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.fs.command;
  
  import alluxio.AlluxioURI;
  import alluxio.annotation.PublicApi;
  import alluxio.cli.CommandUtils;
  import alluxio.client.file.FileInStream;
  import alluxio.client.file.FileSystemContext;
  import alluxio.client.file.URIStatus;
  import alluxio.exception.AlluxioException;
  import alluxio.exception.ExceptionMessage;
  import alluxio.exception.FileDoesNotExistException;
  import alluxio.exception.status.InvalidArgumentException;
  import alluxio.grpc.OpenFilePOptions;
  import alluxio.grpc.ReadPType;
  
  import org.apache.commons.cli.CommandLine;
  import org.apache.commons.codec.digest.DigestUtils;
  
  import java.io.IOException;
  import javax.annotation.concurrent.ThreadSafe;
  
  /**
   * Calculates the MD5 checksum for a file.
   */
  @ThreadSafe
  @PublicApi
  public final class ChecksumCommand extends AbstractFileSystemCommand {
  
    /**
     * @param fsContext the filesystem of Alluxio
     */
    public ChecksumCommand(FileSystemContext fsContext) {
      super(fsContext);
    }
  
    @Override
    protected void runPlainPath(AlluxioURI plainPath, CommandLine cl)
        throws AlluxioException, IOException {
      URIStatus status = mFileSystem.getStatus(plainPath);
      if (status.isFolder()) {
        throw new FileDoesNotExistException(
            ExceptionMessage.PATH_MUST_BE_FILE.getMessage(plainPath.getPath()));
      }
  
      String str = calculateChecksum(plainPath);
      System.out.println("md5sum: " + str + "\n");
    }
  
    @Override
    public String getCommandName() {
      return "checksum";
    }
  
    @Override
    public void validateArgs(CommandLine cl) throws InvalidArgumentException {
      CommandUtils.checkNumOfArgsEquals(this, cl, 1);
    }
  
    @Override
    public int run(CommandLine cl) throws AlluxioException, IOException {
      String[] args = cl.getArgs();
      runWildCardCmd(new AlluxioURI(args[0]), cl);
      return 0;
    }
  
    /**
     * Calculates the md5 checksum for a file.
     *
     * @param filePath The {@link AlluxioURI} path of the file calculate MD5 checksum on
     * @return A string representation of the file's MD5 checksum
     */
    private String calculateChecksum(AlluxioURI filePath)
        throws AlluxioException, IOException {
      OpenFilePOptions options =
          OpenFilePOptions.newBuilder().setReadType(ReadPType.NO_CACHE).build();
      try (FileInStream fis = mFileSystem.openFile(filePath, options)) {
        return DigestUtils.md5Hex(fis);
      }
    }
  
    @Override
    public String getUsage() {
      return "checksum <Alluxio path>";
    }
  
    @Override
    public String getDescription() {
      return "Calculates the md5 checksum of a file in the Alluxio filesystem.";
    }
  }
  