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.BufferedReader;
  import java.io.IOException;
  import java.net.URI;
  import java.util.Properties;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.cassandra.exceptions.ConfigurationException;
  import org.apache.cassandra.io.util.File;
  import org.apache.cassandra.io.util.FileReader;
  import org.apache.cassandra.locator.AbstractCloudMetadataServiceConnector.DefaultCloudMetadataServiceConnector;
  import org.apache.cassandra.tcm.membership.Location;
  import org.apache.cassandra.utils.JVMStabilityInspector;
  
  import static org.apache.cassandra.locator.AbstractCloudMetadataServiceConnector.METADATA_URL_PROPERTY;
  
  public class CloudstackLocationProvider extends CloudMetadataLocationProvider
  {
      private static final Logger logger = LoggerFactory.getLogger(CloudstackLocationProvider.class);
      static final String ZONE_NAME_QUERY_URI = "/latest/meta-data/availability-zone";
  
      private static final String[] LEASE_FILES =
      {
      "file:///var/lib/dhcp/dhclient.eth0.leases",
      "file:///var/lib/dhclient/dhclient.eth0.leases"
      };
  
      /**
       * Used via reflection by DatabaseDescriptor::createInitialLocationProvider
       */
      public CloudstackLocationProvider() throws IOException
      {
          this(new SnitchProperties(new Properties()));
      }
  
      public CloudstackLocationProvider(SnitchProperties snitchProperties) throws IOException
      {
          this(new DefaultCloudMetadataServiceConnector(snitchProperties.putIfAbsent(METADATA_URL_PROPERTY, csMetadataEndpoint())));
      }
  
      public CloudstackLocationProvider(AbstractCloudMetadataServiceConnector connector) throws IOException
      {
          super(connector, CloudstackLocationProvider::resolveLocation);
          logger.warn("{} is deprecated and not actively maintained. It will be removed in the next " +
                      "major version of Cassandra.", CloudstackSnitch.class.getName());
      }
  
      private static Location resolveLocation(AbstractCloudMetadataServiceConnector connector) throws IOException
      {
          String zone = connector.apiCall(ZONE_NAME_QUERY_URI);
          String[] zoneParts = zone.split("-");
  
          if (zoneParts.length != 3)
              throw new ConfigurationException("CloudstackSnitch cannot handle invalid zone format: " + zone);
  
          return new Location(zoneParts[0] + '-' + zoneParts[1], zoneParts[2]);
      }
  
      private static String csMetadataEndpoint() throws ConfigurationException
      {
          for (String lease_uri : LEASE_FILES)
          {
              try
              {
                  File lease_file = new File(new URI(lease_uri));
                  if (lease_file.exists())
                  {
                      return csEndpointFromLease(lease_file);
                  }
              }
              catch (Exception e)
              {
                  JVMStabilityInspector.inspectThrowable(e);
              }
          }
  
          throw new ConfigurationException("No valid DHCP lease file could be found.");
      }
  
      private static String csEndpointFromLease(File lease) throws ConfigurationException
      {
          String line;
          String endpoint = null;
          Pattern identifierPattern = Pattern.compile("^[ \t]*option dhcp-server-identifier (.*);$");
  
          try (BufferedReader reader = new BufferedReader(new FileReader(lease)))
          {
  
              while ((line = reader.readLine()) != null)
              {
                  Matcher matcher = identifierPattern.matcher(line);
  
                  if (matcher.find())
                  {
                      endpoint = matcher.group(1);
                      break;
                  }
              }
          }
          catch (Exception e)
          {
              throw new ConfigurationException("CloudstackSnitch cannot access lease file.");
          }
  
          if (endpoint == null)
          {
              throw new ConfigurationException("No metadata server could be found in lease file.");
          }
  
          return "http://" + endpoint;
      }
  }
  