/*
* Copyright (c) 2007-2014 Concurrent, Inc. All Rights Reserved.
*
* Project and contact information: http://www.cascading.org/
*
* This file is part of the Cascading project.
*
* Licensed 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 cascading.flow.hadoop;
import java.io.IOException;
import java.util.Iterator;
import cascading.CascadingException;
import cascading.flow.FlowException;
import cascading.flow.FlowNode;
import cascading.flow.FlowSession;
import cascading.flow.FlowStep;
import cascading.flow.SliceCounters;
import cascading.flow.hadoop.planner.HadoopFlowStepJob;
import cascading.flow.hadoop.stream.graph.HadoopMapStreamGraph;
import cascading.flow.hadoop.util.HadoopUtil;
import cascading.flow.planner.BaseFlowNode;
import cascading.flow.planner.BaseFlowStep;
import cascading.flow.stream.duct.Duct;
import cascading.flow.stream.element.ElementDuct;
import cascading.flow.stream.element.SourceStage;
import cascading.tap.Tap;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.MapRunnable;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.RecordReader;
import org.apache.hadoop.mapred.Reporter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static cascading.flow.hadoop.util.HadoopMRUtil.readStateFromDistCache;
import static cascading.flow.hadoop.util.HadoopUtil.deserializeBase64;
/** Class FlowMapper is the Hadoop Mapper implementation. */
public class FlowMapper implements MapRunnable
{
private static final Logger LOG = LoggerFactory.getLogger( FlowMapper.class );
private HadoopMapStreamGraph streamGraph;
/** Field currentProcess */
private HadoopFlowProcess currentProcess;
/** Constructor FlowMapper creates a new FlowMapper instance. */
public FlowMapper()
{
}
@Override
public void configure( JobConf jobConf )
{
try
{
HadoopUtil.initLog4j( jobConf );
LOG.info( "cascading version: {}", jobConf.get( "cascading.version", "" ) );
LOG.info( "child jvm opts: {}", jobConf.get( "mapred.child.java.opts", "" ) );
currentProcess = new HadoopFlowProcess( new FlowSession(), jobConf, true );
String mapNodeState = jobConf.getRaw( "cascading.flow.step.node.map" );
if( mapNodeState == null )
mapNodeState = readStateFromDistCache( jobConf, jobConf.get( FlowStep.CASCADING_FLOW_STEP_ID ), "map" );
FlowNode node = deserializeBase64( mapNodeState, jobConf, BaseFlowNode.class );
Tap source = BaseFlowStep.getTapForID( node.getSourceTaps(), jobConf.get( "cascading.step.source" ) );
streamGraph = new HadoopMapStreamGraph( currentProcess, node, source );
for( Duct head : streamGraph.getHeads() )
LOG.info( "sourcing from: " + ( (ElementDuct) head ).getFlowElement() );
for( Duct tail : streamGraph.getTails() )
LOG.info( "sinking to: " + ( (ElementDuct) tail ).getFlowElement() );
for( Tap trap : node.getTraps() )
LOG.info( "trapping to: " + trap );
}
catch( Throwable throwable )
{
reportIfLocal( throwable );
if( throwable instanceof CascadingException )
throw (CascadingException) throwable;
throw new FlowException( "internal error during mapper configuration", throwable );
}
}
@Override
public void run( RecordReader input, OutputCollector output, Reporter reporter ) throws IOException
{
currentProcess.setReporter( reporter );
currentProcess.setOutputCollector( output );
streamGraph.prepare();
long processBeginTime = System.currentTimeMillis();
currentProcess.increment( SliceCounters.Process_Begin_Time, processBeginTime );
SourceStage streamedHead = streamGraph.getStreamedHead();
Iterator<Duct> iterator = streamGraph.getHeads().iterator();
try
{
try
{
while( iterator.hasNext() )
{
Duct next = iterator.next();
if( next != streamedHead )
( (SourceStage) next ).run( null );
}
streamedHead.run( input );
}
catch( OutOfMemoryError error )
{
throw error;
}
catch( IOException exception )
{
reportIfLocal( exception );
throw exception;
}
catch( Throwable throwable )
{
reportIfLocal( throwable );
if( throwable instanceof CascadingException )
throw (CascadingException) throwable;
throw new FlowException( "internal error during mapper execution", throwable );
}
}
finally
{
try
{
streamGraph.cleanup();
}
finally
{
long processEndTime = System.currentTimeMillis();
currentProcess.increment( SliceCounters.Process_End_Time, processEndTime );
currentProcess.increment( SliceCounters.Process_Duration, processEndTime - processBeginTime );
}
}
}
/**
* Report the error to HadoopFlowStepJob if we are running in Hadoops local mode.
*
* @param throwable The throwable that was thrown.
*/
private void reportIfLocal( Throwable throwable )
{
if( HadoopUtil.isLocal( currentProcess.getJobConf() ) )
HadoopFlowStepJob.reportLocalError( throwable );
}
}