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.hdfs.tools.offlineImageViewer; import java.io.EOFException; import java.io.IOException; import java.io.PrintStream; import java.io.RandomAccessFile; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.CommandLineParser; import org.apache.commons.cli.OptionBuilder; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.apache.commons.cli.PosixParser; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.net.NetUtils; /** * OfflineImageViewerPB to dump the contents of an Hadoop image file to XML or * the console. Main entry point into utility, either via the command line or * programatically. */ @InterfaceAudience.Private public class OfflineImageViewerPB { public static final Log LOG = LogFactory.getLog(OfflineImageViewerPB.class); private final static String usage = "Usage: bin/hdfs oiv [OPTIONS] -i INPUTFILE -o OUTPUTFILE\n" + "Offline Image Viewer\n" + "View a Hadoop fsimage INPUTFILE using the specified PROCESSOR,\n" + "saving the results in OUTPUTFILE.\n" + "\n" + "The oiv utility will attempt to parse correctly formed image files\n" + "and will abort fail with mal-formed image files.\n" + "\n" + "The tool works offline and does not require a running cluster in\n" + "order to process an image file.\n" + "\n" + "The following image processors are available:\n" + " * XML: This processor creates an XML document with all elements of\n" + " the fsimage enumerated, suitable for further analysis by XML\n" + " tools.\n" + " * FileDistribution: This processor analyzes the file size\n" + " distribution in the image.\n" + " -maxSize specifies the range [0, maxSize] of file sizes to be\n" + " analyzed (128GB by default).\n" + " -step defines the granularity of the distribution. (2MB by default)\n" + " * Web: Run a viewer to expose read-only WebHDFS API.\n" + " -addr specifies the address to listen. (localhost:5978 by default)\n" + " * Delimited (experimental): Generate a text file with all of the elements common\n" + " to both inodes and inodes-under-construction, separated by a\n" + " delimiter. The default delimiter is \\t, though this may be\n" + " changed via the -delimiter argument.\n" + "\n" + "Required command line arguments:\n" + "-i,--inputFile <arg> FSImage file to process.\n" + "\n" + "Optional command line arguments:\n" + "-o,--outputFile <arg> Name of output file. If the specified\n" + " file exists, it will be overwritten.\n" + " (output to stdout by default)\n" + "-p,--processor <arg> Select which type of processor to apply\n" + " against image file. (XML|FileDistribution|Web|Delimited)\n" + " (Web by default)\n" + "-delimiter <arg> Delimiting string to use with Delimited processor. \n" + "-t,--temp <arg> Use temporary dir to cache intermediate result to generate\n" + " Delimited outputs. If not set, Delimited processor constructs\n" + " the namespace in memory before outputting text.\n" + "-h,--help Display usage information and exit\n"; /** * Build command-line options and descriptions */ private static Options buildOptions() { Options options = new Options(); // Build in/output file arguments, which are required, but there is no // addOption method that can specify this OptionBuilder.isRequired(); OptionBuilder.hasArgs(); OptionBuilder.withLongOpt("inputFile"); options.addOption(OptionBuilder.create("i")); options.addOption("o", "outputFile", true, ""); options.addOption("p", "processor", true, ""); options.addOption("h", "help", false, ""); options.addOption("maxSize", true, ""); options.addOption("step", true, ""); options.addOption("addr", true, ""); options.addOption("delimiter", true, ""); options.addOption("t", "temp", true, ""); return options; } /** * Entry point to command-line-driven operation. User may specify options and * start fsimage viewer from the command line. Program will process image file * and exit cleanly or, if an error is encountered, inform user and exit. * * @param args * Command line options * @throws IOException */ public static void main(String[] args) throws Exception { int status = run(args); System.exit(status); } public static int run(String[] args) throws Exception { Options options = buildOptions(); if (args.length == 0) { printUsage(); return 0; } CommandLineParser parser = new PosixParser(); CommandLine cmd; try { cmd = parser.parse(options, args); } catch (ParseException e) { System.out.println("Error parsing command-line options: "); printUsage(); return -1; } if (cmd.hasOption("h")) { // print help and exit printUsage(); return 0; } String inputFile = cmd.getOptionValue("i"); String processor = cmd.getOptionValue("p", "Web"); String outputFile = cmd.getOptionValue("o", "-"); String delimiter = cmd.getOptionValue("delimiter", PBImageDelimitedTextWriter.DEFAULT_DELIMITER); String tempPath = cmd.getOptionValue("t", ""); Configuration conf = new Configuration(); try (PrintStream out = outputFile.equals("-") ? System.out : new PrintStream(outputFile, "UTF-8")) { switch (processor) { case "FileDistribution": long maxSize = Long.parseLong(cmd.getOptionValue("maxSize", "0")); int step = Integer.parseInt(cmd.getOptionValue("step", "0")); new FileDistributionCalculator(conf, maxSize, step, out) .visit(new RandomAccessFile(inputFile, "r")); break; case "XML": new PBImageXmlWriter(conf, out).visit(new RandomAccessFile(inputFile, "r")); break; case "Web": String addr = cmd.getOptionValue("addr", "localhost:5978"); try (WebImageViewer viewer = new WebImageViewer(NetUtils.createSocketAddr(addr))) { viewer.start(inputFile); } break; case "Delimited": try (PBImageDelimitedTextWriter writer = new PBImageDelimitedTextWriter(out, delimiter, tempPath)) { writer.visit(new RandomAccessFile(inputFile, "r")); } break; } return 0; } catch (EOFException e) { System.err.println("Input file ended unexpectedly. Exiting"); } catch (IOException e) { System.err.println("Encountered exception. Exiting: " + e.getMessage()); } return -1; } /** * Print application usage instructions. */ private static void printUsage() { System.out.println(usage); } }