Add Timelion deprecation warning to the migration assistant

Closes: elastic#63014

src/plugins/timelion/server/plugin.ts

@@ -17,44 +17,50 @@
  * under the License.
  */
 
-import { CoreSetup, Plugin, PluginInitializerContext } from 'src/core/server';
+import { CoreSetup, CoreStart, Plugin, PluginInitializerContext, Logger } from 'src/core/server';
 import { i18n } from '@kbn/i18n';
 import { schema } from '@kbn/config-schema';
 import { TimelionConfigType } from './config';
+import { timelionSheetSavedObjectType } from './saved_objects';
+
+/**
+ * Timelion plugin was deprecated since 7.0, the Timelion app will be removed in 8.0.
+ * To continue using your Timelion worksheets, migrate them to a dashboard.
+ *
+ *  @link https://www.elastic.co/guide/en/kibana/master/timelion.html#timelion-deprecation
+ **/
+const showWarningMessageIfTimelionSteetWasFound = (core: CoreStart, logger: Logger) => {
+  const { savedObjects } = core;
+  const savedObjectsClient = savedObjects.createInternalRepository();
+
+  savedObjectsClient
+    .find({
+      type: 'timelion-sheet',
+      perPage: 1,
+    })
+    .then(
+      ({ total }) =>
+        total &&
+        logger.warn(
+          'Timelion plugin was deprecated since 7.0, the Timelion app will be removed in 8.0.'
+        )
+    );
+};
 
 export class TimelionPlugin implements Plugin {
-  constructor(context: PluginInitializerContext<TimelionConfigType>) {}
+  private logger: Logger;
+
+  constructor(context: PluginInitializerContext<TimelionConfigType>) {
+    this.logger = context.logger.get();
+  }
 
   public setup(core: CoreSetup) {
     core.capabilities.registerProvider(() => ({
       timelion: {
         save: true,
       },
     }));
-    core.savedObjects.registerType({
-      name: 'timelion-sheet',
-      hidden: false,
-      namespaceType: 'single',
-      mappings: {
-        properties: {
-          description: { type: 'text' },
-          hits: { type: 'integer' },
-          kibanaSavedObjectMeta: {
-            properties: {
-              searchSourceJSON: { type: 'text' },
-            },
-          },
-          timelion_chart_height: { type: 'integer' },
-          timelion_columns: { type: 'integer' },
-          timelion_interval: { type: 'keyword' },
-          timelion_other_interval: { type: 'keyword' },
-          timelion_rows: { type: 'integer' },
-          timelion_sheet: { type: 'text' },
-          title: { type: 'text' },
-          version: { type: 'integer' },
-        },
-      },
-    });
+    core.savedObjects.registerType(timelionSheetSavedObjectType);
 
     core.uiSettings.register({
       'timelion:showTutorial': {
@@ -92,6 +98,8 @@ export class TimelionPlugin implements Plugin {
       },
     });
   }
-  start() {}
+  start(core: CoreStart) {
+    showWarningMessageIfTimelionSteetWasFound(core, this.logger);
+  }
   stop() {}
 }

src/plugins/timelion/server/saved_objects/index.ts

@@ -0,0 +1,20 @@
+/*
+ * 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.
+ */
+
+export { timelionSheetSavedObjectType } from './timelion_sheet';

src/plugins/timelion/server/saved_objects/timelion_sheet.ts

@@ -0,0 +1,45 @@
+/*
+ * 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 { SavedObjectsType } from 'kibana/server';
+
+export const timelionSheetSavedObjectType: SavedObjectsType = {
+  name: 'timelion-sheet',
+  hidden: false,
+  namespaceType: 'single',
+  mappings: {
+    properties: {
+      description: { type: 'text' },
+      hits: { type: 'integer' },
+      kibanaSavedObjectMeta: {
+        properties: {
+          searchSourceJSON: { type: 'text' },
+        },
+      },
+      timelion_chart_height: { type: 'integer' },
+      timelion_columns: { type: 'integer' },
+      timelion_interval: { type: 'keyword' },
+      timelion_other_interval: { type: 'keyword' },
+      timelion_rows: { type: 'integer' },
+      timelion_sheet: { type: 'text' },
+      title: { type: 'text' },
+      version: { type: 'integer' },
+    },
+  },
+};