Fix plugin deprecations (#29737)

* [deprecations] convert flattened settings to nested settings

* [deprecations] reuse rename method for elasticsearch.url to elasticsearch.hosts

* newline

* add known issues to docs

docs/CHANGELOG.asciidoc

@@ -87,6 +87,13 @@ This section summarizes the changes in each release.
 [[release-notes-6.6.0]]
 == {kib} 6.6.0
 
+[float]
+[[known-issues-6.6.0]]
+=== Known issues
+
+* {kib} may not start when using deprecated plugin settings in kibana.yml
++
+The server will log an error and the new configuration value.  Updating kibana.yml with the new configuration will allow the server to start.
 
 [float]
 [[breaking-6.6.0]]

src/legacy/core_plugins/elasticsearch/index.js

@@ -106,27 +106,10 @@ export default function (kibana) {
         };
       };
 
-      const url = () => {
-        return (settings, log) => {
-          const deprecatedUrl = get(settings, 'url');
-          const hosts = get(settings, 'hosts.length');
-          if (!deprecatedUrl) {
-            return;
-          }
-          if (hosts) {
-            log('Deprecated config key "elasticsearch.url" conflicts with "elasticsearch.hosts".  Ignoring "elasticsearch.url"');
-          } else {
-            set(settings, 'hosts', [deprecatedUrl]);
-            log('Config key "elasticsearch.url" is deprecated. It has been replaced with "elasticsearch.hosts"');
-          }
-          unset(settings, 'url');
-        };
-      };
-
       return [
         rename('ssl.ca', 'ssl.certificateAuthorities'),
         rename('ssl.cert', 'ssl.certificate'),
-        url(),
+        rename('url', 'hosts'),
         sslVerify(),
         rename('tribe.ssl.ca', 'tribe.ssl.certificateAuthorities'),
         rename('tribe.ssl.cert', 'tribe.ssl.certificate'),

src/server/config/complete.js

@@ -17,7 +17,7 @@
  * under the License.
  */
 
-import { difference } from 'lodash';
+import { difference, get, set } from 'lodash';
 import { transformDeprecations } from './transform_deprecations';
 import { unset, formatListAsProse, getFlattenedObject } from '../../utils';
 import { getTransform } from '../../deprecation';
@@ -39,9 +39,13 @@ async function getUnusedConfigKeys(
     const { spec } = plugins[i];
     const transform = await getTransform(spec);
     const prefix = spec.getConfigPrefix();
-    const pluginSettings = settings[prefix];
+
+    // nested plugin prefixes (a.b) translate to nested objects
+    const pluginSettings = get(settings, prefix);
     if (pluginSettings) {
-      settings[prefix] = transform(pluginSettings);
+      // flattened settings are expected to be converted to nested objects
+      // a.b = true => { a: { b: true }}
+      set(settings, prefix, transform(pluginSettings));
     }
   }
 

src/server/config/complete.test.js

@@ -252,6 +252,41 @@ describe('server/config completeMixin()', function () {
 
       await expect(callCompleteMixin()).resolves.toBe(undefined);
     });
+
+    it('should transform deeply nested deprecated plugin settings', async () => {
+      const { callCompleteMixin } = setup({
+        settings: {
+          xpack: {
+            monitoring: {
+              elasticsearch: {
+                url: 'http://localhost:9200'
+              }
+            }
+          }
+        },
+        configValues: {
+          xpack: {
+            monitoring: {
+              elasticsearch: {
+                hosts: 'http://localhost:9200'
+              }
+            }
+          }
+        },
+        plugins: [
+          {
+            spec: {
+              getDeprecationsProvider() {
+                return async ({ rename }) => [rename('elasticsearch.url', 'elasticsearch.hosts')];
+              },
+              getConfigPrefix: () => 'xpack.monitoring'
+            }
+          }
+        ],
+      });
+
+      await expect(callCompleteMixin()).resolves.toBe(undefined);
+    });
   });
 
   describe('disabled plugins', () => {

x-pack/plugins/monitoring/deprecations.js

@@ -4,7 +4,7 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { get, has, set, unset } from 'lodash';
+import { get, has, set } from 'lodash';
 import { CLUSTER_ALERTS_ADDRESS_CONFIG_KEY } from './common/constants';
 
 /**
@@ -20,6 +20,7 @@ export const deprecations = ({ rename }) => {
   return [
     rename('elasticsearch.ssl.ca', 'elasticsearch.ssl.certificateAuthorities'),
     rename('elasticsearch.ssl.cert', 'elasticsearch.ssl.certificate'),
+    rename('elasticsearch.url', 'elasticsearch.hosts'),
     (settings, log) => {
       if (!has(settings, 'elasticsearch.ssl.verify')) {
         return;
@@ -50,22 +51,6 @@ export const deprecations = ({ rename }) => {
       if (emailNotificationsEnabled && !get(settings, CLUSTER_ALERTS_ADDRESS_CONFIG_KEY)) {
         log(`Config key "${CLUSTER_ALERTS_ADDRESS_CONFIG_KEY}" will be required for email notifications to work in 7.0."`);
       }
-    },
-    (settings, log) => {
-      const deprecatedUrl = get(settings, 'url');
-      const hosts = get(settings, 'hosts.length');
-      if (!deprecatedUrl) {
-        return;
-      }
-      if (hosts) {
-        log('Deprecated config key "xpack.monitoring.elasticsearch.url" ' +
-          'conflicts with "xpack.monitoring.elasticsearch.hosts".  Ignoring "elasticsearch.url"');
-      } else {
-        set(settings, 'hosts', [deprecatedUrl]);
-        log('Config key "xpack.monitoring.elasticsearch.url" is deprecated.' +
-          'It has been replaced with "xpack.monitoring.elasticsearch.hosts"');
-      }
-      unset(settings, 'url');
     }
   ];
 };