HBASE-3627 NPE in EventHandler when region already reassigned

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1085076 13f79535-47bb-0310-9956-ffa450edef68

src/test/java/org/apache/hadoop/hbase/regionserver/handler/TestOpenRegionHandler.java

@@ -0,0 +1,227 @@
+/**
+ * Copyright 2011 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.regionserver.handler;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.HBaseTestingUtility;
+import org.apache.hadoop.hbase.HConstants;
+import org.apache.hadoop.hbase.HRegionInfo;
+import org.apache.hadoop.hbase.HServerInfo;
+import org.apache.hadoop.hbase.HTableDescriptor;
+import org.apache.hadoop.hbase.Server;
+import org.apache.hadoop.hbase.ZooKeeperConnectionException;
+import org.apache.hadoop.hbase.catalog.CatalogTracker;
+import org.apache.hadoop.hbase.ipc.HBaseRpcMetrics;
+import org.apache.hadoop.hbase.regionserver.CompactionRequestor;
+import org.apache.hadoop.hbase.regionserver.FlushRequester;
+import org.apache.hadoop.hbase.regionserver.HRegion;
+import org.apache.hadoop.hbase.regionserver.RegionServerServices;
+import org.apache.hadoop.hbase.regionserver.wal.HLog;
+import org.apache.hadoop.hbase.zookeeper.ZKAssign;
+import org.apache.hadoop.hbase.zookeeper.ZKUtil;
+import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.KeeperException.NodeExistsException;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+/**
+ * Test of the {@link OpenRegionHandler}.
+ */
+public class TestOpenRegionHandler {
+  private static final Log LOG = LogFactory.getLog(TestOpenRegionHandler.class);
+  private final static HBaseTestingUtility HTU = new HBaseTestingUtility();
+
+  @BeforeClass public static void before() throws Exception {
+    HTU.startMiniZKCluster();
+  }
+
+  @AfterClass public static void after() throws IOException {
+    HTU.shutdownMiniZKCluster();
+  }
+
+  /**
+   * Basic mock Server
+   */
+  static class MockServer implements Server {
+    boolean stopped = false;
+    final static String NAME = "MockServer";
+    final ZooKeeperWatcher zk;
+
+    MockServer() throws ZooKeeperConnectionException, IOException {
+      this.zk =  new ZooKeeperWatcher(HTU.getConfiguration(), NAME, this);
+    }
+
+    @Override
+    public void abort(String why, Throwable e) {
+      LOG.fatal("Abort why=" + why, e);
+      this.stopped = true;
+    }
+
+    @Override
+    public void stop(String why) {
+      LOG.debug("Stop why=" + why);
+      this.stopped = true;
+    }
+
+    @Override
+    public boolean isStopped() {
+      return this.stopped;
+    }
+
+    @Override
+    public Configuration getConfiguration() {
+      return HTU.getConfiguration();
+    }
+
+    @Override
+    public ZooKeeperWatcher getZooKeeper() {
+      return this.zk;
+    }
+
+    @Override
+    public CatalogTracker getCatalogTracker() {
+      // TODO Auto-generated method stub
+      return null;
+    }
+
+    @Override
+    public String getServerName() {
+      return NAME;
+    }
+  }
+
+  /**
+   * Basic mock region server services.
+   */
+  static class MockRegionServerServices implements RegionServerServices {
+    final Map<String, HRegion> regions = new HashMap<String, HRegion>();
+    boolean stopping = false;
+
+    @Override
+    public boolean removeFromOnlineRegions(String encodedRegionName) {
+      return this.regions.remove(encodedRegionName) != null;
+    }
+    
+    @Override
+    public HRegion getFromOnlineRegions(String encodedRegionName) {
+      return this.regions.get(encodedRegionName);
+    }
+    
+    @Override
+    public void addToOnlineRegions(HRegion r) {
+      this.regions.put(r.getRegionInfo().getEncodedName(), r);
+    }
+    
+    @Override
+    public void postOpenDeployTasks(HRegion r, CatalogTracker ct, boolean daughter)
+        throws KeeperException, IOException {
+    }
+    
+    @Override
+    public boolean isStopping() {
+      return this.stopping;
+    }
+    
+    @Override
+    public HLog getWAL() {
+      return null;
+    }
+    
+    @Override
+    public HServerInfo getServerInfo() {
+      return null;
+    }
+    
+    @Override
+    public HBaseRpcMetrics getRpcMetrics() {
+      return null;
+    }
+    
+    @Override
+    public FlushRequester getFlushRequester() {
+      return null;
+    }
+    
+    @Override
+    public CompactionRequestor getCompactionRequester() {
+      return null;
+    }
+
+    @Override
+    public CatalogTracker getCatalogTracker() {
+      return null;
+    }
+
+    @Override
+    public ZooKeeperWatcher getZooKeeperWatcher() {
+      return null;
+    }
+  };
+
+  /**
+   * Test the openregionhandler can deal with its znode being yanked out from
+   * under it.
+   * @see <a href="https://issues.apache.org/jira/browse/HBASE-3627">HBASE-3627</a>
+   * @throws IOException
+   * @throws NodeExistsException
+   * @throws KeeperException
+   */
+  @Test public void testOpenRegionHandlerYankingRegionFromUnderIt()
+  throws IOException, NodeExistsException, KeeperException {
+    final Server server = new MockServer();
+    final RegionServerServices rss = new MockRegionServerServices();
+
+    HTableDescriptor htd =
+      new HTableDescriptor("testOpenRegionHandlerYankingRegionFromUnderIt");
+    final HRegionInfo hri =
+      new HRegionInfo(htd, HConstants.EMPTY_END_ROW, HConstants.EMPTY_END_ROW);
+    OpenRegionHandler handler = new OpenRegionHandler(server, rss, hri) {
+      HRegion openRegion() {
+        // Open region first, then remove znode as though it'd been hijacked.
+        HRegion region = super.openRegion();
+        // Don't actually open region BUT remove the znode as though it'd
+        // been hijacked on us.
+        ZooKeeperWatcher zkw = this.server.getZooKeeper();
+        String node = ZKAssign.getNodeName(zkw, hri.getEncodedName());
+        try {
+          ZKUtil.deleteNodeFailSilent(zkw, node);
+        } catch (KeeperException e) {
+          throw new RuntimeException("Ugh failed delete of " + node, e);
+        }
+        return region;
+      }
+    };
+    // Call process without first creating OFFLINE region in zk, see if
+    // exception or just quiet return (expected).
+    handler.process();
+    ZKAssign.createNodeOffline(server.getZooKeeper(), hri, server.getServerName());
+    // Call process again but this time yank the zk znode out from under it
+    // post OPENING; again will expect it to come back w/o NPE or exception.
+    handler.process();
+  }
+}