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.nutch.segment; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.io.PrintStream; import java.io.PrintWriter; import java.io.Writer; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Arrays; import java.util.Date; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.conf.Configured; import org.apache.hadoop.fs.FileStatus; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.MapFile; import org.apache.hadoop.io.SequenceFile; import org.apache.hadoop.io.Text; import org.apache.hadoop.io.Writable; import org.apache.hadoop.io.WritableComparable; import org.apache.hadoop.mapred.FileInputFormat; import org.apache.hadoop.mapred.FileOutputFormat; import org.apache.hadoop.mapred.JobClient; import org.apache.hadoop.mapred.JobConf; import org.apache.hadoop.mapred.MapFileOutputFormat; import org.apache.hadoop.mapred.MapReduceBase; import org.apache.hadoop.mapred.Mapper; import org.apache.hadoop.mapred.OutputCollector; import org.apache.hadoop.mapred.RecordWriter; import org.apache.hadoop.mapred.Reducer; import org.apache.hadoop.mapred.Reporter; import org.apache.hadoop.mapred.SequenceFileInputFormat; import org.apache.hadoop.mapred.SequenceFileOutputFormat; import org.apache.hadoop.util.Progressable; import org.apache.nutch.crawl.CrawlDatum; import org.apache.nutch.crawl.NutchWritable; import org.apache.nutch.parse.ParseData; import org.apache.nutch.parse.ParseText; import org.apache.nutch.protocol.Content; import org.apache.nutch.util.HadoopFSUtil; import org.apache.nutch.util.NutchConfiguration; import org.apache.nutch.util.NutchJob; /** Dump the content of a segment. */ public class SegmentReader extends Configured implements Reducer<Text, NutchWritable, Text, Text> { public static final Logger LOG = LoggerFactory.getLogger(SegmentReader.class); long recNo = 0L; private boolean co, fe, ge, pa, pd, pt; private FileSystem fs; public static class InputCompatMapper extends MapReduceBase implements Mapper<WritableComparable, Writable, Text, NutchWritable> { private Text newKey = new Text(); public void map(WritableComparable key, Writable value, OutputCollector<Text, NutchWritable> collector, Reporter reporter) throws IOException { // convert on the fly from old formats with UTF8 keys. // UTF8 deprecated and replaced by Text. if (key instanceof Text) { newKey.set(key.toString()); key = newKey; } collector.collect((Text) key, new NutchWritable(value)); } } /** Implements a text output format */ public static class TextOutputFormat extends FileOutputFormat<WritableComparable, Writable> { public RecordWriter<WritableComparable, Writable> getRecordWriter(final FileSystem fs, JobConf job, String name, final Progressable progress) throws IOException { final Path segmentDumpFile = new Path(FileOutputFormat.getOutputPath(job), name); // Get the old copy out of the way if (fs.exists(segmentDumpFile)) fs.delete(segmentDumpFile, true); final PrintStream printStream = new PrintStream(fs.create(segmentDumpFile)); return new RecordWriter<WritableComparable, Writable>() { public synchronized void write(WritableComparable key, Writable value) throws IOException { printStream.println(value); } public synchronized void close(Reporter reporter) throws IOException { printStream.close(); } }; } } public SegmentReader() { super(null); } public SegmentReader(Configuration conf, boolean co, boolean fe, boolean ge, boolean pa, boolean pd, boolean pt) { super(conf); this.co = co; this.fe = fe; this.ge = ge; this.pa = pa; this.pd = pd; this.pt = pt; try { this.fs = FileSystem.get(getConf()); } catch (IOException e) { LOG.error("IOException:", e); } } public void configure(JobConf job) { setConf(job); this.co = getConf().getBoolean("segment.reader.co", true); this.fe = getConf().getBoolean("segment.reader.fe", true); this.ge = getConf().getBoolean("segment.reader.ge", true); this.pa = getConf().getBoolean("segment.reader.pa", true); this.pd = getConf().getBoolean("segment.reader.pd", true); this.pt = getConf().getBoolean("segment.reader.pt", true); try { this.fs = FileSystem.get(getConf()); } catch (IOException e) { LOG.error("IOException:", e); } } private JobConf createJobConf() { JobConf job = new NutchJob(getConf()); job.setBoolean("segment.reader.co", this.co); job.setBoolean("segment.reader.fe", this.fe); job.setBoolean("segment.reader.ge", this.ge); job.setBoolean("segment.reader.pa", this.pa); job.setBoolean("segment.reader.pd", this.pd); job.setBoolean("segment.reader.pt", this.pt); return job; } public void close() { } public void reduce(Text key, Iterator<NutchWritable> values, OutputCollector<Text, Text> output, Reporter reporter) throws IOException { StringBuffer dump = new StringBuffer(); dump.append("\nRecno:: ").append(recNo++).append("\n"); dump.append("URL:: " + key.toString() + "\n"); while (values.hasNext()) { Writable value = values.next().get(); // unwrap if (value instanceof CrawlDatum) { dump.append("\nCrawlDatum::\n").append(((CrawlDatum) value).toString()); } else if (value instanceof Content) { dump.append("\nContent::\n").append(((Content) value).toString()); } else if (value instanceof ParseData) { dump.append("\nParseData::\n").append(((ParseData) value).toString()); } else if (value instanceof ParseText) { dump.append("\nParseText::\n").append(((ParseText) value).toString()); } else if (LOG.isWarnEnabled()) { LOG.warn("Unrecognized type: " + value.getClass()); } } output.collect(key, new Text(dump.toString())); } public void dump(Path segment, Path output) throws IOException { if (LOG.isInfoEnabled()) { LOG.info("SegmentReader: dump segment: " + segment); } JobConf job = createJobConf(); job.setJobName("read " + segment); if (ge) FileInputFormat.addInputPath(job, new Path(segment, CrawlDatum.GENERATE_DIR_NAME)); if (fe) FileInputFormat.addInputPath(job, new Path(segment, CrawlDatum.FETCH_DIR_NAME)); if (pa) FileInputFormat.addInputPath(job, new Path(segment, CrawlDatum.PARSE_DIR_NAME)); if (co) FileInputFormat.addInputPath(job, new Path(segment, Content.DIR_NAME)); if (pd) FileInputFormat.addInputPath(job, new Path(segment, ParseData.DIR_NAME)); if (pt) FileInputFormat.addInputPath(job, new Path(segment, ParseText.DIR_NAME)); job.setInputFormat(SequenceFileInputFormat.class); job.setMapperClass(InputCompatMapper.class); job.setReducerClass(SegmentReader.class); Path tempDir = new Path(job.get("hadoop.tmp.dir", "/tmp") + "/segread-" + new java.util.Random().nextInt()); fs.delete(tempDir, true); FileOutputFormat.setOutputPath(job, tempDir); job.setOutputFormat(TextOutputFormat.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(NutchWritable.class); JobClient.runJob(job); // concatenate the output Path dumpFile = new Path(output, job.get("segment.dump.dir", "dump")); // remove the old file fs.delete(dumpFile, true); FileStatus[] fstats = fs.listStatus(tempDir, HadoopFSUtil.getPassAllFilter()); Path[] files = HadoopFSUtil.getPaths(fstats); PrintWriter writer = null; int currentRecordNumber = 0; if (files.length > 0) { writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(fs.create(dumpFile)))); try { for (int i = 0; i < files.length; i++) { Path partFile = (Path) files[i]; try { currentRecordNumber = append(fs, job, partFile, writer, currentRecordNumber); } catch (IOException exception) { if (LOG.isWarnEnabled()) { LOG.warn("Couldn't copy the content of " + partFile.toString() + " into " + dumpFile.toString()); LOG.warn(exception.getMessage()); } } } } finally { writer.close(); } } fs.delete(tempDir, true); if (LOG.isInfoEnabled()) { LOG.info("SegmentReader: done"); } } /** Appends two files and updates the Recno counter */ private int append(FileSystem fs, Configuration conf, Path src, PrintWriter writer, int currentRecordNumber) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(fs.open(src))); try { String line = reader.readLine(); while (line != null) { if (line.startsWith("Recno:: ")) { line = "Recno:: " + currentRecordNumber++; } writer.println(line); line = reader.readLine(); } return currentRecordNumber; } finally { reader.close(); } } private static final String[][] keys = new String[][] { { "co", "Content::\n" }, { "ge", "Crawl Generate::\n" }, { "fe", "Crawl Fetch::\n" }, { "pa", "Crawl Parse::\n" }, { "pd", "ParseData::\n" }, { "pt", "ParseText::\n" } }; public void get(final Path segment, final Text key, Writer writer, final Map<String, List<Writable>> results) throws Exception { LOG.info("SegmentReader: get '" + key + "'"); ArrayList<Thread> threads = new ArrayList<Thread>(); if (co) threads.add(new Thread() { public void run() { try { List<Writable> res = getMapRecords(new Path(segment, Content.DIR_NAME), key); results.put("co", res); } catch (Exception e) { LOG.error("Exception:", e); } } }); if (fe) threads.add(new Thread() { public void run() { try { List<Writable> res = getMapRecords(new Path(segment, CrawlDatum.FETCH_DIR_NAME), key); results.put("fe", res); } catch (Exception e) { LOG.error("Exception:", e); } } }); if (ge) threads.add(new Thread() { public void run() { try { List<Writable> res = getSeqRecords(new Path(segment, CrawlDatum.GENERATE_DIR_NAME), key); results.put("ge", res); } catch (Exception e) { LOG.error("Exception:", e); } } }); if (pa) threads.add(new Thread() { public void run() { try { List<Writable> res = getSeqRecords(new Path(segment, CrawlDatum.PARSE_DIR_NAME), key); results.put("pa", res); } catch (Exception e) { LOG.error("Exception:", e); } } }); if (pd) threads.add(new Thread() { public void run() { try { List<Writable> res = getMapRecords(new Path(segment, ParseData.DIR_NAME), key); results.put("pd", res); } catch (Exception e) { LOG.error("Exception:", e); } } }); if (pt) threads.add(new Thread() { public void run() { try { List<Writable> res = getMapRecords(new Path(segment, ParseText.DIR_NAME), key); results.put("pt", res); } catch (Exception e) { LOG.error("Exception:", e); } } }); Iterator<Thread> it = threads.iterator(); while (it.hasNext()) it.next().start(); int cnt; do { cnt = 0; try { Thread.sleep(5000); } catch (Exception e) { } ; it = threads.iterator(); while (it.hasNext()) { if (it.next().isAlive()) cnt++; } if ((cnt > 0) && (LOG.isDebugEnabled())) { LOG.debug("(" + cnt + " to retrieve)"); } } while (cnt > 0); for (int i = 0; i < keys.length; i++) { List<Writable> res = results.get(keys[i][0]); if (res != null && res.size() > 0) { for (int k = 0; k < res.size(); k++) { writer.write(keys[i][1]); writer.write(res.get(k) + "\n"); } } writer.flush(); } } private List<Writable> getMapRecords(Path dir, Text key) throws Exception { MapFile.Reader[] readers = MapFileOutputFormat.getReaders(fs, dir, getConf()); ArrayList<Writable> res = new ArrayList<Writable>(); Class keyClass = readers[0].getKeyClass(); Class valueClass = readers[0].getValueClass(); if (!keyClass.getName().equals("org.apache.hadoop.io.Text")) throw new IOException("Incompatible key (" + keyClass.getName() + ")"); Writable value = (Writable) valueClass.newInstance(); // we don't know the partitioning schema for (int i = 0; i < readers.length; i++) { if (readers[i].get(key, value) != null) res.add(value); readers[i].close(); } return res; } private List<Writable> getSeqRecords(Path dir, Text key) throws Exception { SequenceFile.Reader[] readers = SequenceFileOutputFormat.getReaders(getConf(), dir); ArrayList<Writable> res = new ArrayList<Writable>(); Class keyClass = readers[0].getKeyClass(); Class valueClass = readers[0].getValueClass(); if (!keyClass.getName().equals("org.apache.hadoop.io.Text")) throw new IOException("Incompatible key (" + keyClass.getName() + ")"); Writable aKey = (Writable) keyClass.newInstance(); Writable value = (Writable) valueClass.newInstance(); for (int i = 0; i < readers.length; i++) { while (readers[i].next(aKey, value)) { if (aKey.equals(key)) res.add(value); } readers[i].close(); } return res; } public static class SegmentReaderStats { public long start = -1L; public long end = -1L; public long generated = -1L; public long fetched = -1L; public long fetchErrors = -1L; public long parsed = -1L; public long parseErrors = -1L; } SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss"); public void list(List<Path> dirs, Writer writer) throws Exception { writer.write("NAME\t\tGENERATED\tFETCHER START\t\tFETCHER END\t\tFETCHED\tPARSED\n"); for (int i = 0; i < dirs.size(); i++) { Path dir = dirs.get(i); SegmentReaderStats stats = new SegmentReaderStats(); getStats(dir, stats); writer.write(dir.getName() + "\t"); if (stats.generated == -1) writer.write("?"); else writer.write(stats.generated + ""); writer.write("\t\t"); if (stats.start == -1) writer.write("?\t"); else writer.write(sdf.format(new Date(stats.start))); writer.write("\t"); if (stats.end == -1) writer.write("?"); else writer.write(sdf.format(new Date(stats.end))); writer.write("\t"); if (stats.fetched == -1) writer.write("?"); else writer.write(stats.fetched + ""); writer.write("\t"); if (stats.parsed == -1) writer.write("?"); else writer.write(stats.parsed + ""); writer.write("\n"); writer.flush(); } } public void getStats(Path segment, final SegmentReaderStats stats) throws Exception { SequenceFile.Reader[] readers = SequenceFileOutputFormat.getReaders(getConf(), new Path(segment, CrawlDatum.GENERATE_DIR_NAME)); long cnt = 0L; Text key = new Text(); for (int i = 0; i < readers.length; i++) { while (readers[i].next(key)) cnt++; readers[i].close(); } stats.generated = cnt; Path fetchDir = new Path(segment, CrawlDatum.FETCH_DIR_NAME); if (fs.exists(fetchDir) && fs.getFileStatus(fetchDir).isDir()) { cnt = 0L; long start = Long.MAX_VALUE; long end = Long.MIN_VALUE; CrawlDatum value = new CrawlDatum(); MapFile.Reader[] mreaders = MapFileOutputFormat.getReaders(fs, fetchDir, getConf()); for (int i = 0; i < mreaders.length; i++) { while (mreaders[i].next(key, value)) { cnt++; if (value.getFetchTime() < start) start = value.getFetchTime(); if (value.getFetchTime() > end) end = value.getFetchTime(); } mreaders[i].close(); } stats.start = start; stats.end = end; stats.fetched = cnt; } Path parseDir = new Path(segment, ParseData.DIR_NAME); if (fs.exists(fetchDir) && fs.getFileStatus(fetchDir).isDir()) { cnt = 0L; long errors = 0L; ParseData value = new ParseData(); MapFile.Reader[] mreaders = MapFileOutputFormat.getReaders(fs, parseDir, getConf()); for (int i = 0; i < mreaders.length; i++) { while (mreaders[i].next(key, value)) { cnt++; if (!value.getStatus().isSuccess()) errors++; } mreaders[i].close(); } stats.parsed = cnt; stats.parseErrors = errors; } } private static final int MODE_DUMP = 0; private static final int MODE_LIST = 1; private static final int MODE_GET = 2; public static void main(String[] args) throws Exception { if (args.length < 2) { usage(); return; } int mode = -1; if (args[0].equals("-dump")) mode = MODE_DUMP; else if (args[0].equals("-list")) mode = MODE_LIST; else if (args[0].equals("-get")) mode = MODE_GET; boolean co = true; boolean fe = true; boolean ge = true; boolean pa = true; boolean pd = true; boolean pt = true; // collect general options for (int i = 1; i < args.length; i++) { if (args[i].equals("-nocontent")) { co = false; args[i] = null; } else if (args[i].equals("-nofetch")) { fe = false; args[i] = null; } else if (args[i].equals("-nogenerate")) { ge = false; args[i] = null; } else if (args[i].equals("-noparse")) { pa = false; args[i] = null; } else if (args[i].equals("-noparsedata")) { pd = false; args[i] = null; } else if (args[i].equals("-noparsetext")) { pt = false; args[i] = null; } } Configuration conf = NutchConfiguration.create(); final FileSystem fs = FileSystem.get(conf); SegmentReader segmentReader = new SegmentReader(conf, co, fe, ge, pa, pd, pt); // collect required args switch (mode) { case MODE_DUMP: String input = args[1]; if (input == null) { System.err.println("Missing required argument: <segment_dir>"); usage(); return; } String output = args.length > 2 ? args[2] : null; if (output == null) { System.err.println("Missing required argument: <output>"); usage(); return; } segmentReader.dump(new Path(input), new Path(output)); return; case MODE_LIST: ArrayList<Path> dirs = new ArrayList<Path>(); for (int i = 1; i < args.length; i++) { if (args[i] == null) continue; if (args[i].equals("-dir")) { Path dir = new Path(args[++i]); FileStatus[] fstats = fs.listStatus(dir, HadoopFSUtil.getPassDirectoriesFilter(fs)); Path[] files = HadoopFSUtil.getPaths(fstats); if (files != null && files.length > 0) { dirs.addAll(Arrays.asList(files)); } } else dirs.add(new Path(args[i])); } segmentReader.list(dirs, new OutputStreamWriter(System.out, "UTF-8")); return; case MODE_GET: input = args[1]; if (input == null) { System.err.println("Missing required argument: <segment_dir>"); usage(); return; } String key = args.length > 2 ? args[2] : null; if (key == null) { System.err.println("Missing required argument: <keyValue>"); usage(); return; } segmentReader.get(new Path(input), new Text(key), new OutputStreamWriter(System.out, "UTF-8"), new HashMap<String, List<Writable>>()); return; default: System.err.println("Invalid operation: " + args[0]); usage(); return; } } private static void usage() { System.err.println("Usage: SegmentReader (-dump ... | -list ... | -get ...) [general options]\n"); System.err.println("* General options:"); System.err.println("\t-nocontent\tignore content directory"); System.err.println("\t-nofetch\tignore crawl_fetch directory"); System.err.println("\t-nogenerate\tignore crawl_generate directory"); System.err.println("\t-noparse\tignore crawl_parse directory"); System.err.println("\t-noparsedata\tignore parse_data directory"); System.err.println("\t-noparsetext\tignore parse_text directory"); System.err.println(); System.err.println("* SegmentReader -dump <segment_dir> <output> [general options]"); System.err.println(" Dumps content of a <segment_dir> as a text file to <output>.\n"); System.err.println("\t<segment_dir>\tname of the segment directory."); System.err.println("\t<output>\tname of the (non-existent) output directory."); System.err.println(); System.err.println("* SegmentReader -list (<segment_dir1> ... | -dir <segments>) [general options]"); System.err.println(" List a synopsis of segments in specified directories, or all segments in"); System.err.println(" a directory <segments>, and print it on System.out\n"); System.err.println("\t<segment_dir1> ...\tlist of segment directories to process"); System.err.println("\t-dir <segments>\t\tdirectory that contains multiple segments"); System.err.println(); System.err.println("* SegmentReader -get <segment_dir> <keyValue> [general options]"); System.err.println(" Get a specified record from a segment, and print it on System.out.\n"); System.err.println("\t<segment_dir>\tname of the segment directory."); System.err.println("\t<keyValue>\tvalue of the key (url)."); System.err.println("\t\tNote: put double-quotes around strings with spaces."); } }