curator-framework/src/test/java/org/apache/curator/framework/imps/TestReadOnly.java

/**
 * 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.imps;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;
import com.google.common.collect.Queues;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.state.ConnectionState;
import org.apache.curator.framework.state.ConnectionStateListener;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.apache.curator.retry.RetryNTimes;
import org.apache.curator.retry.RetryOneTime;
import org.apache.curator.test.BaseClassForTests;
import org.apache.curator.test.InstanceSpec;
import org.apache.curator.test.TestingCluster;
import org.apache.curator.test.Timing;
import org.apache.curator.utils.CloseableUtils;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import java.util.Iterator;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

public class TestReadOnly extends BaseClassForTests
{
    @BeforeEach
    public void setup()
    {
        System.setProperty("readonlymode.enabled", "true");
    }

    @AfterEach
    public void tearDown()
    {
        System.setProperty("readonlymode.enabled", "false");
    }

    @Test
    public void testConnectionStateNewClient() throws Exception
    {
        Timing timing = new Timing();
        CuratorFramework client = null;
        TestingCluster cluster = createAndStartCluster(3);
        try
        {
            final CountDownLatch lostLatch = new CountDownLatch(1);
            client = CuratorFrameworkFactory.newClient(cluster.getConnectString(), timing.session(), timing.connection(), new RetryOneTime(100));
            client.start();
            client.checkExists().forPath("/");
            client.getConnectionStateListenable().addListener(new ConnectionStateListener() {
                @Override
                public void stateChanged(CuratorFramework client, ConnectionState newState) {
                    if (newState == ConnectionState.LOST) {
                        lostLatch.countDown();
                    }
                }
            });

            Iterator<InstanceSpec> iterator = cluster.getInstances().iterator();
            for ( int i = 0; i < 2; ++i )
            {
                cluster.killServer(iterator.next());
            }
            timing.awaitLatch(lostLatch);
            client.close();

            client = CuratorFrameworkFactory.builder()
                .connectString(cluster.getConnectString())
                .sessionTimeoutMs(timing.session())
                .connectionTimeoutMs(timing.connection())
                .retryPolicy(new RetryNTimes(3, timing.milliseconds()))
                .canBeReadOnly(true)
                .build();

            final BlockingQueue<ConnectionState> states = Queues.newLinkedBlockingQueue();
            client.getConnectionStateListenable().addListener
            (
                new ConnectionStateListener()
                {
                    @Override
                    public void stateChanged(CuratorFramework client, ConnectionState newState)
                    {
                        states.add(newState);
                    }
                }
            );
            client.start();

            client.checkExists().forPath("/");

            ConnectionState state = states.poll(timing.forWaiting().milliseconds(), TimeUnit.MILLISECONDS);
            assertEquals(state, ConnectionState.READ_ONLY);
        }
        finally
        {
            CloseableUtils.closeQuietly(client);
            CloseableUtils.closeQuietly(cluster);
        }
    }

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

        CuratorFramework client = null;
        TestingCluster cluster = createAndStartCluster(2);
        try
        {
            client = CuratorFrameworkFactory.builder().connectString(cluster.getConnectString()).canBeReadOnly(true).connectionTimeoutMs(timing.connection()).sessionTimeoutMs(timing.session()).retryPolicy(new ExponentialBackoffRetry(100, 3)).build();
            client.start();

            client.create().forPath("/test");

            final CountDownLatch readOnlyLatch = new CountDownLatch(1);
            final CountDownLatch reconnectedLatch = new CountDownLatch(1);
            ConnectionStateListener listener = new ConnectionStateListener()
            {
                @Override
                public void stateChanged(CuratorFramework client, ConnectionState newState)
                {
                    if ( newState == ConnectionState.READ_ONLY )
                    {
                        readOnlyLatch.countDown();
                    }
                    else if ( newState == ConnectionState.RECONNECTED )
                    {
                        reconnectedLatch.countDown();
                    }
                }
            };
            client.getConnectionStateListenable().addListener(listener);

            InstanceSpec ourInstance = cluster.findConnectionInstance(client.getZookeeperClient().getZooKeeper());
            Iterator<InstanceSpec> iterator = cluster.getInstances().iterator();
            InstanceSpec killInstance = iterator.next();
            if ( killInstance.equals(ourInstance) )
            {
                killInstance = iterator.next(); // kill the instance we're not connected to
            }
            cluster.killServer(killInstance);

            assertEquals(reconnectedLatch.getCount(), 1);
            assertTrue(timing.awaitLatch(readOnlyLatch));

            assertEquals(reconnectedLatch.getCount(), 1);
            cluster.restartServer(killInstance);
            assertTrue(timing.awaitLatch(reconnectedLatch));
        }
        finally
        {
            CloseableUtils.closeQuietly(client);
            CloseableUtils.closeQuietly(cluster);
        }
    }

    @Override
    protected void createServer() throws Exception
    {
        // NOP
    }
}