org.apache.hadoop.mapred.FileInputFormat Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* distributed with this work for additional information
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* 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
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.mapred;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.IdentityHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.PathFilter;
import org.apache.hadoop.mapreduce.security.TokenCache;
import org.apache.hadoop.net.NetworkTopology;
import org.apache.hadoop.net.Node;
import org.apache.hadoop.net.NodeBase;
import org.apache.hadoop.util.ReflectionUtils;
import org.apache.hadoop.util.StringUtils;
/**
* A base class for file-based {@link InputFormat}.
*
* FileInputFormat is the base class for all file-based
* InputFormats. This provides a generic implementation of
* {@link #getSplits(JobConf, int)}.
* Subclasses of FileInputFormat can also override the
* {@link #isSplitable(FileSystem, Path)} method to ensure input-files are
* not split-up and are processed as a whole by {@link Mapper}s.
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public abstract class FileInputFormat implements InputFormat {
public static final Log LOG =
LogFactory.getLog(FileInputFormat.class);
public static final String NUM_INPUT_FILES =
org.apache.hadoop.mapreduce.lib.input.FileInputFormat.NUM_INPUT_FILES;
private static final double SPLIT_SLOP = 1.1; // 10% slop
private long minSplitSize = 1;
private static final PathFilter hiddenFileFilter = new PathFilter(){
public boolean accept(Path p){
String name = p.getName();
return !name.startsWith("_") && !name.startsWith(".");
}
};
protected void setMinSplitSize(long minSplitSize) {
this.minSplitSize = minSplitSize;
}
/**
* Proxy PathFilter that accepts a path only if all filters given in the
* constructor do. Used by the listPaths() to apply the built-in
* hiddenFileFilter together with a user provided one (if any).
*/
private static class MultiPathFilter implements PathFilter {
private List filters;
public MultiPathFilter(List filters) {
this.filters = filters;
}
public boolean accept(Path path) {
for (PathFilter filter : filters) {
if (!filter.accept(path)) {
return false;
}
}
return true;
}
}
/**
* Is the given filename splitable? Usually, true, but if the file is
* stream compressed, it will not be.
*
* FileInputFormat implementations can override this and return
* false to ensure that individual input files are never split-up
* so that {@link Mapper}s process entire files.
*
* @param fs the file system that the file is on
* @param filename the file name to check
* @return is this file splitable?
*/
protected boolean isSplitable(FileSystem fs, Path filename) {
return true;
}
public abstract RecordReader getRecordReader(InputSplit split,
JobConf job,
Reporter reporter)
throws IOException;
/**
* Set a PathFilter to be applied to the input paths for the map-reduce job.
*
* @param filter the PathFilter class use for filtering the input paths.
*/
public static void setInputPathFilter(JobConf conf,
Class filter) {
conf.setClass(org.apache.hadoop.mapreduce.lib.input.
FileInputFormat.PATHFILTER_CLASS, filter, PathFilter.class);
}
/**
* Get a PathFilter instance of the filter set for the input paths.
*
* @return the PathFilter instance set for the job, NULL if none has been set.
*/
public static PathFilter getInputPathFilter(JobConf conf) {
Class filterClass = conf.getClass(
org.apache.hadoop.mapreduce.lib.input.FileInputFormat.PATHFILTER_CLASS,
null, PathFilter.class);
return (filterClass != null) ?
ReflectionUtils.newInstance(filterClass, conf) : null;
}
/**
* Add files in the input path recursively into the results.
* @param result
* The List to store all files.
* @param fs
* The FileSystem.
* @param path
* The input path.
* @param inputFilter
* The input filter that can be used to filter files/dirs.
* @throws IOException
*/
protected void addInputPathRecursively(List result,
FileSystem fs, Path path, PathFilter inputFilter)
throws IOException {
for(FileStatus stat: fs.listStatus(path, inputFilter)) {
if (stat.isDirectory()) {
addInputPathRecursively(result, fs, stat.getPath(), inputFilter);
} else {
result.add(stat);
}
}
}
/** List input directories.
* Subclasses may override to, e.g., select only files matching a regular
* expression.
*
* @param job the job to list input paths for
* @return array of FileStatus objects
* @throws IOException if zero items.
*/
protected FileStatus[] listStatus(JobConf job) throws IOException {
Path[] dirs = getInputPaths(job);
if (dirs.length == 0) {
throw new IOException("No input paths specified in job");
}
// get tokens for all the required FileSystems..
TokenCache.obtainTokensForNamenodes(job.getCredentials(), dirs, job);
// Whether we need to recursive look into the directory structure
boolean recursive = job.getBoolean("mapred.input.dir.recursive", false);
List result = new ArrayList();
List errors = new ArrayList();
// creates a MultiPathFilter with the hiddenFileFilter and the
// user provided one (if any).
List filters = new ArrayList();
filters.add(hiddenFileFilter);
PathFilter jobFilter = getInputPathFilter(job);
if (jobFilter != null) {
filters.add(jobFilter);
}
PathFilter inputFilter = new MultiPathFilter(filters);
for (Path p: dirs) {
FileSystem fs = p.getFileSystem(job);
FileStatus[] matches = fs.globStatus(p, inputFilter);
if (matches == null) {
errors.add(new IOException("Input path does not exist: " + p));
} else if (matches.length == 0) {
errors.add(new IOException("Input Pattern " + p + " matches 0 files"));
} else {
for (FileStatus globStat: matches) {
if (globStat.isDirectory()) {
for(FileStatus stat: fs.listStatus(globStat.getPath(),
inputFilter)) {
if (recursive && stat.isDirectory()) {
addInputPathRecursively(result, fs, stat.getPath(), inputFilter);
} else {
result.add(stat);
}
}
} else {
result.add(globStat);
}
}
}
}
if (!errors.isEmpty()) {
throw new InvalidInputException(errors);
}
LOG.info("Total input paths to process : " + result.size());
return result.toArray(new FileStatus[result.size()]);
}
/**
* A factory that makes the split for this class. It can be overridden
* by sub-classes to make sub-types
*/
protected FileSplit makeSplit(Path file, long start, long length,
String[] hosts) {
return new FileSplit(file, start, length, hosts);
}
/** Splits files returned by {@link #listStatus(JobConf)} when
* they're too big.*/
@SuppressWarnings("deprecation")
public InputSplit[] getSplits(JobConf job, int numSplits)
throws IOException {
FileStatus[] files = listStatus(job);
// Save the number of input files for metrics/loadgen
job.setLong(NUM_INPUT_FILES, files.length);
long totalSize = 0; // compute total size
for (FileStatus file: files) { // check we have valid files
if (file.isDirectory()) {
throw new IOException("Not a file: "+ file.getPath());
}
totalSize += file.getLen();
}
long goalSize = totalSize / (numSplits == 0 ? 1 : numSplits);
long minSize = Math.max(job.getLong(org.apache.hadoop.mapreduce.lib.input.
FileInputFormat.SPLIT_MINSIZE, 1), minSplitSize);
// generate splits
ArrayList splits = new ArrayList(numSplits);
NetworkTopology clusterMap = new NetworkTopology();
for (FileStatus file: files) {
Path path = file.getPath();
FileSystem fs = path.getFileSystem(job);
long length = file.getLen();
BlockLocation[] blkLocations = fs.getFileBlockLocations(file, 0, length);
if ((length != 0) && isSplitable(fs, path)) {
long blockSize = file.getBlockSize();
long splitSize = computeSplitSize(goalSize, minSize, blockSize);
long bytesRemaining = length;
while (((double) bytesRemaining)/splitSize > SPLIT_SLOP) {
String[] splitHosts = getSplitHosts(blkLocations,
length-bytesRemaining, splitSize, clusterMap);
splits.add(makeSplit(path, length-bytesRemaining, splitSize,
splitHosts));
bytesRemaining -= splitSize;
}
if (bytesRemaining != 0) {
String[] splitHosts = getSplitHosts(blkLocations, length
- bytesRemaining, bytesRemaining, clusterMap);
splits.add(makeSplit(path, length - bytesRemaining, bytesRemaining,
splitHosts));
}
} else if (length != 0) {
String[] splitHosts = getSplitHosts(blkLocations,0,length,clusterMap);
splits.add(makeSplit(path, 0, length, splitHosts));
} else {
//Create empty hosts array for zero length files
splits.add(makeSplit(path, 0, length, new String[0]));
}
}
LOG.debug("Total # of splits: " + splits.size());
return splits.toArray(new FileSplit[splits.size()]);
}
protected long computeSplitSize(long goalSize, long minSize,
long blockSize) {
return Math.max(minSize, Math.min(goalSize, blockSize));
}
protected int getBlockIndex(BlockLocation[] blkLocations,
long offset) {
for (int i = 0 ; i < blkLocations.length; i++) {
// is the offset inside this block?
if ((blkLocations[i].getOffset() <= offset) &&
(offset < blkLocations[i].getOffset() + blkLocations[i].getLength())){
return i;
}
}
BlockLocation last = blkLocations[blkLocations.length -1];
long fileLength = last.getOffset() + last.getLength() -1;
throw new IllegalArgumentException("Offset " + offset +
" is outside of file (0.." +
fileLength + ")");
}
/**
* Sets the given comma separated paths as the list of inputs
* for the map-reduce job.
*
* @param conf Configuration of the job
* @param commaSeparatedPaths Comma separated paths to be set as
* the list of inputs for the map-reduce job.
*/
public static void setInputPaths(JobConf conf, String commaSeparatedPaths) {
setInputPaths(conf, StringUtils.stringToPath(
getPathStrings(commaSeparatedPaths)));
}
/**
* Add the given comma separated paths to the list of inputs for
* the map-reduce job.
*
* @param conf The configuration of the job
* @param commaSeparatedPaths Comma separated paths to be added to
* the list of inputs for the map-reduce job.
*/
public static void addInputPaths(JobConf conf, String commaSeparatedPaths) {
for (String str : getPathStrings(commaSeparatedPaths)) {
addInputPath(conf, new Path(str));
}
}
/**
* Set the array of {@link Path}s as the list of inputs
* for the map-reduce job.
*
* @param conf Configuration of the job.
* @param inputPaths the {@link Path}s of the input directories/files
* for the map-reduce job.
*/
public static void setInputPaths(JobConf conf, Path... inputPaths) {
Path path = new Path(conf.getWorkingDirectory(), inputPaths[0]);
StringBuffer str = new StringBuffer(StringUtils.escapeString(path.toString()));
for(int i = 1; i < inputPaths.length;i++) {
str.append(StringUtils.COMMA_STR);
path = new Path(conf.getWorkingDirectory(), inputPaths[i]);
str.append(StringUtils.escapeString(path.toString()));
}
conf.set(org.apache.hadoop.mapreduce.lib.input.
FileInputFormat.INPUT_DIR, str.toString());
}
/**
* Add a {@link Path} to the list of inputs for the map-reduce job.
*
* @param conf The configuration of the job
* @param path {@link Path} to be added to the list of inputs for
* the map-reduce job.
*/
public static void addInputPath(JobConf conf, Path path ) {
path = new Path(conf.getWorkingDirectory(), path);
String dirStr = StringUtils.escapeString(path.toString());
String dirs = conf.get(org.apache.hadoop.mapreduce.lib.input.
FileInputFormat.INPUT_DIR);
conf.set(org.apache.hadoop.mapreduce.lib.input.
FileInputFormat.INPUT_DIR, dirs == null ? dirStr :
dirs + StringUtils.COMMA_STR + dirStr);
}
// This method escapes commas in the glob pattern of the given paths.
private static String[] getPathStrings(String commaSeparatedPaths) {
int length = commaSeparatedPaths.length();
int curlyOpen = 0;
int pathStart = 0;
boolean globPattern = false;
List pathStrings = new ArrayList();
for (int i=0; i mylist) {
Collections.sort(mylist, new Comparator () {
public int compare(NodeInfo obj1, NodeInfo obj2) {
if (obj1 == null || obj2 == null)
return -1;
if (obj1.getValue() == obj2.getValue()) {
return 0;
}
else {
return ((obj1.getValue() < obj2.getValue()) ? 1 : -1);
}
}
}
);
}
/**
* This function identifies and returns the hosts that contribute
* most for a given split. For calculating the contribution, rack
* locality is treated on par with host locality, so hosts from racks
* that contribute the most are preferred over hosts on racks that
* contribute less
* @param blkLocations The list of block locations
* @param offset
* @param splitSize
* @return array of hosts that contribute most to this split
* @throws IOException
*/
protected String[] getSplitHosts(BlockLocation[] blkLocations,
long offset, long splitSize, NetworkTopology clusterMap)
throws IOException {
int startIndex = getBlockIndex(blkLocations, offset);
long bytesInThisBlock = blkLocations[startIndex].getOffset() +
blkLocations[startIndex].getLength() - offset;
//If this is the only block, just return
if (bytesInThisBlock >= splitSize) {
return blkLocations[startIndex].getHosts();
}
long bytesInFirstBlock = bytesInThisBlock;
int index = startIndex + 1;
splitSize -= bytesInThisBlock;
while (splitSize > 0) {
bytesInThisBlock =
Math.min(splitSize, blkLocations[index++].getLength());
splitSize -= bytesInThisBlock;
}
long bytesInLastBlock = bytesInThisBlock;
int endIndex = index - 1;
Map hostsMap = new IdentityHashMap();
Map racksMap = new IdentityHashMap();
String [] allTopos = new String[0];
// Build the hierarchy and aggregate the contribution of
// bytes at each level. See TestGetSplitHosts.java
for (index = startIndex; index <= endIndex; index++) {
// Establish the bytes in this block
if (index == startIndex) {
bytesInThisBlock = bytesInFirstBlock;
}
else if (index == endIndex) {
bytesInThisBlock = bytesInLastBlock;
}
else {
bytesInThisBlock = blkLocations[index].getLength();
}
allTopos = blkLocations[index].getTopologyPaths();
// If no topology information is available, just
// prefix a fakeRack
if (allTopos.length == 0) {
allTopos = fakeRacks(blkLocations, index);
}
// NOTE: This code currently works only for one level of
// hierarchy (rack/host). However, it is relatively easy
// to extend this to support aggregation at different
// levels
for (String topo: allTopos) {
Node node, parentNode;
NodeInfo nodeInfo, parentNodeInfo;
node = clusterMap.getNode(topo);
if (node == null) {
node = new NodeBase(topo);
clusterMap.add(node);
}
nodeInfo = hostsMap.get(node);
if (nodeInfo == null) {
nodeInfo = new NodeInfo(node);
hostsMap.put(node,nodeInfo);
parentNode = node.getParent();
parentNodeInfo = racksMap.get(parentNode);
if (parentNodeInfo == null) {
parentNodeInfo = new NodeInfo(parentNode);
racksMap.put(parentNode,parentNodeInfo);
}
parentNodeInfo.addLeaf(nodeInfo);
}
else {
nodeInfo = hostsMap.get(node);
parentNode = node.getParent();
parentNodeInfo = racksMap.get(parentNode);
}
nodeInfo.addValue(index, bytesInThisBlock);
parentNodeInfo.addValue(index, bytesInThisBlock);
} // for all topos
} // for all indices
return identifyHosts(allTopos.length, racksMap);
}
private String[] identifyHosts(int replicationFactor,
Map racksMap) {
String [] retVal = new String[replicationFactor];
List rackList = new LinkedList();
rackList.addAll(racksMap.values());
// Sort the racks based on their contribution to this split
sortInDescendingOrder(rackList);
boolean done = false;
int index = 0;
// Get the host list for all our aggregated items, sort
// them and return the top entries
for (NodeInfo ni: rackList) {
Set hostSet = ni.getLeaves();
ListhostList = new LinkedList();
hostList.addAll(hostSet);
// Sort the hosts in this rack based on their contribution
sortInDescendingOrder(hostList);
for (NodeInfo host: hostList) {
// Strip out the port number from the host name
retVal[index++] = host.node.getName().split(":")[0];
if (index == replicationFactor) {
done = true;
break;
}
}
if (done == true) {
break;
}
}
return retVal;
}
private String[] fakeRacks(BlockLocation[] blkLocations, int index)
throws IOException {
String[] allHosts = blkLocations[index].getHosts();
String[] allTopos = new String[allHosts.length];
for (int i = 0; i < allHosts.length; i++) {
allTopos[i] = NetworkTopology.DEFAULT_RACK + "/" + allHosts[i];
}
return allTopos;
}
private static class NodeInfo {
final Node node;
final Set blockIds;
final Set leaves;
private long value;
NodeInfo(Node node) {
this.node = node;
blockIds = new HashSet();
leaves = new HashSet();
}
long getValue() {return value;}
void addValue(int blockIndex, long value) {
if (blockIds.add(blockIndex) == true) {
this.value += value;
}
}
Set getLeaves() { return leaves;}
void addLeaf(NodeInfo nodeInfo) {
leaves.add(nodeInfo);
}
}
}