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*
* Licensed to the Apache Software Foundation (ASF) under one
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* 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
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* KIND, either express or implied. See the License for the
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package org.apache.cassandra.locator;
import java.net.InetAddress;
import java.util.*;
import java.util.Map.Entry;
import com.google.common.collect.Multimap;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.config.ConfigurationException;
import org.apache.cassandra.dht.Token;
import org.apache.cassandra.service.*;
import org.apache.cassandra.thrift.ConsistencyLevel;
import org.apache.cassandra.utils.FBUtilities;
/**
* This Replication Strategy takes a property file that gives the intended
* replication factor in each datacenter. The sum total of the datacenter
* replication factor values should be equal to the keyspace replication
* factor.
* <p/>
* So for example, if the keyspace replication factor is 6, the
* datacenter replication factors could be 3, 2, and 1 - so 3 replicas in
* one datacenter, 2 in another, and 1 in another - totalling 6.
* <p/>
* This class also caches the Endpoints and invalidates the cache if there is a
* change in the number of tokens.
*/
public class NetworkTopologyStrategy extends AbstractReplicationStrategy
{
private final IEndpointSnitch snitch;
private final Map<String, Integer> datacenters;
private static final Logger logger = LoggerFactory.getLogger(NetworkTopologyStrategy.class);
public NetworkTopologyStrategy(String table, TokenMetadata tokenMetadata, IEndpointSnitch snitch, Map<String, String> configOptions) throws ConfigurationException
{
super(table, tokenMetadata, snitch, configOptions);
this.snitch = snitch;
Map<String, Integer> newDatacenters = new HashMap<String, Integer>();
if (configOptions != null)
{
for (Entry<String, String> entry : configOptions.entrySet())
{
String dc = entry.getKey();
if (dc.equalsIgnoreCase("replication_factor"))
throw new ConfigurationException("replication_factor is an option for SimpleStrategy, not NetworkTopologyStrategy");
Integer replicas = Integer.valueOf(entry.getValue());
newDatacenters.put(dc, replicas);
}
}
datacenters = Collections.unmodifiableMap(newDatacenters);
logger.debug("Configured datacenter replicas are {}", FBUtilities.toString(datacenters));
}
public List<InetAddress> calculateNaturalEndpoints(Token searchToken, TokenMetadata tokenMetadata)
{
List<InetAddress> endpoints = new ArrayList<InetAddress>(getReplicationFactor());
for (Entry<String, Integer> dcEntry : datacenters.entrySet())
{
String dcName = dcEntry.getKey();
int dcReplicas = dcEntry.getValue();
// collect endpoints in this DC
TokenMetadata dcTokens = new TokenMetadata();
for (Entry<Token, InetAddress> tokenEntry : tokenMetadata.entrySet())
{
if (snitch.getDatacenter(tokenEntry.getValue()).equals(dcName))
dcTokens.updateNormalToken(tokenEntry.getKey(), tokenEntry.getValue());
}
List<InetAddress> dcEndpoints = new ArrayList<InetAddress>(dcReplicas);
Set<String> racks = new HashSet<String>();
// first pass: only collect replicas on unique racks
for (Iterator<Token> iter = TokenMetadata.ringIterator(dcTokens.sortedTokens(), searchToken, false);
dcEndpoints.size() < dcReplicas && iter.hasNext(); )
{
Token token = iter.next();
InetAddress endpoint = dcTokens.getEndpoint(token);
String rack = snitch.getRack(endpoint);
if (!racks.contains(rack))
{
dcEndpoints.add(endpoint);
racks.add(rack);
}
}
// second pass: if replica count has not been achieved from unique racks, add nodes from duplicate racks
for (Iterator<Token> iter = TokenMetadata.ringIterator(dcTokens.sortedTokens(), searchToken, false);
dcEndpoints.size() < dcReplicas && iter.hasNext(); )
{
Token token = iter.next();
InetAddress endpoint = dcTokens.getEndpoint(token);
if (!dcEndpoints.contains(endpoint))
dcEndpoints.add(endpoint);
}
if (logger.isDebugEnabled())
logger.debug("{} endpoints in datacenter {} for token {} ",
new Object[] { StringUtils.join(dcEndpoints, ","), dcName, searchToken});
endpoints.addAll(dcEndpoints);
}
return endpoints;
}
public int getReplicationFactor()
{
int total = 0;
for (int repFactor : datacenters.values())
total += repFactor;
return total;
}
public int getReplicationFactor(String dc)
{
return datacenters.get(dc);
}
public Set<String> getDatacenters()
{
return datacenters.keySet();
}
public void validateOptions() throws ConfigurationException
{
for (Entry<String, String> e : this.configOptions.entrySet())
{
validateReplicationFactor(e.getValue());
}
}
}