/*
* 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.cassandra.gms;
import java.net.InetAddress;
import java.util.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.net.IVerbHandler;
import org.apache.cassandra.net.MessageIn;
import org.apache.cassandra.net.MessageOut;
import org.apache.cassandra.net.MessagingService;
public class GossipDigestSynVerbHandler implements IVerbHandler<GossipDigestSyn>
{
private static final Logger logger = LoggerFactory.getLogger(GossipDigestSynVerbHandler.class);
public void doVerb(MessageIn<GossipDigestSyn> message, int id)
{
InetAddress from = message.from;
if (logger.isTraceEnabled())
logger.trace("Received a GossipDigestSynMessage from {}", from);
if (!Gossiper.instance.isEnabled() && !Gossiper.instance.isInShadowRound())
{
if (logger.isTraceEnabled())
logger.trace("Ignoring GossipDigestSynMessage because gossip is disabled");
return;
}
GossipDigestSyn gDigestMessage = message.payload;
/* If the message is from a different cluster throw it away. */
if (!gDigestMessage.clusterId.equals(DatabaseDescriptor.getClusterName()))
{
logger.warn("ClusterName mismatch from {} {}!={}", from, gDigestMessage.clusterId, DatabaseDescriptor.getClusterName());
return;
}
if (gDigestMessage.partioner != null && !gDigestMessage.partioner.equals(DatabaseDescriptor.getPartitionerName()))
{
logger.warn("Partitioner mismatch from {} {}!={}", from, gDigestMessage.partioner, DatabaseDescriptor.getPartitionerName());
return;
}
List<GossipDigest> gDigestList = gDigestMessage.getGossipDigests();
// if the syn comes from a peer performing a shadow round and this node is
// also currently in a shadow round, send back a minimal ack. This node must
// be in the sender's seed list and doing this allows the sender to
// differentiate between seeds from which it is partitioned and those which
// are in their shadow round
if (!Gossiper.instance.isEnabled() && Gossiper.instance.isInShadowRound())
{
// a genuine syn (as opposed to one from a node currently
// doing a shadow round) will always contain > 0 digests
if (gDigestList.size() > 0)
{
logger.debug("Ignoring non-empty GossipDigestSynMessage because currently in gossip shadow round");
return;
}
logger.debug("Received a shadow round syn from {}. Gossip is disabled but " +
"currently also in shadow round, responding with a minimal ack", from);
MessagingService.instance()
.sendOneWay(new MessageOut<>(MessagingService.Verb.GOSSIP_DIGEST_ACK,
new GossipDigestAck(new ArrayList<>(), new HashMap<>()),
GossipDigestAck.serializer),
from);
return;
}
if (logger.isTraceEnabled())
{
StringBuilder sb = new StringBuilder();
for (GossipDigest gDigest : gDigestList)
{
sb.append(gDigest);
sb.append(" ");
}
logger.trace("Gossip syn digests are : {}", sb);
}
doSort(gDigestList);
List<GossipDigest> deltaGossipDigestList = new ArrayList<GossipDigest>();
Map<InetAddress, EndpointState> deltaEpStateMap = new HashMap<InetAddress, EndpointState>();
Gossiper.instance.examineGossiper(gDigestList, deltaGossipDigestList, deltaEpStateMap);
logger.trace("sending {} digests and {} deltas", deltaGossipDigestList.size(), deltaEpStateMap.size());
MessageOut<GossipDigestAck> gDigestAckMessage = new MessageOut<GossipDigestAck>(MessagingService.Verb.GOSSIP_DIGEST_ACK,
new GossipDigestAck(deltaGossipDigestList, deltaEpStateMap),
GossipDigestAck.serializer);
if (logger.isTraceEnabled())
logger.trace("Sending a GossipDigestAckMessage to {}", from);
MessagingService.instance().sendOneWay(gDigestAckMessage, from);
}
/*
* First construct a map whose key is the endpoint in the GossipDigest and the value is the
* GossipDigest itself. Then build a list of version differences i.e difference between the
* version in the GossipDigest and the version in the local state for a given InetAddress.
* Sort this list. Now loop through the sorted list and retrieve the GossipDigest corresponding
* to the endpoint from the map that was initially constructed.
*/
private void doSort(List<GossipDigest> gDigestList)
{
/* Construct a map of endpoint to GossipDigest. */
Map<InetAddress, GossipDigest> epToDigestMap = new HashMap<InetAddress, GossipDigest>();
for (GossipDigest gDigest : gDigestList)
{
epToDigestMap.put(gDigest.getEndpoint(), gDigest);
}
/*
* These digests have their maxVersion set to the difference of the version
* of the local EndpointState and the version found in the GossipDigest.
*/
List<GossipDigest> diffDigests = new ArrayList<GossipDigest>(gDigestList.size());
for (GossipDigest gDigest : gDigestList)
{
InetAddress ep = gDigest.getEndpoint();
EndpointState epState = Gossiper.instance.getEndpointStateForEndpoint(ep);
int version = (epState != null) ? Gossiper.instance.getMaxEndpointStateVersion(epState) : 0;
int diffVersion = Math.abs(version - gDigest.getMaxVersion());
diffDigests.add(new GossipDigest(ep, gDigest.getGeneration(), diffVersion));
}
gDigestList.clear();
Collections.sort(diffDigests);
int size = diffDigests.size();
/*
* Report the digests in descending order. This takes care of the endpoints
* that are far behind w.r.t this local endpoint
*/
for (int i = size - 1; i >= 0; --i)
{
gDigestList.add(epToDigestMap.get(diffDigests.get(i).getEndpoint()));
}
}
}