Kibana app migration: Local application service

src/legacy/core_plugins/kibana/public/kibana.js

@@ -58,6 +58,11 @@ import 'ui/agg_response';
 import 'ui/agg_types';
 import { showAppRedirectNotification } from 'ui/notify';
 import 'leaflet';
+import { localApplicationService } from './local_application_service';
+
+localApplicationService.forwardApp('foo', 'discover');
+
+localApplicationService.attachToAngular(routes);
 
 routes.enable();
 

src/legacy/core_plugins/kibana/public/local_application_service/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 * from './local_application_service';

src/legacy/core_plugins/kibana/public/local_application_service/local_application_service.ts

@@ -0,0 +1,145 @@
+/*
+ * 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 { App, AppUnmount } from 'kibana/public';
+import { UIRoutes } from 'ui/routes';
+import { IScope } from 'angular';
+import { npStart } from 'ui/new_platform';
+import { htmlIdGenerator } from '@elastic/eui';
+
+interface ForwardDefinition {
+  legacyAppId: string;
+  newAppId: string;
+  keepPrefix: boolean;
+}
+
+const matchAllWithPrefix = (prefixOrApp: string | App) =>
+  `/${typeof prefixOrApp === 'string' ? prefixOrApp : prefixOrApp.id}/:tail*?`;
+
+/**
+ * To be able to migrate and shim parts of the Kibana app plugin
+ * while still running some parts of it in the legacy world, this
+ * service emulates the core application service while using the global
+ * angular router to switch between apps without page reload.
+ *
+ * The id of the apps is used as prefix of the route - when switching between
+ * to apps, the current application is unmounted.
+ *
+ * This service becomes unnecessary once the platform provides a central
+ * router that handles switching between applications without page reload.
+ */
+export class LocalApplicationService {
+  private apps: App[] = [];
+  private forwards: ForwardDefinition[] = [];
+  private idGenerator = htmlIdGenerator('kibanaAppLocalApp');
+
+  /**
+   * Register an app to be managed by the application service.
+   * This method works exactly as `core.application.register`.
+   *
+   * When an app is mounted, it is responsible for routing. The app
+   * won't be mounted again if the route changes within the prefix
+   * of the app (its id). It is fine to use whatever means for handling
+   * routing within the app.
+   *
+   * When switching to a URL outside of the current prefix, the app router
+   * shouldn't do anything because it doesn't own the routing anymore -
+   * the local application service takes over routing again,
+   * unmounts the current app and mounts the next app.
+   *
+   * @param app The app descriptor
+   */
+  register(app: App) {
+    this.apps.push(app);
+  }
+
+  /**
+   * Forwards every URL starting with `legacyAppId` to the same URL starting
+   * with `newAppId` - e.g. `/legacy/my/legacy/path?q=123` gets forwarded to
+   * `/newApp/my/legacy/path?q=123`.
+   *
+   * When setting the `keepPrefix` option, the new app id is simply prepended.
+   * The example above would become `/newApp/legacy/my/legacy/path?q=123`.
+   *
+   * This method can be used to provide backwards compatibility for URLs when
+   * renaming or nesting plugins. For route changes after the prefix, please
+   * use the routing mechanism of your app.
+   *
+   * @param legacyAppId The name of the old app to forward URLs from
+   * @param newAppId The name of the new app that handles the URLs now
+   * @param options Whether the prefix of the old app is kept to nest the legacy
+   * path into the new path
+   */
+  forwardApp(
+    legacyAppId: string,
+    newAppId: string,
+    options: { keepPrefix: boolean } = { keepPrefix: false }
+  ) {
+    this.forwards.push({ legacyAppId, newAppId, ...options });
+  }
+
+  /**
+   * Wires up listeners to handle mounting and unmounting of apps to
+   * the legacy angular route manager. Once all apps within the Kibana
+   * plugin are using the local route manager, this implementation can
+   * be switched to a more lightweight implementation.
+   *
+   * @param angularRouteManager The current `ui/routes` instance
+   */
+  attachToAngular(angularRouteManager: UIRoutes) {
+    this.apps.forEach(app => {
+      const wrapperElementId = this.idGenerator();
+      angularRouteManager.when(matchAllWithPrefix(app), {
+        outerAngularWrapperRoute: true,
+        reloadOnSearch: false,
+        reloadOnUrl: false,
+        template: `<div style="height:100%" id="${wrapperElementId}"></div>`,
+        controller($scope: IScope) {
+          const element = document.getElementById(wrapperElementId)!;
+          let unmountHandler: AppUnmount | null = null;
+          let isUnmounted = false;
+          $scope.$on('$destroy', () => {
+            if (unmountHandler) {
+              unmountHandler();
+            }
+            isUnmounted = true;
+          });
+          (async () => {
+            unmountHandler = await app.mount({ core: npStart.core }, { element, appBasePath: '' });
+            // immediately unmount app if scope got destroyed in the meantime
+            if (isUnmounted) {
+              unmountHandler();
+            }
+          })();
+        },
+      });
+    });
+
+    this.forwards.forEach(({ legacyAppId, newAppId, keepPrefix }) => {
+      angularRouteManager.when(matchAllWithPrefix(legacyAppId), {
+        resolveRedirectTo: ($location: any) => {
+          const url = $location.url();
+          return `/${newAppId}${keepPrefix ? url : url.replace(legacyAppId, '')}`;
+        },
+      });
+    });
+  }
+}
+
+export const localApplicationService = new LocalApplicationService();

src/legacy/ui/public/legacy_compat/angular_config.tsx

@@ -18,6 +18,7 @@
  */
 
 import {
+  auto,
   ICompileProvider,
   IHttpProvider,
   IHttpService,
@@ -48,6 +49,12 @@ import { isSystemApiRequest } from '../system_api';
 
 const URL_LIMIT_WARN_WITHIN = 1000;
 
+function isDummyWrapperRoute($route: any) {
+  return (
+    $route.current && $route.current.$$route && $route.current.$$route.outerAngularWrapperRoute
+  );
+}
+
 export const configureAppAngularModule = (angularModule: IModule) => {
   const newPlatform = npStart.core;
   const legacyMetadata = newPlatform.injectedMetadata.getLegacyMetadata();
@@ -187,6 +194,9 @@ const $setupBreadcrumbsAutoClear = (newPlatform: CoreStart) => (
   });
 
   $rootScope.$on('$routeChangeSuccess', () => {
+    if (isDummyWrapperRoute($route)) {
+      return;
+    }
     const current = $route.current || {};
 
     if (breadcrumbSetSinceRouteChange || (current.$$route && current.$$route.redirectTo)) {
@@ -226,6 +236,9 @@ const $setupBadgeAutoClear = (newPlatform: CoreStart) => (
   });
 
   $rootScope.$on('$routeChangeSuccess', () => {
+    if (isDummyWrapperRoute($route)) {
+      return;
+    }
     const current = $route.current || {};
 
     if (badgeSetSinceRouteChange || (current.$$route && current.$$route.redirectTo)) {
@@ -270,6 +283,9 @@ const $setupHelpExtensionAutoClear = (newPlatform: CoreStart) => (
   const $route = $injector.has('$route') ? $injector.get('$route') : {};
 
   $rootScope.$on('$routeChangeStart', () => {
+    if (isDummyWrapperRoute($route)) {
+      return;
+    }
     helpExtensionSetSinceRouteChange = false;
   });
 
@@ -286,10 +302,15 @@ const $setupHelpExtensionAutoClear = (newPlatform: CoreStart) => (
 
 const $setupUrlOverflowHandling = (newPlatform: CoreStart) => (
   $location: ILocationService,
-  $rootScope: IRootScopeService
+  $rootScope: IRootScopeService,
+  $injector: auto.IInjectorService
 ) => {
+  const $route = $injector.has('$route') ? $injector.get('$route') : {};
   const urlOverflow = new UrlOverflowService();
   const check = () => {
+    if (isDummyWrapperRoute($route)) {
+      return;
+    }
     // disable long url checks when storing state in session storage
     if (newPlatform.uiSettings.get('state:storeInSessionStorage')) {
       return;

src/legacy/ui/public/routes/route_manager.d.ts

@@ -26,7 +26,10 @@ import { ChromeBreadcrumb } from '../../../../core/public';
 interface RouteConfiguration {
   controller?: string | ((...args: any[]) => void);
   redirectTo?: string;
+  resolveRedirectTo?: (...args: any[]) => void;
   reloadOnSearch?: boolean;
+  reloadOnUrl?: boolean;
+  outerAngularWrapperRoute?: boolean;
   resolve?: object;
   template?: string;
   k7Breadcrumbs?: (...args: any[]) => ChromeBreadcrumb[];