com.google.cloud.bigtable.beam.sequencefiles.SequenceFileSink Maven / Gradle / Ivy
/*
* Copyright 2017 Google Inc. All Rights Reserved.
*
* Licensed 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 com.google.cloud.bigtable.beam.sequencefiles;
import com.google.common.collect.Sets;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.channels.WritableByteChannel;
import java.util.Set;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.beam.sdk.io.Compression;
import org.apache.beam.sdk.io.DynamicFileDestinations;
import org.apache.beam.sdk.io.FileBasedSink;
import org.apache.beam.sdk.io.FileBasedSink.Writer;
import org.apache.beam.sdk.io.FileBasedSink.WriteOperation;
import org.apache.beam.sdk.io.fs.ResourceId;
import org.apache.beam.sdk.options.ValueProvider;
import org.apache.beam.sdk.util.MimeTypes;
import org.apache.beam.sdk.values.KV;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem.Statistics;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.serializer.Serialization;
/**
* {@link FileBasedSink} for {@link SequenceFile}s.
*
* @param The type of the {@link SequenceFile} key.
* @param The type of the {@link SequenceFile} value.
*/
class SequenceFileSink extends FileBasedSink, Void, KV> {
private static final Log LOG = LogFactory.getLog(SequenceFileSink.class);
private final Class keyClass;
private final Class valueClass;
private final String[] serializationNames;
/**
* Constructs the sink.
*/
SequenceFileSink(
ValueProvider baseOutputDirectoryProvider,
FilenamePolicy filenamePolicy,
Class keyClass, Class> keySerializationClass,
Class valueClass, Class> valueSerializationClass) {
super(baseOutputDirectoryProvider, DynamicFileDestinations.>constant(filenamePolicy), Compression.UNCOMPRESSED);
this.keyClass = keyClass;
this.valueClass = valueClass;
Set serializationNameSet = Sets.newHashSet();
serializationNameSet.add(keySerializationClass.getName());
serializationNameSet.add(valueSerializationClass.getName());
serializationNames = serializationNameSet.toArray(new String[serializationNameSet.size()]);
}
/**
* {@inheritDoc}
*/
@Override
public WriteOperation> createWriteOperation() {
return new SeqFileWriteOperation<>(this, keyClass, valueClass, serializationNames);
}
/**
* Specialized operation that manages the process of writing to {@link SequenceFileSink}.
* See {@link WriteOperation} for more details.
*
* @param The type of the {@link SequenceFile} key.
* @param The type of the {@link SequenceFile} value.
*/
private static class SeqFileWriteOperation extends WriteOperation> {
private final Class keyClass;
private final Class valueClass;
private final String[] serializationNames;
/**
* Constructs a SeqFileWriteOperation using the default strategy for generating a temporary
* directory from the base output filename.
*
* Default is a uniquely named sibling of baseOutputFilename, e.g. if baseOutputFilename is
* /path/to/foo, the temporary directory will be /path/to/temp-beam-foo-$date.
*
* @param sink The {@link SequenceFileSink} that will be used to configure this write operation.
* @param keyClass The class of the {@link SequenceFile} key.
* @param valueClass The class of the {@link SequenceFile} value.
* @param serializationNames A list of {@link Serialization} class names.
*/
SeqFileWriteOperation(SequenceFileSink sink, Class keyClass,
Class valueClass, String[] serializationNames) {
super(sink);
this.keyClass = keyClass;
this.valueClass = valueClass;
this.serializationNames = serializationNames;
}
/**
* {@inheritDoc}
*/
@Override
public Writer> createWriter() throws Exception {
return new SeqFileWriter<>(this);
}
}
/**
* Wrapper for {@link Writer} that adapts hadoop's {@link SequenceFile} api to Beam's
* {@link org.apache.beam.sdk.io.FileBasedSink.Writer} api.
*
* @param The type of the {@link SequenceFile} key.
* @param The type of the {@link SequenceFile} value.
*/
private static class SeqFileWriter extends Writer> {
private final SeqFileWriteOperation writeOperation;
private SequenceFile.Writer sequenceFile;
private final AtomicLong counter = new AtomicLong();
/**
* Constructs a new instance.
*
* @param writeOperation The parent operation.
*/
SeqFileWriter(SeqFileWriteOperation writeOperation) {
super(writeOperation, MimeTypes.BINARY);
this.writeOperation = writeOperation;
}
/**
* {@inheritDoc}
*/
@Override
protected void prepareWrite(WritableByteChannel channel) throws Exception {
LOG.debug("Opening new writer");
Configuration configuration = new Configuration(false);
configuration.setStrings("io.serializations", writeOperation.serializationNames);
FSDataOutputStream outputStream = new FSDataOutputStream(new OutputStreamWrapper(channel), new Statistics("dataflow"));
sequenceFile = SequenceFile.createWriter(configuration,
SequenceFile.Writer.stream(outputStream),
SequenceFile.Writer.keyClass(writeOperation.keyClass),
SequenceFile.Writer.valueClass(writeOperation.valueClass),
SequenceFile.Writer.compression(SequenceFile.CompressionType.BLOCK)
);
}
/**
* {@inheritDoc}
*/
@Override
protected void finishWrite() throws Exception {
sequenceFile.hflush();
sequenceFile.close();
super.finishWrite();
LOG.debug("Closing writer with " + counter.get() + " items");
}
/**
* {@inheritDoc}
*/
@Override
public void write(KV value) throws Exception {
counter.incrementAndGet();
sequenceFile.append(value.getKey(), value.getValue());
}
}
/**
* Adapter to allow Hadoop's {@link SequenceFile} to write to Beam's {@link WritableByteChannel}.
*/
static class OutputStreamWrapper extends OutputStream {
private final WritableByteChannel inner;
private final ByteBuffer singleByteBuffer = ByteBuffer.allocate(1);
/**
* Constructs a new {@link OutputStreamWrapper}.
*
* @param inner An instance of Beam's {@link WritableByteChannel}.
*/
OutputStreamWrapper(WritableByteChannel inner) {
this.inner = inner;
}
/**
* {@inheritDoc}
*/
@Override
public void write(byte[] b, int off, int len) throws IOException {
int written = 0;
ByteBuffer byteBuffer = ByteBuffer.wrap(b, off, len);
while (written < len) {
// Workaround Java 9 overridden methods with covariant return types
((Buffer)byteBuffer).position(written + off);
written += this.inner.write(byteBuffer);
}
}
/**
* {@inheritDoc}
*/
@Override
public void write(int b) throws IOException {
// Workaround Java 9 overridden methods with covariant return types
((Buffer)singleByteBuffer).clear();
singleByteBuffer.put((byte)b);
int written = 0;
while (written == 0) {
// Workaround Java 9 overridden methods with covariant return types
((Buffer)singleByteBuffer).position(0);
written = this.inner.write(singleByteBuffer);
}
}
}
}