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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.serializer
import java.nio.ByteBuffer
import java.io.{EOFException, InputStream, OutputStream}
import com.esotericsoftware.kryo.serializers.{JavaSerializer => KryoJavaSerializer}
import com.esotericsoftware.kryo.{KryoException, Kryo}
import com.esotericsoftware.kryo.io.{Input => KryoInput, Output => KryoOutput}
import com.twitter.chill.{EmptyScalaKryoInstantiator, AllScalaRegistrar}
import org.apache.spark.{SerializableWritable, Logging}
import org.apache.spark.broadcast.HttpBroadcast
import org.apache.spark.storage.{GetBlock,GotBlock, PutBlock, StorageLevel, TestBlockId}
/**
* A Spark serializer that uses the [[http://code.google.com/p/kryo/wiki/V1Documentation Kryo 1.x library]].
*/
class KryoSerializer extends org.apache.spark.serializer.Serializer with Logging {
private val bufferSize = System.getProperty("spark.kryoserializer.buffer.mb", "2").toInt * 1024 * 1024
def newKryoOutput() = new KryoOutput(bufferSize)
def newKryo(): Kryo = {
val instantiator = new EmptyScalaKryoInstantiator
val kryo = instantiator.newKryo()
val classLoader = Thread.currentThread.getContextClassLoader
val blockId = TestBlockId("1")
// Register some commonly used classes
val toRegister: Seq[AnyRef] = Seq(
ByteBuffer.allocate(1),
StorageLevel.MEMORY_ONLY,
PutBlock(blockId, ByteBuffer.allocate(1), StorageLevel.MEMORY_ONLY),
GotBlock(blockId, ByteBuffer.allocate(1)),
GetBlock(blockId),
1 to 10,
1 until 10,
1L to 10L,
1L until 10L
)
for (obj <- toRegister) kryo.register(obj.getClass)
// Allow sending SerializableWritable
kryo.register(classOf[SerializableWritable[_]], new KryoJavaSerializer())
kryo.register(classOf[HttpBroadcast[_]], new KryoJavaSerializer())
// Allow the user to register their own classes by setting spark.kryo.registrator
try {
Option(System.getProperty("spark.kryo.registrator")).foreach { regCls =>
logDebug("Running user registrator: " + regCls)
val reg = Class.forName(regCls, true, classLoader).newInstance().asInstanceOf[KryoRegistrator]
reg.registerClasses(kryo)
}
} catch {
case _: Exception => println("Failed to register spark.kryo.registrator")
}
// Register Chill's classes; we do this after our ranges and the user's own classes to let
// our code override the generic serialziers in Chill for things like Seq
new AllScalaRegistrar().apply(kryo)
kryo.setClassLoader(classLoader)
// Allow disabling Kryo reference tracking if user knows their object graphs don't have loops
kryo.setReferences(System.getProperty("spark.kryo.referenceTracking", "true").toBoolean)
kryo
}
def newInstance(): SerializerInstance = {
new KryoSerializerInstance(this)
}
}
private[spark]
class KryoSerializationStream(kryo: Kryo, outStream: OutputStream) extends SerializationStream {
val output = new KryoOutput(outStream)
def writeObject[T](t: T): SerializationStream = {
kryo.writeClassAndObject(output, t)
this
}
def flush() { output.flush() }
def close() { output.close() }
}
private[spark]
class KryoDeserializationStream(kryo: Kryo, inStream: InputStream) extends DeserializationStream {
val input = new KryoInput(inStream)
def readObject[T](): T = {
try {
kryo.readClassAndObject(input).asInstanceOf[T]
} catch {
// DeserializationStream uses the EOF exception to indicate stopping condition.
case _: KryoException => throw new EOFException
}
}
def close() {
// Kryo's Input automatically closes the input stream it is using.
input.close()
}
}
private[spark] class KryoSerializerInstance(ks: KryoSerializer) extends SerializerInstance {
val kryo = ks.newKryo()
// Make these lazy vals to avoid creating a buffer unless we use them
lazy val output = ks.newKryoOutput()
lazy val input = new KryoInput()
def serialize[T](t: T): ByteBuffer = {
output.clear()
kryo.writeClassAndObject(output, t)
ByteBuffer.wrap(output.toBytes)
}
def deserialize[T](bytes: ByteBuffer): T = {
input.setBuffer(bytes.array)
kryo.readClassAndObject(input).asInstanceOf[T]
}
def deserialize[T](bytes: ByteBuffer, loader: ClassLoader): T = {
val oldClassLoader = kryo.getClassLoader
kryo.setClassLoader(loader)
input.setBuffer(bytes.array)
val obj = kryo.readClassAndObject(input).asInstanceOf[T]
kryo.setClassLoader(oldClassLoader)
obj
}
def serializeStream(s: OutputStream): SerializationStream = {
new KryoSerializationStream(kryo, s)
}
def deserializeStream(s: InputStream): DeserializationStream = {
new KryoDeserializationStream(kryo, s)
}
}
/**
* Interface implemented by clients to register their classes with Kryo when using Kryo
* serialization.
*/
trait KryoRegistrator {
def registerClasses(kryo: Kryo)
}
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