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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  
21  package org.apache.hadoop.hbase.zookeeper;
22  
23  import java.util.ArrayList;
24  import java.util.List;
25  import java.util.Map.Entry;
26  import java.util.Properties;
27  
28  import org.apache.hadoop.conf.Configuration;
29  import org.apache.hadoop.hbase.HBaseConfiguration;
30  
31  /**
32   * Tool for reading a ZooKeeper server from HBase XML configuration producing
33   * the '-server host:port' argument to pass ZooKeeperMain.  This program
34   * emits either '-server HOST:PORT" where HOST is one of the zk ensemble
35   * members plus zk client port OR it emits '' if no zk servers found (Yes,
36   * it emits '-server' too).
37   */
38  public class ZooKeeperMainServerArg {
39    public String parse(final Configuration c) {
40      // Note that we do not simply grab the property
41      // HConstants.ZOOKEEPER_QUORUM from the HBaseConfiguration because the
42      // user may be using a zoo.cfg file.
43      Properties zkProps = ZKConfig.makeZKProps(c);
44      String host = null;
45      String clientPort = null;
46      List<String> hosts = new ArrayList<String>();
47      for (Entry<Object, Object> entry: zkProps.entrySet()) {
48        String key = entry.getKey().toString().trim();
49        String value = entry.getValue().toString().trim();
50        if (key.startsWith("server.")) {
51          String[] parts = value.split(":");
52          hosts.add(parts[0]);
53        } else if (key.endsWith("clientPort")) {
54          clientPort = value;
55        }
56      }
57      if (hosts.isEmpty() || clientPort == null)
58        return null;
59      for (int i = 0; i < hosts.size(); i++) {
60        if (i > 0)
61          host += "," + hosts.get(i);
62        else
63          host = hosts.get(i);
64      }
65      return host != null ? host + ":" + clientPort : null;
66    }
67  
68    /**
69     * Run the tool.
70     * @param args Command line arguments. First arg is path to zookeepers file.
71     */
72    public static void main(String args[]) {
73      Configuration conf = HBaseConfiguration.create();
74      String hostport = new ZooKeeperMainServerArg().parse(conf);
75      System.out.println((hostport == null || hostport.length() == 0)? "":
76        "-server " + hostport);
77    }
78  }