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1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  package org.apache.hadoop.hbase.zookeeper;
20  
21  import static org.junit.Assert.assertEquals;
22  import static org.junit.Assert.assertFalse;
23  import static org.junit.Assert.assertNotNull;
24  import static org.junit.Assert.assertNull;
25  import static org.junit.Assert.assertTrue;
26  
27  import java.io.IOException;
28  import java.util.Random;
29  import java.util.concurrent.Semaphore;
30  
31  import junit.framework.Assert;
32  import org.apache.commons.logging.Log;
33  import org.apache.commons.logging.LogFactory;
34  import org.apache.hadoop.hbase.*;
35  import org.apache.hadoop.hbase.master.TestActiveMasterManager.NodeDeletionListener;
36  import org.apache.hadoop.hbase.testclassification.MediumTests;
37  import org.apache.hadoop.hbase.util.Bytes;
38  import org.apache.hadoop.hbase.util.Threads;
39  import org.apache.zookeeper.CreateMode;
40  import org.apache.zookeeper.WatchedEvent;
41  import org.apache.zookeeper.Watcher;
42  import org.apache.zookeeper.ZooDefs.Ids;
43  import org.apache.zookeeper.ZooKeeper;
44  import org.junit.AfterClass;
45  import org.junit.BeforeClass;
46  import org.junit.Test;
47  import org.junit.experimental.categories.Category;
48  
49  @Category(MediumTests.class)
50  public class TestZooKeeperNodeTracker {
51    private static final Log LOG = LogFactory.getLog(TestZooKeeperNodeTracker.class);
52    private final static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
53  
54    private final static Random rand = new Random();
55  
56    @BeforeClass
57    public static void setUpBeforeClass() throws Exception {
58      TEST_UTIL.startMiniZKCluster();
59    }
60  
61    @AfterClass
62    public static void tearDownAfterClass() throws Exception {
63      TEST_UTIL.shutdownMiniZKCluster();
64    }
65  
66    /**
67     * Test that we can interrupt a node that is blocked on a wait.
68     * @throws IOException
69     * @throws InterruptedException
70     */
71    @Test public void testInterruptible() throws IOException, InterruptedException {
72      Abortable abortable = new StubAbortable();
73      ZooKeeperWatcher zk = new ZooKeeperWatcher(TEST_UTIL.getConfiguration(),
74        "testInterruptible", abortable);
75      final TestTracker tracker = new TestTracker(zk, "/xyz", abortable);
76      tracker.start();
77      Thread t = new Thread() {
78        @Override
79        public void run() {
80          try {
81            tracker.blockUntilAvailable();
82          } catch (InterruptedException e) {
83            throw new RuntimeException("Interrupted", e);
84          }
85        }
86      };
87      t.start();
88      while (!t.isAlive()) Threads.sleep(1);
89      tracker.stop();
90      t.join();
91      // If it wasn't interruptible, we'd never get to here.
92    }
93  
94    @Test
95    public void testNodeTracker() throws Exception {
96      Abortable abortable = new StubAbortable();
97      ZooKeeperWatcher zk = new ZooKeeperWatcher(TEST_UTIL.getConfiguration(),
98          "testNodeTracker", abortable);
99      ZKUtil.createAndFailSilent(zk, zk.baseZNode);
100 
101     final String node =
102       ZKUtil.joinZNode(zk.baseZNode, new Long(rand.nextLong()).toString());
103 
104     final byte [] dataOne = Bytes.toBytes("dataOne");
105     final byte [] dataTwo = Bytes.toBytes("dataTwo");
106 
107     // Start a ZKNT with no node currently available
108     TestTracker localTracker = new TestTracker(zk, node, abortable);
109     localTracker.start();
110     zk.registerListener(localTracker);
111 
112     // Make sure we don't have a node
113     assertNull(localTracker.getData(false));
114 
115     // Spin up a thread with another ZKNT and have it block
116     WaitToGetDataThread thread = new WaitToGetDataThread(zk, node);
117     thread.start();
118 
119     // Verify the thread doesn't have a node
120     assertFalse(thread.hasData);
121 
122     // Now, start a new ZKNT with the node already available
123     TestTracker secondTracker = new TestTracker(zk, node, null);
124     secondTracker.start();
125     zk.registerListener(secondTracker);
126 
127     // Put up an additional zk listener so we know when zk event is done
128     TestingZKListener zkListener = new TestingZKListener(zk, node);
129     zk.registerListener(zkListener);
130     assertEquals(0, zkListener.createdLock.availablePermits());
131 
132     // Create a completely separate zk connection for test triggers and avoid
133     // any weird watcher interactions from the test
134     final ZooKeeper zkconn = new ZooKeeper(
135         ZKConfig.getZKQuorumServersString(TEST_UTIL.getConfiguration()), 60000,
136         new StubWatcher());
137 
138     // Add the node with data one
139     zkconn.create(node, dataOne, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
140 
141     // Wait for the zk event to be processed
142     zkListener.waitForCreation();
143     thread.join();
144 
145     // Both trackers should have the node available with data one
146     assertNotNull(localTracker.getData(false));
147     assertNotNull(localTracker.blockUntilAvailable());
148     assertTrue(Bytes.equals(localTracker.getData(false), dataOne));
149     assertTrue(thread.hasData);
150     assertTrue(Bytes.equals(thread.tracker.getData(false), dataOne));
151     LOG.info("Successfully got data one");
152 
153     // Make sure it's available and with the expected data
154     assertNotNull(secondTracker.getData(false));
155     assertNotNull(secondTracker.blockUntilAvailable());
156     assertTrue(Bytes.equals(secondTracker.getData(false), dataOne));
157     LOG.info("Successfully got data one with the second tracker");
158 
159     // Drop the node
160     zkconn.delete(node, -1);
161     zkListener.waitForDeletion();
162 
163     // Create a new thread but with the existing thread's tracker to wait
164     TestTracker threadTracker = thread.tracker;
165     thread = new WaitToGetDataThread(zk, node, threadTracker);
166     thread.start();
167 
168     // Verify other guys don't have data
169     assertFalse(thread.hasData);
170     assertNull(secondTracker.getData(false));
171     assertNull(localTracker.getData(false));
172     LOG.info("Successfully made unavailable");
173 
174     // Create with second data
175     zkconn.create(node, dataTwo, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
176 
177     // Wait for the zk event to be processed
178     zkListener.waitForCreation();
179     thread.join();
180 
181     // All trackers should have the node available with data two
182     assertNotNull(localTracker.getData(false));
183     assertNotNull(localTracker.blockUntilAvailable());
184     assertTrue(Bytes.equals(localTracker.getData(false), dataTwo));
185     assertNotNull(secondTracker.getData(false));
186     assertNotNull(secondTracker.blockUntilAvailable());
187     assertTrue(Bytes.equals(secondTracker.getData(false), dataTwo));
188     assertTrue(thread.hasData);
189     assertTrue(Bytes.equals(thread.tracker.getData(false), dataTwo));
190     LOG.info("Successfully got data two on all trackers and threads");
191 
192     // Change the data back to data one
193     zkconn.setData(node, dataOne, -1);
194 
195     // Wait for zk event to be processed
196     zkListener.waitForDataChange();
197 
198     // All trackers should have the node available with data one
199     assertNotNull(localTracker.getData(false));
200     assertNotNull(localTracker.blockUntilAvailable());
201     assertTrue(Bytes.equals(localTracker.getData(false), dataOne));
202     assertNotNull(secondTracker.getData(false));
203     assertNotNull(secondTracker.blockUntilAvailable());
204     assertTrue(Bytes.equals(secondTracker.getData(false), dataOne));
205     assertTrue(thread.hasData);
206     assertTrue(Bytes.equals(thread.tracker.getData(false), dataOne));
207     LOG.info("Successfully got data one following a data change on all trackers and threads");
208   }
209 
210   public static class WaitToGetDataThread extends Thread {
211 
212     TestTracker tracker;
213     boolean hasData;
214 
215     public WaitToGetDataThread(ZooKeeperWatcher zk, String node) {
216       tracker = new TestTracker(zk, node, null);
217       tracker.start();
218       zk.registerListener(tracker);
219       hasData = false;
220     }
221 
222     public WaitToGetDataThread(ZooKeeperWatcher zk, String node,
223         TestTracker tracker) {
224       this.tracker = tracker;
225       hasData = false;
226     }
227 
228     @Override
229     public void run() {
230       LOG.info("Waiting for data to be available in WaitToGetDataThread");
231       try {
232         tracker.blockUntilAvailable();
233       } catch (InterruptedException e) {
234         e.printStackTrace();
235       }
236       LOG.info("Data now available in tracker from WaitToGetDataThread");
237       hasData = true;
238     }
239   }
240 
241   public static class TestTracker extends ZooKeeperNodeTracker {
242     public TestTracker(ZooKeeperWatcher watcher, String node,
243         Abortable abortable) {
244       super(watcher, node, abortable);
245     }
246   }
247 
248   public static class TestingZKListener extends ZooKeeperListener {
249     private static final Log LOG = LogFactory.getLog(NodeDeletionListener.class);
250 
251     private Semaphore deletedLock;
252     private Semaphore createdLock;
253     private Semaphore changedLock;
254     private String node;
255 
256     public TestingZKListener(ZooKeeperWatcher watcher, String node) {
257       super(watcher);
258       deletedLock = new Semaphore(0);
259       createdLock = new Semaphore(0);
260       changedLock = new Semaphore(0);
261       this.node = node;
262     }
263 
264     @Override
265     public void nodeDeleted(String path) {
266       if(path.equals(node)) {
267         LOG.debug("nodeDeleted(" + path + ")");
268         deletedLock.release();
269       }
270     }
271 
272     @Override
273     public void nodeCreated(String path) {
274       if(path.equals(node)) {
275         LOG.debug("nodeCreated(" + path + ")");
276         createdLock.release();
277       }
278     }
279 
280     @Override
281     public void nodeDataChanged(String path) {
282       if(path.equals(node)) {
283         LOG.debug("nodeDataChanged(" + path + ")");
284         changedLock.release();
285       }
286     }
287 
288     public void waitForDeletion() throws InterruptedException {
289       deletedLock.acquire();
290     }
291 
292     public void waitForCreation() throws InterruptedException {
293       createdLock.acquire();
294     }
295 
296     public void waitForDataChange() throws InterruptedException {
297       changedLock.acquire();
298     }
299   }
300 
301   public static class StubAbortable implements Abortable {
302     @Override
303     public void abort(final String msg, final Throwable t) {}
304     
305     @Override
306     public boolean isAborted() {
307       return false;
308     }
309     
310   }
311 
312   public static class StubWatcher implements Watcher {
313     @Override
314     public void process(WatchedEvent event) {}
315   }
316 
317   @Test
318   public void testCleanZNode() throws Exception {
319     ZooKeeperWatcher zkw = new ZooKeeperWatcher(TEST_UTIL.getConfiguration(),
320         "testNodeTracker", new TestZooKeeperNodeTracker.StubAbortable());
321 
322     final ServerName sn = ServerName.valueOf("127.0.0.1:52", 45L);
323 
324     ZKUtil.createAndFailSilent(zkw,
325         TEST_UTIL.getConfiguration().get(HConstants.ZOOKEEPER_ZNODE_PARENT,
326             HConstants.DEFAULT_ZOOKEEPER_ZNODE_PARENT));
327 
328     final String nodeName =  zkw.getMasterAddressZNode();
329 
330     // Check that we manage the case when there is no data
331     ZKUtil.createAndFailSilent(zkw, nodeName);
332     MasterAddressTracker.deleteIfEquals(zkw, sn.toString());
333     Assert.assertFalse(ZKUtil.getData(zkw, nodeName) == null);
334 
335     // Check that we don't delete if we're not supposed to
336     ZKUtil.setData(zkw, nodeName, MasterAddressTracker.toByteArray(sn));
337     MasterAddressTracker.deleteIfEquals(zkw, ServerName.valueOf("127.0.0.2:52", 45L).toString());
338     Assert.assertFalse(ZKUtil.getData(zkw, nodeName) == null);
339 
340     // Check that we delete when we're supposed to
341     ZKUtil.setData(zkw, nodeName,MasterAddressTracker.toByteArray(sn));
342     MasterAddressTracker.deleteIfEquals(zkw, sn.toString());
343     Assert.assertTrue( ZKUtil.getData(zkw, nodeName)== null );
344 
345     // Check that we support the case when the znode does not exist
346     MasterAddressTracker.deleteIfEquals(zkw, sn.toString()); // must not throw an exception
347   }
348 
349 }
350