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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  package org.apache.hadoop.hbase.client;
19  
20  import java.io.IOException;
21  import java.util.Random;
22  import java.util.concurrent.ExecutorService;
23  
24  import org.apache.commons.logging.Log;
25  import org.apache.hadoop.conf.Configuration;
26  import org.apache.hadoop.hbase.HConstants;
27  import org.apache.hadoop.hbase.ServerName;
28  import org.apache.hadoop.hbase.TableName;
29  import org.apache.hadoop.hbase.classification.InterfaceAudience;
30  import org.apache.hadoop.hbase.protobuf.generated.AdminProtos.AdminService;
31  import org.apache.hadoop.hbase.protobuf.generated.ClientProtos.ClientService;
32  import org.apache.hadoop.hbase.security.User;
33  import org.apache.hadoop.hbase.security.UserProvider;
34  
35  import com.google.common.annotations.VisibleForTesting;
36  
37  /**
38   * Utility used by client connections.
39   */
40  @InterfaceAudience.Private
41  public class ConnectionUtils {
42  
43    private static final Random RANDOM = new Random();
44    /**
45     * Calculate pause time.
46     * Built on {@link HConstants#RETRY_BACKOFF}.
47     * @param pause
48     * @param tries
49     * @return How long to wait after <code>tries</code> retries
50     */
51    public static long getPauseTime(final long pause, final int tries) {
52      int ntries = tries;
53      if (ntries >= HConstants.RETRY_BACKOFF.length) {
54        ntries = HConstants.RETRY_BACKOFF.length - 1;
55      }
56  
57      long normalPause = pause * HConstants.RETRY_BACKOFF[ntries];
58      long jitter =  (long)(normalPause * RANDOM.nextFloat() * 0.01f); // 1% possible jitter
59      return normalPause + jitter;
60    }
61  
62  
63    /**
64     * Adds / subs a 10% jitter to a pause time. Minimum is 1.
65     * @param pause the expected pause.
66     * @param jitter the jitter ratio, between 0 and 1, exclusive.
67     */
68    public static long addJitter(final long pause, final float jitter) {
69      float lag = pause * (RANDOM.nextFloat() - 0.5f) * jitter;
70      long newPause = pause + (long) lag;
71      if (newPause <= 0) {
72        return 1;
73      }
74      return newPause;
75    }
76  
77    /**
78     * @param conn The connection for which to replace the generator.
79     * @param cnm Replaces the nonce generator used, for testing.
80     * @return old nonce generator.
81     */
82    public static NonceGenerator injectNonceGeneratorForTesting(
83        ClusterConnection conn, NonceGenerator cnm) {
84      return ConnectionManager.injectNonceGeneratorForTesting(conn, cnm);
85    }
86  
87    /**
88     * Changes the configuration to set the number of retries needed when using HConnection
89     * internally, e.g. for  updating catalog tables, etc.
90     * Call this method before we create any Connections.
91     * @param c The Configuration instance to set the retries into.
92     * @param log Used to log what we set in here.
93     */
94    public static void setServerSideHConnectionRetriesConfig(
95        final Configuration c, final String sn, final Log log) {
96      // TODO: Fix this. Not all connections from server side should have 10 times the retries.
97      int hcRetries = c.getInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER,
98        HConstants.DEFAULT_HBASE_CLIENT_RETRIES_NUMBER);
99      // Go big.  Multiply by 10.  If we can't get to meta after this many retries
100     // then something seriously wrong.
101     int serversideMultiplier = c.getInt("hbase.client.serverside.retries.multiplier", 10);
102     int retries = hcRetries * serversideMultiplier;
103     c.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, retries);
104     log.info(sn + " server-side HConnection retries=" + retries);
105   }
106 
107   /**
108    * Adapt a HConnection so that it can bypass the RPC layer (serialization,
109    * deserialization, networking, etc..) -- i.e. short-circuit -- when talking to a local server.
110    * @param conn the connection to adapt
111    * @param serverName the local server name
112    * @param admin the admin interface of the local server
113    * @param client the client interface of the local server
114    * @return an adapted/decorated HConnection
115    */
116   @Deprecated
117   public static ClusterConnection createShortCircuitHConnection(final Connection conn,
118       final ServerName serverName, final AdminService.BlockingInterface admin,
119       final ClientService.BlockingInterface client) {
120     return new ConnectionAdapter(conn) {
121       @Override
122       public AdminService.BlockingInterface getAdmin(
123           ServerName sn, boolean getMaster) throws IOException {
124         return serverName.equals(sn) ? admin : super.getAdmin(sn, getMaster);
125       }
126 
127       @Override
128       public ClientService.BlockingInterface getClient(
129           ServerName sn) throws IOException {
130         return serverName.equals(sn) ? client : super.getClient(sn);
131       }
132     };
133   }
134 
135   /**
136    * Creates a short-circuit connection that can bypass the RPC layer (serialization,
137    * deserialization, networking, etc..) when talking to a local server.
138    * @param conf the current configuration
139    * @param pool the thread pool to use for batch operations
140    * @param user the user the connection is for
141    * @param serverName the local server name
142    * @param admin the admin interface of the local server
143    * @param client the client interface of the local server
144    * @return a short-circuit connection.
145    * @throws IOException
146    */
147   public static ClusterConnection createShortCircuitConnection(final Configuration conf,
148     ExecutorService pool, User user, final ServerName serverName,
149     final AdminService.BlockingInterface admin, final ClientService.BlockingInterface client)
150     throws IOException {
151     if (user == null) {
152       user = UserProvider.instantiate(conf).getCurrent();
153     }
154     return new ConnectionManager.HConnectionImplementation(conf, false, pool, user) {
155       @Override
156       public AdminService.BlockingInterface getAdmin(ServerName sn, boolean getMaster)
157         throws IOException {
158         return serverName.equals(sn) ? admin : super.getAdmin(sn, getMaster);
159       }
160 
161       @Override
162       public ClientService.BlockingInterface getClient(ServerName sn) throws IOException {
163         return serverName.equals(sn) ? client : super.getClient(sn);
164       }
165     };
166   }
167 
168   /**
169    * Setup the connection class, so that it will not depend on master being online. Used for testing
170    * @param conf configuration to set
171    */
172   @VisibleForTesting
173   public static void setupMasterlessConnection(Configuration conf) {
174     conf.set(HConnection.HBASE_CLIENT_CONNECTION_IMPL,
175       MasterlessConnection.class.getName());
176   }
177 
178   /**
179    * Some tests shut down the master. But table availability is a master RPC which is performed on
180    * region re-lookups.
181    */
182   static class MasterlessConnection extends ConnectionManager.HConnectionImplementation {
183     MasterlessConnection(Configuration conf, boolean managed,
184       ExecutorService pool, User user) throws IOException {
185       super(conf, managed, pool, user);
186     }
187 
188     @Override
189     public boolean isTableDisabled(TableName tableName) throws IOException {
190       // treat all tables as enabled
191       return false;
192     }
193   }
194 }