[Infra] Make nav react to Hosts view enabled flag changing (#142477) (#142585)

* [Infra] Make nav react to Hosts view enabled flag changing (#140996)

* Move comment to more relevant location

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>
(cherry picked from commit d60acf8774)

Co-authored-by: Milton Hultgren <milton.hultgren@elastic.co>

x-pack/plugins/infra/public/plugin.ts

@@ -5,12 +5,17 @@
  * 2.0.
  */
 
+import {
+  AppMountParameters,
+  AppUpdater,
+  CoreStart,
+  DEFAULT_APP_CATEGORIES,
+  PluginInitializerContext,
+} from '@kbn/core/public';
 import { i18n } from '@kbn/i18n';
-import { AppMountParameters, PluginInitializerContext } from '@kbn/core/public';
-import { from } from 'rxjs';
-import { map } from 'rxjs/operators';
-import { DEFAULT_APP_CATEGORIES } from '@kbn/core/public';
 import { enableInfrastructureHostsView } from '@kbn/observability-plugin/public';
+import { BehaviorSubject, combineLatest, from } from 'rxjs';
+import { map } from 'rxjs/operators';
 import { defaultLogViewsStaticConfig } from '../common/log_views';
 import { InfraPublicConfig } from '../common/plugin_config_types';
 import { createInventoryMetricRuleType } from './alerting/inventory';
@@ -38,6 +43,7 @@ import { getLogsHasDataFetcher, getLogsOverviewDataFetcher } from './utils/logs_
 export class Plugin implements InfraClientPluginClass {
   public config: InfraPublicConfig;
   private logViews: LogViewsService;
+  private readonly appUpdater$ = new BehaviorSubject<AppUpdater>(() => ({}));
 
   constructor(context: PluginInitializerContext<InfraPublicConfig>) {
     this.config = context.config.get();
@@ -74,6 +80,11 @@ export class Plugin implements InfraClientPluginClass {
       fetchData: createMetricsFetchData(core.getStartServices),
     });
 
+    const startDep$AndHostViewFlag$ = combineLatest([
+      from(core.getStartServices()),
+      core.uiSettings.get$<boolean>(enableInfrastructureHostsView),
+    ]);
+
     /** !! Need to be kept in sync with the deepLinks in x-pack/plugins/infra/public/plugin.ts */
     const infraEntries = [
       { label: 'Inventory', app: 'metrics', path: '/inventory' },
@@ -81,12 +92,15 @@ export class Plugin implements InfraClientPluginClass {
     ];
     const hostInfraEntry = { label: 'Hosts', app: 'metrics', path: '/hosts' };
     pluginsSetup.observability.navigation.registerSections(
-      from(core.getStartServices()).pipe(
+      startDep$AndHostViewFlag$.pipe(
         map(
           ([
-            {
-              application: { capabilities },
-            },
+            [
+              {
+                application: { capabilities },
+              },
+            ],
+            isInfrastructureHostsViewEnabled,
           ]) => [
             ...(capabilities.logs.show
               ? [
@@ -106,7 +120,7 @@ export class Plugin implements InfraClientPluginClass {
                   {
                     label: 'Infrastructure',
                     sortKey: 300,
-                    entries: core.uiSettings.get(enableInfrastructureHostsView)
+                    entries: isInfrastructureHostsViewEnabled
                       ? [hostInfraEntry, ...infraEntries]
                       : infraEntries,
                   },
@@ -171,6 +185,7 @@ export class Plugin implements InfraClientPluginClass {
       },
     });
 
+    // !! Need to be kept in sync with the routes in x-pack/plugins/infra/public/pages/metrics/index.tsx
     const infraDeepLinks = [
       {
         id: 'inventory',
@@ -210,8 +225,8 @@ export class Plugin implements InfraClientPluginClass {
       order: 8200,
       appRoute: '/app/metrics',
       category: DEFAULT_APP_CATEGORIES.observability,
-      // !! Need to be kept in sync with the routes in x-pack/plugins/infra/public/pages/metrics/index.tsx
-      deepLinks: core.uiSettings.get(enableInfrastructureHostsView)
+      updater$: this.appUpdater$,
+      deepLinks: core.uiSettings.get<boolean>(enableInfrastructureHostsView)
         ? [hostInfraDeepLink, ...infraDeepLinks]
         : infraDeepLinks,
       mount: async (params: AppMountParameters) => {
@@ -223,6 +238,19 @@ export class Plugin implements InfraClientPluginClass {
       },
     });
 
+    startDep$AndHostViewFlag$.subscribe(
+      ([_startServices, isInfrastructureHostsViewEnabled]: [
+        [CoreStart, InfraClientStartDeps, InfraClientStartExports],
+        boolean
+      ]) => {
+        this.appUpdater$.next(() => ({
+          deepLinks: isInfrastructureHostsViewEnabled
+            ? [hostInfraDeepLink, ...infraDeepLinks]
+            : infraDeepLinks,
+        }));
+      }
+    );
+
     /* This exists purely to facilitate URL redirects from the old App ID ("infra"),
     to our new App IDs ("metrics" and "logs"). With version 8.0.0 we can remove this. */
     core.application.register({