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Server functionality for HBase
/**
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.hadoop.hbase.mapreduce;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.classification.InterfaceStability;
import org.apache.hadoop.conf.Configurable;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Mutation;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.OutputCommitter;
import org.apache.hadoop.mapreduce.OutputFormat;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
/**
* Convert Map/Reduce output and write it to an HBase table. The KEY is ignored
* while the output value must be either a {@link Put} or a
* {@link Delete} instance.
*
* @param The type of the key. Ignored in this class.
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public class TableOutputFormat extends OutputFormat
implements Configurable {
private final Log LOG = LogFactory.getLog(TableOutputFormat.class);
/**
* Prefix for configuration property overrides to apply in {@link #setConf(Configuration)}.
* For keys matching this prefix, the prefix is stripped, and the value is set in the
* configuration with the resulting key, ie. the entry "hbase.mapred.output.key1 = value1"
* would be set in the configuration as "key1 = value1". Use this to set properties
* which should only be applied to the {@code TableOutputFormat} configuration and not the
* input configuration.
*/
public static final String OUTPUT_CONF_PREFIX = "hbase.mapred.output.";
/** Job parameter that specifies the output table. */
public static final String OUTPUT_TABLE = OUTPUT_CONF_PREFIX + "outputtable";
/**
* Optional job parameter to specify a peer cluster.
* Used specifying remote cluster when copying between hbase clusters (the
* source is picked up from hbase-site.xml).
* @see TableMapReduceUtil#initTableReducerJob(String, Class, org.apache.hadoop.mapreduce.Job, Class, String, String, String)
*/
public static final String QUORUM_ADDRESS = OUTPUT_CONF_PREFIX + "quorum";
/** Optional job parameter to specify peer cluster's ZK client port */
public static final String QUORUM_PORT = OUTPUT_CONF_PREFIX + "port";
/** Optional specification of the rs class name of the peer cluster */
public static final String REGION_SERVER_CLASS = OUTPUT_CONF_PREFIX + "rs.class";
/** Optional specification of the rs impl name of the peer cluster */
public static final String REGION_SERVER_IMPL = OUTPUT_CONF_PREFIX + "rs.impl";
/** The configuration. */
private Configuration conf = null;
private HTable table;
/**
* Writes the reducer output to an HBase table.
*
* @param The type of the key.
*/
protected static class TableRecordWriter
extends RecordWriter {
/** The table to write to. */
private HTable table;
/**
* Instantiate a TableRecordWriter with the HBase HClient for writing.
*
* @param table The table to write to.
*/
public TableRecordWriter(HTable table) {
this.table = table;
}
/**
* Closes the writer, in this case flush table commits.
*
* @param context The context.
* @throws IOException When closing the writer fails.
* @see org.apache.hadoop.mapreduce.RecordWriter#close(org.apache.hadoop.mapreduce.TaskAttemptContext)
*/
@Override
public void close(TaskAttemptContext context)
throws IOException {
table.close();
}
/**
* Writes a key/value pair into the table.
*
* @param key The key.
* @param value The value.
* @throws IOException When writing fails.
* @see org.apache.hadoop.mapreduce.RecordWriter#write(java.lang.Object, java.lang.Object)
*/
@Override
public void write(KEY key, Mutation value)
throws IOException {
if (value instanceof Put) this.table.put(new Put((Put)value));
else if (value instanceof Delete) this.table.delete(new Delete((Delete)value));
else throw new IOException("Pass a Delete or a Put");
}
}
/**
* Creates a new record writer.
*
* @param context The current task context.
* @return The newly created writer instance.
* @throws IOException When creating the writer fails.
* @throws InterruptedException When the jobs is cancelled.
* @see org.apache.hadoop.mapreduce.lib.output.FileOutputFormat#getRecordWriter(org.apache.hadoop.mapreduce.TaskAttemptContext)
*/
@Override
public RecordWriter getRecordWriter(
TaskAttemptContext context)
throws IOException, InterruptedException {
return new TableRecordWriter(this.table);
}
/**
* Checks if the output target exists.
*
* @param context The current context.
* @throws IOException When the check fails.
* @throws InterruptedException When the job is aborted.
* @see org.apache.hadoop.mapreduce.OutputFormat#checkOutputSpecs(org.apache.hadoop.mapreduce.JobContext)
*/
@Override
public void checkOutputSpecs(JobContext context) throws IOException,
InterruptedException {
// TODO Check if the table exists?
}
/**
* Returns the output committer.
*
* @param context The current context.
* @return The committer.
* @throws IOException When creating the committer fails.
* @throws InterruptedException When the job is aborted.
* @see org.apache.hadoop.mapreduce.OutputFormat#getOutputCommitter(org.apache.hadoop.mapreduce.TaskAttemptContext)
*/
@Override
public OutputCommitter getOutputCommitter(TaskAttemptContext context)
throws IOException, InterruptedException {
return new TableOutputCommitter();
}
public Configuration getConf() {
return conf;
}
@Override
public void setConf(Configuration otherConf) {
String tableName = otherConf.get(OUTPUT_TABLE);
if(tableName == null || tableName.length() <= 0) {
throw new IllegalArgumentException("Must specify table name");
}
String address = otherConf.get(QUORUM_ADDRESS);
int zkClientPort = otherConf.getInt(QUORUM_PORT, 0);
String serverClass = otherConf.get(REGION_SERVER_CLASS);
String serverImpl = otherConf.get(REGION_SERVER_IMPL);
try {
this.conf = HBaseConfiguration.createClusterConf(otherConf, address, OUTPUT_CONF_PREFIX);
if (serverClass != null) {
this.conf.set(HConstants.REGION_SERVER_IMPL, serverImpl);
}
if (zkClientPort != 0) {
this.conf.setInt(HConstants.ZOOKEEPER_CLIENT_PORT, zkClientPort);
}
this.table = new BufferedHTable(this.conf, tableName);
this.table.setAutoFlush(false, true);
LOG.info("Created table instance for " + tableName);
} catch(IOException e) {
LOG.error(e);
throw new RuntimeException(e);
}
}
}