hadoop CosNFileReadTask 源码

  • 2022-10-20
  • 浏览 (469)

haddop CosNFileReadTask 代码

文件路径:/hadoop-cloud-storage-project/hadoop-cos/src/main/java/org/apache/hadoop/fs/cosn/CosNFileReadTask.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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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.cosn;

import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.retry.RetryPolicies;
import org.apache.hadoop.io.retry.RetryPolicy;

/**
 * Used by {@link CosNInputStream} as an asynchronous task
 * submitted to the thread pool.
 * Each task is responsible for reading a part of a large file.
 * It is used to pre-read the data from COS to accelerate file reading process.
 */
public class CosNFileReadTask implements Runnable {
  private static final Logger LOG =
      LoggerFactory.getLogger(CosNFileReadTask.class);

  private final String key;
  private final NativeFileSystemStore store;
  private final CosNInputStream.ReadBuffer readBuffer;

  private RetryPolicy retryPolicy;

  public CosNFileReadTask(
      Configuration conf,
      String key, NativeFileSystemStore store,
      CosNInputStream.ReadBuffer readBuffer) {
    this.key = key;
    this.store = store;
    this.readBuffer = readBuffer;

    RetryPolicy defaultPolicy =
        RetryPolicies.retryUpToMaximumCountWithFixedSleep(
            conf.getInt(
                CosNConfigKeys.COSN_MAX_RETRIES_KEY,
                CosNConfigKeys.DEFAULT_MAX_RETRIES),
            conf.getLong(
                CosNConfigKeys.COSN_RETRY_INTERVAL_KEY,
                CosNConfigKeys.DEFAULT_RETRY_INTERVAL),
            TimeUnit.SECONDS);
    Map<Class<? extends Exception>, RetryPolicy> retryPolicyMap =
        new HashMap<>();
    retryPolicyMap.put(IOException.class, defaultPolicy);
    retryPolicyMap.put(
        IndexOutOfBoundsException.class, RetryPolicies.TRY_ONCE_THEN_FAIL);
    retryPolicyMap.put(
        NullPointerException.class, RetryPolicies.TRY_ONCE_THEN_FAIL);

    this.retryPolicy = RetryPolicies.retryByException(
        defaultPolicy, retryPolicyMap);
  }

  @Override
  public void run() {
    int retries = 0;
    RetryPolicy.RetryAction retryAction;
    try {
      this.readBuffer.lock();
      do {
        try {
          InputStream inputStream = this.store.retrieveBlock(this.key,
              this.readBuffer.getStart(), this.readBuffer.getEnd());
          IOUtils.readFully(inputStream, this.readBuffer.getBuffer(), 0,
              readBuffer.getBuffer().length);
          inputStream.close();
          this.readBuffer.setStatus(CosNInputStream.ReadBuffer.SUCCESS);
          break;
        } catch (IOException e) {
          this.readBuffer.setStatus(CosNInputStream.ReadBuffer.ERROR);
          LOG.warn(
              "Exception occurs when retrieve the block range start: "
                  + String.valueOf(this.readBuffer.getStart()) + " end: "
                  + this.readBuffer.getEnd());
          try {
            retryAction = this.retryPolicy.shouldRetry(
                e, retries++, 0, true);
            if (retryAction.action
                == RetryPolicy.RetryAction.RetryDecision.RETRY) {
              Thread.sleep(retryAction.delayMillis);
            }
          } catch (Exception e1) {
            String errMsg = String.format("Exception occurs when retry[%s] "
                    + "to retrieve the block range start: %s, end:%s",
                this.retryPolicy.toString(),
                String.valueOf(this.readBuffer.getStart()),
                String.valueOf(this.readBuffer.getEnd()));
            LOG.error(errMsg, e1);
            break;
          }
        }
      } while (retryAction.action ==
          RetryPolicy.RetryAction.RetryDecision.RETRY);
      this.readBuffer.signalAll();
    } finally {
      this.readBuffer.unLock();
    }
  }
}

相关信息

hadoop 源码目录

相关文章

hadoop BufferPool 源码

hadoop ByteBufferInputStream 源码

hadoop ByteBufferOutputStream 源码

hadoop ByteBufferWrapper 源码

hadoop Constants 源码

hadoop CosN 源码

hadoop CosNConfigKeys 源码

hadoop CosNCopyFileContext 源码

hadoop CosNCopyFileTask 源码

hadoop CosNFileSystem 源码

0  赞