibana"`*
 
 | `kibana.autocompleteTimeout:` {ess-icon}

src/core/server/kibana_config.test.ts

@@ -0,0 +1,66 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import { config } from './kibana_config';
+import { applyDeprecations, configDeprecationFactory } from '@kbn/config';
+
+const CONFIG_PATH = 'kibana';
+
+const applyKibanaDeprecations = (settings: Record<string, any> = {}) => {
+  const deprecations = config.deprecations!(configDeprecationFactory);
+  const deprecationMessages: string[] = [];
+  const _config: any = {};
+  _config[CONFIG_PATH] = settings;
+  const migrated = applyDeprecations(
+    _config,
+    deprecations.map((deprecation) => ({
+      deprecation,
+      path: CONFIG_PATH,
+    })),
+    (msg) => deprecationMessages.push(msg)
+  );
+  return {
+    messages: deprecationMessages,
+    migrated,
+  };
+};
+
+it('set correct defaults ', () => {
+  const configValue = config.schema.validate({});
+  expect(configValue).toMatchInlineSnapshot(`
+    Object {
+      "autocompleteTerminateAfter": "PT1M40S",
+      "autocompleteTimeout": "PT1S",
+      "enabled": true,
+      "index": ".kibana",
+    }
+  `);
+});
+
+describe('deprecations', () => {
+  ['.foo', '.kibana'].forEach((index) => {
+    it('logs a warning if index is set', () => {
+      const { messages } = applyKibanaDeprecations({ index });
+      expect(messages).toMatchInlineSnapshot(`
+      Array [
+        "\\"kibana.index\\" is deprecated. Multitenancy by changing \\"kibana.index\\" will not be supported starting in 8.0. See https://ela.st/kbn-remove-legacy-multitenancy for more details",
+      ]
+    `);
+    });
+  });
+});

src/core/server/kibana_config.ts

@@ -18,9 +18,22 @@
  */
 
 import { schema, TypeOf } from '@kbn/config-schema';
+import { ConfigDeprecationProvider } from '@kbn/config';
 
 export type KibanaConfigType = TypeOf<typeof config.schema>;
 
+const deprecations: ConfigDeprecationProvider = () => [
+  (settings, fromPath, log) => {
+    const kibana = settings[fromPath];
+    if (kibana?.index) {
+      log(
+        `"kibana.index" is deprecated. Multitenancy by changing "kibana.index" will not be supported starting in 8.0. See https://ela.st/kbn-remove-legacy-multitenancy for more details`
+      );
+    }
+    return settings;
+  },
+];
+
 export const config = {
   path: 'kibana',
   schema: schema.object({
@@ -29,4 +42,5 @@ export const config = {
     autocompleteTerminateAfter: schema.duration({ defaultValue: 100000 }),
     autocompleteTimeout: schema.duration({ defaultValue: 1000 }),
   }),
+  deprecations,
 };