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1   /**
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.hadoop.hbase.rest;
20  
21  import java.io.IOException;
22  
23  import org.apache.hadoop.hbase.classification.InterfaceAudience;
24  import org.apache.hadoop.conf.Configuration;
25  import org.apache.hadoop.hbase.client.HBaseAdmin;
26  import org.apache.hadoop.hbase.client.HTableInterface;
27  import org.apache.hadoop.hbase.security.UserProvider;
28  import org.apache.hadoop.hbase.util.ConnectionCache;
29  import org.apache.hadoop.security.UserGroupInformation;
30  import org.apache.hadoop.security.authorize.ProxyUsers;
31  
32  /**
33   * Singleton class encapsulating global REST servlet state and functions.
34   */
35  @InterfaceAudience.Private
36  public class RESTServlet implements Constants {
37    private static RESTServlet INSTANCE;
38    private final Configuration conf;
39    private final MetricsREST metrics = new MetricsREST();
40    private final ConnectionCache connectionCache;
41    private final UserGroupInformation realUser;
42  
43    static final String CLEANUP_INTERVAL = "hbase.rest.connection.cleanup-interval";
44    static final String MAX_IDLETIME = "hbase.rest.connection.max-idletime";
45    static final String HBASE_REST_SUPPORT_PROXYUSER = "hbase.rest.support.proxyuser";
46  
47    UserGroupInformation getRealUser() {
48      return realUser;
49    }
50  
51    /**
52     * @return the RESTServlet singleton instance
53     */
54    public synchronized static RESTServlet getInstance() {
55      assert(INSTANCE != null);
56      return INSTANCE;
57    }
58  
59    /**
60     * @param conf Existing configuration to use in rest servlet
61     * @param userProvider the login user provider
62     * @return the RESTServlet singleton instance
63     * @throws IOException
64     */
65    public synchronized static RESTServlet getInstance(Configuration conf,
66        UserProvider userProvider) throws IOException {
67      if (INSTANCE == null) {
68        INSTANCE = new RESTServlet(conf, userProvider);
69      }
70      return INSTANCE;
71    }
72  
73    public synchronized static void stop() {
74      if (INSTANCE != null)  INSTANCE = null;
75    }
76  
77    /**
78     * Constructor with existing configuration
79     * @param conf existing configuration
80     * @param userProvider the login user provider
81     * @throws IOException
82     */
83    RESTServlet(final Configuration conf,
84        final UserProvider userProvider) throws IOException {
85      this.realUser = userProvider.getCurrent().getUGI();
86      this.conf = conf;
87  
88      int cleanInterval = conf.getInt(CLEANUP_INTERVAL, 10 * 1000);
89      int maxIdleTime = conf.getInt(MAX_IDLETIME, 10 * 60 * 1000);
90      connectionCache = new ConnectionCache(
91        conf, userProvider, cleanInterval, maxIdleTime);
92      if (supportsProxyuser()) {
93        ProxyUsers.refreshSuperUserGroupsConfiguration(conf);
94      }
95    }
96  
97    HBaseAdmin getAdmin() throws IOException {
98      return connectionCache.getAdmin();
99    }
100 
101   /**
102    * Caller closes the table afterwards.
103    */
104   HTableInterface getTable(String tableName) throws IOException {
105     return connectionCache.getTable(tableName);
106   }
107 
108   Configuration getConfiguration() {
109     return conf;
110   }
111 
112   MetricsREST getMetrics() {
113     return metrics;
114   }
115 
116   /**
117    * Helper method to determine if server should
118    * only respond to GET HTTP method requests.
119    * @return boolean for server read-only state
120    */
121   boolean isReadOnly() {
122     return getConfiguration().getBoolean("hbase.rest.readonly", false);
123   }
124 
125   void setEffectiveUser(String effectiveUser) {
126     connectionCache.setEffectiveUser(effectiveUser);
127   }
128 
129   boolean supportsProxyuser() {
130     return conf.getBoolean(HBASE_REST_SUPPORT_PROXYUSER, false);
131   }
132 }