001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.zookeeper;
019
020import static org.junit.Assert.assertEquals;
021import static org.junit.Assert.assertFalse;
022import static org.junit.Assert.assertNotNull;
023import static org.junit.Assert.assertNull;
024import static org.junit.Assert.assertTrue;
025
026import java.io.IOException;
027import java.util.concurrent.Semaphore;
028import java.util.concurrent.ThreadLocalRandom;
029import org.apache.hadoop.hbase.Abortable;
030import org.apache.hadoop.hbase.HBaseClassTestRule;
031import org.apache.hadoop.hbase.HBaseZKTestingUtil;
032import org.apache.hadoop.hbase.HConstants;
033import org.apache.hadoop.hbase.ServerName;
034import org.apache.hadoop.hbase.testclassification.MediumTests;
035import org.apache.hadoop.hbase.testclassification.ZKTests;
036import org.apache.hadoop.hbase.util.Bytes;
037import org.apache.hadoop.hbase.util.Threads;
038import org.apache.zookeeper.CreateMode;
039import org.apache.zookeeper.ZooDefs.Ids;
040import org.apache.zookeeper.ZooKeeper;
041import org.junit.AfterClass;
042import org.junit.BeforeClass;
043import org.junit.ClassRule;
044import org.junit.Test;
045import org.junit.experimental.categories.Category;
046import org.slf4j.Logger;
047import org.slf4j.LoggerFactory;
048
049@Category({ ZKTests.class, MediumTests.class })
050public class TestZKNodeTracker {
051  @ClassRule
052  public static final HBaseClassTestRule CLASS_RULE =
053    HBaseClassTestRule.forClass(TestZKNodeTracker.class);
054
055  private static final Logger LOG = LoggerFactory.getLogger(TestZKNodeTracker.class);
056  private final static HBaseZKTestingUtil TEST_UTIL = new HBaseZKTestingUtil();
057
058  @BeforeClass
059  public static void setUpBeforeClass() throws Exception {
060    TEST_UTIL.startMiniZKCluster();
061  }
062
063  @AfterClass
064  public static void tearDownAfterClass() throws Exception {
065    TEST_UTIL.shutdownMiniZKCluster();
066  }
067
068  /**
069   * Test that we can interrupt a node that is blocked on a wait.
070   */
071  @Test
072  public void testInterruptible() throws IOException, InterruptedException {
073    Abortable abortable = new StubAbortable();
074    ZKWatcher zk = new ZKWatcher(TEST_UTIL.getConfiguration(), "testInterruptible", abortable);
075    final TestTracker tracker = new TestTracker(zk, "/xyz", abortable);
076    tracker.start();
077    Thread t = new Thread(() -> {
078      try {
079        tracker.blockUntilAvailable();
080      } catch (InterruptedException e) {
081        throw new RuntimeException("Interrupted", e);
082      }
083    });
084    t.start();
085    while (!t.isAlive()) {
086      Threads.sleep(1);
087    }
088    tracker.stop();
089    t.join();
090    // If it wasn't interruptible, we'd never get to here.
091  }
092
093  @Test
094  public void testNodeTracker() throws Exception {
095    Abortable abortable = new StubAbortable();
096    ZKWatcher zk = new ZKWatcher(TEST_UTIL.getConfiguration(), "testNodeTracker", abortable);
097    ZKUtil.createAndFailSilent(zk, zk.getZNodePaths().baseZNode);
098
099    final String node = ZNodePaths.joinZNode(zk.getZNodePaths().baseZNode,
100      Long.toString(ThreadLocalRandom.current().nextLong()));
101
102    final byte[] dataOne = Bytes.toBytes("dataOne");
103    final byte[] dataTwo = Bytes.toBytes("dataTwo");
104
105    // Start a ZKNT with no node currently available
106    TestTracker localTracker = new TestTracker(zk, node, abortable);
107    localTracker.start();
108    zk.registerListener(localTracker);
109
110    // Make sure we don't have a node
111    assertNull(localTracker.getData(false));
112
113    // Spin up a thread with another ZKNT and have it block
114    WaitToGetDataThread thread = new WaitToGetDataThread(zk, node);
115    thread.start();
116
117    // Verify the thread doesn't have a node
118    assertFalse(thread.hasData);
119
120    // Now, start a new ZKNT with the node already available
121    TestTracker secondTracker = new TestTracker(zk, node, null);
122    secondTracker.start();
123    zk.registerListener(secondTracker);
124
125    // Put up an additional zk listener so we know when zk event is done
126    TestingZKListener zkListener = new TestingZKListener(zk, node);
127    zk.registerListener(zkListener);
128    assertEquals(0, zkListener.createdLock.availablePermits());
129
130    // Create a completely separate zk connection for test triggers and avoid
131    // any weird watcher interactions from the test
132    final ZooKeeper zkconn = ZooKeeperHelper.getConnectedZooKeeper(
133      ZKConfig.getZKQuorumServersString(TEST_UTIL.getConfiguration()), 60000);
134
135    // Add the node with data one
136    zkconn.create(node, dataOne, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
137
138    // Wait for the zk event to be processed
139    zkListener.waitForCreation();
140    thread.join();
141
142    // Both trackers should have the node available with data one
143    assertNotNull(localTracker.getData(false));
144    assertNotNull(localTracker.blockUntilAvailable());
145    assertTrue(Bytes.equals(localTracker.getData(false), dataOne));
146    assertTrue(thread.hasData);
147    assertTrue(Bytes.equals(thread.tracker.getData(false), dataOne));
148    LOG.info("Successfully got data one");
149
150    // Make sure it's available and with the expected data
151    assertNotNull(secondTracker.getData(false));
152    assertNotNull(secondTracker.blockUntilAvailable());
153    assertTrue(Bytes.equals(secondTracker.getData(false), dataOne));
154    LOG.info("Successfully got data one with the second tracker");
155
156    // Drop the node
157    zkconn.delete(node, -1);
158    zkListener.waitForDeletion();
159
160    // Create a new thread but with the existing thread's tracker to wait
161    TestTracker threadTracker = thread.tracker;
162    thread = new WaitToGetDataThread(threadTracker);
163    thread.start();
164
165    // Verify other guys don't have data
166    assertFalse(thread.hasData);
167    assertNull(secondTracker.getData(false));
168    assertNull(localTracker.getData(false));
169    LOG.info("Successfully made unavailable");
170
171    // Create with second data
172    zkconn.create(node, dataTwo, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
173
174    // Wait for the zk event to be processed
175    zkListener.waitForCreation();
176    thread.join();
177
178    // All trackers should have the node available with data two
179    assertNotNull(localTracker.getData(false));
180    assertNotNull(localTracker.blockUntilAvailable());
181    assertTrue(Bytes.equals(localTracker.getData(false), dataTwo));
182    assertNotNull(secondTracker.getData(false));
183    assertNotNull(secondTracker.blockUntilAvailable());
184    assertTrue(Bytes.equals(secondTracker.getData(false), dataTwo));
185    assertTrue(thread.hasData);
186    assertTrue(Bytes.equals(thread.tracker.getData(false), dataTwo));
187    LOG.info("Successfully got data two on all trackers and threads");
188
189    // Change the data back to data one
190    zkconn.setData(node, dataOne, -1);
191
192    // Wait for zk event to be processed
193    zkListener.waitForDataChange();
194
195    // All trackers should have the node available with data one
196    assertNotNull(localTracker.getData(false));
197    assertNotNull(localTracker.blockUntilAvailable());
198    assertTrue(Bytes.equals(localTracker.getData(false), dataOne));
199    assertNotNull(secondTracker.getData(false));
200    assertNotNull(secondTracker.blockUntilAvailable());
201    assertTrue(Bytes.equals(secondTracker.getData(false), dataOne));
202    assertTrue(thread.hasData);
203    assertTrue(Bytes.equals(thread.tracker.getData(false), dataOne));
204    LOG.info("Successfully got data one following a data change on all trackers and threads");
205  }
206
207  public static class WaitToGetDataThread extends Thread {
208    TestTracker tracker;
209    boolean hasData;
210
211    WaitToGetDataThread(ZKWatcher zk, String node) {
212      tracker = new TestTracker(zk, node, null);
213      tracker.start();
214      zk.registerListener(tracker);
215      hasData = false;
216    }
217
218    WaitToGetDataThread(TestTracker tracker) {
219      this.tracker = tracker;
220      hasData = false;
221    }
222
223    @Override
224    public void run() {
225      LOG.info("Waiting for data to be available in WaitToGetDataThread");
226      try {
227        tracker.blockUntilAvailable();
228      } catch (InterruptedException e) {
229        e.printStackTrace();
230      }
231      LOG.info("Data now available in tracker from WaitToGetDataThread");
232      hasData = true;
233    }
234  }
235
236  public static class TestTracker extends ZKNodeTracker {
237    TestTracker(ZKWatcher watcher, String node, Abortable abortable) {
238      super(watcher, node, abortable);
239    }
240  }
241
242  public static class TestingZKListener extends ZKListener {
243    private static final Logger LOG = LoggerFactory.getLogger(TestingZKListener.class);
244
245    private Semaphore deletedLock;
246    private Semaphore createdLock;
247    private Semaphore changedLock;
248    private String node;
249
250    TestingZKListener(ZKWatcher watcher, String node) {
251      super(watcher);
252      deletedLock = new Semaphore(0);
253      createdLock = new Semaphore(0);
254      changedLock = new Semaphore(0);
255      this.node = node;
256    }
257
258    @Override
259    public void nodeDeleted(String path) {
260      if (path.equals(node)) {
261        LOG.debug("nodeDeleted(" + path + ")");
262        deletedLock.release();
263      }
264    }
265
266    @Override
267    public void nodeCreated(String path) {
268      if (path.equals(node)) {
269        LOG.debug("nodeCreated(" + path + ")");
270        createdLock.release();
271      }
272    }
273
274    @Override
275    public void nodeDataChanged(String path) {
276      if (path.equals(node)) {
277        LOG.debug("nodeDataChanged(" + path + ")");
278        changedLock.release();
279      }
280    }
281
282    void waitForDeletion() throws InterruptedException {
283      deletedLock.acquire();
284    }
285
286    void waitForCreation() throws InterruptedException {
287      createdLock.acquire();
288    }
289
290    void waitForDataChange() throws InterruptedException {
291      changedLock.acquire();
292    }
293  }
294
295  public static class StubAbortable implements Abortable {
296    @Override
297    public void abort(final String msg, final Throwable t) {
298    }
299
300    @Override
301    public boolean isAborted() {
302      return false;
303    }
304  }
305
306  @Test
307  public void testCleanZNode() throws Exception {
308    ZKWatcher zkw = new ZKWatcher(TEST_UTIL.getConfiguration(), "testNodeTracker",
309      new TestZKNodeTracker.StubAbortable());
310
311    final ServerName sn = ServerName.valueOf("127.0.0.1:52", 45L);
312
313    ZKUtil.createAndFailSilent(zkw, TEST_UTIL.getConfiguration()
314      .get(HConstants.ZOOKEEPER_ZNODE_PARENT, HConstants.DEFAULT_ZOOKEEPER_ZNODE_PARENT));
315
316    final String nodeName = zkw.getZNodePaths().masterAddressZNode;
317
318    // Check that we manage the case when there is no data
319    ZKUtil.createAndFailSilent(zkw, nodeName);
320    MasterAddressTracker.deleteIfEquals(zkw, sn.toString());
321    assertNotNull(ZKUtil.getData(zkw, nodeName));
322
323    // Check that we don't delete if we're not supposed to
324    ZKUtil.setData(zkw, nodeName, MasterAddressTracker.toByteArray(sn, 0));
325    MasterAddressTracker.deleteIfEquals(zkw, ServerName.valueOf("127.0.0.2:52", 45L).toString());
326    assertNotNull(ZKUtil.getData(zkw, nodeName));
327
328    // Check that we delete when we're supposed to
329    ZKUtil.setData(zkw, nodeName, MasterAddressTracker.toByteArray(sn, 0));
330    MasterAddressTracker.deleteIfEquals(zkw, sn.toString());
331    assertNull(ZKUtil.getData(zkw, nodeName));
332
333    // Check that we support the case when the znode does not exist
334    MasterAddressTracker.deleteIfEquals(zkw, sn.toString()); // must not throw an exception
335  }
336}