ZenPingService.java

/*
 * Licensed to ElasticSearch and Shay Banon under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. ElasticSearch 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.elasticsearch.discovery.zen.ping;

import com.google.common.collect.ImmutableList;
import org.elasticsearch.ElasticSearchException;
import org.elasticsearch.ElasticSearchIllegalStateException;
import org.elasticsearch.cluster.ClusterName;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.component.AbstractLifecycleComponent;
import org.elasticsearch.common.inject.Inject;
import org.elasticsearch.common.network.NetworkService;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.unit.TimeValue;
import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
import org.elasticsearch.discovery.zen.DiscoveryNodesProvider;
import org.elasticsearch.discovery.zen.ping.multicast.MulticastZenPing;
import org.elasticsearch.discovery.unicast.UnicastHostsProvider;
import org.elasticsearch.discovery.zen.ping.unicast.UnicastZenPing;
import org.elasticsearch.threadpool.ThreadPool;
import org.elasticsearch.transport.TransportService;

import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicReference;

/**
 *
 */
public class ZenPingService extends AbstractLifecycleComponent<ZenPing> implements ZenPing {

    private volatile ImmutableList<? extends ZenPing> zenPings = ImmutableList.of();

    @Inject
    public ZenPingService(Settings settings, ThreadPool threadPool, TransportService transportService, ClusterName clusterName, NetworkService networkService,
                          @Nullable Set<UnicastHostsProvider> unicastHostsProviders) {
        super(settings);

        ImmutableList.Builder<ZenPing> zenPingsBuilder = ImmutableList.builder();
        if (componentSettings.getAsBoolean("multicast.enabled", true)) {
            zenPingsBuilder.add(new MulticastZenPing(settings, threadPool, transportService, clusterName, networkService));
        }
        // always add the unicast hosts, so it will be able to receive unicast requests even when working in multicast
        zenPingsBuilder.add(new UnicastZenPing(settings, threadPool, transportService, clusterName, unicastHostsProviders));

        this.zenPings = zenPingsBuilder.build();
    }

    public ImmutableList<? extends ZenPing> zenPings() {
        return this.zenPings;
    }

    public void zenPings(ImmutableList<? extends ZenPing> pings) {
        this.zenPings = pings;
        if (lifecycle.started()) {
            for (ZenPing zenPing : zenPings) {
                zenPing.start();
            }
        } else if (lifecycle.stopped()) {
            for (ZenPing zenPing : zenPings) {
                zenPing.stop();
            }
        }
    }

    @Override
    public void setNodesProvider(DiscoveryNodesProvider nodesProvider) {
        if (lifecycle.started()) {
            throw new ElasticSearchIllegalStateException("Can't set nodes provider when started");
        }
        for (ZenPing zenPing : zenPings) {
            zenPing.setNodesProvider(nodesProvider);
        }
    }

    @Override
    protected void doStart() throws ElasticSearchException {
        for (ZenPing zenPing : zenPings) {
            zenPing.start();
        }
    }

    @Override
    protected void doStop() throws ElasticSearchException {
        for (ZenPing zenPing : zenPings) {
            zenPing.stop();
        }
    }

    @Override
    protected void doClose() throws ElasticSearchException {
        for (ZenPing zenPing : zenPings) {
            zenPing.close();
        }
    }

    public PingResponse[] pingAndWait(TimeValue timeout) {
        final AtomicReference<PingResponse[]> response = new AtomicReference<PingResponse[]>();
        final CountDownLatch latch = new CountDownLatch(1);
        ping(new PingListener() {
            @Override
            public void onPing(PingResponse[] pings) {
                response.set(pings);
                latch.countDown();
            }
        }, timeout);
        try {
            latch.await();
            return response.get();
        } catch (InterruptedException e) {
            return null;
        }
    }

    @Override
    public void ping(PingListener listener, TimeValue timeout) throws ElasticSearchException {
        ImmutableList<? extends ZenPing> zenPings = this.zenPings;
        CompoundPingListener compoundPingListener = new CompoundPingListener(listener, zenPings);
        for (ZenPing zenPing : zenPings) {
            zenPing.ping(compoundPingListener, timeout);
        }
    }

    private static class CompoundPingListener implements PingListener {

        private final PingListener listener;

        private final ImmutableList<? extends ZenPing> zenPings;

        private final AtomicInteger counter;

        private ConcurrentMap<DiscoveryNode, PingResponse> responses = ConcurrentCollections.newConcurrentMap();

        private CompoundPingListener(PingListener listener, ImmutableList<? extends ZenPing> zenPings) {
            this.listener = listener;
            this.zenPings = zenPings;
            this.counter = new AtomicInteger(zenPings.size());
        }

        @Override
        public void onPing(PingResponse[] pings) {
            if (pings != null) {
                for (PingResponse pingResponse : pings) {
                    responses.put(pingResponse.target(), pingResponse);
                }
            }
            if (counter.decrementAndGet() == 0) {
                listener.onPing(responses.values().toArray(new PingResponse[responses.size()]));
            }
        }
    }
}