IndexerMapReduce.java

/*
 * 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.
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package org.apache.nutch.indexer;

import java.io.IOException;
import java.util.Collection;
import java.util.Iterator;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapred.FileInputFormat;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.Mapper;
import org.apache.hadoop.mapred.OutputCollector;
import org.apache.hadoop.mapred.Reducer;
import org.apache.hadoop.mapred.Reporter;
import org.apache.hadoop.mapred.SequenceFileInputFormat;
import org.apache.nutch.crawl.CrawlDatum;
import org.apache.nutch.crawl.CrawlDb;
import org.apache.nutch.crawl.Inlinks;
import org.apache.nutch.crawl.LinkDb;
import org.apache.nutch.crawl.NutchWritable;
import org.apache.nutch.metadata.Metadata;
import org.apache.nutch.metadata.Nutch;
import org.apache.nutch.parse.Parse;
import org.apache.nutch.parse.ParseData;
import org.apache.nutch.parse.ParseImpl;
import org.apache.nutch.parse.ParseText;
import org.apache.nutch.scoring.ScoringFilterException;
import org.apache.nutch.scoring.ScoringFilters;

public class IndexerMapReduce extends Configured
implements Mapper<Text, Writable, Text, NutchWritable>,
          Reducer<Text, NutchWritable, Text, NutchDocument> {

  public static final Log LOG = LogFactory.getLog(IndexerMapReduce.class);

  private IndexingFilters filters;
  private ScoringFilters scfilters;

  public void configure(JobConf job) {
    setConf(job);
    this.filters = new IndexingFilters(getConf());
    this.scfilters = new ScoringFilters(getConf());
  }

  public void map(Text key, Writable value,
      OutputCollector<Text, NutchWritable> output, Reporter reporter) throws IOException {
    output.collect(key, new NutchWritable(value));
  }

  public void reduce(Text key, Iterator<NutchWritable> values,
                     OutputCollector<Text, NutchDocument> output, Reporter reporter)
    throws IOException {
    Inlinks inlinks = null;
    CrawlDatum dbDatum = null;
    CrawlDatum fetchDatum = null;
    ParseData parseData = null;
    ParseText parseText = null;
    while (values.hasNext()) {
      final Writable value = values.next().get(); // unwrap
      if (value instanceof Inlinks) {
        inlinks = (Inlinks)value;
      } else if (value instanceof CrawlDatum) {
        final CrawlDatum datum = (CrawlDatum)value;
        if (CrawlDatum.hasDbStatus(datum))
          dbDatum = datum;
        else if (CrawlDatum.hasFetchStatus(datum)) {
          // don't index unmodified (empty) pages
          if (datum.getStatus() != CrawlDatum.STATUS_FETCH_NOTMODIFIED)
            fetchDatum = datum;
        } else if (CrawlDatum.STATUS_LINKED == datum.getStatus() ||
                   CrawlDatum.STATUS_SIGNATURE == datum.getStatus()) {
          continue;
        } else {
          throw new RuntimeException("Unexpected status: "+datum.getStatus());
        }
      } else if (value instanceof ParseData) {
        parseData = (ParseData)value;
      } else if (value instanceof ParseText) {
        parseText = (ParseText)value;
      } else if (LOG.isWarnEnabled()) {
        LOG.warn("Unrecognized type: "+value.getClass());
      }
    }

    if (fetchDatum == null || dbDatum == null
        || parseText == null || parseData == null) {
      return;                                     // only have inlinks
    }

    if (!parseData.getStatus().isSuccess() ||
        fetchDatum.getStatus() != CrawlDatum.STATUS_FETCH_SUCCESS) {
      return;
    }

    NutchDocument doc = new NutchDocument();
    final Metadata metadata = parseData.getContentMeta();

    // add segment, used to map from merged index back to segment files
    doc.add("segment", metadata.get(Nutch.SEGMENT_NAME_KEY));

    // add digest, used by dedup
    doc.add("digest", metadata.get(Nutch.SIGNATURE_KEY));

    final Parse parse = new ParseImpl(parseText, parseData);
    try {
      // extract information from dbDatum and pass it to
      // fetchDatum so that indexing filters can use it
      final Text url = (Text) dbDatum.getMetaData().get(Nutch.WRITABLE_REPR_URL_KEY);
      if (url != null) {
        fetchDatum.getMetaData().put(Nutch.WRITABLE_REPR_URL_KEY, url);
      }
      // run indexing filters
      doc = this.filters.filter(doc, parse, key, fetchDatum, inlinks);
    } catch (final IndexingException e) {
      if (LOG.isWarnEnabled()) { LOG.warn("Error indexing "+key+": "+e); }
      return;
    }

    // skip documents discarded by indexing filters
    if (doc == null) return;

    float boost = 1.0f;
    // run scoring filters
    try {
      boost = this.scfilters.indexerScore(key, doc, dbDatum,
              fetchDatum, parse, inlinks, boost);
    } catch (final ScoringFilterException e) {
      if (LOG.isWarnEnabled()) {
        LOG.warn("Error calculating score " + key + ": " + e);
      }
      return;
    }
    // apply boost to all indexed fields.
    doc.setScore(boost);
    // store boost for use by explain and dedup
    doc.add("boost", Float.toString(boost));

    output.collect(key, doc);
  }

  public void close() throws IOException { }

  public static void initMRJob(Path crawlDb, Path linkDb,
                           Collection<Path> segments,
                           JobConf job) {

    LOG.info("IndexerMapReduce: crawldb: " + crawlDb);
    LOG.info("IndexerMapReduce: linkdb: " + linkDb);

    for (final Path segment : segments) {
      LOG.info("IndexerMapReduces: adding segment: " + segment);
      FileInputFormat.addInputPath(job, new Path(segment, CrawlDatum.FETCH_DIR_NAME));
      FileInputFormat.addInputPath(job, new Path(segment, CrawlDatum.PARSE_DIR_NAME));
      FileInputFormat.addInputPath(job, new Path(segment, ParseData.DIR_NAME));
      FileInputFormat.addInputPath(job, new Path(segment, ParseText.DIR_NAME));
    }

    FileInputFormat.addInputPath(job, new Path(crawlDb, CrawlDb.CURRENT_NAME));
    FileInputFormat.addInputPath(job, new Path(linkDb, LinkDb.CURRENT_NAME));
    job.setInputFormat(SequenceFileInputFormat.class);

    job.setMapperClass(IndexerMapReduce.class);
    job.setReducerClass(IndexerMapReduce.class);

    job.setOutputFormat(IndexerOutputFormat.class);
    job.setOutputKeyClass(Text.class);
    job.setMapOutputValueClass(NutchWritable.class);
    job.setOutputValueClass(NutchWritable.class);
  }
}