/**
* Copyright The Apache Software Foundation
*
* 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.hadoop.hbase.zookeeper.lock;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.DaemonThreadFactory;
import org.apache.hadoop.hbase.HBaseTestingUtility;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.InterProcessLock;
import org.apache.hadoop.hbase.InterProcessLock.MetadataHandler;
import org.apache.hadoop.hbase.testclassification.MediumTests;
import org.apache.hadoop.hbase.MultithreadedTestUtil;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.zookeeper.ZKUtil;
import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.experimental.categories.Category;
import com.google.common.collect.Lists;
@Category(MediumTests.class)
public class TestZKInterProcessReadWriteLock {
private static final Log LOG =
LogFactory.getLog(TestZKInterProcessReadWriteLock.class);
private static final HBaseTestingUtility TEST_UTIL =
new HBaseTestingUtility();
private static final int NUM_THREADS = 10;
private static Configuration conf;
private final AtomicBoolean isLockHeld = new AtomicBoolean(false);
private final ExecutorService executor =
Executors.newFixedThreadPool(NUM_THREADS,
new DaemonThreadFactory("TestZKInterProcessReadWriteLock-"));
@BeforeClass
public static void beforeAllTests() throws Exception {
conf = TEST_UTIL.getConfiguration();
TEST_UTIL.startMiniZKCluster();
conf.setInt(HConstants.ZK_SESSION_TIMEOUT, 1000);
ZooKeeperWatcher zkw = getZooKeeperWatcher("setup");
ZKUtil.createWithParents(zkw, zkw.tableLockZNode);
}
@AfterClass
public static void afterAllTests() throws Exception {
TEST_UTIL.shutdownMiniZKCluster();
}
@After
public void tearDown() {
executor.shutdown();
}
private static ZooKeeperWatcher getZooKeeperWatcher(String desc)
throws IOException {
return TEST_UTIL.getZooKeeperWatcher();
}
@Test(timeout = 30000)
public void testWriteLockExcludesWriters() throws Exception {
final String testName = "testWriteLockExcludesWriters";
final ZKInterProcessReadWriteLock readWriteLock =
getReadWriteLock(testName);
List<Future<Void>> results = Lists.newArrayList();
for (int i = 0; i < NUM_THREADS; ++i) {
final String threadDesc = testName + i;
results.add(executor.submit(new Callable<Void>() {
@Override
public Void call() throws IOException {
ZKInterProcessWriteLock writeLock =
readWriteLock.writeLock(Bytes.toBytes(threadDesc));
try {
writeLock.acquire();
try {
// No one else should hold the lock
assertTrue(isLockHeld.compareAndSet(false, true));
Thread.sleep(1000);
// No one else should have released the lock
assertTrue(isLockHeld.compareAndSet(true, false));
} finally {
isLockHeld.set(false);
writeLock.release();
}
} catch (InterruptedException e) {
LOG.warn(threadDesc + " interrupted", e);
Thread.currentThread().interrupt();
throw new InterruptedIOException();
}
return null;
}
}));
}
MultithreadedTestUtil.assertOnFutures(results);
}
@Test(timeout = 30000)
public void testReadLockDoesNotExcludeReaders() throws Exception {
final String testName = "testReadLockDoesNotExcludeReaders";
final ZKInterProcessReadWriteLock readWriteLock =
getReadWriteLock(testName);
final CountDownLatch locksAcquiredLatch = new CountDownLatch(NUM_THREADS);
final AtomicInteger locksHeld = new AtomicInteger(0);
List<Future<Void>> results = Lists.newArrayList();
for (int i = 0; i < NUM_THREADS; ++i) {
final String threadDesc = testName + i;
results.add(executor.submit(new Callable<Void>() {
@Override
public Void call() throws Exception {
ZKInterProcessReadLock readLock =
readWriteLock.readLock(Bytes.toBytes(threadDesc));
readLock.acquire();
try {
locksHeld.incrementAndGet();
locksAcquiredLatch.countDown();
Thread.sleep(1000);
} finally {
readLock.release();
locksHeld.decrementAndGet();
}
return null;
}
}));
}
locksAcquiredLatch.await();
assertEquals(locksHeld.get(), NUM_THREADS);
MultithreadedTestUtil.assertOnFutures(results);
}
@Test(timeout = 30000)
public void testReadLockExcludesWriters() throws Exception {
// Submit a read lock request first
// Submit a write lock request second
final String testName = "testReadLockExcludesWriters";
List<Future<Void>> results = Lists.newArrayList();
final CountDownLatch readLockAcquiredLatch = new CountDownLatch(1);
Callable<Void> acquireReadLock = new Callable<Void>() {
@Override
public Void call() throws Exception {
final String threadDesc = testName + "-acquireReadLock";
ZKInterProcessReadLock readLock =
getReadWriteLock(testName).readLock(Bytes.toBytes(threadDesc));
readLock.acquire();
try {
assertTrue(isLockHeld.compareAndSet(false, true));
readLockAcquiredLatch.countDown();
Thread.sleep(1000);
} finally {
isLockHeld.set(false);
readLock.release();
}
return null;
}
};
Callable<Void> acquireWriteLock = new Callable<Void>() {
@Override
public Void call() throws Exception {
final String threadDesc = testName + "-acquireWriteLock";
ZKInterProcessWriteLock writeLock =
getReadWriteLock(testName).writeLock(Bytes.toBytes(threadDesc));
readLockAcquiredLatch.await();
assertTrue(isLockHeld.get());
writeLock.acquire();
try {
assertFalse(isLockHeld.get());
} finally {
writeLock.release();
}
return null;
}
};
results.add(executor.submit(acquireReadLock));
results.add(executor.submit(acquireWriteLock));
MultithreadedTestUtil.assertOnFutures(results);
}
private static ZKInterProcessReadWriteLock getReadWriteLock(String testName)
throws IOException {
MetadataHandler handler = new MetadataHandler() {
@Override
public void handleMetadata(byte[] ownerMetadata) {
LOG.info("Lock info: " + Bytes.toString(ownerMetadata));
}
};
ZooKeeperWatcher zkWatcher = getZooKeeperWatcher(testName);
String znode = ZKUtil.joinZNode(zkWatcher.tableLockZNode, testName);
return new ZKInterProcessReadWriteLock(zkWatcher, znode, handler);
}
@Test(timeout = 30000)
public void testWriteLockExcludesReaders() throws Exception {
// Submit a read lock request first
// Submit a write lock request second
final String testName = "testReadLockExcludesWriters";
List<Future<Void>> results = Lists.newArrayList();
final CountDownLatch writeLockAcquiredLatch = new CountDownLatch(1);
Callable<Void> acquireWriteLock = new Callable<Void>() {
@Override
public Void call() throws Exception {
final String threadDesc = testName + "-acquireWriteLock";
ZKInterProcessWriteLock writeLock =
getReadWriteLock(testName).writeLock(Bytes.toBytes(threadDesc));
writeLock.acquire();
try {
writeLockAcquiredLatch.countDown();
assertTrue(isLockHeld.compareAndSet(false, true));
Thread.sleep(1000);
} finally {
isLockHeld.set(false);
writeLock.release();
}
return null;
}
};
Callable<Void> acquireReadLock = new Callable<Void>() {
@Override
public Void call() throws Exception {
final String threadDesc = testName + "-acquireReadLock";
ZKInterProcessReadLock readLock =
getReadWriteLock(testName).readLock(Bytes.toBytes(threadDesc));
writeLockAcquiredLatch.await();
readLock.acquire();
try {
assertFalse(isLockHeld.get());
} finally {
readLock.release();
}
return null;
}
};
results.add(executor.submit(acquireWriteLock));
results.add(executor.submit(acquireReadLock));
MultithreadedTestUtil.assertOnFutures(results);
}
@Test(timeout = 60000)
public void testTimeout() throws Exception {
final String testName = "testTimeout";
final CountDownLatch lockAcquiredLatch = new CountDownLatch(1);
Callable<Void> shouldHog = new Callable<Void>() {
@Override
public Void call() throws Exception {
final String threadDesc = testName + "-shouldHog";
ZKInterProcessWriteLock lock =
getReadWriteLock(testName).writeLock(Bytes.toBytes(threadDesc));
lock.acquire();
lockAcquiredLatch.countDown();
Thread.sleep(10000);
lock.release();
return null;
}
};
Callable<Void> shouldTimeout = new Callable<Void>() {
@Override
public Void call() throws Exception {
final String threadDesc = testName + "-shouldTimeout";
ZKInterProcessWriteLock lock =
getReadWriteLock(testName).writeLock(Bytes.toBytes(threadDesc));
lockAcquiredLatch.await();
assertFalse(lock.tryAcquire(5000));
return null;
}
};
Callable<Void> shouldAcquireLock = new Callable<Void>() {
@Override
public Void call() throws Exception {
final String threadDesc = testName + "-shouldAcquireLock";
ZKInterProcessWriteLock lock =
getReadWriteLock(testName).writeLock(Bytes.toBytes(threadDesc));
lockAcquiredLatch.await();
assertTrue(lock.tryAcquire(30000));
lock.release();
return null;
}
};
List<Future<Void>> results = Lists.newArrayList();
results.add(executor.submit(shouldHog));
results.add(executor.submit(shouldTimeout));
results.add(executor.submit(shouldAcquireLock));
MultithreadedTestUtil.assertOnFutures(results);
}
@Test(timeout = 60000)
public void testMultipleClients() throws Exception {
//tests lock usage from multiple zookeeper clients with different sessions.
//acquire one read lock, then one write lock
final String testName = "testMultipleClients";
//different zookeeper sessions with separate identifiers
ZooKeeperWatcher zkWatcher1 = new ZooKeeperWatcher(conf, "testMultipleClients-1", null);
ZooKeeperWatcher zkWatcher2 = new ZooKeeperWatcher(conf, "testMultipleClients-2", null);
String znode = ZKUtil.joinZNode(zkWatcher1.tableLockZNode, testName);
ZKInterProcessReadWriteLock clientLock1
= new ZKInterProcessReadWriteLock(zkWatcher1, znode, null);
ZKInterProcessReadWriteLock clientLock2
= new ZKInterProcessReadWriteLock(zkWatcher2, znode, null);
InterProcessLock lock1 = clientLock1.readLock(Bytes.toBytes("client1"));
lock1.acquire();
//try to acquire, but it will timeout. We are testing whether this will cause any problems
//due to the read lock being from another client
InterProcessLock lock2 = clientLock2.writeLock(Bytes.toBytes("client2"));
assertFalse(lock2.tryAcquire(1000));
lock1.release();
//this time it will acquire
assertTrue(lock2.tryAcquire(5000));
lock2.release();
zkWatcher1.close();
zkWatcher2.close();
}
}