001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, software 013 * distributed under the License is distributed on an "AS IS" BASIS, 014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 015 * See the License for the specific language governing permissions and 016 * limitations under the License. 017 */ 018package org.apache.hadoop.hbase.client.example; 019 020import static org.apache.hadoop.hbase.util.FutureUtils.addListener; 021 022import java.util.concurrent.CompletableFuture; 023import java.util.concurrent.CountDownLatch; 024import java.util.concurrent.ExecutorService; 025import java.util.concurrent.Executors; 026import java.util.concurrent.atomic.AtomicReference; 027import java.util.stream.IntStream; 028import org.apache.commons.io.IOUtils; 029import org.apache.hadoop.conf.Configured; 030import org.apache.hadoop.hbase.TableName; 031import org.apache.hadoop.hbase.client.AsyncConnection; 032import org.apache.hadoop.hbase.client.AsyncTable; 033import org.apache.hadoop.hbase.client.ConnectionFactory; 034import org.apache.hadoop.hbase.client.Get; 035import org.apache.hadoop.hbase.client.Put; 036import org.apache.hadoop.hbase.util.Bytes; 037import org.apache.hadoop.hbase.util.Threads; 038import org.apache.hadoop.util.Tool; 039import org.apache.hadoop.util.ToolRunner; 040import org.apache.yetus.audience.InterfaceAudience; 041import org.slf4j.Logger; 042import org.slf4j.LoggerFactory; 043 044import org.apache.hbase.thirdparty.com.google.common.util.concurrent.ThreadFactoryBuilder; 045 046/** 047 * A simple example shows how to use asynchronous client. 048 */ 049@InterfaceAudience.Private 050public class AsyncClientExample extends Configured implements Tool { 051 052 private static final Logger LOG = LoggerFactory.getLogger(AsyncClientExample.class); 053 054 /** 055 * The size for thread pool. 056 */ 057 private static final int THREAD_POOL_SIZE = 16; 058 059 /** 060 * The default number of operations. 061 */ 062 private static final int DEFAULT_NUM_OPS = 100; 063 064 /** 065 * The name of the column family. d for default. 066 */ 067 private static final byte[] FAMILY = Bytes.toBytes("d"); 068 069 /** 070 * For the example we're just using one qualifier. 071 */ 072 private static final byte[] QUAL = Bytes.toBytes("test"); 073 074 private final AtomicReference<CompletableFuture<AsyncConnection>> future = 075 new AtomicReference<>(); 076 077 private CompletableFuture<AsyncConnection> getConn() { 078 CompletableFuture<AsyncConnection> f = future.get(); 079 if (f != null) { 080 return f; 081 } 082 for (;;) { 083 if (future.compareAndSet(null, new CompletableFuture<>())) { 084 CompletableFuture<AsyncConnection> toComplete = future.get(); 085 addListener(ConnectionFactory.createAsyncConnection(getConf()), (conn, error) -> { 086 if (error != null) { 087 toComplete.completeExceptionally(error); 088 // we need to reset the future holder so we will get a chance to recreate an async 089 // connection at next try. 090 future.set(null); 091 return; 092 } 093 toComplete.complete(conn); 094 }); 095 return toComplete; 096 } else { 097 f = future.get(); 098 if (f != null) { 099 return f; 100 } 101 } 102 } 103 } 104 105 @edu.umd.cs.findbugs.annotations.SuppressWarnings(value = "NP_NONNULL_PARAM_VIOLATION", 106 justification = "it is valid to pass NULL to CompletableFuture#completedFuture") 107 private CompletableFuture<Void> closeConn() { 108 CompletableFuture<AsyncConnection> f = future.get(); 109 if (f == null) { 110 return CompletableFuture.completedFuture(null); 111 } 112 CompletableFuture<Void> closeFuture = new CompletableFuture<>(); 113 addListener(f, (conn, error) -> { 114 if (error == null) { 115 IOUtils.closeQuietly(conn, e -> LOG.warn("failed to close conn", e)); 116 } 117 closeFuture.complete(null); 118 }); 119 return closeFuture; 120 } 121 122 private byte[] getKey(int i) { 123 return Bytes.toBytes(String.format("%08x", i)); 124 } 125 126 @Override 127 public int run(String[] args) throws Exception { 128 if (args.length < 1 || args.length > 2) { 129 System.out.println("Usage: " + this.getClass().getName() + " tableName [num_operations]"); 130 return -1; 131 } 132 TableName tableName = TableName.valueOf(args[0]); 133 int numOps = args.length > 1 ? Integer.parseInt(args[1]) : DEFAULT_NUM_OPS; 134 ExecutorService threadPool = Executors.newFixedThreadPool(THREAD_POOL_SIZE, 135 new ThreadFactoryBuilder().setNameFormat("AsyncClientExample-pool-%d").setDaemon(true) 136 .setUncaughtExceptionHandler(Threads.LOGGING_EXCEPTION_HANDLER).build()); 137 // We use AsyncTable here so we need to provide a separated thread pool. RawAsyncTable does not 138 // need a thread pool and may have a better performance if you use it correctly as it can save 139 // some context switches. But if you use RawAsyncTable incorrectly, you may have a very bad 140 // impact on performance so use it with caution. 141 CountDownLatch latch = new CountDownLatch(numOps); 142 IntStream.range(0, numOps).forEach(i -> { 143 CompletableFuture<AsyncConnection> future = getConn(); 144 addListener(future, (conn, error) -> { 145 if (error != null) { 146 LOG.warn("failed to get async connection for " + i, error); 147 latch.countDown(); 148 return; 149 } 150 AsyncTable<?> table = conn.getTable(tableName, threadPool); 151 addListener(table.put(new Put(getKey(i)).addColumn(FAMILY, QUAL, Bytes.toBytes(i))), 152 (putResp, putErr) -> { 153 if (putErr != null) { 154 LOG.warn("put failed for " + i, putErr); 155 latch.countDown(); 156 return; 157 } 158 LOG.info("put for " + i + " succeeded, try getting"); 159 addListener(table.get(new Get(getKey(i))), (result, getErr) -> { 160 if (getErr != null) { 161 LOG.warn("get failed for " + i); 162 latch.countDown(); 163 return; 164 } 165 if (result.isEmpty()) { 166 LOG.warn("get failed for " + i + ", server returns empty result"); 167 } else if (!result.containsColumn(FAMILY, QUAL)) { 168 LOG.warn("get failed for " + i + ", the result does not contain " 169 + Bytes.toString(FAMILY) + ":" + Bytes.toString(QUAL)); 170 } else { 171 int v = Bytes.toInt(result.getValue(FAMILY, QUAL)); 172 if (v != i) { 173 LOG.warn("get failed for " + i + ", the value of " + Bytes.toString(FAMILY) + ":" 174 + Bytes.toString(QUAL) + " is " + v + ", exected " + i); 175 } else { 176 LOG.info("get for " + i + " succeeded"); 177 } 178 } 179 latch.countDown(); 180 }); 181 }); 182 }); 183 }); 184 latch.await(); 185 closeConn().get(); 186 return 0; 187 } 188 189 public static void main(String[] args) throws Exception { 190 ToolRunner.run(new AsyncClientExample(), args); 191 } 192}