package org.apache.cassandra.hadoop;
/*
*
* 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.
*
*/
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.auth.SimpleAuthenticator;
import org.apache.cassandra.avro.Mutation;
import org.apache.cassandra.thrift.*;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.*;
import org.apache.thrift.TException;
import org.apache.thrift.transport.TFramedTransport;
import org.apache.thrift.transport.TSocket;
/**
* The <code>ColumnFamilyOutputFormat</code> acts as a Hadoop-specific
* OutputFormat that allows reduce tasks to store keys (and corresponding
* values) as Cassandra rows (and respective columns) in a given
* ColumnFamily.
*
* <p>
* As is the case with the {@link ColumnFamilyInputFormat}, you need to set the
* Keyspace and ColumnFamily in your
* Hadoop job Configuration. The {@link ConfigHelper} class, through its
* {@link ConfigHelper#setOutputColumnFamily} method, is provided to make this
* simple.
* </p>
*
* <p>
* For the sake of performance, this class employs a lazy write-back caching
* mechanism, where its record writer batches mutations created based on the
* reduce's inputs (in a task-specific map), and periodically makes the changes
* official by sending a batch mutate request to Cassandra.
* </p>
*/
public class ColumnFamilyOutputFormat extends OutputFormat<ByteBuffer,List<Mutation>>
implements org.apache.hadoop.mapred.OutputFormat<ByteBuffer,List<Mutation>>
{
private static final Logger logger = LoggerFactory.getLogger(ColumnFamilyOutputFormat.class);
public static final String BATCH_THRESHOLD = "mapreduce.output.columnfamilyoutputformat.batch.threshold";
public static final String QUEUE_SIZE = "mapreduce.output.columnfamilyoutputformat.queue.size";
/**
* Check for validity of the output-specification for the job.
*
* @param context
* information about the job
* @throws IOException
* when output should not be attempted
*/
@Override
public void checkOutputSpecs(JobContext context)
{
checkOutputSpecs(context.getConfiguration());
}
private void checkOutputSpecs(Configuration conf)
{
if (ConfigHelper.getOutputKeyspace(conf) == null || ConfigHelper.getOutputColumnFamily(conf) == null)
{
throw new UnsupportedOperationException("you must set the keyspace and columnfamily with setColumnFamily()");
}
}
/**
* The OutputCommitter for this format does not write any data to the DFS.
*
* @param context
* the task context
* @return an output committer
* @throws IOException
* @throws InterruptedException
*/
@Override
public OutputCommitter getOutputCommitter(TaskAttemptContext context) throws IOException, InterruptedException
{
return new NullOutputCommitter();
}
/** Fills the deprecated OutputFormat interface for streaming. */
@Deprecated
public void checkOutputSpecs(org.apache.hadoop.fs.FileSystem filesystem, org.apache.hadoop.mapred.JobConf job) throws IOException
{
checkOutputSpecs(job);
}
/** Fills the deprecated OutputFormat interface for streaming. */
@Deprecated @Override
public ColumnFamilyRecordWriter getRecordWriter(org.apache.hadoop.fs.FileSystem filesystem, org.apache.hadoop.mapred.JobConf job, String name, org.apache.hadoop.util.Progressable progress) throws IOException
{
return new ColumnFamilyRecordWriter(job);
}
/**
* Get the {@link RecordWriter} for the given task.
*
* @param context
* the information about the current task.
* @return a {@link RecordWriter} to write the output for the job.
* @throws IOException
*/
@Override
public ColumnFamilyRecordWriter getRecordWriter(final TaskAttemptContext context) throws IOException, InterruptedException
{
return new ColumnFamilyRecordWriter(context);
}
/**
* Return a client based on the given socket that points to the configured
* keyspace, and is logged in with the configured credentials.
*
* @param socket a socket pointing to a particular node, seed or otherwise
* @param conf a job configuration
* @return a cassandra client
* @throws InvalidRequestException
* @throws TException
* @throws AuthenticationException
* @throws AuthorizationException
*/
public static Cassandra.Client createAuthenticatedClient(TSocket socket, Configuration conf)
throws InvalidRequestException, TException, AuthenticationException, AuthorizationException
{
TBinaryProtocol binaryProtocol = new TBinaryProtocol(new TFramedTransport(socket));
Cassandra.Client client = new Cassandra.Client(binaryProtocol);
socket.open();
client.set_keyspace(ConfigHelper.getOutputKeyspace(conf));
if (ConfigHelper.getOutputKeyspaceUserName(conf) != null)
{
Map<String, String> creds = new HashMap<String, String>();
creds.put(SimpleAuthenticator.USERNAME_KEY, ConfigHelper.getOutputKeyspaceUserName(conf));
creds.put(SimpleAuthenticator.PASSWORD_KEY, ConfigHelper.getOutputKeyspacePassword(conf));
AuthenticationRequest authRequest = new AuthenticationRequest(creds);
client.login(authRequest);
}
return client;
}
/**
* An {@link OutputCommitter} that does nothing.
*/
public static class NullOutputCommitter extends OutputCommitter
{
public void abortTask(TaskAttemptContext taskContext) { }
public void cleanupJob(JobContext jobContext) { }
public void commitTask(TaskAttemptContext taskContext) { }
public boolean needsTaskCommit(TaskAttemptContext taskContext)
{
return false;
}
public void setupJob(JobContext jobContext) { }
public void setupTask(TaskAttemptContext taskContext) { }
}
}