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.atlas.ha;
  
  import org.apache.atlas.AtlasConstants;
  import org.apache.atlas.AtlasException;
  import org.apache.commons.configuration.Configuration;
  import org.apache.commons.lang.StringUtils;
  import org.apache.hadoop.net.NetUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.net.InetSocketAddress;
  
  public class AtlasServerIdSelector {
      private static final Logger LOG = LoggerFactory.getLogger(AtlasServerIdSelector.class);
  
      private AtlasServerIdSelector() {
          throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
      }
  
      /**
       * Return the ID corresponding to this Atlas instance.
       *
       * The match is done by looking for an ID configured in {@link HAConfiguration#ATLAS_SERVER_IDS} key
       * that has a host:port entry for the key {@link HAConfiguration#ATLAS_SERVER_ADDRESS_PREFIX}+ID where
       * the host is a local IP address and port is set in the system property
       * {@link AtlasConstants#SYSTEM_PROPERTY_APP_PORT}.
       *
       * @param configuration
       * @return
       * @throws AtlasException if no ID is found that maps to a local IP Address or port
       */
      public static String selectServerId(Configuration configuration) throws AtlasException {
          // ids are already trimmed by this method
          String[] ids              = configuration.getStringArray(HAConfiguration.ATLAS_SERVER_IDS);
          String   matchingServerId = null;
          int      appPort          = Integer.parseInt(System.getProperty(AtlasConstants.SYSTEM_PROPERTY_APP_PORT));
  
          for (String id : ids) {
              String hostPort = configuration.getString(HAConfiguration.ATLAS_SERVER_ADDRESS_PREFIX + id);
  
              if (!StringUtils.isEmpty(hostPort)) {
                  InetSocketAddress socketAddress;
  
                  try {
                      socketAddress = NetUtils.createSocketAddr(hostPort);
                  } catch (Exception e) {
                      LOG.warn("Exception while trying to get socket address for {}", hostPort, e);
  
                      continue;
                  }
  
                  if (!socketAddress.isUnresolved() && NetUtils.isLocalAddress(socketAddress.getAddress()) && appPort == socketAddress.getPort()) {
                      LOG.info("Found matched server id {} with host port: {}", id, hostPort);
  
                      matchingServerId = id;
  
                      break;
                  }
              } else {
                  LOG.info("Could not find matching address entry for id: {}", id);
              }
          }
  
          if (matchingServerId == null) {
              String msg = String.format("Could not find server id for this instance. Unable to find IDs matching any local host and port binding among %s", StringUtils.join(ids, ","));
  
              throw new AtlasException(msg);
          }
  
          return matchingServerId;
      }
  }
  