LeaderElectionSupportTest.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.zookeeper.recipes.leader;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.recipes.leader.LeaderElectionSupport.EventType;
import org.apache.zookeeper.test.ClientBase;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Test for {@link LeaderElectionSupport}.
*/
public class LeaderElectionSupportTest extends ClientBase {
private static final Logger LOGGER = LoggerFactory.getLogger(LeaderElectionSupportTest.class);
private static final String TEST_ROOT_NODE = "/" + System.currentTimeMillis() + "_";
private ZooKeeper zooKeeper;
@BeforeEach
public void setUp() throws Exception {
super.setUp();
zooKeeper = createClient();
zooKeeper.create(
TEST_ROOT_NODE + Thread.currentThread().getId(),
new byte[0],
ZooDefs.Ids.OPEN_ACL_UNSAFE,
CreateMode.PERSISTENT);
}
@AfterEach
public void tearDown() throws Exception {
if (zooKeeper != null) {
zooKeeper.delete(TEST_ROOT_NODE + Thread.currentThread().getId(), -1);
}
super.tearDown();
}
@Test
public void testNode() throws Exception {
LeaderElectionSupport electionSupport = createLeaderElectionSupport();
electionSupport.start();
Thread.sleep(3000);
electionSupport.stop();
}
@Test
public void testNodes3() throws Exception {
int testIterations = 3;
final CountDownLatch latch = new CountDownLatch(testIterations);
final AtomicInteger failureCounter = new AtomicInteger();
for (int i = 0; i < testIterations; i++) {
runElectionSupportThread(latch, failureCounter);
}
assertEquals(0, failureCounter.get());
if (!latch.await(10, TimeUnit.SECONDS)) {
LOGGER.info("Waited for all threads to start, but timed out. We had {} failures.", failureCounter);
}
}
@Test
public void testNodes9() throws Exception {
int testIterations = 9;
final CountDownLatch latch = new CountDownLatch(testIterations);
final AtomicInteger failureCounter = new AtomicInteger();
for (int i = 0; i < testIterations; i++) {
runElectionSupportThread(latch, failureCounter);
}
assertEquals(0, failureCounter.get());
if (!latch.await(10, TimeUnit.SECONDS)) {
LOGGER.info("Waited for all threads to start, but timed out. We had {} failures.", failureCounter);
}
}
@Test
public void testNodes20() throws Exception {
int testIterations = 20;
final CountDownLatch latch = new CountDownLatch(testIterations);
final AtomicInteger failureCounter = new AtomicInteger();
for (int i = 0; i < testIterations; i++) {
runElectionSupportThread(latch, failureCounter);
}
assertEquals(0, failureCounter.get());
if (!latch.await(10, TimeUnit.SECONDS)) {
LOGGER.info("Waited for all threads to start, but timed out. We had {} failures.", failureCounter);
}
}
@Test
public void testNodes100() throws Exception {
int testIterations = 100;
final CountDownLatch latch = new CountDownLatch(testIterations);
final AtomicInteger failureCounter = new AtomicInteger();
for (int i = 0; i < testIterations; i++) {
runElectionSupportThread(latch, failureCounter);
}
assertEquals(0, failureCounter.get());
if (!latch.await(20, TimeUnit.SECONDS)) {
LOGGER.info("Waited for all threads to start, but timed out. We had {} failures.", failureCounter);
}
}
@Test
public void testOfferShuffle() throws InterruptedException {
int testIterations = 10;
final CountDownLatch latch = new CountDownLatch(testIterations);
final AtomicInteger failureCounter = new AtomicInteger();
List<Thread> threads = new ArrayList<>(testIterations);
for (int i = 1; i <= testIterations; i++) {
threads.add(runElectionSupportThread(latch, failureCounter, Math.min(i * 1200, 10000)));
}
if (!latch.await(60, TimeUnit.SECONDS)) {
LOGGER.info("Waited for all threads to start, but timed out. We had {} failures.", failureCounter);
}
}
@Test
public void testGetLeaderHostName() throws Exception {
LeaderElectionSupport electionSupport = createLeaderElectionSupport();
electionSupport.start();
// Sketchy: We assume there will be a leader (probably us) in 3 seconds.
Thread.sleep(3000);
String leaderHostName = electionSupport.getLeaderHostName();
assertNotNull(leaderHostName);
assertEquals("foohost", leaderHostName);
electionSupport.stop();
}
@Test
public void testReadyOffer() throws Exception {
final ArrayList<EventType> events = new ArrayList<>();
final CountDownLatch electedComplete = new CountDownLatch(1);
final LeaderElectionSupport electionSupport1 = createLeaderElectionSupport();
electionSupport1.start();
LeaderElectionSupport electionSupport2 = createLeaderElectionSupport();
LeaderElectionAware listener = new LeaderElectionAware() {
boolean stoppedElectedNode = false;
@Override
public void onElectionEvent(EventType eventType) {
events.add(eventType);
if (!stoppedElectedNode
&& eventType == EventType.DETERMINE_COMPLETE) {
stoppedElectedNode = true;
try {
// stopping the ELECTED node, so re-election will happen.
electionSupport1.stop();
} catch (Exception e) {
LOGGER.error("Unexpected exception", e);
}
}
if (eventType == EventType.ELECTED_COMPLETE) {
electedComplete.countDown();
}
}
};
electionSupport2.addListener(listener);
electionSupport2.start();
// waiting for re-election.
electedComplete.await(CONNECTION_TIMEOUT / 3, TimeUnit.MILLISECONDS);
final ArrayList<EventType> expectedevents = new ArrayList<>();
expectedevents.add(EventType.START);
expectedevents.add(EventType.OFFER_START);
expectedevents.add(EventType.OFFER_COMPLETE);
expectedevents.add(EventType.DETERMINE_START);
expectedevents.add(EventType.DETERMINE_COMPLETE);
expectedevents.add(EventType.DETERMINE_START);
expectedevents.add(EventType.DETERMINE_COMPLETE);
expectedevents.add(EventType.ELECTED_START);
expectedevents.add(EventType.ELECTED_COMPLETE);
assertEquals(expectedevents, events, "Events has failed to executed in the order");
electionSupport2.stop();
}
private LeaderElectionSupport createLeaderElectionSupport() {
LeaderElectionSupport electionSupport = new LeaderElectionSupport();
electionSupport.setZooKeeper(zooKeeper);
electionSupport.setRootNodeName(TEST_ROOT_NODE + Thread.currentThread().getId());
electionSupport.setHostName("foohost");
return electionSupport;
}
private Thread runElectionSupportThread(
final CountDownLatch latch,
final AtomicInteger failureCounter) {
return runElectionSupportThread(latch, failureCounter, 3000);
}
private Thread runElectionSupportThread(
final CountDownLatch latch,
final AtomicInteger failureCounter,
final long sleepDuration) {
final LeaderElectionSupport electionSupport = createLeaderElectionSupport();
Thread t = new Thread(() -> {
try {
electionSupport.start();
Thread.sleep(sleepDuration);
electionSupport.stop();
latch.countDown();
} catch (Exception e) {
LOGGER.warn("Failed to run leader election.", e);
failureCounter.incrementAndGet();
}
});
t.start();
return t;
}
}