/*
* 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.cassandra.hadoop;
import java.io.IOException;
import java.net.InetAddress;
import java.util.*;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.TimeUnit;
import org.apache.cassandra.client.RingCache;
import org.apache.cassandra.thrift.*;
import org.apache.cassandra.utils.FBUtilities;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.thrift.transport.TTransport;
import org.apache.hadoop.util.Progressable;
/**
* The <code>ColumnFamilyRecordWriter</code> maps the output <key, value>
* pairs to a Cassandra column family. In particular, it applies all mutations
* in the value, which it associates with the key, and in turn the responsible
* endpoint.
*
* <p>
* Furthermore, this writer groups the mutations by the endpoint responsible for
* the rows being affected. This allows the mutations to be executed in parallel,
* directly to a responsible endpoint.
* </p>
*
* @see ColumnFamilyOutputFormat
*/
public abstract class AbstractColumnFamilyRecordWriter<K, Y> extends RecordWriter<K, Y> implements org.apache.hadoop.mapred.RecordWriter<K, Y>
{
// The configuration this writer is associated with.
protected final Configuration conf;
// The ring cache that describes the token ranges each node in the ring is
// responsible for. This is what allows us to group the mutations by
// the endpoints they should be targeted at. The targeted endpoint
// essentially
// acts as the primary replica for the rows being affected by the mutations.
protected final RingCache ringCache;
// The number of mutations to buffer per endpoint
protected final int queueSize;
protected final long batchThreshold;
protected final ConsistencyLevel consistencyLevel;
protected Progressable progressable;
protected TaskAttemptContext context;
protected AbstractColumnFamilyRecordWriter(Configuration conf)
{
this.conf = conf;
this.ringCache = new RingCache(conf);
this.queueSize = conf.getInt(AbstractColumnFamilyOutputFormat.QUEUE_SIZE, 32 * FBUtilities.getAvailableProcessors());
batchThreshold = conf.getLong(AbstractColumnFamilyOutputFormat.BATCH_THRESHOLD, 32);
consistencyLevel = ConsistencyLevel.valueOf(ConfigHelper.getWriteConsistencyLevel(conf));
}
/**
* Close this <code>RecordWriter</code> to future operations, but not before
* flushing out the batched mutations.
*
* @param context the context of the task
* @throws IOException
*/
public void close(TaskAttemptContext context) throws IOException, InterruptedException
{
close();
}
/** Fills the deprecated RecordWriter interface for streaming. */
@Deprecated
public void close(org.apache.hadoop.mapred.Reporter reporter) throws IOException
{
close();
}
protected abstract void close() throws IOException;
/**
* A client that runs in a threadpool and connects to the list of endpoints for a particular
* range. Mutations for keys in that range are sent to this client via a queue.
*/
public abstract class AbstractRangeClient<K> extends Thread
{
// The list of endpoints for this range
protected final List<InetAddress> endpoints;
// A bounded queue of incoming mutations for this range
protected final BlockingQueue<K> queue = new ArrayBlockingQueue<K>(queueSize);
protected volatile boolean run = true;
// we want the caller to know if something went wrong, so we record any unrecoverable exception while writing
// so we can throw it on the caller's stack when he calls put() again, or if there are no more put calls,
// when the client is closed.
protected volatile IOException lastException;
protected Cassandra.Client client;
/**
* Constructs an {@link AbstractRangeClient} for the given endpoints.
* @param endpoints the possible endpoints to execute the mutations on
*/
public AbstractRangeClient(List<InetAddress> endpoints)
{
super("client-" + endpoints);
this.endpoints = endpoints;
}
/**
* enqueues the given value to Cassandra
*/
public void put(K value) throws IOException
{
while (true)
{
if (lastException != null)
throw lastException;
try
{
if (queue.offer(value, 100, TimeUnit.MILLISECONDS))
break;
}
catch (InterruptedException e)
{
throw new AssertionError(e);
}
}
}
public void close() throws IOException
{
// stop the run loop. this will result in closeInternal being called by the time join() finishes.
run = false;
interrupt();
try
{
this.join();
}
catch (InterruptedException e)
{
throw new AssertionError(e);
}
if (lastException != null)
throw lastException;
}
protected void closeInternal()
{
if (client != null)
{
TTransport transport = client.getOutputProtocol().getTransport();
if (transport.isOpen())
transport.close();
}
}
/**
* Loops collecting mutations from the queue and sending to Cassandra
*/
public abstract void run();
@Override
public String toString()
{
return "#<Client for " + endpoints.toString() + ">";
}
}
}