[SIEM] Adds ability to infer the newsfeed.enabled setting (#56236)

* Always return a contract from the newsfeed plugin

Without a contract, dependent plugins have no way of knowing whether the
plugin is enabled or not as the contract will always be undefined.

* Export newsfeed contract types from public index

So that dependent plugins can use them.

* Declare newsfeed as an optional dependency of SIEM

We're going to use the availability of the newsfeed plugin as part of our
determination for whether or not to show the security newsfeed. If users
set `newsfeed.enabled: false`, the plugin will be unavailable and the
security feed will not be shown.

* Respect global newsfeed.enabled config in Security newsfeed

The presence of the newsfeed plugin means that newsfeed.enabled is true.
If both that and our local setting are true, we will show the Security
feed.

* Prefer object type over empty interface

Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>

src/plugins/newsfeed/public/index.ts

@@ -18,7 +18,9 @@
  */
 
 import { PluginInitializerContext } from 'src/core/public';
-import { NewsfeedPublicPlugin } from './plugin';
+import { Setup, Start, NewsfeedPublicPlugin } from './plugin';
+
+export { Setup, Start };
 
 export function plugin(initializerContext: PluginInitializerContext) {
   return new NewsfeedPublicPlugin(initializerContext);

src/plugins/newsfeed/public/plugin.tsx

@@ -27,8 +27,8 @@ import { FetchResult, NewsfeedPluginInjectedConfig } from '../types';
 import { NewsfeedNavButton, NewsfeedApiFetchResult } from './components/newsfeed_header_nav_button';
 import { getApi } from './lib/api';
 
-export type Setup = void;
-export type Start = void;
+export type Setup = object;
+export type Start = object;
 
 export class NewsfeedPublicPlugin implements Plugin<Setup, Start> {
   private readonly kibanaVersion: string;
@@ -38,14 +38,18 @@ export class NewsfeedPublicPlugin implements Plugin<Setup, Start> {
     this.kibanaVersion = initializerContext.env.packageInfo.version;
   }
 
-  public setup(core: CoreSetup): Setup {}
+  public setup(core: CoreSetup): Setup {
+    return {};
+  }
 
   public start(core: CoreStart): Start {
     const api$ = this.fetchNewsfeed(core);
     core.chrome.navControls.registerRight({
       order: 1000,
       mount: target => this.mount(api$, target),
     });
+
+    return {};
   }
 
   public stop() {

x-pack/legacy/plugins/siem/public/components/news_feed/index.tsx

@@ -8,18 +8,22 @@ import React, { useEffect, useState } from 'react';
 import chrome from 'ui/chrome';
 
 import { fetchNews, getNewsFeedUrl, getNewsItemsFromApiResponse } from './helpers';
-import { useUiSetting$ } from '../../lib/kibana';
+import { useKibana, useUiSetting$ } from '../../lib/kibana';
 import { NewsFeed } from './news_feed';
 import { NewsItem } from './types';
 
 export const StatefulNewsFeed = React.memo<{
   enableNewsFeedSetting: string;
   newsFeedSetting: string;
 }>(({ enableNewsFeedSetting, newsFeedSetting }) => {
+  const kibanaNewsfeedEnabled = useKibana().services.newsfeed;
   const [enableNewsFeed] = useUiSetting$<boolean>(enableNewsFeedSetting);
   const [newsFeedUrlSetting] = useUiSetting$<string>(newsFeedSetting);
   const [news, setNews] = useState<NewsItem[] | null>(null);
 
+  // respect kibana's global newsfeed.enabled setting
+  const newsfeedEnabled = kibanaNewsfeedEnabled && enableNewsFeed;
+
   const newsFeedUrl = getNewsFeedUrl({
     newsFeedUrlSetting,
     getKibanaVersion: chrome.getKibanaVersion,
@@ -42,16 +46,16 @@ export const StatefulNewsFeed = React.memo<{
       }
     };
 
-    if (enableNewsFeed) {
+    if (newsfeedEnabled) {
       fetchData();
     }
 
     return () => {
       canceled = true;
     };
-  }, [enableNewsFeed, newsFeedUrl]);
+  }, [newsfeedEnabled, newsFeedUrl]);
 
-  return <>{enableNewsFeed ? <NewsFeed news={news} /> : null}</>;
+  return <>{newsfeedEnabled ? <NewsFeed news={news} /> : null}</>;
 });
 
 StatefulNewsFeed.displayName = 'StatefulNewsFeed';

x-pack/legacy/plugins/siem/public/plugin.tsx

@@ -14,6 +14,7 @@ import {
 import { HomePublicPluginSetup } from '../../../../../src/plugins/home/public';
 import { DataPublicPluginStart } from '../../../../../src/plugins/data/public';
 import { IEmbeddableStart } from '../../../../../src/plugins/embeddable/public';
+import { Start as NewsfeedStart } from '../../../../../src/plugins/newsfeed/public';
 import { Start as InspectorStart } from '../../../../../src/plugins/inspector/public';
 import { IUiActionsStart } from '../../../../../src/plugins/ui_actions/public';
 import { UsageCollectionSetup } from '../../../../../src/plugins/usage_collection/public';
@@ -29,6 +30,7 @@ export interface StartPlugins {
   data: DataPublicPluginStart;
   embeddable: IEmbeddableStart;
   inspector: InspectorStart;
+  newsfeed?: NewsfeedStart;
   uiActions: IUiActionsStart;
 }
 export type StartServices = CoreStart & StartPlugins;