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