com.netflix.curator.framework.recipes.leader.TestLeaderSelectorCluster.java Source code

Introduction

Here is the source code for com.netflix.curator.framework.recipes.leader.TestLeaderSelectorCluster.java

Source

/*
 * Copyright 2012 Netflix, Inc.
 *
 *    Licensed 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 com.netflix.curator.framework.recipes.leader;

import java.util.Collection;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Semaphore;
import java.util.concurrent.atomic.AtomicReference;

import org.apache.commons.io.IOUtils;
import org.testng.Assert;
import org.testng.annotations.Test;

import com.netflix.curator.framework.CuratorFramework;
import com.netflix.curator.framework.CuratorFrameworkFactory;
import com.netflix.curator.framework.state.ConnectionState;
import com.netflix.curator.retry.RetryOneTime;
import com.netflix.curator.test.InstanceSpec;
import com.netflix.curator.test.TestingCluster;
import com.netflix.curator.test.Timing;
import com.netflix.curator.utils.ZKPaths;

@SuppressWarnings("ThrowableResultOfMethodCallIgnored")
public class TestLeaderSelectorCluster {
    @Test
    public void testRestart() throws Exception {
        final Timing timing = new Timing();

        CuratorFramework client = null;
        TestingCluster cluster = new TestingCluster(3);
        cluster.start();
        try {
            client = CuratorFrameworkFactory.newClient(cluster.getConnectString(), timing.session(),
                    timing.connection(), new RetryOneTime(1));
            client.start();

            final Semaphore semaphore = new Semaphore(0);
            LeaderSelectorListener listener = new LeaderSelectorListener() {
                @Override
                public void takeLeadership(CuratorFramework client) throws Exception {
                    List<String> names = client.getChildren().forPath("/leader");
                    Assert.assertTrue(names.size() > 0);
                    semaphore.release();
                }

                @Override
                public void stateChanged(CuratorFramework client, ConnectionState newState) {
                }
            };
            LeaderSelector selector = new LeaderSelector(client, "/leader", listener);
            selector.autoRequeue();
            selector.start();
            Assert.assertTrue(timing.acquireSemaphore(semaphore));

            InstanceSpec connectionInstance = cluster
                    .findConnectionInstance(client.getZookeeperClient().getZooKeeper());
            cluster.killServer(connectionInstance);

            Assert.assertTrue(timing.multiple(4).acquireSemaphore(semaphore));
        } finally {
            IOUtils.closeQuietly(client);
            IOUtils.closeQuietly(cluster);
        }
    }

    @Test
    public void testLostRestart() throws Exception {
        final Timing timing = new Timing();

        CuratorFramework client = null;
        TestingCluster cluster = new TestingCluster(3);
        cluster.start();
        try {
            client = CuratorFrameworkFactory.newClient(cluster.getConnectString(), timing.session(),
                    timing.connection(), new RetryOneTime(1));
            client.start();
            client.sync("/", null);

            final AtomicReference<Exception> error = new AtomicReference<Exception>(null);
            final AtomicReference<String> lockNode = new AtomicReference<String>(null);
            final Semaphore semaphore = new Semaphore(0);
            final CountDownLatch lostLatch = new CountDownLatch(1);
            final CountDownLatch internalLostLatch = new CountDownLatch(1);
            LeaderSelectorListener listener = new LeaderSelectorListener() {
                @Override
                public void takeLeadership(CuratorFramework client) throws Exception {
                    try {
                        List<String> names = client.getChildren().forPath("/leader");
                        if (names.size() != 1) {
                            semaphore.release();
                            Exception exception = new Exception("Names size isn't 1: " + names.size());
                            error.set(exception);
                            return;
                        }
                        lockNode.set(names.get(0));

                        semaphore.release();
                        if (!timing.multiple(4).awaitLatch(internalLostLatch)) {
                            error.set(new Exception("internalLostLatch await failed"));
                        }
                    } finally {
                        lostLatch.countDown();
                    }
                }

                @Override
                public void stateChanged(CuratorFramework client, ConnectionState newState) {
                    if (newState == ConnectionState.LOST) {
                        internalLostLatch.countDown();
                    }
                }
            };
            LeaderSelector selector = new LeaderSelector(client, "/leader", listener);
            selector.start();
            Assert.assertTrue(timing.multiple(4).acquireSemaphore(semaphore));
            if (error.get() != null) {
                throw new AssertionError(error.get());
            }

            Collection<InstanceSpec> instances = cluster.getInstances();
            cluster.stop();

            Assert.assertTrue(timing.multiple(4).awaitLatch(lostLatch));
            timing.sleepABit();
            Assert.assertFalse(selector.hasLeadership());

            Assert.assertNotNull(lockNode.get());

            cluster = new TestingCluster(instances.toArray(new InstanceSpec[instances.size()]));
            cluster.start();

            try {
                client.delete().forPath(ZKPaths.makePath("/leader", lockNode.get())); // simulate the lock deleting due to session expiration
            } catch (Exception ignore) {
                // ignore
            }

            Assert.assertTrue(semaphore.availablePermits() == 0);
            Assert.assertFalse(selector.hasLeadership());

            selector.requeue();
            Assert.assertTrue(timing.multiple(4).acquireSemaphore(semaphore));
        } finally {
            IOUtils.closeQuietly(client);
            IOUtils.closeQuietly(cluster);
        }
    }
}