1 /** 2 * Copyright 2010 The Apache Software Foundation 3 * 4 * Licensed to the Apache Software Foundation (ASF) under one 5 * or more contributor license agreements. See the NOTICE file 6 * distributed with this work for additional information 7 * regarding copyright ownership. The ASF licenses this file 8 * to you under the Apache License, Version 2.0 (the 9 * "License"); you may not use this file except in compliance 10 * with the License. You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, software 15 * distributed under the License is distributed on an "AS IS" BASIS, 16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 17 * See the License for the specific language governing permissions and 18 * limitations under the License. 19 */ 20 package org.apache.hadoop.hbase.zookeeper; 21 22 import org.apache.hadoop.hbase.Abortable; 23 import org.apache.hadoop.hbase.ServerName; 24 import org.apache.hadoop.hbase.catalog.RootLocationEditor; 25 import org.apache.hadoop.hbase.util.Addressing; 26 import org.apache.hadoop.hbase.util.Bytes; 27 import org.apache.zookeeper.KeeperException; 28 29 /** 30 * Tracks the root region server location node in zookeeper. 31 * Root region location is set by {@link RootLocationEditor} usually called 32 * out of <code>RegionServerServices</code>. 33 * This class has a watcher on the root location and notices changes. 34 */ 35 public class RootRegionTracker extends ZooKeeperNodeTracker { 36 /** 37 * Creates a root region location tracker. 38 * 39 * <p>After construction, use {@link #start} to kick off tracking. 40 * 41 * @param watcher 42 * @param abortable 43 */ 44 public RootRegionTracker(ZooKeeperWatcher watcher, Abortable abortable) { 45 super(watcher, watcher.rootServerZNode, abortable); 46 } 47 48 /** 49 * Checks if the root region location is available. 50 * @return true if root region location is available, false if not 51 */ 52 public boolean isLocationAvailable() { 53 return super.getData(true) != null; 54 } 55 56 /** 57 * Gets the root region location, if available. Null if not. Does not block. 58 * @return server name 59 * @throws InterruptedException 60 */ 61 public ServerName getRootRegionLocation() throws InterruptedException { 62 return dataToServerName(super.getData(true)); 63 } 64 65 /** 66 * Gets the root region location, if available, and waits for up to the 67 * specified timeout if not immediately available. 68 * Given the zookeeper notification could be delayed, we will try to 69 * get the latest data. 70 * @param timeout maximum time to wait, in millis 71 * @return server name for server hosting root region formatted as per 72 * {@link ServerName}, or null if none available 73 * @throws InterruptedException if interrupted while waiting 74 */ 75 public ServerName waitRootRegionLocation(long timeout) 76 throws InterruptedException { 77 if (false == checkIfBaseNodeAvailable()) { 78 String errorMsg = "Check the value configured in 'zookeeper.znode.parent'. " 79 + "There could be a mismatch with the one configured in the master."; 80 LOG.error(errorMsg); 81 throw new IllegalArgumentException(errorMsg); 82 } 83 return dataToServerName(super.blockUntilAvailable(timeout, true)); 84 } 85 86 /* 87 * @param data 88 * @return Returns null if <code>data</code> is null else converts passed data 89 * to a ServerName instance. 90 */ 91 private static ServerName dataToServerName(final byte [] data) { 92 // The str returned could be old style -- pre hbase-1502 -- which was 93 // hostname and port seperated by a colon rather than hostname, port and 94 // startcode delimited by a ','. 95 if (data == null || data.length <= 0) return null; 96 String str = Bytes.toString(data); 97 int index = str.indexOf(ServerName.SERVERNAME_SEPARATOR); 98 if (index != -1) { 99 // Presume its ServerName.toString() format. 100 return ServerName.parseServerName(str); 101 } 102 // Presume it a hostname:port format. 103 String hostname = Addressing.parseHostname(str); 104 int port = Addressing.parsePort(str); 105 return new ServerName(hostname, port, -1L); 106 } 107 }