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.HBaseZKTestingUtility;
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 HBaseZKTestingUtility TEST_UTIL = new HBaseZKTestingUtility();
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(),
097        "testNodeTracker", abortable);
098    ZKUtil.createAndFailSilent(zk, zk.getZNodePaths().baseZNode);
099
100    final String node = ZNodePaths.joinZNode(zk.getZNodePaths().baseZNode,
101      Long.toString(ThreadLocalRandom.current().nextLong()));
102
103    final byte [] dataOne = Bytes.toBytes("dataOne");
104    final byte [] dataTwo = Bytes.toBytes("dataTwo");
105
106    // Start a ZKNT with no node currently available
107    TestTracker localTracker = new TestTracker(zk, node, abortable);
108    localTracker.start();
109    zk.registerListener(localTracker);
110
111    // Make sure we don't have a node
112    assertNull(localTracker.getData(false));
113
114    // Spin up a thread with another ZKNT and have it block
115    WaitToGetDataThread thread = new WaitToGetDataThread(zk, node);
116    thread.start();
117
118    // Verify the thread doesn't have a node
119    assertFalse(thread.hasData);
120
121    // Now, start a new ZKNT with the node already available
122    TestTracker secondTracker = new TestTracker(zk, node, null);
123    secondTracker.start();
124    zk.registerListener(secondTracker);
125
126    // Put up an additional zk listener so we know when zk event is done
127    TestingZKListener zkListener = new TestingZKListener(zk, node);
128    zk.registerListener(zkListener);
129    assertEquals(0, zkListener.createdLock.availablePermits());
130
131    // Create a completely separate zk connection for test triggers and avoid
132    // any weird watcher interactions from the test
133    final ZooKeeper zkconn = ZooKeeperHelper.
134        getConnectedZooKeeper(ZKConfig.getZKQuorumServersString(TEST_UTIL.getConfiguration()),
135            60000);
136
137    // Add the node with data one
138    zkconn.create(node, dataOne, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
139
140    // Wait for the zk event to be processed
141    zkListener.waitForCreation();
142    thread.join();
143
144    // Both trackers should have the node available with data one
145    assertNotNull(localTracker.getData(false));
146    assertNotNull(localTracker.blockUntilAvailable());
147    assertTrue(Bytes.equals(localTracker.getData(false), dataOne));
148    assertTrue(thread.hasData);
149    assertTrue(Bytes.equals(thread.tracker.getData(false), dataOne));
150    LOG.info("Successfully got data one");
151
152    // Make sure it's available and with the expected data
153    assertNotNull(secondTracker.getData(false));
154    assertNotNull(secondTracker.blockUntilAvailable());
155    assertTrue(Bytes.equals(secondTracker.getData(false), dataOne));
156    LOG.info("Successfully got data one with the second tracker");
157
158    // Drop the node
159    zkconn.delete(node, -1);
160    zkListener.waitForDeletion();
161
162    // Create a new thread but with the existing thread's tracker to wait
163    TestTracker threadTracker = thread.tracker;
164    thread = new WaitToGetDataThread(threadTracker);
165    thread.start();
166
167    // Verify other guys don't have data
168    assertFalse(thread.hasData);
169    assertNull(secondTracker.getData(false));
170    assertNull(localTracker.getData(false));
171    LOG.info("Successfully made unavailable");
172
173    // Create with second data
174    zkconn.create(node, dataTwo, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
175
176    // Wait for the zk event to be processed
177    zkListener.waitForCreation();
178    thread.join();
179
180    // All trackers should have the node available with data two
181    assertNotNull(localTracker.getData(false));
182    assertNotNull(localTracker.blockUntilAvailable());
183    assertTrue(Bytes.equals(localTracker.getData(false), dataTwo));
184    assertNotNull(secondTracker.getData(false));
185    assertNotNull(secondTracker.blockUntilAvailable());
186    assertTrue(Bytes.equals(secondTracker.getData(false), dataTwo));
187    assertTrue(thread.hasData);
188    assertTrue(Bytes.equals(thread.tracker.getData(false), dataTwo));
189    LOG.info("Successfully got data two on all trackers and threads");
190
191    // Change the data back to data one
192    zkconn.setData(node, dataOne, -1);
193
194    // Wait for zk event to be processed
195    zkListener.waitForDataChange();
196
197    // All trackers should have the node available with data one
198    assertNotNull(localTracker.getData(false));
199    assertNotNull(localTracker.blockUntilAvailable());
200    assertTrue(Bytes.equals(localTracker.getData(false), dataOne));
201    assertNotNull(secondTracker.getData(false));
202    assertNotNull(secondTracker.blockUntilAvailable());
203    assertTrue(Bytes.equals(secondTracker.getData(false), dataOne));
204    assertTrue(thread.hasData);
205    assertTrue(Bytes.equals(thread.tracker.getData(false), dataOne));
206    LOG.info("Successfully got data one following a data change on all trackers and threads");
207  }
208
209  public static class WaitToGetDataThread extends Thread {
210    TestTracker tracker;
211    boolean hasData;
212
213    WaitToGetDataThread(ZKWatcher zk, String node) {
214      tracker = new TestTracker(zk, node, null);
215      tracker.start();
216      zk.registerListener(tracker);
217      hasData = false;
218    }
219
220    WaitToGetDataThread(TestTracker tracker) {
221      this.tracker = tracker;
222      hasData = false;
223    }
224
225    @Override
226    public void run() {
227      LOG.info("Waiting for data to be available in WaitToGetDataThread");
228      try {
229        tracker.blockUntilAvailable();
230      } catch (InterruptedException e) {
231        e.printStackTrace();
232      }
233      LOG.info("Data now available in tracker from WaitToGetDataThread");
234      hasData = true;
235    }
236  }
237
238  public static class TestTracker extends ZKNodeTracker {
239    TestTracker(ZKWatcher watcher, String node, Abortable abortable) {
240      super(watcher, node, abortable);
241    }
242  }
243
244  public static class TestingZKListener extends ZKListener {
245    private static final Logger LOG = LoggerFactory.getLogger(TestingZKListener.class);
246
247    private Semaphore deletedLock;
248    private Semaphore createdLock;
249    private Semaphore changedLock;
250    private String node;
251
252    TestingZKListener(ZKWatcher watcher, String node) {
253      super(watcher);
254      deletedLock = new Semaphore(0);
255      createdLock = new Semaphore(0);
256      changedLock = new Semaphore(0);
257      this.node = node;
258    }
259
260    @Override
261    public void nodeDeleted(String path) {
262      if(path.equals(node)) {
263        LOG.debug("nodeDeleted(" + path + ")");
264        deletedLock.release();
265      }
266    }
267
268    @Override
269    public void nodeCreated(String path) {
270      if(path.equals(node)) {
271        LOG.debug("nodeCreated(" + path + ")");
272        createdLock.release();
273      }
274    }
275
276    @Override
277    public void nodeDataChanged(String path) {
278      if(path.equals(node)) {
279        LOG.debug("nodeDataChanged(" + path + ")");
280        changedLock.release();
281      }
282    }
283
284    void waitForDeletion() throws InterruptedException {
285      deletedLock.acquire();
286    }
287
288    void waitForCreation() throws InterruptedException {
289      createdLock.acquire();
290    }
291
292    void waitForDataChange() throws InterruptedException {
293      changedLock.acquire();
294    }
295  }
296
297  public static class StubAbortable implements Abortable {
298    @Override
299    public void abort(final String msg, final Throwable t) {}
300
301    @Override
302    public boolean isAborted() {
303      return false;
304    }
305  }
306
307  @Test
308  public void testCleanZNode() throws Exception {
309    ZKWatcher zkw = new ZKWatcher(TEST_UTIL.getConfiguration(),
310        "testNodeTracker", new TestZKNodeTracker.StubAbortable());
311
312    final ServerName sn = ServerName.valueOf("127.0.0.1:52", 45L);
313
314    ZKUtil.createAndFailSilent(zkw,
315        TEST_UTIL.getConfiguration().get(HConstants.ZOOKEEPER_ZNODE_PARENT,
316            HConstants.DEFAULT_ZOOKEEPER_ZNODE_PARENT));
317
318    final String nodeName =  zkw.getZNodePaths().masterAddressZNode;
319
320    // Check that we manage the case when there is no data
321    ZKUtil.createAndFailSilent(zkw, nodeName);
322    MasterAddressTracker.deleteIfEquals(zkw, sn.toString());
323    assertNotNull(ZKUtil.getData(zkw, nodeName));
324
325    // Check that we don't delete if we're not supposed to
326    ZKUtil.setData(zkw, nodeName, MasterAddressTracker.toByteArray(sn, 0));
327    MasterAddressTracker.deleteIfEquals(zkw, ServerName.valueOf("127.0.0.2:52", 45L).toString());
328    assertNotNull(ZKUtil.getData(zkw, nodeName));
329
330    // Check that we delete when we're supposed to
331    ZKUtil.setData(zkw, nodeName,MasterAddressTracker.toByteArray(sn, 0));
332    MasterAddressTracker.deleteIfEquals(zkw, sn.toString());
333    assertNull(ZKUtil.getData(zkw, nodeName));
334
335    // Check that we support the case when the znode does not exist
336    MasterAddressTracker.deleteIfEquals(zkw, sn.toString()); // must not throw an exception
337  }
338}