k8s: Add a dev only feature flag and simple service to get a client (#60204)

public/app/features/storage/k8s/K8SPage.tsx

@@ -0,0 +1,63 @@
+import { css } from '@emotion/css';
+import React from 'react';
+import { useAsync } from 'react-use';
+
+import { GrafanaTheme2 } from '@grafana/data';
+import { getBackendSrv } from '@grafana/runtime';
+import { useStyles2, Spinner, Alert } from '@grafana/ui';
+import { Page } from 'app/core/components/Page/Page';
+import { useNavModel } from 'app/core/hooks/useNavModel';
+import { GrafanaRouteComponentProps } from 'app/core/navigation/types';
+
+interface RouteParams {
+  // path: string;
+}
+
+interface QueryParams {
+  // view: StorageView;
+}
+
+interface Props extends GrafanaRouteComponentProps<RouteParams, QueryParams> {}
+
+export default function K8SPage(props: Props) {
+  const styles = useStyles2(getStyles);
+  const navModel = useNavModel('k8s');
+  const info = useAsync(() => {
+    return getBackendSrv().get('/api/k8s/info');
+  });
+
+  const renderView = () => {
+    if (info.value) {
+      return <pre>{JSON.stringify(info.value, null, 2)}</pre>;
+    }
+    if (info.loading) {
+      return <Spinner />;
+    }
+
+    return (
+      <div className={styles.wrapper}>
+        <Alert title="No k8s client configured." severity="warning" />
+        At startup, a service tries to load a client using:
+        <ul>
+          <li>
+            Default <a href="https://github.com/kubernetes/client-go/blob/master/rest/config.go#L511">in cluster</a>{' '}
+            configs
+          </li>
+          <li>$HOME/.kube/config, perhaps with minikube running</li>
+        </ul>
+      </div>
+    );
+  };
+
+  return (
+    <Page navModel={navModel}>
+      <Page.Contents isLoading={info.loading}>{renderView()}</Page.Contents>
+    </Page>
+  );
+}
+
+const getStyles = (theme: GrafanaTheme2) => ({
+  wrapper: css`
+    display: block;
+  `,
+});

public/app/routes/routes.tsx

@@ -359,6 +359,13 @@ export function getAppRoutes(): RouteDescriptor[] {
         () => import(/* webpackChunkName: "AdminEditOrgPage" */ 'app/features/admin/AdminEditOrgPage')
       ),
     },
+    {
+      path: '/admin/storage/k8s',
+      roles: () => ['Admin'],
+      component: SafeDynamicImport(
+        () => import(/* webpackChunkName: "K8SStoragePage" */ 'app/features/storage/k8s/K8SPage')
+      ),
+    },
     {
       path: '/admin/storage/:path*',
       roles: () => ['Admin'],