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