001/*
002 *
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *     http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing, software
014 * distributed under the License is distributed on an "AS IS" BASIS,
015 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016 * See the License for the specific language governing permissions and
017 * limitations under the License.
018 */
019
020package org.apache.hadoop.hbase.zookeeper;
021
022import java.util.LinkedList;
023import java.util.List;
024
025import org.apache.hadoop.conf.Configuration;
026import org.apache.hadoop.hbase.HBaseConfiguration;
027import org.apache.hadoop.hbase.HBaseInterfaceAudience;
028import org.apache.hadoop.hbase.HConstants;
029import org.apache.hadoop.hbase.ServerName;
030import org.apache.yetus.audience.InterfaceAudience;
031
032/**
033 * Tool for reading ZooKeeper servers from HBase XML configuration and producing
034 * a line-by-line list for use by bash scripts.
035 */
036@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.TOOLS)
037public final class ZKServerTool {
038  private ZKServerTool() {
039  }
040
041  public static ServerName[] readZKNodes(Configuration conf) {
042    List<ServerName> hosts = new LinkedList<>();
043    String quorum = conf.get(HConstants.ZOOKEEPER_QUORUM, HConstants.LOCALHOST);
044
045    String[] values = quorum.split(",");
046    for (String value : values) {
047      String[] parts = value.split(":");
048      String host = parts[0];
049      int port = HConstants.DEFAULT_ZOOKEEPER_CLIENT_PORT;
050      if (parts.length > 1) {
051        port = Integer.parseInt(parts[1]);
052      }
053      hosts.add(ServerName.valueOf(host, port, -1));
054    }
055    return hosts.toArray(new ServerName[hosts.size()]);
056  }
057
058  /**
059   * Run the tool.
060   * @param args Command line arguments.
061   */
062  public static void main(String[] args) {
063    for(ServerName server: readZKNodes(HBaseConfiguration.create())) {
064      // bin/zookeeper.sh relies on the "ZK host" string for grepping which is case sensitive.
065      System.out.println("ZK host: " + server.getHostname());
066    }
067  }
068}