| /** |
| * 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.io.IOException; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.hbase.classification.InterfaceAudience; |
| import org.apache.hadoop.hbase.Abortable; |
| import org.apache.hadoop.hbase.exceptions.DeserializationException; |
| import org.apache.hadoop.hbase.protobuf.ProtobufUtil; |
| import org.apache.hadoop.hbase.protobuf.generated.LoadBalancerProtos; |
| import org.apache.hadoop.hbase.util.Bytes; |
| import org.apache.zookeeper.KeeperException; |
| |
| /** |
| * Tracks the load balancer state up in ZK |
| */ |
| @InterfaceAudience.Private |
| public class LoadBalancerTracker extends ZooKeeperNodeTracker { |
| private static final Log LOG = LogFactory.getLog(LoadBalancerTracker.class); |
| |
| public LoadBalancerTracker(ZooKeeperWatcher watcher, |
| Abortable abortable) { |
| super(watcher, watcher.balancerZNode, abortable); |
| } |
| |
| /** |
| * Return true if the balance switch is on, false otherwise |
| */ |
| public boolean isBalancerOn() { |
| byte [] upData = super.getData(false); |
| try { |
| // if data in ZK is null, use default of on. |
| return upData == null || parseFrom(upData).getBalancerOn(); |
| } catch (DeserializationException dex) { |
| LOG.error("ZK state for LoadBalancer could not be parsed " + Bytes.toStringBinary(upData)); |
| // return false to be safe. |
| return false; |
| } |
| } |
| |
| /** |
| * Set the balancer on/off |
| * @param balancerOn |
| * @throws KeeperException |
| */ |
| public void setBalancerOn(boolean balancerOn) throws KeeperException { |
| byte [] upData = toByteArray(balancerOn); |
| try { |
| ZKUtil.setData(watcher, watcher.balancerZNode, upData); |
| } catch(KeeperException.NoNodeException nne) { |
| ZKUtil.createAndWatch(watcher, watcher.balancerZNode, upData); |
| } |
| super.nodeDataChanged(watcher.balancerZNode); |
| } |
| |
| private byte [] toByteArray(boolean isBalancerOn) { |
| LoadBalancerProtos.LoadBalancerState.Builder builder = |
| LoadBalancerProtos.LoadBalancerState.newBuilder(); |
| builder.setBalancerOn(isBalancerOn); |
| return ProtobufUtil.prependPBMagic(builder.build().toByteArray()); |
| } |
| |
| private LoadBalancerProtos.LoadBalancerState parseFrom(byte [] pbBytes) |
| throws DeserializationException { |
| ProtobufUtil.expectPBMagicPrefix(pbBytes); |
| LoadBalancerProtos.LoadBalancerState.Builder builder = |
| LoadBalancerProtos.LoadBalancerState.newBuilder(); |
| try { |
| int magicLen = ProtobufUtil.lengthOfPBMagic(); |
| ProtobufUtil.mergeFrom(builder, pbBytes, magicLen, pbBytes.length - magicLen); |
| } catch (IOException e) { |
| throw new DeserializationException(e); |
| } |
| return builder.build(); |
| } |
| } |