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

import java.io.IOException;
import java.lang.invoke.MethodHandles;
import java.util.Collection;
import java.util.Iterator;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.StringUtils;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.FileSystem;
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.net.URLFilters;
import org.apache.nutch.net.URLNormalizers;
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.protocol.Content;
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, NutchIndexAction> {

  private static final Logger LOG = LoggerFactory
      .getLogger(MethodHandles.lookup().lookupClass());

  public static final String INDEXER_PARAMS = "indexer.additional.params";
  public static final String INDEXER_DELETE = "indexer.delete";
  public static final String INDEXER_DELETE_ROBOTS_NOINDEX = "indexer.delete.robots.noindex";
  public static final String INDEXER_DELETE_SKIPPED = "indexer.delete.skipped.by.indexingfilter";
  public static final String INDEXER_SKIP_NOTMODIFIED = "indexer.skip.notmodified";
  public static final String URL_FILTERING = "indexer.url.filters";
  public static final String URL_NORMALIZING = "indexer.url.normalizers";
  public static final String INDEXER_BINARY_AS_BASE64 = "indexer.binary.base64";

  private boolean skip = false;
  private boolean delete = false;
  private boolean deleteRobotsNoIndex = false;
  private boolean deleteSkippedByIndexingFilter = false;
  private boolean base64 = false;
  private IndexingFilters filters;
  private ScoringFilters scfilters;

  // using normalizers and/or filters
  private boolean normalize = false;
  private boolean filter = false;

  // url normalizers, filters and job configuration
  private URLNormalizers urlNormalizers;
  private URLFilters urlFilters;

  /** Predefined action to delete documents from the index */
  private static final NutchIndexAction DELETE_ACTION = new NutchIndexAction(
      null, NutchIndexAction.DELETE);

  public void configure(JobConf job) {
    setConf(job);
    this.filters = new IndexingFilters(getConf());
    this.scfilters = new ScoringFilters(getConf());
    this.delete = job.getBoolean(INDEXER_DELETE, false);
    this.deleteRobotsNoIndex = job.getBoolean(INDEXER_DELETE_ROBOTS_NOINDEX,
        false);
    this.deleteSkippedByIndexingFilter = job.getBoolean(INDEXER_DELETE_SKIPPED,
        false);
    this.skip = job.getBoolean(INDEXER_SKIP_NOTMODIFIED, false);
    this.base64 = job.getBoolean(INDEXER_BINARY_AS_BASE64, false);

    normalize = job.getBoolean(URL_NORMALIZING, false);
    filter = job.getBoolean(URL_FILTERING, false);

    if (normalize) {
      urlNormalizers = new URLNormalizers(getConf(),
          URLNormalizers.SCOPE_INDEXER);
    }

    if (filter) {
      urlFilters = new URLFilters(getConf());
    }
  }

  /**
   * Normalizes and trims extra whitespace from the given url.
   * 
   * @param url
   *          The url to normalize.
   * 
   * @return The normalized url.
   */
  private String normalizeUrl(String url) {
    if (!normalize) {
      return url;
    }

    String normalized = null;
    if (urlNormalizers != null) {
      try {

        // normalize and trim the url
        normalized = urlNormalizers
            .normalize(url, URLNormalizers.SCOPE_INDEXER);
        normalized = normalized.trim();
      } catch (Exception e) {
        LOG.warn("Skipping " + url + ":" + e);
        normalized = null;
      }
    }

    return normalized;
  }

  /**
   * Filters the given url.
   * 
   * @param url
   *          The url to filter.
   * 
   * @return The filtered url or null.
   */
  private String filterUrl(String url) {
    if (!filter) {
      return url;
    }

    try {
      url = urlFilters.filter(url);
    } catch (Exception e) {
      url = null;
    }

    return url;
  }

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

    String urlString = filterUrl(normalizeUrl(key.toString()));
    if (urlString == null) {
      return;
    } else {
      key.set(urlString);
    }

    output.collect(key, new NutchWritable(value));
  }

  public void reduce(Text key, Iterator<NutchWritable> values,
      OutputCollector<Text, NutchIndexAction> output, Reporter reporter)
          throws IOException {
    Inlinks inlinks = null;
    CrawlDatum dbDatum = null;
    CrawlDatum fetchDatum = null;
    Content content = 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()
            || CrawlDatum.STATUS_PARSE_META == datum.getStatus()) {
          continue;
        } else {
          throw new RuntimeException("Unexpected status: " + datum.getStatus());
        }
      } else if (value instanceof ParseData) {
        parseData = (ParseData) value;

        // Handle robots meta? https://issues.apache.org/jira/browse/NUTCH-1434
        if (deleteRobotsNoIndex) {
          // Get the robots meta data
          String robotsMeta = parseData.getMeta("robots");

          // Has it a noindex for this url?
          if (robotsMeta != null
              && robotsMeta.toLowerCase().indexOf("noindex") != -1) {
            // Delete it!
            output.collect(key, DELETE_ACTION);
            reporter.incrCounter("IndexerStatus", "deleted (robots=noindex)", 1);
            return;
          }
        }
      } else if (value instanceof ParseText) {
        parseText = (ParseText) value;
      } else if (value instanceof Content) {
        content = (Content)value;
      } else if (LOG.isWarnEnabled()) {
        LOG.warn("Unrecognized type: " + value.getClass());
      }
    }

    // Whether to delete GONE or REDIRECTS
    if (delete && fetchDatum != null && dbDatum != null) {
      if (fetchDatum.getStatus() == CrawlDatum.STATUS_FETCH_GONE
          || dbDatum.getStatus() == CrawlDatum.STATUS_DB_GONE) {
        reporter.incrCounter("IndexerStatus", "deleted (gone)", 1);
        output.collect(key, DELETE_ACTION);
        return;
      }

      if (fetchDatum.getStatus() == CrawlDatum.STATUS_FETCH_REDIR_PERM
          || fetchDatum.getStatus() == CrawlDatum.STATUS_FETCH_REDIR_TEMP
          || dbDatum.getStatus() == CrawlDatum.STATUS_DB_REDIR_PERM
          || dbDatum.getStatus() == CrawlDatum.STATUS_DB_REDIR_TEMP) {
        reporter.incrCounter("IndexerStatus", "deleted (redirects)", 1);
        output.collect(key, DELETE_ACTION);
        return;
      }
    }

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

    // Whether to delete pages marked as duplicates
    if (delete && dbDatum.getStatus() == CrawlDatum.STATUS_DB_DUPLICATE) {
      reporter.incrCounter("IndexerStatus", "deleted (duplicates)", 1);
      output.collect(key, DELETE_ACTION);
      return;
    }

    // Whether to skip DB_NOTMODIFIED pages
    if (skip && dbDatum.getStatus() == CrawlDatum.STATUS_DB_NOTMODIFIED) {
      reporter.incrCounter("IndexerStatus", "skipped (not modified)", 1);
      return;
    }

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

    NutchDocument doc = new NutchDocument();
    doc.add("id", key.toString());

    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);
    float boost = 1.0f;
    // run scoring filters
    try {
      boost = this.scfilters.indexerScore(key, doc, dbDatum, fetchDatum, parse,
          inlinks, boost);
    } catch (final ScoringFilterException e) {
      reporter.incrCounter("IndexerStatus", "errors (ScoringFilter)", 1);
      if (LOG.isWarnEnabled()) {
        LOG.warn("Error calculating score {}: {}", key, e);
      }
      return;
    }
    // apply boost to all indexed fields.
    doc.setWeight(boost);
    // store boost for use by explain and dedup
    doc.add("boost", Float.toString(boost));

    try {
      // Indexing filters may also be interested in the signature
      fetchDatum.setSignature(dbDatum.getSignature());
      
      // 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) {
        // Representation URL also needs normalization and filtering.
        // If repr URL is excluded by filters we still accept this document
        // but represented by its primary URL ("key") which has passed URL
        // filters.
        String urlString = filterUrl(normalizeUrl(url.toString()));
        if (urlString != null) {
          url.set(urlString);
          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);
      }
      reporter.incrCounter("IndexerStatus", "errors (IndexingFilter)", 1);
      return;
    }

    // skip documents discarded by indexing filters
    if (doc == null) {
      // https://issues.apache.org/jira/browse/NUTCH-1449
      if (deleteSkippedByIndexingFilter) {
        NutchIndexAction action = new NutchIndexAction(null, NutchIndexAction.DELETE);
        output.collect(key, action);
        reporter.incrCounter("IndexerStatus", "deleted (IndexingFilter)", 1);
      } else {
        reporter.incrCounter("IndexerStatus", "skipped (IndexingFilter)", 1);
      }
      return;
    }

    if (content != null) {
      // Add the original binary content
      String binary;
      if (base64) {
        // optionally encode as base64
        binary = Base64.encodeBase64String(content.getContent());
      } else {
        binary = new String(content.getContent());
      }
      doc.add("binaryContent", binary);
    }

    reporter.incrCounter("IndexerStatus", "indexed (add/update)", 1);

    NutchIndexAction action = new NutchIndexAction(doc, NutchIndexAction.ADD);
    output.collect(key, action);
  }

  public void close() throws IOException {
  }

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

    LOG.info("IndexerMapReduce: crawldb: {}", crawlDb);

    if (linkDb != null)
      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));

      if (addBinaryContent) {
        FileInputFormat.addInputPath(job, new Path(segment, Content.DIR_NAME));
      }
    }

    FileInputFormat.addInputPath(job, new Path(crawlDb, CrawlDb.CURRENT_NAME));

    if (linkDb != null) {
      Path currentLinkDb = new Path(linkDb, LinkDb.CURRENT_NAME);
      try {
        if (currentLinkDb.getFileSystem(job).exists(currentLinkDb)) {
          FileInputFormat.addInputPath(job, currentLinkDb);
        } else {
          LOG.warn("Ignoring linkDb for indexing, no linkDb found in path: {}",
              linkDb);
        }
      } catch (IOException e) {
        LOG.warn("Failed to use linkDb ({}) for indexing: {}", linkDb,
            org.apache.hadoop.util.StringUtils.stringifyException(e));
      }
    }

    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);
  }
}