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413 lines
18 KiB
413 lines
18 KiB
// PeerSelection.java
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// -------------------------------------
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// (C) by Michael Peter Christen; mc@yacy.net
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// first published 05.11.2008 on http://yacy.net
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// Frankfurt, Germany, 2008
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//
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// $LastChangedDate$
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// $LastChangedRevision$
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// $LastChangedBy$
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//
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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package net.yacy.peers;
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import java.lang.reflect.Array;
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import java.util.ArrayList;
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import java.util.Collection;
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import java.util.HashSet;
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import java.util.Iterator;
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import java.util.LinkedHashSet;
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import java.util.List;
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import java.util.Random;
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import java.util.Set;
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import java.util.SortedSet;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.ConcurrentMap;
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import net.yacy.cora.document.encoding.ASCII;
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import net.yacy.cora.federate.yacy.Distribution;
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import net.yacy.cora.order.Base64Order;
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import net.yacy.cora.order.Digest;
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import net.yacy.cora.sorting.OrderedScoreMap;
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import net.yacy.cora.storage.HandleSet;
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import net.yacy.cora.util.LookAheadIterator;
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import net.yacy.kelondro.data.word.Word;
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import net.yacy.kelondro.util.kelondroException;
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import net.yacy.peers.operation.yacyVersion;
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/**
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* This package is a collection of peer selection iterations that had been
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* part of yacyPeerActions, yacyDHTActions and yacySeedDB
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*/
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public class DHTSelection {
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public static Set<Seed> selectClusterPeers(final SeedDB seedDB, final SortedSet<byte[]> peerhashes) {
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final Set<Seed> l = new HashSet<Seed>();
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Seed s;
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for (byte[] hashb: peerhashes) {
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s = seedDB.get(ASCII.String(hashb)); // should be getConnected; get only during testing time
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if (s != null) l.add(s);
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}
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return l;
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}
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/**
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*
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* @param seedDB
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* @param wordhashes
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* @param minage
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* @param omit
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* @param maxcount
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* @param r we must use a random factor for the selection to prevent that all peers do the same and therefore overload the same peers
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* @return
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*/
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public static Collection<Seed> selectExtraTargets(
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final SeedDB seedDB,
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final HandleSet wordhashes,
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final int minage,
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final Collection<Seed> omit,
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final int maxcount,
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final Random r) {
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Collection<Seed> extraSeeds = new HashSet<Seed>();
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if (seedDB != null) {
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final OrderedScoreMap<Seed> seedSelection = new OrderedScoreMap<Seed>(null);
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// create sets that contains only robinson/node/large/young peers
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Iterator<Seed> dhtEnum = seedDB.seedsConnected(true, false, null, 0.50f);
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Seed seed;
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while (dhtEnum.hasNext()) {
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seed = dhtEnum.next();
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if (seed == null) continue;
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if (omit != null && omit.contains(seed)) continue; // sort out peers that are target for DHT
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if (seed.isLastSeenTimeout(3600000)) continue; // do not ask peers that had not been seen more than one hour (happens during a startup situation)
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if (!seed.getFlagSolrAvailable()) continue; // extra peers always use solr direct, skip if solr interface is not available
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if (!seed.getFlagAcceptRemoteIndex() && seed.matchPeerTags(wordhashes)) seedSelection.dec(seed, r.nextInt(10) + 2); // robinson peers with matching peer tags
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if (seed.getFlagRootNode()) seedSelection.dec(seed, r.nextInt(30) + 6); // root nodes (fast peers)
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if (seed.getAge() < minage) seedSelection.dec(seed, r.nextInt(15) + 3); // young peers (with fresh info)
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if (seed.getAge() < 1) seedSelection.dec(seed, r.nextInt(40) + 8); // the 'workshop feature', fresh peers should be seen
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if (seed.getLinkCount() >= 100000 && seed.getLinkCount() < 1000000) { // peers above 100.000 links take part on a selection of medium-size peers
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seedSelection.dec(seed, r.nextInt(25) + 5);
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}
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if (seed.getLinkCount() >= 1000000) { // peers above 1 million links take part on a selection of large peers
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int pf = 1 + (int) (20000000 / seed.getLinkCount());
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seedSelection.dec(seed, r.nextInt(pf) + pf / 5); // large peers; choose large one less frequent to reduce load on their peer
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}
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}
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// select the maxount
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Iterator<Seed> i = seedSelection.iterator();
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int count = 0;
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while (i.hasNext() && count++ < maxcount) {
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seed = i.next();
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if (RemoteSearch.log.isInfo()) {
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RemoteSearch.log.info("selectPeers/extra: " + seed.hash + ":" + seed.getName() + ", " + seed.getLinkCount() + " URLs" +
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(seed.getLinkCount() >= 1000000 ? " LARGE-SIZE" : "") +
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(seed.getLinkCount() >= 100000 && seed.getLinkCount() < 1000000 ? " MEDIUM-SIZE" : "") +
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(!seed.getFlagAcceptRemoteIndex() && seed.matchPeerTags(wordhashes) ? " ROBINSON" : "") +
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(seed.getFlagRootNode() ? " NODE" : "") +
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(seed.getAge() < 1 ? " FRESH" : "")
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);
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}
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extraSeeds.add(seed);
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}
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}
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return extraSeeds;
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}
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public static Set<Seed> selectDHTSearchTargets(final SeedDB seedDB, final HandleSet wordhashes, final int minage, final int redundancy, final int maxredundancy, final Random random) {
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// put in seeds according to dht
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Set<Seed> seeds = new LinkedHashSet<Seed>(); // dht position seeds
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if (seedDB != null) {
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Iterator<byte[]> iter = wordhashes.iterator();
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while (iter.hasNext()) {
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seeds.addAll(collectHorizontalDHTPositions(seedDB, iter.next(), minage, redundancy, maxredundancy, random));
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}
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}
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return seeds;
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}
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private static ArrayList<Seed> collectHorizontalDHTPositions(final SeedDB seedDB, final byte[] wordhash, final int minage, final int redundancy, final int maxredundancy, Random random) {
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// this method is called from the search target computation
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ArrayList<Seed> collectedSeeds = new ArrayList<Seed>(redundancy * seedDB.scheme.verticalPartitions());
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for (int verticalPosition = 0; verticalPosition < seedDB.scheme.verticalPartitions(); verticalPosition++) {
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ArrayList<Seed> seeds = selectVerticalDHTPositions(seedDB, wordhash, minage, maxredundancy, verticalPosition);
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if (seeds.size() <= redundancy) {
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collectedSeeds.addAll(seeds);
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} else {
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// we pick some random peers from the vertical position.
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// All of them should be valid, but picking a random subset is a distributed load balancing on the whole YaCy network.
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// without picking a random subset, always the same peers would be targeted for the same word resulting in (possible) DoS on the target.
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for (int i = 0; i < redundancy; i++) {
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collectedSeeds.add(seeds.remove(random.nextInt(seeds.size())));
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}
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}
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}
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return collectedSeeds;
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}
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@SuppressWarnings("unchecked")
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public static List<Seed>[] selectDHTDistributionTargets(final SeedDB seedDB, final byte[] wordhash, final int minage, final int redundancy) {
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// this method is called from the distribution target computation
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List<Seed>[] seedlists = (List<Seed>[]) Array.newInstance(ArrayList.class, seedDB.scheme.verticalPartitions());
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for (int verticalPosition = 0; verticalPosition < seedDB.scheme.verticalPartitions(); verticalPosition++) {
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seedlists[verticalPosition] = selectVerticalDHTPositions(seedDB, wordhash, minage, redundancy, verticalPosition);
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}
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return seedlists;
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}
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/**
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* collecting vertical positions: that chooses for each of the DHT partition a collection of redundant storage positions
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* @param seedDB the database of seeds
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* @param wordhash the word we are searching for
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* @param minage the minimum age of a seed in days (to prevent that too young seeds which cannot have results yet are asked)
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* @param redundancy the number of redundant peer position for this parition, minimum is 1
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* @param verticalPosition the verical position, thats the number of the partition 0 <= verticalPosition < seedDB.scheme.verticalPartitions()
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* @return a list of seeds for the redundant positions
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*/
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private static ArrayList<Seed> selectVerticalDHTPositions(final SeedDB seedDB, final byte[] wordhash, final int minage, final int redundancy, int verticalPosition) {
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// this method is called from the search target computation
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ArrayList<Seed> seeds = new ArrayList<Seed>(redundancy);
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final long dhtVerticalTarget = seedDB.scheme.verticalDHTPosition(wordhash, verticalPosition);
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final byte[] verticalhash = Distribution.positionToHash(dhtVerticalTarget);
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final Iterator<Seed> dhtEnum = getAcceptRemoteIndexSeeds(seedDB, verticalhash, redundancy, false);
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int c = Math.min(seedDB.sizeConnected(), redundancy);
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int cc = 20; // in case that the network grows rapidly, we may jump to several additional peers but that must have a limit
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while (dhtEnum.hasNext() && c > 0 && cc-- > 0) {
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Seed seed = dhtEnum.next();
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if (seed == null || seed.hash == null) continue;
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if (!seed.getFlagAcceptRemoteIndex()) continue; // probably a robinson peer
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if (seed.getAge() < minage) continue; // prevent bad results because of too strong network growth
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if (RemoteSearch.log.isInfo()) RemoteSearch.log.info("selectPeers/DHTorder: " + seed.hash + ":" + seed.getName() + "/ score " + c);
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seeds.add(seed);
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c--;
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}
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return seeds;
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}
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public static byte[] selectRandomTransferStart() {
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return ASCII.getBytes(Base64Order.enhancedCoder.encode(Digest.encodeMD5Raw(Long.toString(System.currentTimeMillis()))).substring(2, 2 + Word.commonHashLength));
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}
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public static byte[] limitOver(final SeedDB seedDB, final byte[] startHash) {
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final Iterator<Seed> seeds = getAcceptRemoteIndexSeeds(seedDB, startHash, 1, false);
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if (seeds.hasNext()) return ASCII.getBytes(seeds.next().hash);
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return null;
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}
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public static List<Seed> getAcceptRemoteIndexSeedsList(
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SeedDB seedDB,
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final byte[] starthash,
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int max,
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boolean alsoMyOwn) {
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final Iterator<Seed> seedIter = getAcceptRemoteIndexSeeds(seedDB, starthash, max, alsoMyOwn);
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final ArrayList<Seed> targets = new ArrayList<Seed>();
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while (seedIter.hasNext() && max-- > 0) targets.add(seedIter.next());
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return targets;
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}
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/**
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* returns an enumeration of yacySeed-Objects that have the AcceptRemoteIndex-Flag set
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* the seeds are enumerated in the right order according to the DHT
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* @param seedDB
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* @param starthash
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* @param max
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* @param alsoMyOwn
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* @return
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*/
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public static Iterator<Seed> getAcceptRemoteIndexSeeds(final SeedDB seedDB, final byte[] starthash, final int max, final boolean alsoMyOwn) {
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return new acceptRemoteIndexSeedEnum(seedDB, starthash, Math.min(max, seedDB.sizeConnected()), alsoMyOwn);
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}
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private static class acceptRemoteIndexSeedEnum extends LookAheadIterator<Seed> implements Iterator<Seed>, Iterable<Seed> {
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private final Iterator<Seed> se;
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private final SeedDB seedDB;
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private int remaining;
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private final boolean alsoMyOwn;
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private acceptRemoteIndexSeedEnum(SeedDB seedDB, final byte[] starthash, int max, boolean alsoMyOwn) {
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this.seedDB = seedDB;
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this.se = new seedDHTEnum(seedDB, starthash, alsoMyOwn);
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this.remaining = max;
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this.alsoMyOwn = alsoMyOwn;
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}
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@Override
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protected Seed next0() {
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if (this.remaining <= 0) return null;
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Seed s = null;
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try {
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while (this.se.hasNext()) {
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s = this.se.next();
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if (s == null) return null;
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if (s.getFlagAcceptRemoteIndex() ||
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(this.alsoMyOwn && s.hash.equals(this.seedDB.mySeed().hash)) // Accept own peer regardless of FlagAcceptRemoteIndex
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) {
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this.remaining--;
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break;
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}
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}
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return s;
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} catch (final kelondroException e) {
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System.out.println("DEBUG acceptRemoteIndexSeedEnum:" + e.getMessage());
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Network.log.severe("database inconsistency (" + e.getMessage() + "), re-set of db.");
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this.seedDB.resetActiveTable();
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return null;
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}
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}
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}
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private static class seedDHTEnum implements Iterator<Seed> {
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private Iterator<Seed> e;
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private int steps;
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private final SeedDB seedDB;
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private boolean alsoMyOwn;
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private int pass, insertOwnInPass;
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private Seed nextSeed;
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private seedDHTEnum(final SeedDB seedDB, final byte[] firstHash, final boolean alsoMyOwn) {
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this.seedDB = seedDB;
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this.steps = seedDB.sizeConnected() + ((alsoMyOwn) ? 1 : 0);
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this.e = seedDB.seedsConnected(true, false, firstHash, yacyVersion.YACY_HANDLES_COLLECTION_INDEX);
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this.pass = 1;
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this.alsoMyOwn = alsoMyOwn;
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if (alsoMyOwn) {
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this.insertOwnInPass = (Base64Order.enhancedCoder.compare(ASCII.getBytes(seedDB.mySeed().hash), firstHash) > 0) ? 1 : 2;
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} else {
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this.insertOwnInPass = 0;
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}
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this.nextSeed = nextInternal();
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}
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@Override
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public boolean hasNext() {
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return (this.nextSeed != null) || this.alsoMyOwn;
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}
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public Seed nextInternal() {
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if (this.steps == 0) return null;
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this.steps--;
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if (!this.e.hasNext() && this.pass == 1) {
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// rotate from the beginning; this closes the ordering of the DHT at the ends
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this.e = this.seedDB.seedsConnected(true, false, null, yacyVersion.YACY_HANDLES_COLLECTION_INDEX);
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this.pass = 2;
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}
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if (this.e.hasNext()) {
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return this.e.next();
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}
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this.steps = 0;
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return null;
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}
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@Override
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public Seed next() {
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if (this.alsoMyOwn &&
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((this.pass > this.insertOwnInPass) ||
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(this.pass == this.insertOwnInPass && this.nextSeed == null) || // Own hash is last in line
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(this.pass == this.insertOwnInPass && this.nextSeed != null && (Base64Order.enhancedCoder.compare(ASCII.getBytes(this.seedDB.mySeed().hash), ASCII.getBytes(this.nextSeed.hash)) < 0)))
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) {
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// take my own seed hash instead the enumeration result
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this.alsoMyOwn = false;
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return this.seedDB.mySeed();
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}
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final Seed next = this.nextSeed;
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this.nextSeed = nextInternal();
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return next;
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}
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@Override
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public void remove() {
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throw new UnsupportedOperationException();
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}
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}
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/**
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* enumerate peers that provide remote crawl urls
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* @param seedDB
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* @return an iterator of seed objects
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*/
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public static Iterator<Seed> getProvidesRemoteCrawlURLs(final SeedDB seedDB) {
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return new providesRemoteCrawlURLsEnum(seedDB);
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}
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private static class providesRemoteCrawlURLsEnum extends LookAheadIterator<Seed> implements Iterator<Seed>, Iterable<Seed> {
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private final Iterator<Seed> se;
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private final SeedDB seedDB;
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private providesRemoteCrawlURLsEnum(final SeedDB seedDB) {
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this.seedDB = seedDB;
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this.se = seedDB.seedsConnected(true, false, null, yacyVersion.YACY_POVIDES_REMOTECRAWL_LISTS);
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}
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@Override
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protected Seed next0() {
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Seed s;
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try {
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while (this.se.hasNext()) {
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s = this.se.next();
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if (s == null) return null;
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if (s.getLong(Seed.RCOUNT, 0) > 0) return s;
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}
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} catch (final kelondroException e) {
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System.out.println("DEBUG providesRemoteCrawlURLsEnum:" + e.getMessage());
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Network.log.severe("database inconsistency (" + e.getMessage() + "), re-set of db.");
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this.seedDB.resetActiveTable();
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return null;
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}
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return null;
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}
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}
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/**
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* get either the youngest or oldest peers from the seed db. Count as many as requested
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* @param seedDB
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* @param up if up = true then get the most recent peers, if up = false then get oldest
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* @param count number of wanted peers
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* @return a hash map of peer hashes to seed object
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*/
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public static ConcurrentMap<String, Seed> seedsByAge(final SeedDB seedDB, final boolean up, int count) {
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if (count > seedDB.sizeConnected()) count = seedDB.sizeConnected();
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Seed ys;
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//long age;
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final Iterator<Seed> s = seedDB.seedsSortedConnected(!up, Seed.LASTSEEN);
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try {
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final ConcurrentMap<String, Seed> result = new ConcurrentHashMap<String, Seed>();
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while (s.hasNext() && count-- > 0) {
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ys = s.next();
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if (ys != null && ys.hash != null) {
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//age = (System.currentTimeMillis() - ys.getLastSeenUTC()) / 1000 / 60;
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//System.out.println("selected seedsByAge up=" + up + ", age/min = " + age);
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result.put(ys.hash, ys);
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}
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}
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return result;
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} catch (final kelondroException e) {
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Network.log.severe("Internal Error at yacySeedDB.seedsByAge: " + e.getMessage(), e);
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return null;
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}
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}
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} |