001/* 002 * Copyright (c) 2007-2015 Concurrent, Inc. All Rights Reserved. 003 * 004 * Project and contact information: http://www.cascading.org/ 005 * 006 * This file is part of the Cascading project. 007 * 008 * Licensed under the Apache License, Version 2.0 (the "License"); 009 * you may not use this file except in compliance with the License. 010 * You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, software 015 * distributed under the License is distributed on an "AS IS" BASIS, 016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 017 * See the License for the specific language governing permissions and 018 * limitations under the License. 019 */ 020 021package cascading.tap.hadoop; 022 023import java.io.IOException; 024import java.net.URI; 025import java.util.ArrayList; 026import java.util.List; 027 028import cascading.flow.FlowProcess; 029import cascading.flow.hadoop.util.HadoopUtil; 030import cascading.tap.DecoratorTap; 031import cascading.tap.MultiSourceTap; 032import cascading.tap.Tap; 033import cascading.tap.TapException; 034import cascading.tuple.TupleEntryIterator; 035import org.apache.hadoop.conf.Configuration; 036import org.apache.hadoop.fs.FileStatus; 037import org.apache.hadoop.fs.FileSystem; 038import org.apache.hadoop.fs.Path; 039import org.apache.hadoop.mapred.OutputCollector; 040import org.apache.hadoop.mapred.RecordReader; 041import org.slf4j.Logger; 042import org.slf4j.LoggerFactory; 043 044/** 045 * 046 */ 047public abstract class BaseDistCacheTap extends DecoratorTap<Void, Configuration, RecordReader, OutputCollector> 048 { 049 /** logger. */ 050 private static final Logger LOG = LoggerFactory.getLogger( DistCacheTap.class ); 051 052 public BaseDistCacheTap( Tap<Configuration, RecordReader, OutputCollector> original ) 053 { 054 super( original ); 055 } 056 057 @Override 058 public void sourceConfInit( FlowProcess<? extends Configuration> process, Configuration conf ) 059 { 060 if( HadoopUtil.isLocal( conf ) || 061 Tap.id( this ).equals( conf.get( "cascading.node.source" ) ) || 062 Tap.id( this ).equals( conf.get( "cascading.step.source" ) ) ) 063 { 064 LOG.info( "can't use distributed cache. reading '{}' from hdfs", super.getIdentifier() ); 065 super.sourceConfInit( process, conf ); 066 return; 067 } 068 try 069 { 070 registerHfs( process, conf, getHfs() ); 071 } 072 catch( IOException exception ) 073 { 074 throw new TapException( exception ); 075 } 076 } 077 078 @Override 079 public TupleEntryIterator openForRead( FlowProcess<? extends Configuration> flowProcess, RecordReader input ) throws IOException 080 { 081 // always read via Hadoop FileSystem if in standalone/local mode, or if an RecordReader is provided 082 if( HadoopUtil.isLocal( flowProcess.getConfig() ) || input != null ) 083 { 084 LOG.info( "delegating to parent" ); 085 return super.openForRead( flowProcess, input ); 086 } 087 088 Path[] cachedFiles = getLocalCacheFiles( flowProcess ); 089 090 if( cachedFiles == null || cachedFiles.length == 0 ) 091 return super.openForRead( flowProcess, null ); 092 093 List<Path> paths = new ArrayList<>(); 094 List<Tap> taps = new ArrayList<>(); 095 096 if( isSimpleGlob() ) 097 { 098 FileSystem fs = FileSystem.get( flowProcess.getConfig() ); 099 FileStatus[] statuses = fs.globStatus( getHfs().getPath() ); 100 101 for( FileStatus status : statuses ) 102 paths.add( status.getPath() ); 103 } 104 else 105 { 106 paths.add( getHfs().getPath() ); 107 } 108 109 for( Path pathToFind : paths ) 110 { 111 for( Path path : cachedFiles ) 112 { 113 if( path.toString().endsWith( pathToFind.getName() ) ) 114 { 115 LOG.info( "found {} in distributed cache", path ); 116 taps.add( new Lfs( getScheme(), path.toString() ) ); 117 } 118 } 119 } 120 121 if( paths.isEmpty() ) // not in cache, read from HDFS 122 { 123 LOG.info( "could not find files in local resource path. delegating to parent: {}", super.getIdentifier() ); 124 return super.openForRead( flowProcess, input ); 125 } 126 127 return new MultiSourceTap( taps.toArray( new Tap[ taps.size() ] ) ).openForRead( flowProcess, input ); 128 } 129 130 private void registerHfs( FlowProcess<? extends Configuration> process, Configuration conf, Hfs hfs ) throws IOException 131 { 132 if( isSimpleGlob() ) 133 { 134 FileSystem fs = FileSystem.get( conf ); 135 FileStatus[] statuses = fs.globStatus( getHfs().getPath() ); 136 137 if( statuses == null || statuses.length == 0 ) 138 throw new TapException( String.format( "glob expression %s does not match any files on the filesystem", getHfs().getPath() ) ); 139 140 for( FileStatus fileStatus : statuses ) 141 registerURI( conf, fileStatus.getPath() ); 142 } 143 else 144 { 145 registerURI( conf, hfs.getPath() ); 146 } 147 148 hfs.sourceConfInitComplete( process, conf ); 149 } 150 151 private void registerURI( Configuration conf, Path path ) 152 { 153 URI uri = path.toUri(); 154 LOG.info( "adding {} to local resource configuration ", uri ); 155 addLocalCacheFiles( conf, uri ); 156 } 157 158 private Hfs getHfs() 159 { 160 return (Hfs) getOriginal(); 161 } 162 163 private boolean isSimpleGlob() 164 { 165 return getHfs().getIdentifier().contains( "*" ); 166 } 167 168 protected abstract Path[] getLocalCacheFiles( FlowProcess<? extends Configuration> flowProcess ) throws IOException; 169 170 protected abstract void addLocalCacheFiles( Configuration conf, URI uri ); 171 }