content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.cassandra.locator;
  
  import java.io.IOException;
  import java.net.InetAddress;
  import java.net.UnknownHostException;
  
  import com.google.common.annotations.VisibleForTesting;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.cassandra.config.DatabaseDescriptor;
  import org.apache.cassandra.exceptions.ConfigurationException;
  import org.apache.cassandra.utils.FBUtilities;
  
  public class Ec2MultiRegionAddressConfig implements NodeAddressConfig
  {
      private static final Logger logger = LoggerFactory.getLogger(Ec2MultiRegionAddressConfig.class);
  
      @VisibleForTesting
      public static final String PUBLIC_IP_QUERY = "/latest/meta-data/public-ipv4";
      @VisibleForTesting
      public static final String PRIVATE_IP_QUERY = "/latest/meta-data/local-ipv4";
      private final String localPublicAddress;
      private final String localPrivateAddress;
  
      /**
       * Used via reflection by DatabaseDescriptor::createAddressConfig
       */
      public Ec2MultiRegionAddressConfig() throws IOException
      {
          this(Ec2MetadataServiceConnector.create(new SnitchProperties()));
      }
  
      @VisibleForTesting
      public Ec2MultiRegionAddressConfig(AbstractCloudMetadataServiceConnector connector) throws IOException
      {
          this.localPublicAddress = connector.apiCall(PUBLIC_IP_QUERY);
          logger.info("EC2 multi region address config using publicIP as identifier: {}", localPublicAddress);
          this.localPrivateAddress = connector.apiCall(PRIVATE_IP_QUERY);
      }
  
      @Override
      public void configureAddresses()
      {
          // use the Public IP to broadcast Address to other nodes.
          try
          {
              InetAddress broadcastAddress = InetAddress.getByName(localPublicAddress);
              DatabaseDescriptor.setBroadcastAddress(broadcastAddress);
              if (DatabaseDescriptor.getBroadcastRpcAddress() == null)
              {
                  logger.info("broadcast_rpc_address unset, broadcasting public IP as rpc_address: {}", localPublicAddress);
                  DatabaseDescriptor.setBroadcastRpcAddress(broadcastAddress);
              }
          }
          catch (UnknownHostException e)
          {
              throw new ConfigurationException("Unable to obtain public address for node from cloud metadata service", e);
          }
  
          try
          {
              InetAddress privateAddress = InetAddress.getByName(localPrivateAddress);
              FBUtilities.setLocalAddress(privateAddress);
          }
          catch (UnknownHostException e)
          {
              throw new ConfigurationException("Unable to obtain private address for node from cloud metadata service", e);
          }
      }
  
      @Override
      public boolean preferLocalConnections()
      {
          // Always prefer re-connecting on private addresses if in the same datacenter (i.e. region)
          return true;
      }
  }
  