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/*
* 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.spark.io
import java.io.{InputStream, OutputStream}
import com.ning.compress.lzf.{LZFInputStream, LZFOutputStream}
import net.jpountz.lz4.{LZ4BlockInputStream, LZ4BlockOutputStream}
import org.xerial.snappy.{SnappyInputStream, SnappyOutputStream}
import org.apache.spark.SparkConf
import org.apache.spark.annotation.DeveloperApi
import org.apache.spark.util.Utils
/**
* :: DeveloperApi ::
* CompressionCodec allows the customization of choosing different compression implementations
* to be used in block storage.
*
* Note: The wire protocol for a codec is not guaranteed compatible across versions of Spark.
* This is intended for use as an internal compression utility within a single
* Spark application.
*/
@DeveloperApi
trait CompressionCodec {
def compressedOutputStream(s: OutputStream): OutputStream
def compressedInputStream(s: InputStream): InputStream
}
private[spark] object CompressionCodec {
private val shortCompressionCodecNames = Map(
"lz4" -> classOf[LZ4CompressionCodec].getName,
"lzf" -> classOf[LZFCompressionCodec].getName,
"snappy" -> classOf[SnappyCompressionCodec].getName)
def createCodec(conf: SparkConf): CompressionCodec = {
createCodec(conf, conf.get("spark.io.compression.codec", DEFAULT_COMPRESSION_CODEC))
}
def createCodec(conf: SparkConf, codecName: String): CompressionCodec = {
val codecClass = shortCompressionCodecNames.getOrElse(codecName.toLowerCase, codecName)
val ctor = Class.forName(codecClass, true, Utils.getContextOrSparkClassLoader)
.getConstructor(classOf[SparkConf])
ctor.newInstance(conf).asInstanceOf[CompressionCodec]
}
val DEFAULT_COMPRESSION_CODEC = "snappy"
}
/**
* :: DeveloperApi ::
* LZ4 implementation of [[org.apache.spark.io.CompressionCodec]].
* Block size can be configured by `spark.io.compression.lz4.block.size`.
*
* Note: The wire protocol for this codec is not guaranteed to be compatible across versions
* of Spark. This is intended for use as an internal compression utility within a single Spark
* application.
*/
@DeveloperApi
class LZ4CompressionCodec(conf: SparkConf) extends CompressionCodec {
override def compressedOutputStream(s: OutputStream): OutputStream = {
val blockSize = conf.getInt("spark.io.compression.lz4.block.size", 32768)
new LZ4BlockOutputStream(s, blockSize)
}
override def compressedInputStream(s: InputStream): InputStream = new LZ4BlockInputStream(s)
}
/**
* :: DeveloperApi ::
* LZF implementation of [[org.apache.spark.io.CompressionCodec]].
*
* Note: The wire protocol for this codec is not guaranteed to be compatible across versions
* of Spark. This is intended for use as an internal compression utility within a single Spark
* application.
*/
@DeveloperApi
class LZFCompressionCodec(conf: SparkConf) extends CompressionCodec {
override def compressedOutputStream(s: OutputStream): OutputStream = {
new LZFOutputStream(s).setFinishBlockOnFlush(true)
}
override def compressedInputStream(s: InputStream): InputStream = new LZFInputStream(s)
}
/**
* :: DeveloperApi ::
* Snappy implementation of [[org.apache.spark.io.CompressionCodec]].
* Block size can be configured by `spark.io.compression.snappy.block.size`.
*
* Note: The wire protocol for this codec is not guaranteed to be compatible across versions
* of Spark. This is intended for use as an internal compression utility within a single Spark
* application.
*/
@DeveloperApi
class SnappyCompressionCodec(conf: SparkConf) extends CompressionCodec {
override def compressedOutputStream(s: OutputStream): OutputStream = {
val blockSize = conf.getInt("spark.io.compression.snappy.block.size", 32768)
new SnappyOutputStream(s, blockSize)
}
override def compressedInputStream(s: InputStream): InputStream = new SnappyInputStream(s)
}
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