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* 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.twill.discovery;
import com.google.common.collect.Maps;
import com.google.common.util.concurrent.Futures;
import org.apache.twill.common.Cancellable;
import org.apache.twill.common.Services;
import org.apache.twill.internal.zookeeper.InMemoryZKServer;
import org.apache.twill.internal.zookeeper.KillZKSession;
import org.apache.twill.zookeeper.RetryStrategies;
import org.apache.twill.zookeeper.ZKClientService;
import org.apache.twill.zookeeper.ZKClientServices;
import org.apache.twill.zookeeper.ZKClients;
import org.junit.AfterClass;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Map;
import java.util.concurrent.TimeUnit;
/**
* Test Zookeeper based discovery service.
*/
public class ZKDiscoveryServiceTest extends DiscoveryServiceTestBase {
private static final Logger LOG = LoggerFactory.getLogger(ZKDiscoveryServiceTest.class);
private static InMemoryZKServer zkServer;
private static ZKClientService zkClient;
@BeforeClass
public static void beforeClass() {
zkServer = InMemoryZKServer.builder().setTickTime(100000).build();
zkServer.startAndWait();
zkClient = ZKClientServices.delegate(
ZKClients.retryOnFailure(
ZKClients.reWatchOnExpire(
ZKClientService.Builder.of(zkServer.getConnectionStr()).build()),
RetryStrategies.fixDelay(1, TimeUnit.SECONDS)));
zkClient.startAndWait();
}
@AfterClass
public static void afterClass() {
Futures.getUnchecked(Services.chainStop(zkClient, zkServer));
}
@Test (timeout = 5000)
public void testDoubleRegister() throws Exception {
Map.Entry<DiscoveryService, DiscoveryServiceClient> entry = create();
DiscoveryService discoveryService = entry.getKey();
DiscoveryServiceClient discoveryServiceClient = entry.getValue();
// Register on the same host port, it shouldn't fail.
Cancellable cancellable = register(discoveryService, "test_double_reg", "localhost", 54321);
Cancellable cancellable2 = register(discoveryService, "test_double_reg", "localhost", 54321);
ServiceDiscovered discoverables = discoveryServiceClient.discover("test_double_reg");
Assert.assertTrue(waitTillExpected(1, discoverables));
cancellable.cancel();
cancellable2.cancel();
// Register again with two different clients, but killing session of the first one.
final ZKClientService zkClient2 = ZKClientServices.delegate(
ZKClients.retryOnFailure(
ZKClients.reWatchOnExpire(
ZKClientService.Builder.of(zkServer.getConnectionStr()).build()),
RetryStrategies.fixDelay(1, TimeUnit.SECONDS)));
zkClient2.startAndWait();
try {
DiscoveryService discoveryService2 = new ZKDiscoveryService(zkClient2);
cancellable2 = register(discoveryService2, "test_multi_client", "localhost", 54321);
// Schedule a thread to shutdown zkClient2.
new Thread() {
@Override
public void run() {
try {
TimeUnit.SECONDS.sleep(2);
zkClient2.stopAndWait();
} catch (InterruptedException e) {
LOG.error(e.getMessage(), e);
}
}
}.start();
// This call would block until zkClient2 is shutdown.
cancellable = register(discoveryService, "test_multi_client", "localhost", 54321);
cancellable.cancel();
} finally {
zkClient2.stopAndWait();
}
}
@Test
public void testSessionExpires() throws Exception {
Map.Entry<DiscoveryService, DiscoveryServiceClient> entry = create();
DiscoveryService discoveryService = entry.getKey();
DiscoveryServiceClient discoveryServiceClient = entry.getValue();
Cancellable cancellable = register(discoveryService, "test_expires", "localhost", 54321);
ServiceDiscovered discoverables = discoveryServiceClient.discover("test_expires");
// Discover that registered host:port.
Assert.assertTrue(waitTillExpected(1, discoverables));
KillZKSession.kill(zkClient.getZooKeeperSupplier().get(), zkServer.getConnectionStr(), 5000);
// Register one more endpoint to make sure state has been reflected after reconnection
Cancellable cancellable2 = register(discoveryService, "test_expires", "localhost", 54322);
// Reconnection would trigger re-registration.
Assert.assertTrue(waitTillExpected(2, discoverables));
cancellable.cancel();
cancellable2.cancel();
// Verify that both are now gone.
Assert.assertTrue(waitTillExpected(0, discoverables));
}
@Override
protected Map.Entry<DiscoveryService, DiscoveryServiceClient> create() {
DiscoveryService discoveryService = new ZKDiscoveryService(zkClient);
DiscoveryServiceClient discoveryServiceClient = new ZKDiscoveryService(zkClient);
return Maps.immutableEntry(discoveryService, discoveryServiceClient);
}
}