1   /**
2    *
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *     http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS,
15   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16   * See the License for the specific language governing permissions and
17   * limitations under the License.
18   */
19  
20  package org.apache.hadoop.hbase.zookeeper;
21  
22  import java.util.ArrayList;
23  import java.util.List;
24  import java.util.Map.Entry;
25  import java.util.Properties;
26  
27  import org.apache.hadoop.conf.Configuration;
28  import org.apache.hadoop.hbase.HBaseConfiguration;
29  
30  /**
31   * Tool for reading a ZooKeeper server from HBase XML configuration producing
32   * the '-server host:port' argument to pass ZooKeeperMain.  This program
33   * emits either '-server HOST:PORT" where HOST is one of the zk ensemble
34   * members plus zk client port OR it emits '' if no zk servers found (Yes,
35   * it emits '-server' too).
36   */
37  public class ZooKeeperMainServerArg {
38    public String parse(final Configuration c) {
39      // Note that we do not simply grab the property
40      // HConstants.ZOOKEEPER_QUORUM from the HBaseConfiguration because the
41      // user may be using a zoo.cfg file.
42      Properties zkProps = ZKConfig.makeZKProps(c);
43      String host = null;
44      String clientPort = null;
45      List<String> hosts = new ArrayList<String>();
46      for (Entry<Object, Object> entry: zkProps.entrySet()) {
47        String key = entry.getKey().toString().trim();
48        String value = entry.getValue().toString().trim();
49        if (key.startsWith("server.")) {
50          String[] parts = value.split(":");
51          hosts.add(parts[0]);
52        } else if (key.endsWith("clientPort")) {
53          clientPort = value;
54        }
55      }
56      if (hosts.isEmpty() || clientPort == null)
57        return null;
58      for (int i = 0; i < hosts.size(); i++) {
59        if (i > 0)
60          host += "," + hosts.get(i);
61        else
62          host = hosts.get(i);
63      }
64      return host != null ? host + ":" + clientPort : null;
65    }
66  
67    /**
68     * Run the tool.
69     * @param args Command line arguments. First arg is path to zookeepers file.
70     */
71    public static void main(String args[]) {
72      Configuration conf = HBaseConfiguration.create();
73      String hostport = new ZooKeeperMainServerArg().parse(conf);
74      System.out.println((hostport == null || hostport.length() == 0)? "":
75        "-server " + hostport);
76    }
77  }