[Remote Clusters] Add IPv6 support (#233415)

fixes #228298

- Add IPv6 address support for remote cluster seed nodes and proxy
addresses using bracket notation ( [::1]:9300 )
- Move address validation from client-side to shared common library
using ipaddr.js for robust IPv4/IPv6 validation
- Update cluster serialization and cloud URL parsing to handle IPv6
addresses correctly

## How to test

1. Spin up local kibana and es on default ports (`yarn es snapshot` and
`yarn start --no-base-path`)
2. Go to `/app/management/data/remote_clusters`
3. Click "add new cluster"
4. Click "certificates celect"
5. Add loopback ipv6 address to seed pointing to cluster communication
port `[::1]:9300`
6. Observe no client side error for `seed` field, proving that ipv6
syntax is now valid
7. Add `test` name
8. `Uncheck skip_unavailable`
10. Click `next`
11. Click `create remote cluster`
12. Observe live cluster connection in the list of remote clusters

## Release Note
Added IPv6 support to address fields in Remote Clusters UI

---------

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

Author: kapral18

x-pack/platform/plugins/private/remote_clusters/__jest__/client_integration/add/remote_clusters_add.test.ts

@@ -151,13 +151,13 @@ describe('Create Remote cluster', () => {
         });
 
         describe('seeds', () => {
-          test('should only allow alpha-numeric characters and "-" (dash) in the node "host" part', async () => {
+          test('should only allow hostname, ipv4 and ipv6 format in the node "host" part', async () => {
             await actions.formStep.button.click(); // display form errors
 
             const expectInvalidChar = (char: string) => {
               actions.formStep.seedsInput.setValue(`192.16${char}:3000`);
               expect(actions.getErrorMessages()).toContain(
-                `Seed node must use host:port format. Example: 127.0.0.1:9400, localhost:9400. Hosts can only consist of letters, numbers, and dashes.`
+                `Seed node must use host:port format. Example: 127.0.0.1:9400, [::1]:9400 or localhost:9400. Hosts can only consist of letters, numbers, and dashes.`
               );
             };
 
@@ -289,7 +289,7 @@ describe('Create Remote cluster', () => {
             const expectInvalidChar = (char: string) => {
               actions.formStep.proxyAddressInput.setValue(`192.16${char}:3000`);
               expect(actions.getErrorMessages()).toContain(
-                'Address must use host:port format. Example: 127.0.0.1:9400, localhost:9400. Hosts can only consist of letters, numbers, and dashes.'
+                'Address must use host:port format. Example: 127.0.0.1:9400, [::1]:9400 or localhost:9400. Hosts can only consist of letters, numbers, and dashes.'
               );
             };
 

x-pack/platform/plugins/private/remote_clusters/common/lib/cluster_serialization.test.ts

@@ -135,41 +135,52 @@ describe('cluster_serialization', () => {
       });
     });
 
-    it('should deserialize a cluster that contains a deprecated proxy address and is in cloud', () => {
-      expect(
-        deserializeCluster(
-          'test_cluster',
-          {
-            seeds: ['localhost:9300'],
-            connected: true,
-            num_nodes_connected: 1,
-            max_connections_per_cluster: 3,
-            initial_connect_timeout: '30s',
-            skip_unavailable: false,
-            transport: {
-              ping_schedule: '-1',
-              compress: false,
+    it.each([
+      { title: '(hostname)', address: 'localhost:3000', host: 'localhost' },
+      { title: '(IPv4)', address: '123.1.2.142:3000', host: '123.1.2.142' },
+      {
+        title: '(IPv6)',
+        address: '[2001:0db8:85a3:0000:0000:8a2e:0370:7334]:3000',
+        host: '[2001:0db8:85a3:0000:0000:8a2e:0370:7334]',
+      },
+    ])(
+      'should deserialize a cluster that contains a deprecated proxy address and is in cloud $title',
+      ({ address, host }) => {
+        expect(
+          deserializeCluster(
+            'test_cluster',
+            {
+              seeds: [address],
+              connected: true,
+              num_nodes_connected: 1,
+              max_connections_per_cluster: 3,
+              initial_connect_timeout: '30s',
+              skip_unavailable: false,
+              transport: {
+                ping_schedule: '-1',
+                compress: false,
+              },
             },
-          },
-          'localhost:9300',
-          true
-        )
-      ).toEqual({
-        name: 'test_cluster',
-        proxyAddress: 'localhost:9300',
-        mode: 'proxy',
-        hasDeprecatedProxySetting: true,
-        isConnected: true,
-        connectedNodesCount: 1,
-        maxConnectionsPerCluster: 3,
-        initialConnectTimeout: '30s',
-        skipUnavailable: false,
-        transportPingSchedule: '-1',
-        transportCompress: false,
-        serverName: 'localhost',
-        securityModel: SECURITY_MODEL.CERTIFICATE,
-      });
-    });
+            address,
+            true
+          )
+        ).toEqual({
+          name: 'test_cluster',
+          proxyAddress: address,
+          mode: 'proxy',
+          hasDeprecatedProxySetting: true,
+          isConnected: true,
+          connectedNodesCount: 1,
+          maxConnectionsPerCluster: 3,
+          initialConnectTimeout: '30s',
+          skipUnavailable: false,
+          transportPingSchedule: '-1',
+          transportCompress: false,
+          serverName: host,
+          securityModel: SECURITY_MODEL.CERTIFICATE,
+        });
+      }
+    );
 
     it('should deserialize a cluster object with arbitrary missing properties', () => {
       expect(

x-pack/platform/plugins/private/remote_clusters/common/lib/cluster_serialization.ts

@@ -5,6 +5,7 @@
  * 2.0.
  */
 
+import { extractHostAndPort } from './validate_address';
 import { PROXY_MODE, SNIFF_MODE, SECURITY_MODEL } from '../constants';
 
 // Values returned from ES GET /_remote/info
@@ -143,19 +144,21 @@ export function deserializeCluster(
     };
   }
 
+  const deprecatedProxyHost = deprecatedProxyAddress
+    ? extractHostAndPort(deprecatedProxyAddress)?.host
+    : undefined;
+
   // If a user has a remote cluster with the deprecated proxy setting,
   // we transform the data to support the new implementation and also flag the deprecation
-  if (deprecatedProxyAddress) {
-    // Cloud-specific logic: Create default server name, since field doesn't exist in deprecated implementation
-    const defaultServerName = deprecatedProxyAddress.split(':')[0];
-
+  if (deprecatedProxyAddress && deprecatedProxyHost) {
     deserializedClusterObject = {
       ...deserializedClusterObject,
       proxyAddress: deprecatedProxyAddress,
       seeds: undefined,
       hasDeprecatedProxySetting: true,
       mode: PROXY_MODE,
-      serverName: isCloudEnabled ? defaultServerName : undefined,
+      // Cloud-specific logic: Create default server name, since this field doesn't exist in deprecated implementation
+      serverName: isCloudEnabled ? deprecatedProxyHost : undefined,
     };
   }
 

x-pack/platform/plugins/private/remote_clusters/common/lib/index.ts

@@ -12,3 +12,4 @@ export type {
   ClusterPayloadEs,
 } from './cluster_serialization';
 export { deserializeCluster, serializeCluster } from './cluster_serialization';
+export { extractHostAndPort, isAddressValid, isPortValid } from './validate_address';