Package org.apache.hcatalog.data.transfer.impl

Source Code of org.apache.hcatalog.data.transfer.impl.HCatOutputFormatWriter

/**
* 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.hcatalog.data.transfer.impl;

import java.io.IOException;
import java.util.Iterator;
import java.util.Map;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.JobStatus.State;
import org.apache.hadoop.mapreduce.OutputCommitter;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.TaskAttemptID;
import org.apache.hadoop.mapreduce.TaskID;
import org.apache.hcatalog.common.ErrorType;
import org.apache.hcatalog.common.HCatException;
import org.apache.hcatalog.data.HCatRecord;
import org.apache.hcatalog.data.transfer.HCatWriter;
import org.apache.hcatalog.data.transfer.WriteEntity;
import org.apache.hcatalog.data.transfer.WriterContext;
import org.apache.hcatalog.data.transfer.state.StateProvider;
import org.apache.hcatalog.mapreduce.HCatOutputFormat;
import org.apache.hcatalog.mapreduce.OutputJobInfo;

/** This writer writes via {@link HCatOutputFormat}
*
*/
public class HCatOutputFormatWriter extends HCatWriter {

  public HCatOutputFormatWriter(WriteEntity we, Map<String, String> config) {
    super(we, config);
  }

  public HCatOutputFormatWriter(Configuration config, StateProvider sp) {
    super(config, sp);
  }

  @Override
  public WriterContext prepareWrite() throws HCatException {
    OutputJobInfo jobInfo = OutputJobInfo.create(we.getDbName(), we.getTableName(), we.getPartitionKVs());
    Job job;
    try {
      job = new Job(conf);
      HCatOutputFormat.setOutput(job, jobInfo);
      HCatOutputFormat.setSchema(job, HCatOutputFormat.getTableSchema(job));
      HCatOutputFormat outFormat = new HCatOutputFormat();
      outFormat.checkOutputSpecs(job);
      outFormat.getOutputCommitter(new TaskAttemptContext(job.getConfiguration(), new TaskAttemptID())).setupJob(job);
    } catch (IOException e) {
      throw new HCatException(ErrorType.ERROR_NOT_INITIALIZED, e);
    } catch (InterruptedException e) {
      throw new HCatException(ErrorType.ERROR_NOT_INITIALIZED, e);
    }
    WriterContext cntxt = new WriterContext();
    cntxt.setConf(job.getConfiguration());
    return cntxt;
  }

  @Override
  public void write(Iterator<HCatRecord> recordItr) throws HCatException {
   
    int id = sp.getId();
    setVarsInConf(id);
    HCatOutputFormat outFormat = new HCatOutputFormat();
    TaskAttemptContext cntxt = new TaskAttemptContext(conf, new TaskAttemptID(new TaskID(), id));
    OutputCommitter committer = null;
    RecordWriter<WritableComparable<?>, HCatRecord> writer;
    try {
      committer = outFormat.getOutputCommitter(cntxt);
      committer.setupTask(cntxt);
      writer   = outFormat.getRecordWriter(cntxt);
      while(recordItr.hasNext()){
        HCatRecord rec = recordItr.next();
        writer.write(null, rec);
      }
      writer.close(cntxt);
      if(committer.needsTaskCommit(cntxt)){
        committer.commitTask(cntxt);       
      }
    } catch (IOException e) {
      if(null != committer) {
        try {
          committer.abortTask(cntxt);
        } catch (IOException e1) {
          throw new HCatException(ErrorType.ERROR_INTERNAL_EXCEPTION, e1);
        }
      }
      throw new HCatException("Failed while writing",e);
    } catch (InterruptedException e) {
      if(null != committer) {
        try {
          committer.abortTask(cntxt);
        } catch (IOException e1) {
          throw new HCatException(ErrorType.ERROR_INTERNAL_EXCEPTION, e1);
        }
      }
      throw new HCatException("Failed while writing", e);
    }
  }

  @Override
  public void commit(WriterContext context) throws HCatException {
    try {
      new HCatOutputFormat().getOutputCommitter(new TaskAttemptContext(context.getConf(), new TaskAttemptID()))
      .commitJob(new JobContext(context.getConf(), null));
    } catch (IOException e) {
      throw new HCatException(ErrorType.ERROR_NOT_INITIALIZED, e);
    } catch (InterruptedException e) {
      throw new HCatException(ErrorType.ERROR_NOT_INITIALIZED, e);
    }
  }

  @Override
  public void abort(WriterContext context) throws HCatException {
    try {
      new HCatOutputFormat().getOutputCommitter(new TaskAttemptContext(context.getConf(), new TaskAttemptID()))
      .abortJob(new JobContext(context.getConf(), null),State.FAILED);
    } catch (IOException e) {
      throw new HCatException(ErrorType.ERROR_NOT_INITIALIZED, e);
    } catch (InterruptedException e) {
      throw new HCatException(ErrorType.ERROR_NOT_INITIALIZED, e);
    }
  }
 
  private void setVarsInConf(int id) {
   
    // Following two config keys are required by FileOutputFormat to work correctly.
    // In usual case of Hadoop, JobTracker will set these before launching tasks.
    // Since there is no jobtracker here, we set it ourself.
    conf.setInt("mapred.task.partition", id);
    conf.set("mapred.task.id", "attempt__0000_r_000000_"+id);
  }
}
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