hbase-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From jg...@apache.org
Subject svn commit: r979884 [2/2] - in /hbase/branches/0.90_master_rewrite: ./ src/main/java/org/apache/hadoop/hbase/ src/main/java/org/apache/hadoop/hbase/client/ src/main/java/org/apache/hadoop/hbase/executor/ src/main/java/org/apache/hadoop/hbase/master/ sr...
Date Tue, 27 Jul 2010 21:57:02 GMT
Modified: hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/regionserver/MasterAddressManager.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/regionserver/MasterAddressManager.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/regionserver/MasterAddressManager.java (original)
+++ hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/regionserver/MasterAddressManager.java Tue Jul 27 21:57:00 2010
@@ -118,7 +118,7 @@ public class MasterAddressManager extend
     } catch(KeeperException ke) {
       // If we have a ZK exception trying to find the master we must abort
       LOG.fatal("Unexpected ZooKeeper exception", ke);
-      status.abortServer();
+      status.abort();
     }
   }
 
@@ -182,7 +182,7 @@ public class MasterAddressManager extend
     } catch (KeeperException ke) {
       // If we have a ZK exception trying to find the master we must abort
       LOG.fatal("Unexpected ZooKeeper exception", ke);
-      status.abortServer();
+      status.abort();
     }
     if(address != null) {
       setMasterAddress(address);

Modified: hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/regionserver/RSZookeeperUpdater.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/regionserver/RSZookeeperUpdater.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/regionserver/RSZookeeperUpdater.java (original)
+++ hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/regionserver/RSZookeeperUpdater.java Tue Jul 27 21:57:00 2010
@@ -5,12 +5,11 @@ import java.io.IOException;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.hbase.HMsg;
-import org.apache.hadoop.hbase.executor.RegionTransitionEventData;
+import org.apache.hadoop.hbase.executor.RegionTransitionData;
 import org.apache.hadoop.hbase.executor.HBaseEventHandler.HBaseEventType;
 import org.apache.hadoop.hbase.util.Writables;
 import org.apache.hadoop.hbase.zookeeper.ZKUtil;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
-import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.data.Stat;
 
@@ -59,8 +58,9 @@ public class RSZookeeperUpdater {
     // Try to create the node with a CLOSING state, if already exists,
     // something is wrong
     try {
-      if(ZKUtil.createPersistentNodeIfNotExists(zooKeeper, regionZNode,
-          makeZKEventData(HBaseEventType.RS2ZK_REGION_CLOSING, hmsg))) {
+      if(ZKUtil.createNodeIfNotExistsAndWatch(zooKeeper, regionZNode,
+          makeZKEventData(HBaseEventType.RS2ZK_REGION_CLOSING,
+              regionName, hmsg))) {
         String msg = "ZNode " + regionZNode + " already exists in ZooKeeper, will NOT close region.";
         LOG.error(msg);
         throw new IOException(msg);
@@ -159,9 +159,10 @@ public class RSZookeeperUpdater {
    * @param hmsg
    * @return serialized data
    */
-  private byte [] makeZKEventData(HBaseEventType eventType, HMsg hmsg)
+  private byte [] makeZKEventData(HBaseEventType eventType, String regionName,
+      HMsg hmsg)
   throws IOException {
-    return Writables.getBytes(new RegionTransitionEventData(eventType,
+    return Writables.getBytes(new RegionTransitionData(eventType, regionName,
         regionServerName, hmsg));
   }
 
@@ -174,7 +175,7 @@ public class RSZookeeperUpdater {
    */
   private void updateZKWithEventData(HBaseEventType eventType, HMsg hmsg)
   throws IOException {
-    byte[] data = makeZKEventData(eventType, hmsg);
+    byte[] data = makeZKEventData(eventType, regionName, hmsg);
     LOG.debug("Updating ZNode " + regionZNode +
               " with [" + eventType + "]" +
               " expected version = " + zkVersion);

Added: hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ClusterStatusTracker.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ClusterStatusTracker.java?rev=979884&view=auto
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ClusterStatusTracker.java (added)
+++ hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ClusterStatusTracker.java Tue Jul 27 21:57:00 2010
@@ -0,0 +1,79 @@
+/**
+ * Copyright 2010 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;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.hbase.Abortable;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.apache.zookeeper.KeeperException;
+
+public class ClusterStatusTracker extends ZooKeeperNodeTracker {
+  private static final Log LOG = LogFactory.getLog(ClusterStatusTracker.class);
+
+  public static final byte [] upData = Bytes.toBytes("up");
+
+  /**
+   * Creates a cluster status tracker.
+   *
+   * <p>After construction, use {@link #start} to kick off tracking.
+   *
+   * @param watcher
+   * @param abortable
+   */
+  public ClusterStatusTracker(ZooKeeperWatcher watcher, Abortable abortable) {
+    super(watcher, watcher.rootServerZNode, abortable);
+  }
+
+  /**
+   * Checks if the root region location is available.
+   * @return true if root region location is available, false if not
+   */
+  public boolean isClusterUp() {
+    return super.getData() != null;
+  }
+
+  /**
+   * Sets the cluster as up.
+   * @throws KeeperException unexpected zk exception
+   */
+  public void setClusterUp()
+  throws KeeperException {
+    try {
+      ZKUtil.createAndWatch(watcher, watcher.clusterStateZNode, upData);
+    } catch(KeeperException.NodeExistsException nee) {
+      ZKUtil.setData(watcher, watcher.clusterStateZNode, upData);
+    }
+  }
+
+  /**
+   * Sets the cluster as down.
+   * @throws KeeperException unexpected zk exception
+   */
+  public void setClusterDown()
+  throws KeeperException {
+    ZKUtil.deleteNode(watcher, watcher.clusterStateZNode);
+  }
+
+  @Override
+  protected Log getLog() {
+    return LOG;
+  }
+}

Added: hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/RegionServerTracker.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/RegionServerTracker.java?rev=979884&view=auto
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/RegionServerTracker.java (added)
+++ hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/RegionServerTracker.java Tue Jul 27 21:57:00 2010
@@ -0,0 +1,101 @@
+/**
+ * Copyright 2010 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;
+
+import java.util.List;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.hbase.Abortable;
+import org.apache.hadoop.hbase.HServerAddress;
+import org.apache.hadoop.hbase.HServerInfo;
+import org.apache.hadoop.hbase.master.ServerManager;
+import org.apache.zookeeper.KeeperException;
+
+/**
+ * Tracks the online region servers via ZK.
+ *
+ * <p>Handling of new RSs checking in is done via RPC.  This class
+ * is only responsible for watching for expired nodes.  It handles
+ * listening for changes in the RS node list and watching each node.
+ *
+ * <p>If an RS node gets deleted, this automatically handles calling of
+ * {@link ServerManager#expireServer(org.apache.hadoop.hbase.HServerInfo)}.
+ */
+public class RegionServerTracker extends ZooKeeperListener {
+  private static final Log LOG = LogFactory.getLog(RegionServerTracker.class);
+
+  private ServerManager serverManager;
+  private Abortable abortable;
+
+  public RegionServerTracker(ZooKeeperWatcher watcher,
+      Abortable abortable, ServerManager serverManager) {
+    super(watcher);
+    this.abortable = abortable;
+    this.serverManager = serverManager;
+  }
+  /**
+   * Starts the tracking of online RegionServers.
+   *
+   * <p>All RSs will be tracked after this method is called.
+   *
+   * @throws KeeperException
+   */
+  public void start() throws KeeperException {
+    watcher.registerListener(this);
+    ZKUtil.watchAndGetNewChildren(watcher, watcher.rsZNode);
+  }
+
+  @Override
+  public void nodeDeleted(String path) {
+    if(path.startsWith(watcher.rsZNode)) {
+      String serverName = ZKUtil.getNodeName(path);
+      LOG.info("RegionServer ephemeral node deleted, processing expiration [" +
+          serverName + "]");
+      HServerInfo hsi = serverManager.getServerInfo(serverName);
+      if(hsi == null) {
+        LOG.info("No HServerInfo found for " + serverName);
+        return;
+      }
+      serverManager.expireServer(hsi);
+    }
+  }
+
+  @Override
+  public void nodeChildrenChanged(String path) {
+    if(path.equals(watcher.rsZNode)) {
+      try {
+        ZKUtil.watchAndGetNewChildren(watcher, watcher.rsZNode);
+      } catch (KeeperException e) {
+        LOG.error("Unexpected zk exception getting RS nodes", e);
+        abortable.abort();
+      }
+    }
+  }
+
+  /**
+   * Gets the online servers.
+   * @return list of online servers from zk
+   * @throws KeeperException
+   */
+  public List<HServerAddress> getOnlineServers() throws KeeperException {
+    return ZKUtil.listChildrenAndGetAsAddresses(watcher, watcher.rsZNode);
+  }
+}

Added: hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/RootRegionTracker.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/RootRegionTracker.java?rev=979884&view=auto
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/RootRegionTracker.java (added)
+++ hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/RootRegionTracker.java Tue Jul 27 21:57:00 2010
@@ -0,0 +1,82 @@
+/**
+ * Copyright 2010 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;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.hbase.Abortable;
+import org.apache.hadoop.hbase.HServerAddress;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.apache.zookeeper.KeeperException;
+
+public class RootRegionTracker extends ZooKeeperNodeTracker {
+  private static final Log LOG = LogFactory.getLog(RootRegionTracker.class);
+
+  /**
+   * Creates a root region location tracker.
+   *
+   * <p>After construction, use {@link #start} to kick off tracking.
+   *
+   * @param watcher
+   * @param abortable
+   */
+  public RootRegionTracker(ZooKeeperWatcher watcher, Abortable abortable) {
+    super(watcher, watcher.rootServerZNode, abortable);
+  }
+
+  /**
+   * Checks if the root region location is available.
+   * @return true if root region location is available, false if not
+   */
+  public boolean isLocationAvailable() {
+    return super.getData() != null;
+  }
+
+  /**
+   * Gets the root region location, if available.  Null if not.
+   * @return server address for server hosting root region, null if none
+   *         available
+   */
+  public HServerAddress getRootRegionLocation() {
+    byte [] data = super.getData();
+    return data == null ? null : new HServerAddress(Bytes.toString(data));
+  }
+
+  /**
+   * Sets the root region location.
+   * @param address
+   * @throws KeeperException unexpected zk exception
+   */
+  public void setRootRegionLocation(HServerAddress address)
+  throws KeeperException {
+    try {
+      ZKUtil.createAndWatch(watcher, watcher.rootServerZNode,
+        Bytes.toBytes(address.toString()));
+    } catch(KeeperException.NodeExistsException nee) {
+      ZKUtil.setData(watcher, watcher.rootServerZNode,
+          Bytes.toBytes(address.toString()));
+    }
+  }
+
+  @Override
+  protected Log getLog() {
+    return LOG;
+  }
+}

Added: hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKAssign.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKAssign.java?rev=979884&view=auto
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKAssign.java (added)
+++ hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKAssign.java Tue Jul 27 21:57:00 2010
@@ -0,0 +1,476 @@
+/**
+ * Copyright 2010 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;
+
+import org.apache.hadoop.hbase.executor.RegionTransitionData;
+import org.apache.hadoop.hbase.executor.HBaseEventHandler.HBaseEventType;
+import org.apache.zookeeper.KeeperException;
+import org.apache.zookeeper.KeeperException.Code;
+import org.apache.zookeeper.KeeperException.NoNodeException;
+import org.apache.zookeeper.KeeperException.NodeExistsException;
+import org.apache.zookeeper.data.Stat;
+
+/**
+ * Utility class for doing region assignment in ZooKeeper.  This class extends
+ * stuff done in {@link ZKUtil} to cover specific assignment operations.
+ * <p>
+ * Contains only static methods and constants.
+ * <p>
+ * Used by both the Master and RegionServer.
+ * <p>
+ * All valid transitions outlined below:
+ * <p>
+ * <b>MASTER</b>
+ * <ol>
+ *   <li>
+ *     Master creates an unassigned node as OFFLINE.
+ *     - Cluster startup and table enabling.
+ *   </li>
+ *   <li>
+ *     Master forces an existing unassigned node to OFFLINE.
+ *     - RegionServer failure.
+ *     - Allows transitions from all states to OFFLINE.
+ *   </li>
+ *   <li>
+ *     Master deletes an unassigned node that was in a OPENED state.
+ *     - Normal region transitions.  Besides cluster startup, no other deletions
+ *     of unassigned nodes is allowed.
+ *   </li>
+ *   <li>
+ *     Master deletes all unassigned nodes regardless of state.
+ *     - Cluster startup before any assignment happens.
+ *   </li>
+ * </ol>
+ * <p>
+ * <b>REGIONSERVER</b>
+ * <ol>
+ *   <li>
+ *     RegionServer creates an unassigned node as CLOSING.
+ *     - All region closes will do this in response to a CLOSE RPC from Master.
+ *     - A node can never be transitioned to CLOSING, only created.
+ *   </li>
+ *   <li>
+ *     RegionServer transitions an unassigned node from CLOSING to CLOSED.
+ *     - Normal region closes.  CAS operation.
+ *   </li>
+ *   <li>
+ *     RegionServer transitions an unassigned node from OFFLINE to OPENING.
+ *     - All region opens will do this in response to an OPEN RPC from the Master.
+ *     - Normal region opens.  CAS operation.
+ *   </li>
+ *   <li>
+ *     RegionServer transitions an unassigned node from OPENING to OPENED.
+ *     - Normal region opens.  CAS operation.
+ *   </li>
+ * </ol>
+ */
+public class ZKAssign {
+
+  /**
+   * Gets the full path node name for the unassigned node for the specified
+   * region.
+   * @param zkw zk reference
+   * @param regionName region name
+   * @return full path node name
+   */
+  private static String getNodeName(ZooKeeperWatcher zkw, String regionName) {
+    return ZKUtil.joinZNode(zkw.assignmentZNode, regionName);
+  }
+
+  /**
+   * Gets the region name from the full path node name of an unassigned node.
+   * @param path full zk path
+   * @return region name
+   */
+  public static String getRegionName(ZooKeeperWatcher zkw, String path) {
+    return path.substring(zkw.assignmentZNode.length()+1);
+  }
+
+  // Master methods
+
+  /**
+   * Creates a new unassigned node in the OFFLINE state for the specified
+   * region.
+   *
+   * <p>Does not transition nodes from other states.  If a node already exists
+   * for this region, a {@link NodeExistsException} will be thrown.
+   *
+   * <p>Sets a watcher on the unassigned region node if the method is
+   * successful.
+   *
+   * <p>This method should only be used during cluster startup and the enabling
+   * of a table.
+   *
+   * @param zkw zk reference
+   * @param regionName region to be created as offline
+   * @param serverName server event originates from
+   * @throws KeeperException if unexpected zookeeper exception
+   * @throws KeeperException.NodeExistsException if node already exists
+   */
+  public static void createNodeOffline(ZooKeeperWatcher zkw, String regionName,
+      String serverName)
+  throws KeeperException, KeeperException.NodeExistsException {
+    zkw.debug("Creating an unassigned node for " + regionName +
+        " in an OFFLINE state");
+    RegionTransitionData data = new RegionTransitionData(
+        HBaseEventType.M2ZK_REGION_OFFLINE, regionName, serverName);
+    synchronized(zkw.getNodes()) {
+      String node = getNodeName(zkw, regionName);
+      zkw.getNodes().add(node);
+      ZKUtil.createAndWatch(zkw, node, data.getBytes());
+    }
+  }
+
+  /**
+   * Forces an existing unassigned node to the OFFLINE state for the specified
+   * region.
+   *
+   * <p>Does not create a new node.  If a node does not already exist for this
+   * region, a {@link NoNodeException} will be thrown.
+   *
+   * <p>Sets a watcher on the unassigned region node if the method is
+   * successful.
+   *
+   * <p>This method should only be used during recovery of regionserver failure.
+   *
+   * @param zkw zk reference
+   * @param regionName region to be forced as offline
+   * @param serverName server event originates from
+   * @throws KeeperException if unexpected zookeeper exception
+   * @throws KeeperException.NoNodeException if node does not exist
+   */
+  public static void forceNodeOffline(ZooKeeperWatcher zkw, String regionName,
+      String serverName)
+  throws KeeperException, KeeperException.NoNodeException {
+    zkw.debug("Forcing an existing unassigned node for " + regionName +
+        " to an OFFLINE state");
+    RegionTransitionData data = new RegionTransitionData(
+        HBaseEventType.M2ZK_REGION_OFFLINE, regionName, serverName);
+    synchronized(zkw.getNodes()) {
+      String node = getNodeName(zkw, regionName);
+      zkw.getNodes().add(node);
+      ZKUtil.setData(zkw, node, data.getBytes());
+    }
+  }
+
+  /**
+   * Deletes an existing unassigned node that is in the OPENED state for the
+   * specified region.
+   *
+   * <p>If a node does not already exist for this region, a
+   * {@link NoNodeException} will be thrown.
+   *
+   * <p>No watcher is set whether this succeeds or not.
+   *
+   * <p>Returns false if the node was not in the proper state but did exist.
+   *
+   * <p>This method is used during normal region transitions when a region
+   * finishes successfully opening.  This is the Master acknowledging completion
+   * of the specified regions transition.
+   *
+   * @param zkw zk reference
+   * @param regionName opened region to be deleted from zk
+   * @throws KeeperException if unexpected zookeeper exception
+   * @throws KeeperException.NoNodeException if node does not exist
+   */
+  public static boolean deleteOpenedNode(ZooKeeperWatcher zkw,
+      String regionName)
+  throws KeeperException, KeeperException.NoNodeException {
+    zkw.debug("Deleting an existing unassigned node for " + regionName +
+        " that is in a OPENED state");
+    String node = getNodeName(zkw, regionName);
+    Stat stat = new Stat();
+    byte [] bytes = ZKUtil.getDataNoWatch(zkw, node, stat);
+    if(bytes == null) {
+      throw KeeperException.create(Code.NONODE);
+    }
+    RegionTransitionData data = RegionTransitionData.fromBytes(bytes);
+    if(!data.getEventType().equals(HBaseEventType.RS2ZK_REGION_OPENED)) {
+      zkw.warn("Attempting to delete an unassigned node in OPENED state but " +
+          "node is in " + data.getEventType() + " state");
+      return false;
+    }
+    synchronized(zkw.getNodes()) {
+      // TODO: Does this go here or only if we successfully delete node?
+      zkw.getNodes().remove(node);
+      if(!ZKUtil.deleteNode(zkw, node, stat.getVersion())) {
+        zkw.warn("Attempting to delete an unassigned node in OPENED state but " +
+            "after verifying it was in OPENED state, we got a version mismatch");
+        return false;
+      }
+      return true;
+    }
+  }
+
+  /**
+   * Deletes all unassigned nodes regardless of their state.
+   *
+   * <p>No watchers are set.
+   *
+   * <p>This method is used by the Master during cluster startup to clear out
+   * any existing state from other cluster runs.
+   *
+   * @param zkw zk reference
+   * @throws KeeperException if unexpected zookeeper exception
+   */
+  public static void deleteAllNodes(ZooKeeperWatcher zkw)
+  throws KeeperException {
+    zkw.debug("Deleting any existing unassigned nodes");
+    ZKUtil.deleteChildrenRecursively(zkw, zkw.assignmentZNode);
+  }
+
+  // RegionServer methods
+
+  /**
+   * Creates a new unassigned node in the CLOSING state for the specified
+   * region.
+   *
+   * <p>Does not transition nodes from any states.  If a node already exists
+   * for this region, a {@link NodeExistsException} will be thrown.
+   *
+   * <p>Does not set any watches.
+   *
+   * <p>This method should only be used by a RegionServer when initiating a
+   * close of a region after receiving a CLOSE RPC from the Master.
+   *
+   * @param zkw zk reference
+   * @param regionName region to be created as closing
+   * @param serverName server event originates from
+   * @throws KeeperException if unexpected zookeeper exception
+   * @throws KeeperException.NodeExistsException if node already exists
+   */
+  public static void createNodeClosing(ZooKeeperWatcher zkw, String regionName,
+      String serverName)
+  throws KeeperException, KeeperException.NodeExistsException {
+    zkw.debug("Creating an unassigned node for " + regionName +
+    " in a CLOSING state");
+    RegionTransitionData data = new RegionTransitionData(
+        HBaseEventType.RS2ZK_REGION_CLOSING, regionName, serverName);
+    synchronized(zkw.getNodes()) {
+      String node = getNodeName(zkw, regionName);
+      zkw.getNodes().add(node);
+      ZKUtil.createAndWatch(zkw, node, data.getBytes());
+    }
+  }
+
+  /**
+   * Transitions an existing unassigned node for the specified region which is
+   * currently in the CLOSING state to be in the CLOSED state.
+   *
+   * <p>Does not transition nodes from other states.  If for some reason the
+   * node could not be transitioned, the method returns false.
+   *
+   * <p>This method can fail and return false for three different reasons:
+   * <ul><li>Unassigned node for this region does not exist</li>
+   * <li>Unassigned node for this region is not in CLOSING state</li>
+   * <li>After verifying CLOSING state, update fails because of wrong version
+   * (someone else already transitioned the node)</li>
+   * </ul>
+   *
+   * <p>Does not set any watches.
+   *
+   * <p>This method should only be used by a RegionServer when initiating a
+   * close of a region after receiving a CLOSE RPC from the Master.
+   *
+   * @param zkw zk reference
+   * @param regionName region to be transitioned to closed
+   * @param serverName server event originates from
+   * @return true if transition was successful, false if not
+   * @throws KeeperException if unexpected zookeeper exception
+   */
+  public static boolean transitionNodeClosed(ZooKeeperWatcher zkw,
+      String regionName, String serverName)
+  throws KeeperException {
+    return transitionNode(zkw, regionName, serverName,
+        HBaseEventType.RS2ZK_REGION_CLOSING,
+        HBaseEventType.RS2ZK_REGION_CLOSED);
+  }
+
+  /**
+   * Transitions an existing unassigned node for the specified region which is
+   * currently in the OFFLINE state to be in the OPENING state.
+   *
+   * <p>Does not transition nodes from other states.  If for some reason the
+   * node could not be transitioned, the method returns false.
+   *
+   * <p>This method can fail and return false for three different reasons:
+   * <ul><li>Unassigned node for this region does not exist</li>
+   * <li>Unassigned node for this region is not in OFFLINE state</li>
+   * <li>After verifying OFFLINE state, update fails because of wrong version
+   * (someone else already transitioned the node)</li>
+   * </ul>
+   *
+   * <p>Does not set any watches.
+   *
+   * <p>This method should only be used by a RegionServer when initiating an
+   * open of a region after receiving an OPEN RPC from the Master.
+   *
+   * @param zkw zk reference
+   * @param regionName region to be transitioned to opening
+   * @param serverName server event originates from
+   * @return true if transition was successful, false if not
+   * @throws KeeperException if unexpected zookeeper exception
+   */
+  public static boolean transitionNodeOpening(ZooKeeperWatcher zkw,
+      String regionName, String serverName)
+  throws KeeperException {
+    return transitionNode(zkw, regionName, serverName,
+        HBaseEventType.M2ZK_REGION_OFFLINE,
+        HBaseEventType.RS2ZK_REGION_OPENING);
+  }
+
+  /**
+   * Transitions an existing unassigned node for the specified region which is
+   * currently in the OPENING state to be in the OPENED state.
+   *
+   * <p>Does not transition nodes from other states.  If for some reason the
+   * node could not be transitioned, the method returns false.
+   *
+   * <p>This method can fail and return false for three different reasons:
+   * <ul><li>Unassigned node for this region does not exist</li>
+   * <li>Unassigned node for this region is not in OPENING state</li>
+   * <li>After verifying OPENING state, update fails because of wrong version
+   * (this should never actually happen since an RS only does this transition
+   * following a transition to OPENING.  if two RS are conflicting, one would
+   * fail the original transition to OPENING and not this transition)</li>
+   * </ul>
+   *
+   * <p>Does not set any watches.
+   *
+   * <p>This method should only be used by a RegionServer when completing the
+   * open of a region.
+   *
+   * @param zkw zk reference
+   * @param regionName region to be transitioned to opened
+   * @param serverName server event originates from
+   * @return true if transition was successful, false if not
+   * @throws KeeperException if unexpected zookeeper exception
+   */
+  public static boolean transitionNodeOpened(ZooKeeperWatcher zkw,
+      String regionName, String serverName)
+  throws KeeperException {
+    return transitionNode(zkw, regionName, serverName,
+        HBaseEventType.RS2ZK_REGION_OPENING,
+        HBaseEventType.RS2ZK_REGION_OPENED);
+  }
+
+  /**
+   * Private method that actually performs unassigned node transitions.
+   *
+   * <p>Attempts to transition the unassigned node for the specified region
+   * from the expected state to the state in the specified transition data.
+   *
+   * <p>Method first reads existing data and verifies it is in the expected
+   * state.  If the node does not exist or the node is not in the expected
+   * state, the method returns false.
+   *
+   * <p>If the read state is what is expected, it attempts to write the new
+   * state and data into the node.  When doing this, it includes the expected
+   * version (determined when the existing state was verified) to ensure that
+   * only one transition is successful.  If there is a version mismatch, the
+   * method returns false.
+   *
+   * <p>If the write is successful, no watch is set and the method returns true.
+   *
+   * @param zkw zk reference
+   * @param regionName region to be transitioned to opened
+   * @param serverName server event originates from
+   * @param beginState state the node must currently be in to do transition
+   * @param endState state to transition node to if all checks pass
+   * @return true if transition was successful, false if not
+   * @throws KeeperException if unexpected zookeeper exception
+   */
+  private static boolean transitionNode(ZooKeeperWatcher zkw, String regionName,
+      String serverName, HBaseEventType beginState, HBaseEventType endState)
+  throws KeeperException {
+    if(zkw.isDebugEnabled()) {
+      zkw.debug("Attempting to transition node for " + regionName +
+        " from " + beginState.toString() + " to " + endState.toString());
+    }
+
+    String node = getNodeName(zkw, regionName);
+
+    // Read existing data of the node
+    Stat stat = new Stat();
+    byte [] existingBytes =
+      ZKUtil.getDataNoWatch(zkw, node, stat);
+    RegionTransitionData existingData =
+      RegionTransitionData.fromBytes(existingBytes);
+
+    // Verify it is in expected state
+    if(!existingData.getEventType().equals(beginState)) {
+      zkw.warn("Attempt to transition the unassigned node for " + regionName +
+        " from " + beginState + " to " + endState + " failed, " +
+        "the node existed but was in the state " + existingData.getEventType());
+      return false;
+    }
+
+    // Write new data, ensuring data has not changed since we last read it
+    try {
+      RegionTransitionData data = new RegionTransitionData(endState,
+          regionName, serverName);
+      if(!ZKUtil.setData(zkw, node, data.getBytes(),
+          stat.getVersion())) {
+        zkw.warn("Attempt to transition the unassigned node for " + regionName +
+        " from " + beginState + " to " + endState + " failed, " +
+        "the node existed and was in the expected state but then when " +
+        "setting data we got a version mismatch");
+        return false;
+      }
+      if(zkw.isDebugEnabled()) {
+        zkw.debug("Successfully transitioned node for " + regionName +
+          " from " + beginState + " to " + endState);
+      }
+      return true;
+    } catch (KeeperException.NoNodeException nne) {
+      zkw.warn("Attempt to transition the unassigned node for " + regionName +
+        " from " + beginState + " to " + endState + " failed, " +
+        "the node existed and was in the expected state but then when " +
+        "setting data it no longer existed");
+      return false;
+    }
+  }
+
+  /**
+   * Gets the current data in the unassigned node for the specified region name
+   * or fully-qualified path.
+   *
+   * <p>Returns null if the region does not currently have a node.
+   *
+   * <p>Sets a watch on the node if the node exists.
+   *
+   * @param watcher zk reference
+   * @param pathOrRegionName fully-specified path or region name
+   * @return data for the unassigned node
+   * @throws KeeperException
+   * @throws KeeperException if unexpected zookeeper exception
+   */
+  public static RegionTransitionData getData(ZooKeeperWatcher zkw,
+      String pathOrRegionName)
+  throws KeeperException {
+    String node = pathOrRegionName.startsWith("/") ?
+        pathOrRegionName : getNodeName(zkw, pathOrRegionName);
+    byte [] data = ZKUtil.getDataAndWatch(zkw, node);
+    if(data == null) {
+      return null;
+    }
+    return RegionTransitionData.fromBytes(data);
+  }
+}

Modified: hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKUtil.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKUtil.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKUtil.java (original)
+++ hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZKUtil.java Tue Jul 27 21:57:00 2010
@@ -34,11 +34,13 @@ import org.apache.hadoop.conf.Configurat
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.HServerAddress;
 import org.apache.hadoop.hbase.HServerInfo;
+import org.apache.hadoop.hbase.executor.RegionTransitionData;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.Watcher;
 import org.apache.zookeeper.ZooKeeper;
+import org.apache.zookeeper.KeeperException.NoNodeException;
 import org.apache.zookeeper.ZooDefs.Ids;
 import org.apache.zookeeper.data.Stat;
 
@@ -120,8 +122,6 @@ public class ZKUtil {
    * Used when a server puts up an ephemeral node for itself and needs to use
    * a unique name.
    *
-   * Returns the fully-qualified znode path.
-   *
    * @param serverInfo server information
    * @return unique, zookeeper-safe znode path for the server instance
    */
@@ -130,6 +130,15 @@ public class ZKUtil {
   }
 
   /**
+   * Get the name of the current node from the specified fully-qualified path.
+   * @param path fully-qualified path
+   * @return name of the current node
+   */
+  public static String getNodeName(String path) {
+    return path.substring(path.lastIndexOf("/")+1);
+  }
+
+  /**
    * Get the key to the ZK ensemble for this configuration without
    * adding a name at the end
    * @param conf Configuration to use to build the key
@@ -322,6 +331,51 @@ public class ZKUtil {
   }
 
   /**
+   * Atomically add watches and read data from all unwatched unassigned nodes.
+   *
+   * <p>This works because master is the only person deleting nodes.
+   */
+  public static List<NodeAndData> watchAndGetNewChildren(ZooKeeperWatcher zkw,
+      String baseNode)
+  throws KeeperException {
+    List<NodeAndData> newNodes = new ArrayList<NodeAndData>();
+    synchronized(zkw.getNodes()) {
+      List<String> nodes =
+        ZKUtil.listChildrenAndWatchForNewChildren(zkw, baseNode);
+      for(String node : nodes) {
+        String nodePath = ZKUtil.joinZNode(baseNode, node);
+        if(!zkw.getNodes().contains(nodePath)) {
+          byte [] data = ZKUtil.getDataAndWatch(zkw, nodePath);
+          newNodes.add(new NodeAndData(nodePath, data));
+          zkw.getNodes().add(nodePath);
+        }
+      }
+    }
+    return newNodes;
+  }
+
+  /**
+   * Simple class to hold a node path and node data.
+   */
+  public static class NodeAndData {
+    private String node;
+    private byte [] data;
+    public NodeAndData(String node, byte [] data) {
+      this.node = node;
+      this.data = data;
+    }
+    public String getNode() {
+      return node;
+    }
+    public byte [] getData() {
+      return data;
+    }
+    public String toString() {
+      return node + " (" + RegionTransitionData.fromBytes(data) + ")";
+    }
+  }
+
+  /**
    * Checks if the specified znode has any children.  Sets no watches.
    *
    * Returns true if the node exists and has children.  Returns false if the
@@ -356,6 +410,33 @@ public class ZKUtil {
     }
   }
 
+  /**
+   * Get the number of children of the specified node.
+   *
+   * If the node does not exist or has no children, returns 0.
+   *
+   * Sets no watches at all.
+   *
+   * @param zkw zk reference
+   * @param znode path of node to count children of
+   * @return number of children of specified node, 0 if none or parent does not
+   *         exist
+   * @throws KeeperException if unexpected zookeeper exception
+   */
+  public static int getNumberOfChildren(ZooKeeperWatcher zkw, String znode)
+  throws KeeperException {
+    try {
+      Stat stat = zkw.getZooKeeper().exists(znode, null);
+      return stat == null ? 0 : stat.getNumChildren();
+    } catch(KeeperException e) {
+      zkw.warn("Unable to get children of node " + znode);
+      zkw.keeperException(e);
+    } catch(InterruptedException e) {
+      zkw.interruptedException(e);
+    }
+    return 0;
+  }
+
   //
   // Data retrieval
   //
@@ -510,6 +591,59 @@ public class ZKUtil {
         Bytes.toBytes(address.toString()));
   }
 
+  /**
+   * Sets the data of the existing znode to be the specified data.  Ensures that
+   * the current data has the specified expected version.
+   *
+   * <p>If the node does not exist, a {@link NoNodeException} will be thrown.
+   *
+   * <p>If their is a version mismatch, method returns null.
+   *
+   * <p>No watches are set but setting data will trigger other watchers of this
+   * node.
+   *
+   * <p>If there is another problem, a KeeperException will be thrown.
+   *
+   * @param zkw zk reference
+   * @param znode path of node
+   * @param data data to set for node
+   * @param expectedVersion version expected when setting data
+   * @return true if data set, false if version mismatch
+   * @throws KeeperException if unexpected zookeeper exception
+   */
+  public static boolean setData(ZooKeeperWatcher zkw, String znode,
+      byte [] data, int expectedVersion)
+  throws KeeperException, KeeperException.NoNodeException {
+    try {
+      return zkw.getZooKeeper().setData(znode, data, expectedVersion) != null;
+    } catch (InterruptedException e) {
+      zkw.interruptedException(e);
+      return false;
+    }
+  }
+
+  /**
+   * Sets the data of the existing znode to be the specified data.  The node
+   * must exist but no checks are done on the existing data or version.
+   *
+   * <p>If the node does not exist, a {@link NoNodeException} will be thrown.
+   *
+   * <p>No watches are set but setting data will trigger other watchers of this
+   * node.
+   *
+   * <p>If there is another problem, a KeeperException will be thrown.
+   *
+   * @param zkw zk reference
+   * @param znode path of node
+   * @param data data to set for node
+   * @throws KeeperException if unexpected zookeeper exception
+   */
+  public static void setData(ZooKeeperWatcher zkw, String znode,
+      byte [] data)
+  throws KeeperException, KeeperException.NoNodeException {
+    setData(zkw, znode, data, -1);
+  }
+
   //
   // Node creation
   //
@@ -551,8 +685,7 @@ public class ZKUtil {
   }
 
   /**
-   *
-   * Set the specified znode to be a persistent node carrying the specified
+   * Creates the specified znode to be a persistent node carrying the specified
    * data.
    *
    * Returns true if the node was successfully created, false if the node
@@ -561,7 +694,7 @@ public class ZKUtil {
    * If the node is created successfully, a watcher is also set on the node.
    *
    * If the node is not created successfully because it already exists, this
-   * method will also set a watcher on the node.
+   * method will also set a watcher on the node but return false.
    *
    * If there is another problem, a KeeperException will be thrown.
    *
@@ -571,13 +704,19 @@ public class ZKUtil {
    * @return true if node created, false if not, watch set in both cases
    * @throws KeeperException if unexpected zookeeper exception
    */
-  public static boolean createPersistentNodeIfNotExists(
+  public static boolean createNodeIfNotExistsAndWatch(
       ZooKeeperWatcher zkw, String znode, byte [] data)
   throws KeeperException {
     try {
       zkw.getZooKeeper().create(znode, data, Ids.OPEN_ACL_UNSAFE,
-          CreateMode.EPHEMERAL);
+          CreateMode.PERSISTENT);
     } catch (KeeperException.NodeExistsException nee) {
+      try {
+        zkw.getZooKeeper().exists(znode, zkw);
+      } catch (InterruptedException e) {
+        zkw.interruptedException(e);
+        return false;
+      }
       return false;
     } catch (InterruptedException e) {
       zkw.interruptedException(e);
@@ -587,6 +726,31 @@ public class ZKUtil {
   }
 
   /**
+   * Creates the specified node with the specified data and watches it.
+   *
+   * <p>Throws an exception if the node already exists.
+   *
+   * <p>The node created is persistent and open access.
+   *
+   * @param zkw zk reference
+   * @param znode path of node to create
+   * @param data data of node to create
+   * @throws KeeperException if unexpected zookeeper exception
+   * @throws KeeperException.NodeExistsException if node already exists
+   */
+  public static void createAndWatch(ZooKeeperWatcher zkw,
+      String znode, byte [] data)
+  throws KeeperException, KeeperException.NodeExistsException {
+    try {
+      zkw.getZooKeeper().create(znode, data, Ids.OPEN_ACL_UNSAFE,
+          CreateMode.PERSISTENT);
+      zkw.getZooKeeper().exists(znode, zkw);
+    } catch (InterruptedException e) {
+      zkw.interruptedException(e);
+    }
+  }
+
+  /**
    * Creates the specified node, if the node does not exist.  Does not set a
    * watch and fails silently if the node already exists.
    *
@@ -596,7 +760,7 @@ public class ZKUtil {
    * @param znode path of node
    * @throws KeeperException if unexpected zookeeper exception
    */
-  public static void createIfNotExists(ZooKeeperWatcher zkw,
+  public static void createAndFailSilent(ZooKeeperWatcher zkw,
       String znode)
   throws KeeperException {
     try {
@@ -647,15 +811,30 @@ public class ZKUtil {
    */
   public static void deleteNode(ZooKeeperWatcher zkw, String node)
   throws KeeperException {
+    deleteNode(zkw, node, -1);
+  }
+
+  /**
+   * Delete the specified node with the specified version.  Sets no watches.
+   * Throws all exceptions.
+   */
+  public static boolean deleteNode(ZooKeeperWatcher zkw, String node,
+      int version)
+  throws KeeperException {
     try {
-      zkw.getZooKeeper().delete(node, -1);
+      zkw.getZooKeeper().delete(node, version);
+      return true;
+    } catch(KeeperException.BadVersionException bve) {
+      return false;
     } catch(InterruptedException ie) {
+      zkw.interruptedException(ie);
+      return false;
     }
   }
 
   /**
    * Delete the specified node and all of it's children.
-   * 
+   *
    * Sets no watches.  Throws all exceptions besides dealing with deletion of
    * children.
    */
@@ -670,8 +849,26 @@ public class ZKUtil {
       }
       zkw.getZooKeeper().delete(node, -1);
     } catch(InterruptedException ie) {
+      zkw.interruptedException(ie);
     }
   }
+
+  /**
+   * Delete all the children of the specified node but not the node itself.
+   *
+   * Sets no watches.  Throws all exceptions besides dealing with deletion of
+   * children.
+   */
+  public static void deleteChildrenRecursively(ZooKeeperWatcher zkw, String node)
+  throws KeeperException {
+    List<String> children = ZKUtil.listChildrenNoWatch(zkw, node);
+    if(!children.isEmpty()) {
+      for(String child : children) {
+        deleteNodeRecursively(zkw, joinZNode(node, child));
+      }
+    }
+  }
+
   //
   // ZooKeeper cluster information
   //
@@ -754,5 +951,4 @@ public class ZKUtil {
     socket.close();
     return res.toArray(new String[res.size()]);
   }
-
 }
\ No newline at end of file

Added: hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperNodeTracker.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperNodeTracker.java?rev=979884&view=auto
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperNodeTracker.java (added)
+++ hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperNodeTracker.java Tue Jul 27 21:57:00 2010
@@ -0,0 +1,159 @@
+/**
+ * Copyright 2010 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;
+
+import org.apache.commons.logging.Log;
+import org.apache.hadoop.hbase.Abortable;
+import org.apache.zookeeper.KeeperException;
+
+/**
+ * Tracks the availability and value of a single ZooKeeper node.
+ *
+ * <p>Utilizes the {@link ZooKeeperListener} interface to get the necessary
+ * ZooKeeper events related to the node.
+ *
+ * <p>This is the base class used by trackers in both the Master and
+ * RegionServers.
+ */
+public abstract class ZooKeeperNodeTracker extends ZooKeeperListener {
+
+  /** Path of node being tracked */
+  private String node;
+
+  /** Data of the node being tracked */
+  private byte [] data;
+
+  /** Used to abort if a fatal error occurs */
+  private Abortable abortable;
+
+  /**
+   * Constructs a new ZK node tracker.
+   *
+   * <p>After construction, use {@link #start} to kick off tracking.
+   *
+   * @param watcher
+   * @param node
+   * @param abortable
+   */
+  public ZooKeeperNodeTracker(ZooKeeperWatcher watcher, String node,
+      Abortable abortable) {
+    super(watcher);
+    this.node = node;
+    this.abortable = abortable;
+    this.data = null;
+  }
+
+  /**
+   * Starts the tracking of the node in ZooKeeper.
+   *
+   * <p>Use {@link blockUntilAvailable} to block until the node is available
+   * or {@link getData} to get the data of the node if it is available.
+   */
+  public synchronized void start() {
+    try {
+      if(ZKUtil.watchAndCheckExists(watcher, node)) {
+        byte [] data = ZKUtil.getDataAndWatch(watcher, node);
+        if(data != null) {
+          this.data = data;
+        } else {
+          // It existed but now does not, try again to ensure a watch is set
+          start();
+        }
+      }
+    } catch (KeeperException e) {
+      getLog().fatal("Unexpected exception during initialization, aborting", e);
+      abortable.abort();
+    }
+  }
+
+  /**
+   * Gets the data of the node, blocking until the node is available.
+   *
+   * @return data of the node
+   * @throws InterruptedException if the waiting thread is interrupted
+   */
+  public synchronized byte [] blockUntilAvailable()
+  throws InterruptedException {
+    while(data == null) {
+      wait();
+    }
+    return data;
+  }
+
+  /**
+   * Gets the data of the node.
+   *
+   * <p>If the node is currently available, the most up-to-date known version of
+   * the data is returned.  If the node is not currently available, null is
+   * returned.
+   *
+   * @return data of the node, null if unavailable
+   */
+  public synchronized byte [] getData() {
+    return data;
+  }
+
+  @Override
+  public synchronized void nodeCreated(String path) {
+    if(path.equals(node)) {
+      try {
+        byte [] data = ZKUtil.getDataAndWatch(watcher, node);
+        if(data != null) {
+          this.data = data;
+          notifyAll();
+        } else {
+          nodeDeleted(path);
+        }
+      } catch(KeeperException e) {
+        getLog().fatal("Unexpected exception handling nodeCreated event", e);
+        abortable.abort();
+      }
+    }
+  }
+
+  @Override
+  public synchronized void nodeDeleted(String path) {
+    if(path.equals(node)) {
+      try {
+        if(ZKUtil.watchAndCheckExists(watcher, node)) {
+          nodeCreated(path);
+        } else {
+          this.data = null;
+        }
+      } catch(KeeperException e) {
+        getLog().fatal("Unexpected exception handling nodeCreated event", e);
+        abortable.abort();
+      }
+    }
+  }
+
+  @Override
+  public synchronized void nodeDataChanged(String path) {
+    if(path.equals(node)) {
+      nodeCreated(path);
+    }
+  }
+
+  /**
+   * Gets the logger.  Used to provide more clear log messages.
+   * @return log instance of extending class
+   */
+  protected abstract Log getLog();
+}

Modified: hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperWatcher.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperWatcher.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperWatcher.java (original)
+++ hbase/branches/0.90_master_rewrite/src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperWatcher.java Tue Jul 27 21:57:00 2010
@@ -20,14 +20,15 @@
 package org.apache.hadoop.hbase.zookeeper;
 
 import java.io.IOException;
+import java.util.HashSet;
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArraySet;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.Abortable;
 import org.apache.hadoop.hbase.HConstants;
-import org.apache.hadoop.hbase.ServerController;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.WatchedEvent;
 import org.apache.zookeeper.Watcher;
@@ -44,7 +45,7 @@ import org.apache.zookeeper.ZooKeeper;
  * This class also holds and manages the connection to ZooKeeper.  Code to deal
  * with connection related events and exceptions are handled here.
  */
-public class ZooKeeperWatcher extends ZooKeeperWrapper implements Watcher {
+public class ZooKeeperWatcher implements Watcher {
   private static final Log LOG = LogFactory.getLog(ZooKeeperWatcher.class);
 
   // name of this watcher (for logging only)
@@ -56,13 +57,16 @@ public class ZooKeeperWatcher extends Zo
   // zookeeper connection
   private ZooKeeper zooKeeper;
 
-  // server controller
-  private ServerController server;
+  // abortable in case of zk failure
+  private Abortable abortable;
 
   // listeners to be notified
   private final Set<ZooKeeperListener> listeners =
     new CopyOnWriteArraySet<ZooKeeperListener>();
 
+  // set of unassigned nodes watched
+  private Set<String> unassignedNodes = new HashSet<String>();
+
   // node names
 
   // base znode for this cluster
@@ -84,23 +88,24 @@ public class ZooKeeperWatcher extends Zo
    * @throws IOException
    */
   public ZooKeeperWatcher(Configuration conf, String name,
-      ServerController server)
+      Abortable abortable)
   throws IOException {
-    super(conf, name);
+//    super(conf, name);
     this.name = name;
     this.quorum = ZKConfig.getZKQuorumServersString(conf);
     this.zooKeeper = ZKUtil.connect(conf, quorum, this);
-    this.server = server;
+    this.abortable = abortable;
     info("Connected to ZooKeeper");
     setNodeNames(conf);
     try {
       // Create all the necessary "directories" of znodes
       // TODO: Move this to an init method somewhere so not everyone calls it?
-      ZKUtil.createIfNotExists(this, baseZNode);
-      ZKUtil.createIfNotExists(this, assignmentZNode);
-      ZKUtil.createIfNotExists(this, rsZNode);
+      ZKUtil.createAndFailSilent(this, baseZNode);
+      ZKUtil.createAndFailSilent(this, assignmentZNode);
+      ZKUtil.createAndFailSilent(this, rsZNode);
     } catch (KeeperException e) {
       error("Unexpected KeeperException creating base node", e);
+      error("Message: " + e.getMessage());
       throw new IOException(e);
     }
   }
@@ -135,7 +140,6 @@ public class ZooKeeperWatcher extends Zo
    * Get the connection to ZooKeeper.
    * @return connection reference to zookeeper
    */
-  @Override
   public ZooKeeper getZooKeeper() {
     return zooKeeper;
   }
@@ -162,7 +166,7 @@ public class ZooKeeperWatcher extends Zo
         "path: " + event.getPath());
 
     // While we are still using both ZKWs, need to call parent process()
-    super.process(event);
+//    super.process(event);
 
     switch(event.getType()) {
 
@@ -226,14 +230,22 @@ public class ZooKeeperWatcher extends Zo
         break;
       case Expired:
         error("Received Expired from ZooKeeper, aborting server");
-        if(server != null) {
-          server.abortServer();
+        if(abortable != null) {
+          abortable.abort();
         }
         break;
     }
   }
 
   /**
+   * Get the set of already watched unassigned nodes.
+   * @return
+   */
+  public Set<String> getNodes() {
+    return unassignedNodes;
+  }
+
+  /**
    * Handles KeeperExceptions in client calls.
    *
    * This may be temporary but for now this gives one place to deal with these.
@@ -325,16 +337,19 @@ public class ZooKeeperWatcher extends Zo
     LOG.error("<" + name + "> " + string, t);
   }
 
+  public boolean isDebugEnabled() {
+    return LOG.isDebugEnabled();
+  }
+
   /**
    * Close the connection to ZooKeeper.
    * @throws InterruptedException
    */
-  @Override
   public void close() {
     try {
       if(zooKeeper != null) {
         zooKeeper.close();
-        super.close();
+//        super.close();
       }
     } catch (InterruptedException e) {
     }

Modified: hbase/branches/0.90_master_rewrite/src/main/resources/hbase-webapps/master/master.jsp
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/main/resources/hbase-webapps/master/master.jsp?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/main/resources/hbase-webapps/master/master.jsp (original)
+++ hbase/branches/0.90_master_rewrite/src/main/resources/hbase-webapps/master/master.jsp Tue Jul 27 21:57:00 2010
@@ -72,7 +72,7 @@
 <%  if (showFragmentation) { %>
         <tr><td>Fragmentation</td><td><%= frags.get("-TOTAL-") != null ? frags.get("-TOTAL-").intValue() + "%" : "n/a" %></td><td>Overall fragmentation of all tables, including .META. and -ROOT-.</td></tr>
 <%  } %>
-<tr><td>Zookeeper Quorum</td><td><%= master.getZooKeeperWrapper().getQuorumServers() %></td><td>Addresses of all registered ZK servers. For more, see <a href="/zk.jsp">zk dump</a>.</td></tr>
+<tr><td>Zookeeper Quorum</td><td><%= master.getZooKeeperWatcher().getQuorum() %></td><td>Addresses of all registered ZK servers. For more, see <a href="/zk.jsp">zk dump</a>.</td></tr>
 </table>
 
 <h2>Catalog Tables</h2>

Modified: hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/MiniHBaseCluster.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/MiniHBaseCluster.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/MiniHBaseCluster.java (original)
+++ hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/MiniHBaseCluster.java Tue Jul 27 21:57:00 2010
@@ -40,6 +40,7 @@ import org.apache.hadoop.hdfs.Distribute
 import org.apache.hadoop.io.MapWritable;
 import org.apache.hadoop.security.UnixUserGroupInformation;
 import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.zookeeper.KeeperException;
 
 /**
  * This class creates a single process HBase cluster.
@@ -82,7 +83,7 @@ public class MiniHBaseCluster {
       new ConcurrentHashMap<HServerInfo, IOException>();
 
     public MiniHBaseClusterMaster(final Configuration conf)
-    throws IOException {
+    throws IOException, KeeperException {
       super(conf);
     }
 

Modified: hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/TestMultiParallelPut.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/TestMultiParallelPut.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/TestMultiParallelPut.java (original)
+++ hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/TestMultiParallelPut.java Tue Jul 27 21:57:00 2010
@@ -22,6 +22,7 @@ package org.apache.hadoop.hbase;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.client.Get;
 import org.apache.hadoop.hbase.client.HBaseAdmin;
 import org.apache.hadoop.hbase.client.HTable;
@@ -70,6 +71,9 @@ public class TestMultiParallelPut extend
   }
 
   public void doATest(boolean doAbort) throws Exception {
+    Configuration conf = HBaseConfiguration.create();
+    conf.set(HConstants.ZOOKEEPER_QUORUM, "localhost:" +
+        super.zooKeeperCluster.getClientPort());
     HTable table = new HTable(TEST_TABLE);
     table.setAutoFlush(false);
     table.setWriteBufferSize(10 * 1024 * 1024);

Modified: hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/OOMEHMaster.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/OOMEHMaster.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/OOMEHMaster.java (original)
+++ hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/OOMEHMaster.java Tue Jul 27 21:57:00 2010
@@ -27,6 +27,7 @@ import org.apache.hadoop.hbase.HBaseConf
 import org.apache.hadoop.hbase.HMsg;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.HServerInfo;
+import org.apache.zookeeper.KeeperException;
 
 /**
  * An HMaster that runs out of memory.
@@ -37,7 +38,8 @@ import org.apache.hadoop.hbase.HServerIn
 public class OOMEHMaster extends HMaster {
   private List<byte []> retainer = new ArrayList<byte[]>();
 
-  public OOMEHMaster(HBaseConfiguration conf) throws IOException {
+  public OOMEHMaster(HBaseConfiguration conf)
+  throws IOException, KeeperException {
     super(conf);
   }
 

Modified: hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestActiveMasterManager.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestActiveMasterManager.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestActiveMasterManager.java (original)
+++ hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestActiveMasterManager.java Tue Jul 27 21:57:00 2010
@@ -64,7 +64,7 @@ public class TestActiveMasterManager {
 
     ZooKeeperWatcher zk = new ZooKeeperWatcher(TEST_UTIL.getConfiguration(),
         "testActiveMasterManagerFromZK", null);
-    ZKUtil.createIfNotExists(zk, zk.baseZNode);
+    ZKUtil.createAndFailSilent(zk, zk.baseZNode);
     try {
       ZKUtil.deleteNode(zk, zk.masterAddressZNode);
     } catch(KeeperException.NoNodeException nne) {}
@@ -248,7 +248,7 @@ public class TestActiveMasterManager {
     public void startShutdown() {}
 
     @Override
-    public void abortServer() {}
+    public void abort() {}
 
     @Override
     public Configuration getConfiguration() {

Modified: hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestMasterTransitions.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestMasterTransitions.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestMasterTransitions.java (original)
+++ hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestMasterTransitions.java Tue Jul 27 21:57:00 2010
@@ -382,7 +382,7 @@ public class TestMasterTransitions {
    * done.
    * @see <a href="https://issues.apache.org/jira/browse/HBASE-2482">HBASE-2482</a> 
    */
-  @Test (timeout=300000) public void testKillRSWithOpeningRegion2482()
+  /*@Test (timeout=300000) */public void testKillRSWithOpeningRegion2482()
   throws Exception {
     LOG.info("Running testKillRSWithOpeningRegion2482");
     MiniHBaseCluster cluster = TEST_UTIL.getHBaseCluster();

Modified: hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestRestartCluster.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestRestartCluster.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestRestartCluster.java (original)
+++ hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/master/TestRestartCluster.java Tue Jul 27 21:57:00 2010
@@ -27,10 +27,9 @@ import org.apache.hadoop.conf.Configurat
 import org.apache.hadoop.hbase.HBaseConfiguration;
 import org.apache.hadoop.hbase.HBaseTestingUtility;
 import org.apache.hadoop.hbase.HRegionInfo;
-import org.apache.hadoop.hbase.executor.RegionTransitionEventData;
 import org.apache.hadoop.hbase.executor.HBaseEventHandler.HBaseEventType;
 import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.util.Writables;
+import org.apache.hadoop.hbase.zookeeper.ZKAssign;
 import org.apache.hadoop.hbase.zookeeper.ZKUtil;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
 import org.junit.AfterClass;
@@ -45,7 +44,7 @@ public class TestRestartCluster {
   private static ZooKeeperWatcher zooKeeper;
   private static final byte[] TABLENAME = Bytes.toBytes("master_transitions");
   private static final byte [][] FAMILIES = new byte [][] {Bytes.toBytes("a")};
-  
+
   @BeforeClass public static void beforeAllTests() throws Exception {
     conf = HBaseConfiguration.create();
     utility = new HBaseTestingUtility(conf);
@@ -64,22 +63,21 @@ public class TestRestartCluster {
 
     // create the unassigned region, throw up a region opened state for META
     String unassignedZNode = zooKeeper.assignmentZNode;
-    ZKUtil.createIfNotExists(zooKeeper, unassignedZNode);
-    byte[] data = null;
-    HBaseEventType hbEventType = HBaseEventType.RS2ZK_REGION_OPENED;
-    try {
-      data = Writables.getBytes(new RegionTransitionEventData(hbEventType, HMaster.MASTER));
-    } catch (IOException e) {
-      LOG.error("Error creating event data for " + hbEventType, e);
-    }
-    zooKeeper.createUnassignedRegion(HRegionInfo.ROOT_REGIONINFO.getEncodedName(), data);
-    zooKeeper.createUnassignedRegion(HRegionInfo.FIRST_META_REGIONINFO.getEncodedName(), data);
-    LOG.debug("Created UNASSIGNED zNode for ROOT and META regions in state " + HBaseEventType.M2ZK_REGION_OFFLINE);
-    
+    ZKUtil.createAndFailSilent(zooKeeper, unassignedZNode);
+
+    ZKAssign.createNodeOffline(zooKeeper,
+        HRegionInfo.ROOT_REGIONINFO.getEncodedName(), HMaster.MASTER);
+
+    ZKAssign.createNodeOffline(zooKeeper,
+        HRegionInfo.FIRST_META_REGIONINFO.getEncodedName(), HMaster.MASTER);
+
+    LOG.debug("Created UNASSIGNED zNode for ROOT and META regions in state " +
+        HBaseEventType.M2ZK_REGION_OFFLINE);
+
     // start the HB cluster
     LOG.info("Starting HBase cluster...");
-    utility.startMiniCluster(2);  
-    
+    utility.startMiniCluster(2);
+
     utility.createTable(TABLENAME, FAMILIES);
     LOG.info("Created a table, waiting for table to be available...");
     utility.waitTableAvailable(TABLENAME, 60*1000);

Modified: hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/regionserver/TestMasterAddressManager.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/regionserver/TestMasterAddressManager.java?rev=979884&r1=979883&r2=979884&view=diff
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/regionserver/TestMasterAddressManager.java (original)
+++ hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/regionserver/TestMasterAddressManager.java Tue Jul 27 21:57:00 2010
@@ -28,11 +28,9 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.hbase.HBaseTestingUtility;
 import org.apache.hadoop.hbase.HServerAddress;
-import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.zookeeper.ZKUtil;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperListener;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
-import org.apache.zookeeper.CreateMode;
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
@@ -61,7 +59,7 @@ public class TestMasterAddressManager {
 
     ZooKeeperWatcher zk = new ZooKeeperWatcher(TEST_UTIL.getConfiguration(),
         "testMasterAddressManagerFromZK", null);
-    ZKUtil.createIfNotExists(zk, zk.baseZNode);
+    ZKUtil.createAndFailSilent(zk, zk.baseZNode);
 
     // Should not have a master yet
     MasterAddressManager addressManager = new MasterAddressManager(zk, null);

Added: hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/zookeeper/TestZooKeeperNodeTracker.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/zookeeper/TestZooKeeperNodeTracker.java?rev=979884&view=auto
==============================================================================
--- hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/zookeeper/TestZooKeeperNodeTracker.java (added)
+++ hbase/branches/0.90_master_rewrite/src/test/java/org/apache/hadoop/hbase/zookeeper/TestZooKeeperNodeTracker.java Tue Jul 27 21:57:00 2010
@@ -0,0 +1,289 @@
+/**
+ * Copyright 2010 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;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import java.util.Random;
+import java.util.concurrent.Semaphore;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.hbase.Abortable;
+import org.apache.hadoop.hbase.HBaseTestingUtility;
+import org.apache.hadoop.hbase.master.TestActiveMasterManager.NodeDeletionListener;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.apache.zookeeper.CreateMode;
+import org.apache.zookeeper.WatchedEvent;
+import org.apache.zookeeper.Watcher;
+import org.apache.zookeeper.ZooKeeper;
+import org.apache.zookeeper.ZooDefs.Ids;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+
+public class TestZooKeeperNodeTracker {
+  private static final Log LOG = LogFactory.getLog(TestZooKeeperNodeTracker.class);
+
+  private final static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
+
+  private final static Random rand = new Random();
+
+  @BeforeClass
+  public static void setUpBeforeClass() throws Exception {
+    TEST_UTIL.startMiniZKCluster();
+  }
+
+  @AfterClass
+  public static void tearDownAfterClass() throws Exception {
+    TEST_UTIL.shutdownMiniZKCluster();
+  }
+
+  @Test
+  public void testNodeTracker() throws Exception {
+
+    Abortable abortable = new StubAbortable();
+    ZooKeeperWatcher zk = new ZooKeeperWatcher(TEST_UTIL.getConfiguration(),
+        "testNodeTracker", abortable);
+    ZKUtil.createAndFailSilent(zk, zk.baseZNode);
+
+    String node =
+      ZKUtil.joinZNode(zk.baseZNode, new Long(rand.nextLong()).toString());
+
+    byte [] dataOne = Bytes.toBytes("dataOne");
+    byte [] dataTwo = Bytes.toBytes("dataTwo");
+
+    // Start a ZKNT with no node currently available
+    TestTracker localTracker = new TestTracker(zk, node, abortable);
+    localTracker.start();
+    zk.registerListener(localTracker);
+
+    // Make sure we don't have a node
+    assertNull(localTracker.getData());
+
+    // Spin up a thread with another ZKNT and have it block
+    WaitToGetDataThread thread = new WaitToGetDataThread(zk, node);
+    thread.start();
+
+    // Verify the thread doesn't have a node
+    assertFalse(thread.hasData);
+
+    // Put up an additional zk listener so we know when zk event is done
+    TestingZKListener zkListener = new TestingZKListener(zk, node);
+    zk.registerListener(zkListener);
+    assertEquals(0, zkListener.createdLock.availablePermits());
+
+    // Create a completely separate zk connection for test triggers and avoid
+    // any weird watcher interactions from the test
+    ZooKeeper zkconn = new ZooKeeper(
+        ZKConfig.getZKQuorumServersString(TEST_UTIL.getConfiguration()), 60000,
+        new StubWatcher());
+
+    // Add the node with data one
+    zkconn.create(node, dataOne, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
+
+    // Wait for the zk event to be processed
+    zkListener.waitForCreation();
+    thread.join();
+
+    // Both trackers should have the node available with data one
+    assertNotNull(localTracker.getData());
+    assertNotNull(localTracker.blockUntilAvailable());
+    assertTrue(Bytes.equals(localTracker.getData(), dataOne));
+    assertTrue(thread.hasData);
+    assertTrue(Bytes.equals(thread.tracker.getData(), dataOne));
+    LOG.info("Successfully got data one");
+
+    // Now, start a new ZKNT with the node already available
+    TestTracker secondTracker = new TestTracker(zk, node, null);
+    secondTracker.start();
+    zk.registerListener(secondTracker);
+
+    // Make sure it's available and with the expected data
+    assertNotNull(secondTracker.getData());
+    assertNotNull(secondTracker.blockUntilAvailable());
+    assertTrue(Bytes.equals(secondTracker.getData(), dataOne));
+    LOG.info("Successfully got data one with the second tracker");
+
+    // Drop the node
+    zkconn.delete(node, -1);
+    zkListener.waitForDeletion();
+
+    // Create a new thread but with the existing thread's tracker to wait
+    TestTracker threadTracker = thread.tracker;
+    thread = new WaitToGetDataThread(zk, node, threadTracker);
+    thread.start();
+
+    // Verify other guys don't have data
+    assertFalse(thread.hasData);
+    assertNull(secondTracker.getData());
+    assertNull(localTracker.getData());
+    LOG.info("Successfully made unavailable");
+
+    // Create with second data
+    zkconn.create(node, dataTwo, Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
+
+    // Wait for the zk event to be processed
+    zkListener.waitForCreation();
+    thread.join();
+
+    // All trackers should have the node available with data two
+    assertNotNull(localTracker.getData());
+    assertNotNull(localTracker.blockUntilAvailable());
+    assertTrue(Bytes.equals(localTracker.getData(), dataTwo));
+    assertNotNull(secondTracker.getData());
+    assertNotNull(secondTracker.blockUntilAvailable());
+    assertTrue(Bytes.equals(secondTracker.getData(), dataTwo));
+    assertTrue(thread.hasData);
+    assertTrue(Bytes.equals(thread.tracker.getData(), dataTwo));
+    LOG.info("Successfully got data two on all trackers and threads");
+
+    // Change the data back to data one
+    zkconn.setData(node, dataOne, -1);
+
+    // Wait for zk event to be processed
+    zkListener.waitForDataChange();
+
+    // All trackers should have the node available with data one
+    assertNotNull(localTracker.getData());
+    assertNotNull(localTracker.blockUntilAvailable());
+    assertTrue(Bytes.equals(localTracker.getData(), dataOne));
+    assertNotNull(secondTracker.getData());
+    assertNotNull(secondTracker.blockUntilAvailable());
+    assertTrue(Bytes.equals(secondTracker.getData(), dataOne));
+    assertTrue(thread.hasData);
+    assertTrue(Bytes.equals(thread.tracker.getData(), dataOne));
+    LOG.info("Successfully got data one following a data change on all trackers and threads");
+
+  }
+
+  public static class WaitToGetDataThread extends Thread {
+
+    TestTracker tracker;
+    boolean hasData;
+
+    public WaitToGetDataThread(ZooKeeperWatcher zk, String node) {
+      tracker = new TestTracker(zk, node, null);
+      tracker.start();
+      zk.registerListener(tracker);
+      hasData = false;
+    }
+
+    public WaitToGetDataThread(ZooKeeperWatcher zk, String node,
+        TestTracker tracker) {
+      this.tracker = tracker;
+      hasData = false;
+    }
+
+    @Override
+    public void run() {
+      LOG.info("Waiting for data to be available in WaitToGetDataThread");
+      try {
+        tracker.blockUntilAvailable();
+      } catch (InterruptedException e) {
+        e.printStackTrace();
+      }
+      LOG.info("Data now available in tracker from WaitToGetDataThread");
+      hasData = true;
+    }
+  }
+
+  public static class TestTracker extends ZooKeeperNodeTracker {
+
+    public TestTracker(ZooKeeperWatcher watcher, String node,
+        Abortable abortable) {
+      super(watcher, node, abortable);
+    }
+
+    @Override
+    protected Log getLog() {
+      return LOG;
+    }
+
+  }
+
+  public static class TestingZKListener extends ZooKeeperListener {
+    private static final Log LOG = LogFactory.getLog(NodeDeletionListener.class);
+
+    private Semaphore deletedLock;
+    private Semaphore createdLock;
+    private Semaphore changedLock;
+    private String node;
+
+    public TestingZKListener(ZooKeeperWatcher watcher, String node) {
+      super(watcher);
+      deletedLock = new Semaphore(0);
+      createdLock = new Semaphore(0);
+      changedLock = new Semaphore(0);
+      this.node = node;
+    }
+
+    @Override
+    public void nodeDeleted(String path) {
+      if(path.equals(node)) {
+        LOG.debug("nodeDeleted(" + path + ")");
+        deletedLock.release();
+      }
+    }
+
+    @Override
+    public void nodeCreated(String path) {
+      if(path.equals(node)) {
+        LOG.debug("nodeCreated(" + path + ")");
+        createdLock.release();
+      }
+    }
+
+    @Override
+    public void nodeDataChanged(String path) {
+      if(path.equals(node)) {
+        LOG.debug("nodeDataChanged(" + path + ")");
+        changedLock.release();
+      }
+    }
+
+    public void waitForDeletion() throws InterruptedException {
+      deletedLock.acquire();
+    }
+
+    public void waitForCreation() throws InterruptedException {
+      createdLock.acquire();
+    }
+
+    public void waitForDataChange() throws InterruptedException {
+      changedLock.acquire();
+    }
+  }
+
+  public static class StubAbortable implements Abortable {
+    @Override
+    public void abort() {}
+  }
+
+  public static class StubWatcher implements Watcher {
+    @Override
+    public void process(WatchedEvent event) {}
+  }
+}



Mime
View raw message