content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.cli.hdfs;
  
  import alluxio.cli.AbstractValidationTask;
  import alluxio.cli.ApplicableUfsType;
  import alluxio.cli.ValidationTaskResult;
  import alluxio.cli.ValidationUtils;
  import alluxio.conf.AlluxioConfiguration;
  import alluxio.conf.PropertyKey;
  import alluxio.util.ExceptionUtils;
  import alluxio.util.ShellUtils;
  
  import java.io.IOException;
  import java.util.Map;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  
  /**
   * Validates if the HDFS version works with the UFS version specified in
   * alluxio configuration.
   * */
  @ApplicableUfsType(ApplicableUfsType.Type.HDFS)
  public class HdfsVersionValidationTask extends AbstractValidationTask {
    private final AlluxioConfiguration mConf;
    public static final String HADOOP_PREFIX = "hadoop-";
    public static final String CDH_PREFIX = "cdh-";
  
    // An example output from "hadoop version" command:
    //    Hadoop 2.7.2
    //    Subversion https://git-wip-us.apache.org/repos/asf/hadoop.git
    //      -r b165c4fe8a74265c792ce23f546c64604acf0e41
    //    Compiled by jenkins on 2016-01-26T00:08Z
    //    Compiled with protoc 2.5.0
    //    From source with checksum d0fda26633fa762bff87ec759ebe689c
    //    This command was run using /tmp/hadoop/share/hadoop/common/hadoop-common-2.7.2.jar
    private static final Pattern HADOOP_PATTERN =
            Pattern.compile("Hadoop\\s+(?<version>([0-9]\\.)+[0-9]+)");
    // An example Hadoop version for CDH distribution is
    // Hadoop 2.6.0-cdh5.16.2
    private static final Pattern CDH_PATTERN =
            Pattern.compile("cdh(?<cdhVersion>([0-9]+\\.)+[0-9]+)");
  
    /**
     * Creates a new instance of {@link HdfsVersionValidationTask}
     * for validating HDFS version.
     * @param conf configuration
     */
    public HdfsVersionValidationTask(AlluxioConfiguration conf) {
      mConf = conf;
    }
  
    @Override
    public String getName() {
      return "ValidateHdfsVersion";
    }
  
    protected String parseVersion(String output) {
      Matcher cdhMatcher = CDH_PATTERN.matcher(output);
      // Use CDH version if it is CDH
      if (cdhMatcher.find()) {
        String cdhVersion = cdhMatcher.group("cdhVersion");
        return "cdh" + cdhVersion;
      }
      // Use Hadoop version otherwise
      String version = "";
      Matcher matcher = HADOOP_PATTERN.matcher(output);
      if (matcher.find()) {
        version = matcher.group("version");
      }
      return version;
    }
  
    @Override
    public ValidationTaskResult validateImpl(Map<String, String> optionMap)
            throws InterruptedException {
      String hadoopVersion;
      try {
        hadoopVersion = getHadoopVersion();
      } catch (IOException e) {
        return new ValidationTaskResult(ValidationUtils.State.FAILED, getName(),
                String.format("Failed to get hadoop version:%n%s.", ExceptionUtils.asPlainText(e)),
                "Please check if hadoop is on your PATH.");
      }
  
      String version = mConf.getString(PropertyKey.UNDERFS_VERSION);
      for (String prefix : new String[] {CDH_PREFIX, HADOOP_PREFIX}) {
        if (version.startsWith(prefix)) {
          version = version.substring(prefix.length());
          break;
        }
      }
      if (hadoopVersion.contains(version)) {
        return new ValidationTaskResult(ValidationUtils.State.OK, getName(),
                String.format("Hadoop version %s contains UFS version defined in alluxio %s=%s.",
                        hadoopVersion, PropertyKey.UNDERFS_VERSION, version),
                "");
      }
  
      return new ValidationTaskResult(ValidationUtils.State.FAILED, getName(),
              String.format("Hadoop version %s does not match %s=%s.",
                      hadoopVersion, PropertyKey.UNDERFS_VERSION, version),
              String.format("Please configure %s to match the HDFS version.",
                      PropertyKey.UNDERFS_VERSION));
    }
  
    protected String getHadoopVersion() throws IOException {
      String[] cmd = new String[]{"hadoop", "version"};
      String version = ShellUtils.execCommand(cmd);
      return parseVersion(version);
    }
  }
  