/**
* 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.hadoop.mapreduce.lib.input;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
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.fs.BlockLocation;
import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.security.TokenCache;
import org.apache.hadoop.util.ReflectionUtils;
import org.apache.hadoop.util.StringUtils;
/**
* A base class for file-based {@link InputFormat}s.
*
* <p><code>FileInputFormat</code> is the base class for all file-based
* <code>InputFormat</code>s. This provides a generic implementation of
* {@link #getSplits(JobContext)}.
* Subclasses of <code>FileInputFormat</code> can also override the
* {@link #isSplitable(JobContext, Path)} method to ensure input-files are
* not split-up and are processed as a whole by {@link Mapper}s.
*/
public abstract class FileInputFormat<K, V> extends InputFormat<K, V> {
private static final Log LOG = LogFactory.getLog(FileInputFormat.class);
private static final double SPLIT_SLOP = 1.1; // 10% slop
private static final PathFilter hiddenFileFilter = new PathFilter(){
public boolean accept(Path p){
String name = p.getName();
return !name.startsWith("_") && !name.startsWith(".");
}
};
static final String NUM_INPUT_FILES = "mapreduce.input.num.files";
/**
* 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<PathFilter> filters;
public MultiPathFilter(List<PathFilter> filters) {
this.filters = filters;
}
public boolean accept(Path path) {
for (PathFilter filter : filters) {
if (!filter.accept(path)) {
return false;
}
}
return true;
}
}
/**
* Get the lower bound on split size imposed by the format.
* @return the number of bytes of the minimal split for this format
*/
protected long getFormatMinSplitSize() {
return 1;
}
/**
* Is the given filename splitable? Usually, true, but if the file is
* stream compressed, it will not be.
*
* <code>FileInputFormat</code> implementations can override this and return
* <code>false</code> to ensure that individual input files are never split-up
* so that {@link Mapper}s process entire files.
*
* @param context the job context
* @param filename the file name to check
* @return is this file splitable?
*/
protected boolean isSplitable(JobContext context, Path filename) {
return true;
}
/**
* Set a PathFilter to be applied to the input paths for the map-reduce job.
* @param job the job to modify
* @param filter the PathFilter class use for filtering the input paths.
*/
public static void setInputPathFilter(Job job,
Class<? extends PathFilter> filter) {
job.getConfiguration().setClass("mapred.input.pathFilter.class", filter,
PathFilter.class);
}
/**
* Set the minimum input split size
* @param job the job to modify
* @param size the minimum size
*/
public static void setMinInputSplitSize(Job job,
long size) {
job.getConfiguration().setLong("mapred.min.split.size", size);
}
/**
* Get the minimum split size
* @param job the job
* @return the minimum number of bytes that can be in a split
*/
public static long getMinSplitSize(JobContext job) {
return job.getConfiguration().getLong("mapred.min.split.size", 1L);
}
/**
* Set the maximum split size
* @param job the job to modify
* @param size the maximum split size
*/
public static void setMaxInputSplitSize(Job job,
long size) {
job.getConfiguration().setLong("mapred.max.split.size", size);
}
/**
* Get the maximum split size.
* @param context the job to look at.
* @return the maximum number of bytes a split can include
*/
public static long getMaxSplitSize(JobContext context) {
return context.getConfiguration().getLong("mapred.max.split.size",
Long.MAX_VALUE);
}
/**
* 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(JobContext context) {
Configuration conf = context.getConfiguration();
Class<?> filterClass = conf.getClass("mapred.input.pathFilter.class", null,
PathFilter.class);
return (filterClass != null) ?
(PathFilter) ReflectionUtils.newInstance(filterClass, conf) : null;
}
/** 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 List<FileStatus> listStatus(JobContext job
) throws IOException {
List<FileStatus> result = new ArrayList<FileStatus>();
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.getConfiguration());
List<IOException> errors = new ArrayList<IOException>();
// creates a MultiPathFilter with the hiddenFileFilter and the
// user provided one (if any).
List<PathFilter> filters = new ArrayList<PathFilter>();
filters.add(hiddenFileFilter);
PathFilter jobFilter = getInputPathFilter(job);
if (jobFilter != null) {
filters.add(jobFilter);
}
PathFilter inputFilter = new MultiPathFilter(filters);
for (int i=0; i < dirs.length; ++i) {
Path p = dirs[i];
FileSystem fs = p.getFileSystem(job.getConfiguration());
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.isDir()) {
for(FileStatus stat: fs.listStatus(globStat.getPath(),
inputFilter)) {
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;
}
/**
* Generate the list of files and make them into FileSplits.
*/
public List<InputSplit> getSplits(JobContext job
) throws IOException {
long minSize = Math.max(getFormatMinSplitSize(), getMinSplitSize(job));
long maxSize = getMaxSplitSize(job);
// generate splits
List<InputSplit> splits = new ArrayList<InputSplit>();
List<FileStatus>files = listStatus(job);
for (FileStatus file: files) {
Path path = file.getPath();
FileSystem fs = path.getFileSystem(job.getConfiguration());
long length = file.getLen();
BlockLocation[] blkLocations = fs.getFileBlockLocations(file, 0, length);
if ((length != 0) && isSplitable(job, path)) {
long blockSize = file.getBlockSize();
long splitSize = computeSplitSize(blockSize, minSize, maxSize);
long bytesRemaining = length;
while (((double) bytesRemaining)/splitSize > SPLIT_SLOP) {
int blkIndex = getBlockIndex(blkLocations, length-bytesRemaining);
splits.add(new FileSplit(path, length-bytesRemaining, splitSize,
blkLocations[blkIndex].getHosts()));
bytesRemaining -= splitSize;
}
if (bytesRemaining != 0) {
splits.add(new FileSplit(path, length-bytesRemaining, bytesRemaining,
blkLocations[blkLocations.length-1].getHosts()));
}
} else if (length != 0) {
splits.add(new FileSplit(path, 0, length, blkLocations[0].getHosts()));
} else {
//Create empty hosts array for zero length files
splits.add(new FileSplit(path, 0, length, new String[0]));
}
}
// Save the number of input files in the job-conf
job.getConfiguration().setLong(NUM_INPUT_FILES, files.size());
LOG.debug("Total # of splits: " + splits.size());
return splits;
}
protected long computeSplitSize(long blockSize, long minSize,
long maxSize) {
return Math.max(minSize, Math.min(maxSize, 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 job the job
* @param commaSeparatedPaths Comma separated paths to be set as
* the list of inputs for the map-reduce job.
*/
public static void setInputPaths(Job job,
String commaSeparatedPaths
) throws IOException {
setInputPaths(job, StringUtils.stringToPath(
getPathStrings(commaSeparatedPaths)));
}
/**
* Add the given comma separated paths to the list of inputs for
* the map-reduce job.
*
* @param job The job to modify
* @param commaSeparatedPaths Comma separated paths to be added to
* the list of inputs for the map-reduce job.
*/
public static void addInputPaths(Job job,
String commaSeparatedPaths
) throws IOException {
for (String str : getPathStrings(commaSeparatedPaths)) {
addInputPath(job, new Path(str));
}
}
/**
* Set the array of {@link Path}s as the list of inputs
* for the map-reduce job.
*
* @param job The job to modify
* @param inputPaths the {@link Path}s of the input directories/files
* for the map-reduce job.
*/
public static void setInputPaths(Job job,
Path... inputPaths) throws IOException {
Configuration conf = job.getConfiguration();
Path path = inputPaths[0].getFileSystem(conf).makeQualified(inputPaths[0]);
StringBuffer str = new StringBuffer(StringUtils.escapeString(path.toString()));
for(int i = 1; i < inputPaths.length;i++) {
str.append(StringUtils.COMMA_STR);
path = inputPaths[i].getFileSystem(conf).makeQualified(inputPaths[i]);
str.append(StringUtils.escapeString(path.toString()));
}
conf.set("mapred.input.dir", str.toString());
}
/**
* Add a {@link Path} to the list of inputs for the map-reduce job.
*
* @param job The {@link Job} to modify
* @param path {@link Path} to be added to the list of inputs for
* the map-reduce job.
*/
public static void addInputPath(Job job,
Path path) throws IOException {
Configuration conf = job.getConfiguration();
path = path.getFileSystem(conf).makeQualified(path);
String dirStr = StringUtils.escapeString(path.toString());
String dirs = conf.get("mapred.input.dir");
conf.set("mapred.input.dir", dirs == null ? dirStr : dirs + "," + 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<String> pathStrings = new ArrayList<String>();
for (int i=0; i<length; i++) {
char ch = commaSeparatedPaths.charAt(i);
switch(ch) {
case '{' : {
curlyOpen++;
if (!globPattern) {
globPattern = true;
}
break;
}
case '}' : {
curlyOpen--;
if (curlyOpen == 0 && globPattern) {
globPattern = false;
}
break;
}
case ',' : {
if (!globPattern) {
pathStrings.add(commaSeparatedPaths.substring(pathStart, i));
pathStart = i + 1 ;
}
break;
}
}
}
pathStrings.add(commaSeparatedPaths.substring(pathStart, length));
return pathStrings.toArray(new String[0]);
}
/**
* Get the list of input {@link Path}s for the map-reduce job.
*
* @param context The job
* @return the list of input {@link Path}s for the map-reduce job.
*/
public static Path[] getInputPaths(JobContext context) {
String dirs = context.getConfiguration().get("mapred.input.dir", "");
String [] list = StringUtils.split(dirs);
Path[] result = new Path[list.length];
for (int i = 0; i < list.length; i++) {
result[i] = new Path(StringUtils.unEscapeString(list[i]));
}
return result;
}
}