hadoop MagicCommitTracker 源码

haddop MagicCommitTracker 代码

文件路径：/hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/commit/magic/MagicCommitTracker.java

/*
 * 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.hadoop.fs.s3a.commit.magic;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.amazonaws.services.s3.model.PartETag;
import com.amazonaws.services.s3.model.PutObjectRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.commons.lang3.StringUtils;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.s3a.Retries;
import org.apache.hadoop.fs.s3a.WriteOperationHelper;
import org.apache.hadoop.fs.s3a.commit.PutTracker;
import org.apache.hadoop.fs.s3a.commit.files.SinglePendingCommit;
import org.apache.hadoop.fs.s3a.impl.PutObjectOptions;
import org.apache.hadoop.fs.s3a.statistics.PutTrackerStatistics;
import org.apache.hadoop.fs.statistics.IOStatistics;
import org.apache.hadoop.fs.statistics.IOStatisticsSnapshot;
import org.apache.hadoop.util.Preconditions;

import static java.util.Objects.requireNonNull;
import static org.apache.hadoop.fs.s3a.Statistic.COMMITTER_MAGIC_MARKER_PUT;
import static org.apache.hadoop.fs.s3a.commit.CommitConstants.X_HEADER_MAGIC_MARKER;
import static org.apache.hadoop.fs.statistics.impl.IOStatisticsBinding.trackDurationOfInvocation;

/**
 * Put tracker for Magic commits.
 * <p>Important</p>: must not directly or indirectly import a class which
 * uses any datatype in hadoop-mapreduce.
 */
@InterfaceAudience.Private
public class MagicCommitTracker extends PutTracker {
  public static final Logger LOG = LoggerFactory.getLogger(
      MagicCommitTracker.class);

  private final String originalDestKey;
  private final String pendingPartKey;
  private final Path path;
  private final WriteOperationHelper writer;
  private final String bucket;
  private static final byte[] EMPTY = new byte[0];
  private final PutTrackerStatistics trackerStatistics;

  /**
   * Magic commit tracker.
   * @param path path nominally being written to
   * @param bucket dest bucket
   * @param originalDestKey the original key, in the magic directory.
   * @param destKey key for the destination
   * @param pendingsetKey key of the pendingset file
   * @param writer writer instance to use for operations; includes audit span
   * @param trackerStatistics tracker statistics
   */
  public MagicCommitTracker(Path path,
      String bucket,
      String originalDestKey,
      String destKey,
      String pendingsetKey,
      WriteOperationHelper writer,
      PutTrackerStatistics trackerStatistics) {
    super(destKey);
    this.bucket = bucket;
    this.path = path;
    this.originalDestKey = originalDestKey;
    this.pendingPartKey = pendingsetKey;
    this.writer = writer;
    this.trackerStatistics = requireNonNull(trackerStatistics);
    LOG.info("File {} is written as magic file to path {}",
        path, destKey);
  }

  /**
   * Initialize the tracker.
   * @return true, indicating that the multipart commit must start.
   * @throws IOException any IO problem.
   */
  @Override
  public boolean initialize() throws IOException {
    return true;
  }

  /**
   * Flag to indicate that output is not visible after the stream
   * is closed.
   * @return true
   */
  @Override
  public boolean outputImmediatelyVisible() {
    return false;
  }

  /**
   * Complete operation: generate the final commit data, put it.
   * @param uploadId Upload ID
   * @param parts list of parts
   * @param bytesWritten bytes written
   * @param iostatistics nullable IO statistics
   * @return false, indicating that the commit must fail.
   * @throws IOException any IO problem.
   * @throws IllegalArgumentException bad argument
   */
  @Override
  public boolean aboutToComplete(String uploadId,
      List<PartETag> parts,
      long bytesWritten,
      final IOStatistics iostatistics)
      throws IOException {
    Preconditions.checkArgument(StringUtils.isNotEmpty(uploadId),
        "empty/null upload ID: "+ uploadId);
    Preconditions.checkArgument(parts != null,
        "No uploaded parts list");
    Preconditions.checkArgument(!parts.isEmpty(),
        "No uploaded parts to save");

    // put a 0-byte file with the name of the original under-magic path
    // Add the final file length as a header
    // this is done before the task commit, so its duration can be
    // included in the statistics
    Map<String, String> headers = new HashMap<>();
    headers.put(X_HEADER_MAGIC_MARKER, Long.toString(bytesWritten));
    PutObjectRequest originalDestPut = writer.createPutObjectRequest(
        originalDestKey,
        new ByteArrayInputStream(EMPTY),
        0,
        new PutObjectOptions(true, null, headers));
    upload(originalDestPut);

    // build the commit summary
    SinglePendingCommit commitData = new SinglePendingCommit();
    commitData.touch(System.currentTimeMillis());
    commitData.setDestinationKey(getDestKey());
    commitData.setBucket(bucket);
    commitData.setUri(path.toUri().toString());
    commitData.setUploadId(uploadId);
    commitData.setText("");
    commitData.setLength(bytesWritten);
    commitData.bindCommitData(parts);
    commitData.setIOStatistics(
        new IOStatisticsSnapshot(iostatistics));

    byte[] bytes = commitData.toBytes(SinglePendingCommit.serializer());
    LOG.info("Uncommitted data pending to file {};"
            + " commit metadata for {} parts in {}. size: {} byte(s)",
        path.toUri(), parts.size(), pendingPartKey, bytesWritten);
    LOG.debug("Closed MPU to {}, saved commit information to {}; data=:\n{}",
        path, pendingPartKey, commitData);
    PutObjectRequest put = writer.createPutObjectRequest(
        pendingPartKey,
        new ByteArrayInputStream(bytes),
        bytes.length, null);
    upload(put);
    return false;

  }
  /**
   * PUT an object.
   * @param request the request
   * @throws IOException on problems
   */
  @Retries.RetryTranslated
  private void upload(PutObjectRequest request) throws IOException {
    trackDurationOfInvocation(trackerStatistics,
        COMMITTER_MAGIC_MARKER_PUT.getSymbol(), () ->
            writer.uploadObject(request, PutObjectOptions.keepingDirs()));
  }

  @Override
  public String toString() {
    final StringBuilder sb = new StringBuilder(
        "MagicCommitTracker{");
    sb.append(", destKey=").append(getDestKey());
    sb.append(", pendingPartKey='").append(pendingPartKey).append('\'');
    sb.append(", path=").append(path);
    sb.append(", writer=").append(writer);
    sb.append('}');
    return sb.toString();
  }
}

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