CR: Only validate form of seed address not hostname lookup

server/src/main/java/org/elasticsearch/transport/RemoteClusterAware.java

@@ -56,7 +56,7 @@ public abstract class RemoteClusterAware extends AbstractComponent {
  key, Collections.emptyList(),
  s -> {
  // validate seed address
- RemoteClusterAware.parseSeedAddress(s);
+ parsePort(s);
  return s;
  },
  Setting.Property.NodeScope, Setting.Property.Dynamic
@@ -151,28 +151,36 @@ public void listenForUpdates(ClusterSettings clusterSettings) {
  }
 
  protected static InetSocketAddress parseSeedAddress(String remoteHost) {
- int portSeparator = remoteHost.lastIndexOf(':'); // in case we have a IPv6 address ie. [::1]:9300
- if (portSeparator == -1 || portSeparator == remoteHost.length()) {
- throw new IllegalArgumentException("remote hosts need to be configured as [host:port], found [" + remoteHost + "] instead");
- }
- String host = remoteHost.substring(0, portSeparator);
+ String host = remoteHost.substring(0, indexOfPortSeparator(remoteHost));
  InetAddress hostAddress;
  try {
  hostAddress = InetAddress.getByName(host);
  } catch (UnknownHostException e) {
  throw new IllegalArgumentException("unknown host [" + host + "]", e);
  }
+ return new InetSocketAddress(hostAddress, parsePort(remoteHost));
+ }
+
+ private static int parsePort(String remoteHost) {
  try {
- int port = Integer.valueOf(remoteHost.substring(portSeparator + 1));
+ int port = Integer.valueOf(remoteHost.substring(indexOfPortSeparator(remoteHost) + 1));
  if (port <= 0) {
  throw new IllegalArgumentException("port number must be > 0 but was: [" + port + "]");
  }
- return new InetSocketAddress(hostAddress, port);
+ return port;
  } catch (NumberFormatException e) {
  throw new IllegalArgumentException("port must be a number", e);
  }
  }
 
+ private static int indexOfPortSeparator(String remoteHost) {
+ int portSeparator = remoteHost.lastIndexOf(':'); // in case we have a IPv6 address ie. [::1]:9300
+ if (portSeparator == -1 || portSeparator == remoteHost.length()) {
+ throw new IllegalArgumentException("remote hosts need to be configured as [host:port], found [" + remoteHost + "] instead");
+ }
+ return portSeparator;
+ }
+
  public static String buildRemoteIndexName(String clusterAlias, String indexName) {
  return clusterAlias != null ? clusterAlias + REMOTE_CLUSTER_INDEX_SEPARATOR + indexName : indexName;
  }