Address PR comments

Signed-off-by: Shivansh Arora <hishiv@amazon.com>

libs/core/src/main/java/org/opensearch/core/common/transport/TransportAddress.java

@@ -41,9 +41,11 @@
 import org.opensearch.core.xcontent.XContentBuilder;
 
 import java.io.IOException;
+import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.UnknownHostException;
+import java.util.Arrays;
 
 /**
  * A transport address used for IP socket address (wraps {@link java.net.InetSocketAddress}).
@@ -166,15 +168,18 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
     /**
     * Converts a string in the format [hostname/ip]:[port] into a transport address.
     * @throws UnknownHostException if the hostname or ip address is invalid
-    * @throws IllegalArgumentException if invalid string format provided
     */
     public static TransportAddress fromString(String address) throws UnknownHostException {
         String[] addressSplit = address.split(":");
-        if (addressSplit.length != 2) {
-            throw new IllegalArgumentException("address must be of the form [hostname/ip]:[port]");
+        if (addressSplit.length == 2) {
+            String hostname = addressSplit[0];
+            int port = Integer.parseInt(addressSplit[1]);
+            return new TransportAddress(InetAddress.getByName(hostname), port);
+        } else {
+            // this should be an IPv6 ip
+            int port = Integer.parseInt(addressSplit[addressSplit.length - 1]);
+            String hostname = String.join(":", Arrays.copyOfRange(addressSplit, 0, addressSplit.length - 1));
+            return new TransportAddress(Inet6Address.getByName(hostname), port);
         }
-        String hostname = addressSplit[0];
-        int port = Integer.parseInt(addressSplit[1]);
-        return new TransportAddress(InetAddress.getByName(hostname), port);
     }
 }

server/src/main/java/org/opensearch/cluster/node/DiscoveryNode.java

@@ -32,6 +32,8 @@
 
 package org.opensearch.cluster.node;
 
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.opensearch.Version;
 import org.opensearch.cluster.metadata.Metadata;
 import org.opensearch.common.UUIDs;
@@ -85,6 +87,7 @@ public class DiscoveryNode implements Writeable, ToXContentFragment {
     static final String KEY_ATTRIBUTES = "attributes";
     static final String KEY_VERSION = "version";
     static final String KEY_ROLES = "roles";
+    private static final Logger logger = LogManager.getLogger(DiscoveryNode.class);
 
     public static boolean nodeRequiresLocalStorage(Settings settings) {
         boolean localStorageEnable = Node.NODE_LOCAL_STORAGE_SETTING.get(settings);
@@ -583,6 +586,10 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         return builder;
     }
 
+    /**
+     * This method is able to parse either a complete XContentObject with start and end object
+     * or only a fragment with the key and value.
+     */
     public static DiscoveryNode fromXContent(XContentParser parser) throws IOException {
         if (parser.currentToken() == null) { // fresh parser? move to the first token
             parser.nextToken();
@@ -627,7 +634,7 @@ public static DiscoveryNode fromXContent(XContentParser parser) throws IOExcepti
                         version = Version.fromString(parser.text());
                         break;
                     default:
-                        throw new IllegalArgumentException("Unexpected field [ " + currentFieldName + " ]");
+                        logger.warn("unknown field [{}]", currentFieldName);
                 }
             } else if (token == XContentParser.Token.START_OBJECT) {
                 assert currentFieldName.equals(KEY_ATTRIBUTES) : "expecting field with name ["

server/src/test/java/org/opensearch/core/common/TransportAddressTests.java

@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.core.common;
+
+import org.opensearch.core.common.transport.TransportAddress;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.net.UnknownHostException;
+
+public class TransportAddressTests extends OpenSearchTestCase {
+    public void testFromString() throws UnknownHostException {
+        TransportAddress address = TransportAddress.fromString("127.0.0.1:9300");
+        assertEquals("127.0.0.1", address.getAddress());
+        assertEquals(9300, address.getPort());
+
+        address = TransportAddress.fromString("1080:0:0:0:8:800:200C:417A:9300");
+        assertEquals("1080::8:800:200c:417a", address.getAddress());
+        assertEquals(9300, address.getPort());
+
+        address = TransportAddress.fromString("FF01:0:0:0:0:0:0:101:9300");
+        assertEquals("ff01::101", address.getAddress());
+        assertEquals(9300, address.getPort());
+
+        address = TransportAddress.fromString("FEDC:BA98:7654:3210:FEDC:BA98:7654:3210:9200");
+        assertEquals("fedc:ba98:7654:3210:fedc:ba98:7654:3210", address.getAddress());
+        assertEquals(9200, address.getPort());
+    }
+}