com.palantir.atlasdb.factory.Leaders.java Source code

Introduction

Here is the source code for com.palantir.atlasdb.factory.Leaders.java

Source

/**
 * Copyright 2015 Palantir Technologies
 *
 * Licensed under the BSD-3 License (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://opensource.org/licenses/BSD-3-Clause
 *
 * 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 com.palantir.atlasdb.factory;

import java.util.Collection;
import java.util.IdentityHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import javax.net.ssl.SSLSocketFactory;

import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Sets;
import com.google.common.net.HostAndPort;
import com.palantir.atlasdb.config.LeaderConfig;
import com.palantir.atlasdb.factory.TransactionManagers.Environment;
import com.palantir.atlasdb.http.AtlasDbHttpClients;
import com.palantir.atlasdb.http.NotCurrentLeaderExceptionMapper;
import com.palantir.leader.LeaderElectionService;
import com.palantir.leader.PaxosLeaderElectionService;
import com.palantir.leader.PingableLeader;
import com.palantir.paxos.PaxosAcceptor;
import com.palantir.paxos.PaxosAcceptorImpl;
import com.palantir.paxos.PaxosLearner;
import com.palantir.paxos.PaxosLearnerImpl;
import com.palantir.paxos.PaxosProposer;
import com.palantir.paxos.PaxosProposerImpl;

public class Leaders {

    /**
     * Creates a LeaderElectionService using the supplied configuration and
     * registers appropriate endpoints for that service.
     */
    public static LeaderElectionService create(Optional<SSLSocketFactory> sslSocketFactory, Environment env,
            LeaderConfig config) {

        PaxosAcceptor ourAcceptor = PaxosAcceptorImpl.newAcceptor(config.acceptorLogDir().getPath());
        PaxosLearner ourLearner = PaxosLearnerImpl.newLearner(config.learnerLogDir().getPath());

        Set<String> remoteLeaderUris = Sets.newHashSet(config.leaders());
        remoteLeaderUris.remove(config.localServer());

        List<PaxosLearner> learners = AtlasDbHttpClients.createProxies(sslSocketFactory, remoteLeaderUris,
                PaxosLearner.class);
        learners.add(ourLearner);

        List<PaxosAcceptor> acceptors = AtlasDbHttpClients.createProxies(sslSocketFactory, remoteLeaderUris,
                PaxosAcceptor.class);
        acceptors.add(ourAcceptor);

        Map<PingableLeader, HostAndPort> otherLeaders = generatePingables(remoteLeaderUris, sslSocketFactory);

        ExecutorService executor = Executors.newCachedThreadPool();

        PaxosProposer proposer = PaxosProposerImpl.newProposer(ourLearner, ImmutableList.copyOf(acceptors),
                ImmutableList.copyOf(learners), config.quorumSize(), executor);

        PaxosLeaderElectionService leader = new PaxosLeaderElectionService(proposer, ourLearner, otherLeaders,
                ImmutableList.copyOf(acceptors), ImmutableList.copyOf(learners), executor, config.pingRateMs(),
                config.randomWaitBeforeProposingLeadershipMs(), config.leaderPingResponseWaitMs());

        env.register(ourAcceptor);
        env.register(ourLearner);

        env.register(leader);
        env.register(new NotCurrentLeaderExceptionMapper());

        return leader;
    }

    public static Map<PingableLeader, HostAndPort> generatePingables(Collection<String> remoteEndpoints,
            Optional<SSLSocketFactory> sslSocketFactory) {
        /* The interface used as a key here may be a proxy, which may have strange .equals() behavior.
         * This is circumvented by using an IdentityHashMap which will just use native == for equality.
         */
        Map<PingableLeader, HostAndPort> pingables = new IdentityHashMap<PingableLeader, HostAndPort>();
        for (String endpoint : remoteEndpoints) {
            PingableLeader remoteInterface = AtlasDbHttpClients.createProxy(sslSocketFactory, endpoint,
                    PingableLeader.class);
            HostAndPort hostAndPort = HostAndPort.fromString(endpoint);
            pingables.put(remoteInterface, hostAndPort);
        }
        return pingables;
    }

}