Java tutorial
/** * 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.fs; import java.io.BufferedReader; import java.io.DataInputStream; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintStream; import java.util.Date; import java.util.StringTokenizer; import java.util.TreeSet; import java.util.Vector; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.io.SequenceFile; import org.apache.hadoop.io.Text; import org.apache.hadoop.io.SequenceFile.CompressionType; import org.apache.hadoop.mapred.*; import org.apache.hadoop.util.Tool; import org.apache.hadoop.util.ToolRunner; import org.junit.Test; /** * Distributed checkup of the file system consistency. * <p> * Test file system consistency by reading each block of each file * of the specified file tree. * Report corrupted blocks and general file statistics. * <p> * Optionally displays statistics on read performance. * */ public class DistributedFSCheck extends Configured implements Tool { // Constants private static final Log LOG = LogFactory.getLog(DistributedFSCheck.class); private static final int TEST_TYPE_READ = 0; private static final int TEST_TYPE_CLEANUP = 2; private static final int DEFAULT_BUFFER_SIZE = 1000000; private static final String DEFAULT_RES_FILE_NAME = "DistributedFSCheck_results.log"; private static final long MEGA = 0x100000; private static Configuration fsConfig = new Configuration(); private static Path TEST_ROOT_DIR = new Path( System.getProperty("test.build.data", "/benchmarks/DistributedFSCheck")); private static Path MAP_INPUT_DIR = new Path(TEST_ROOT_DIR, "map_input"); private static Path READ_DIR = new Path(TEST_ROOT_DIR, "io_read"); private FileSystem fs; private long nrFiles; DistributedFSCheck(Configuration conf) throws Exception { fsConfig = conf; this.fs = FileSystem.get(conf); } /** * Run distributed checkup for the entire files system. * * @throws Exception */ @Test public void testFSBlocks() throws Exception { testFSBlocks("/"); } /** * Run distributed checkup for the specified directory. * * @param rootName root directory name * @throws Exception */ public void testFSBlocks(String rootName) throws Exception { createInputFile(rootName); runDistributedFSCheck(); cleanup(); // clean up after all to restore the system state } private void createInputFile(String rootName) throws IOException { cleanup(); // clean up if previous run failed Path inputFile = new Path(MAP_INPUT_DIR, "in_file"); SequenceFile.Writer writer = SequenceFile.createWriter(fs, fsConfig, inputFile, Text.class, LongWritable.class, CompressionType.NONE); try { nrFiles = 0; listSubtree(new Path(rootName), writer); } finally { writer.close(); } LOG.info("Created map input files."); } private void listSubtree(Path rootFile, SequenceFile.Writer writer) throws IOException { FileStatus rootStatus = fs.getFileStatus(rootFile); listSubtree(rootStatus, writer); } private void listSubtree(FileStatus rootStatus, SequenceFile.Writer writer) throws IOException { Path rootFile = rootStatus.getPath(); if (!rootStatus.isDir()) { nrFiles++; // For a regular file generate <fName,offset> pairs long blockSize = fs.getDefaultBlockSize(); long fileLength = rootStatus.getLen(); for (long offset = 0; offset < fileLength; offset += blockSize) writer.append(new Text(rootFile.toString()), new LongWritable(offset)); return; } FileStatus[] children = null; try { children = fs.listStatus(rootFile); } catch (FileNotFoundException fnfe) { throw new IOException("Could not get listing for " + rootFile); } for (int i = 0; i < children.length; i++) listSubtree(children[i], writer); } /** * DistributedFSCheck mapper class. */ public static class DistributedFSCheckMapper extends IOMapperBase<Object> { public DistributedFSCheckMapper() { } public Object doIO(Reporter reporter, String name, long offset) throws IOException { // open file FSDataInputStream in = null; try { in = fs.open(new Path(name)); } catch (IOException e) { return name + "@(missing)"; } in.seek(offset); long actualSize = 0; try { long blockSize = fs.getDefaultBlockSize(); reporter.setStatus("reading " + name + "@" + offset + "/" + blockSize); for (int curSize = bufferSize; curSize == bufferSize && actualSize < blockSize; actualSize += curSize) { curSize = in.read(buffer, 0, bufferSize); } } catch (IOException e) { LOG.info("Corrupted block detected in \"" + name + "\" at " + offset); return name + "@" + offset; } finally { in.close(); } return new Long(actualSize); } void collectStats(OutputCollector<Text, Text> output, String name, long execTime, Object corruptedBlock) throws IOException { output.collect(new Text(AccumulatingReducer.VALUE_TYPE_LONG + "blocks"), new Text(String.valueOf(1))); if (corruptedBlock.getClass().getName().endsWith("String")) { output.collect(new Text(AccumulatingReducer.VALUE_TYPE_STRING + "badBlocks"), new Text((String) corruptedBlock)); return; } long totalSize = ((Long) corruptedBlock).longValue(); float ioRateMbSec = (float) totalSize * 1000 / (execTime * 0x100000); LOG.info("Number of bytes processed = " + totalSize); LOG.info("Exec time = " + execTime); LOG.info("IO rate = " + ioRateMbSec); output.collect(new Text(AccumulatingReducer.VALUE_TYPE_LONG + "size"), new Text(String.valueOf(totalSize))); output.collect(new Text(AccumulatingReducer.VALUE_TYPE_LONG + "time"), new Text(String.valueOf(execTime))); output.collect(new Text(AccumulatingReducer.VALUE_TYPE_FLOAT + "rate"), new Text(String.valueOf(ioRateMbSec * 1000))); } } private void runDistributedFSCheck() throws Exception { JobConf job = new JobConf(fs.getConf(), DistributedFSCheck.class); FileInputFormat.setInputPaths(job, MAP_INPUT_DIR); job.setInputFormat(SequenceFileInputFormat.class); job.setMapperClass(DistributedFSCheckMapper.class); job.setReducerClass(AccumulatingReducer.class); FileOutputFormat.setOutputPath(job, READ_DIR); job.setOutputKeyClass(Text.class); job.setOutputValueClass(Text.class); job.setNumReduceTasks(1); JobClient.runJob(job); } public static void main(String[] args) throws Exception { int res = ToolRunner.run(new TestDFSIO(), args); System.exit(res); } private void analyzeResult(long execTime, String resFileName, boolean viewStats) throws IOException { Path reduceFile = new Path(READ_DIR, "part-00000"); DataInputStream in; in = new DataInputStream(fs.open(reduceFile)); BufferedReader lines; lines = new BufferedReader(new InputStreamReader(in)); long blocks = 0; long size = 0; long time = 0; float rate = 0; StringTokenizer badBlocks = null; long nrBadBlocks = 0; String line; while ((line = lines.readLine()) != null) { StringTokenizer tokens = new StringTokenizer(line, " \t\n\r\f%"); String attr = tokens.nextToken(); if (attr.endsWith("blocks")) blocks = Long.parseLong(tokens.nextToken()); else if (attr.endsWith("size")) size = Long.parseLong(tokens.nextToken()); else if (attr.endsWith("time")) time = Long.parseLong(tokens.nextToken()); else if (attr.endsWith("rate")) rate = Float.parseFloat(tokens.nextToken()); else if (attr.endsWith("badBlocks")) { badBlocks = new StringTokenizer(tokens.nextToken(), ";"); nrBadBlocks = badBlocks.countTokens(); } } Vector<String> resultLines = new Vector<String>(); resultLines.add("----- DistributedFSCheck ----- : "); resultLines.add(" Date & time: " + new Date(System.currentTimeMillis())); resultLines.add(" Total number of blocks: " + blocks); resultLines.add(" Total number of files: " + nrFiles); resultLines.add("Number of corrupted blocks: " + nrBadBlocks); int nrBadFilesPos = resultLines.size(); TreeSet<String> badFiles = new TreeSet<String>(); long nrBadFiles = 0; if (nrBadBlocks > 0) { resultLines.add(""); resultLines.add("----- Corrupted Blocks (file@offset) ----- : "); while (badBlocks.hasMoreTokens()) { String curBlock = badBlocks.nextToken(); resultLines.add(curBlock); badFiles.add(curBlock.substring(0, curBlock.indexOf('@'))); } nrBadFiles = badFiles.size(); } resultLines.insertElementAt(" Number of corrupted files: " + nrBadFiles, nrBadFilesPos); if (viewStats) { resultLines.add(""); resultLines.add("----- Performance ----- : "); resultLines.add(" Total MBytes read: " + size / MEGA); resultLines.add(" Throughput mb/sec: " + (float) size * 1000.0 / (time * MEGA)); resultLines.add(" Average IO rate mb/sec: " + rate / 1000 / blocks); resultLines.add(" Test exec time sec: " + (float) execTime / 1000); } PrintStream res = new PrintStream(new FileOutputStream(new File(resFileName), true)); for (int i = 0; i < resultLines.size(); i++) { String cur = resultLines.get(i); LOG.info(cur); res.println(cur); } } private void cleanup() throws IOException { LOG.info("Cleaning up test files"); fs.delete(TEST_ROOT_DIR, true); } @Override public int run(String[] args) throws Exception { int testType = TEST_TYPE_READ; int bufferSize = DEFAULT_BUFFER_SIZE; String resFileName = DEFAULT_RES_FILE_NAME; String rootName = "/"; boolean viewStats = false; String usage = "Usage: DistributedFSCheck [-root name] [-clean] [-resFile resultFileName] [-bufferSize Bytes] [-stats] "; if (args.length == 1 && args[0].startsWith("-h")) { System.err.println(usage); return -1; } for (int i = 0; i < args.length; i++) { // parse command line if (args[i].equals("-root")) { rootName = args[++i]; } else if (args[i].startsWith("-clean")) { testType = TEST_TYPE_CLEANUP; } else if (args[i].equals("-bufferSize")) { bufferSize = Integer.parseInt(args[++i]); } else if (args[i].equals("-resFile")) { resFileName = args[++i]; } else if (args[i].startsWith("-stat")) { viewStats = true; } } LOG.info("root = " + rootName); LOG.info("bufferSize = " + bufferSize); Configuration conf = new Configuration(); conf.setInt("test.io.file.buffer.size", bufferSize); DistributedFSCheck test = new DistributedFSCheck(conf); if (testType == TEST_TYPE_CLEANUP) { test.cleanup(); return 0; } test.createInputFile(rootName); long tStart = System.currentTimeMillis(); test.runDistributedFSCheck(); long execTime = System.currentTimeMillis() - tStart; test.analyzeResult(execTime, resFileName, viewStats); // test.cleanup(); // clean up after all to restore the system state return 0; } }