/**
* 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.curator.framework.recipes.leader;
import com.google.common.collect.Lists;
import org.apache.curator.utils.CloseableUtils;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.apache.curator.retry.RetryOneTime;
import org.apache.curator.test.InstanceSpec;
import org.apache.curator.test.TestingCluster;
import org.apache.curator.test.Timing;
import org.testng.Assert;
import org.testng.annotations.Test;
import java.util.Collection;
import java.util.List;
public class TestLeaderLatchCluster
{
private static final int MAX_LOOPS = 5;
private static class ClientAndLatch
{
final CuratorFramework client;
final LeaderLatch latch;
final int index;
private ClientAndLatch(CuratorFramework client, LeaderLatch latch, int index)
{
this.client = client;
this.latch = latch;
this.index = index;
}
}
@Test
public void testInCluster() throws Exception
{
final int PARTICIPANT_QTY = 3;
List<ClientAndLatch> clients = Lists.newArrayList();
Timing timing = new Timing();
TestingCluster cluster = new TestingCluster(PARTICIPANT_QTY);
try
{
cluster.start();
List<InstanceSpec> instances = Lists.newArrayList(cluster.getInstances());
for ( int i = 0; i < PARTICIPANT_QTY; ++i )
{
CuratorFramework client = CuratorFrameworkFactory.newClient(instances.get(i).getConnectString(), timing.session(), timing.connection(), new ExponentialBackoffRetry(100, 3));
LeaderLatch latch = new LeaderLatch(client, "/latch");
clients.add(new ClientAndLatch(client, latch, i));
client.start();
latch.start();
}
ClientAndLatch leader = waitForALeader(clients, timing);
Assert.assertNotNull(leader);
cluster.killServer(instances.get(leader.index));
Thread.sleep(timing.multiple(2).session());
leader = waitForALeader(clients, timing);
Assert.assertNotNull(leader);
Assert.assertEquals(getLeaders(clients).size(), 1);
}
finally
{
for ( ClientAndLatch client : clients )
{
CloseableUtils.closeQuietly(client.latch);
CloseableUtils.closeQuietly(client.client);
}
CloseableUtils.closeQuietly(cluster);
}
}
private ClientAndLatch waitForALeader(List<ClientAndLatch> latches, Timing timing) throws InterruptedException
{
for ( int i = 0; i < MAX_LOOPS; ++i )
{
List<ClientAndLatch> leaders = getLeaders(latches);
if ( leaders.size() != 0 )
{
return leaders.get(0);
}
timing.sleepABit();
}
return null;
}
private List<ClientAndLatch> getLeaders(Collection<ClientAndLatch> latches)
{
List<ClientAndLatch> leaders = Lists.newArrayList();
for ( ClientAndLatch clientAndLatch : latches )
{
if ( clientAndLatch.latch.hasLeadership() )
{
leaders.add(clientAndLatch);
}
}
return leaders;
}
}