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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.broadcast
import java.io.{File, FileOutputStream, ObjectInputStream, ObjectOutputStream, OutputStream}
import java.io.{BufferedInputStream, BufferedOutputStream}
import java.net.{URL, URLConnection, URI}
import java.util.concurrent.TimeUnit
import scala.reflect.ClassTag
import org.apache.spark.{HttpServer, Logging, SecurityManager, SparkConf, SparkEnv}
import org.apache.spark.io.CompressionCodec
import org.apache.spark.storage.{BroadcastBlockId, StorageLevel}
import org.apache.spark.util.{MetadataCleaner, MetadataCleanerType, TimeStampedHashSet, Utils}
/**
* A [[org.apache.spark.broadcast.Broadcast]] implementation that uses HTTP server
* as a broadcast mechanism. The first time a HTTP broadcast variable (sent as part of a
* task) is deserialized in the executor, the broadcasted data is fetched from the driver
* (through a HTTP server running at the driver) and stored in the BlockManager of the
* executor to speed up future accesses.
*/
private[spark] class HttpBroadcast[T: ClassTag](
@transient var value_ : T, isLocal: Boolean, id: Long)
extends Broadcast[T](id) with Logging with Serializable {
override protected def getValue() = value_
private val blockId = BroadcastBlockId(id)
/*
* Broadcasted data is also stored in the BlockManager of the driver. The BlockManagerMaster
* does not need to be told about this block as not only need to know about this data block.
*/
HttpBroadcast.synchronized {
SparkEnv.get.blockManager.putSingle(
blockId, value_, StorageLevel.MEMORY_AND_DISK, tellMaster = false)
}
if (!isLocal) {
HttpBroadcast.write(id, value_)
}
/**
* Remove all persisted state associated with this HTTP broadcast on the executors.
*/
override protected def doUnpersist(blocking: Boolean) {
HttpBroadcast.unpersist(id, removeFromDriver = false, blocking)
}
/**
* Remove all persisted state associated with this HTTP broadcast on the executors and driver.
*/
override protected def doDestroy(blocking: Boolean) {
HttpBroadcast.unpersist(id, removeFromDriver = true, blocking)
}
/** Used by the JVM when serializing this object. */
private def writeObject(out: ObjectOutputStream) {
assertValid()
out.defaultWriteObject()
}
/** Used by the JVM when deserializing this object. */
private def readObject(in: ObjectInputStream) {
in.defaultReadObject()
HttpBroadcast.synchronized {
SparkEnv.get.blockManager.getSingle(blockId) match {
case Some(x) => value_ = x.asInstanceOf[T]
case None => {
logInfo("Started reading broadcast variable " + id)
val start = System.nanoTime
value_ = HttpBroadcast.read[T](id)
/*
* We cache broadcast data in the BlockManager so that subsequent tasks using it
* do not need to re-fetch. This data is only used locally and no other node
* needs to fetch this block, so we don't notify the master.
*/
SparkEnv.get.blockManager.putSingle(
blockId, value_, StorageLevel.MEMORY_AND_DISK, tellMaster = false)
val time = (System.nanoTime - start) / 1e9
logInfo("Reading broadcast variable " + id + " took " + time + " s")
}
}
}
}
}
private[broadcast] object HttpBroadcast extends Logging {
private var initialized = false
private var broadcastDir: File = null
private var compress: Boolean = false
private var bufferSize: Int = 65536
private var serverUri: String = null
private var server: HttpServer = null
private var securityManager: SecurityManager = null
// TODO: This shouldn't be a global variable so that multiple SparkContexts can coexist
private val files = new TimeStampedHashSet[File]
private val httpReadTimeout = TimeUnit.MILLISECONDS.convert(5, TimeUnit.MINUTES).toInt
private var compressionCodec: CompressionCodec = null
private var cleaner: MetadataCleaner = null
def initialize(isDriver: Boolean, conf: SparkConf, securityMgr: SecurityManager) {
synchronized {
if (!initialized) {
bufferSize = conf.getInt("spark.buffer.size", 65536)
compress = conf.getBoolean("spark.broadcast.compress", true)
securityManager = securityMgr
if (isDriver) {
createServer(conf)
conf.set("spark.httpBroadcast.uri", serverUri)
}
serverUri = conf.get("spark.httpBroadcast.uri")
cleaner = new MetadataCleaner(MetadataCleanerType.HTTP_BROADCAST, cleanup, conf)
compressionCodec = CompressionCodec.createCodec(conf)
initialized = true
}
}
}
def stop() {
synchronized {
if (server != null) {
server.stop()
server = null
}
if (cleaner != null) {
cleaner.cancel()
cleaner = null
}
compressionCodec = null
initialized = false
}
}
private def createServer(conf: SparkConf) {
broadcastDir = Utils.createTempDir(Utils.getLocalDir(conf))
val broadcastPort = conf.getInt("spark.broadcast.port", 0)
server = new HttpServer(broadcastDir, securityManager, broadcastPort, "HTTP broadcast server")
server.start()
serverUri = server.uri
logInfo("Broadcast server started at " + serverUri)
}
def getFile(id: Long) = new File(broadcastDir, BroadcastBlockId(id).name)
private def write(id: Long, value: Any) {
val file = getFile(id)
val fileOutputStream = new FileOutputStream(file)
try {
val out: OutputStream = {
if (compress) {
compressionCodec.compressedOutputStream(fileOutputStream)
} else {
new BufferedOutputStream(fileOutputStream, bufferSize)
}
}
val ser = SparkEnv.get.serializer.newInstance()
val serOut = ser.serializeStream(out)
serOut.writeObject(value)
serOut.close()
files += file
} finally {
fileOutputStream.close()
}
}
private def read[T: ClassTag](id: Long): T = {
logDebug("broadcast read server: " + serverUri + " id: broadcast-" + id)
val url = serverUri + "/" + BroadcastBlockId(id).name
var uc: URLConnection = null
if (securityManager.isAuthenticationEnabled()) {
logDebug("broadcast security enabled")
val newuri = Utils.constructURIForAuthentication(new URI(url), securityManager)
uc = newuri.toURL.openConnection()
uc.setAllowUserInteraction(false)
} else {
logDebug("broadcast not using security")
uc = new URL(url).openConnection()
}
val in = {
uc.setReadTimeout(httpReadTimeout)
val inputStream = uc.getInputStream
if (compress) {
compressionCodec.compressedInputStream(inputStream)
} else {
new BufferedInputStream(inputStream, bufferSize)
}
}
val ser = SparkEnv.get.serializer.newInstance()
val serIn = ser.deserializeStream(in)
val obj = serIn.readObject[T]()
serIn.close()
obj
}
/**
* Remove all persisted blocks associated with this HTTP broadcast on the executors.
* If removeFromDriver is true, also remove these persisted blocks on the driver
* and delete the associated broadcast file.
*/
def unpersist(id: Long, removeFromDriver: Boolean, blocking: Boolean) = synchronized {
SparkEnv.get.blockManager.master.removeBroadcast(id, removeFromDriver, blocking)
if (removeFromDriver) {
val file = getFile(id)
files.remove(file)
deleteBroadcastFile(file)
}
}
/**
* Periodically clean up old broadcasts by removing the associated map entries and
* deleting the associated files.
*/
private def cleanup(cleanupTime: Long) {
val iterator = files.internalMap.entrySet().iterator()
while(iterator.hasNext) {
val entry = iterator.next()
val (file, time) = (entry.getKey, entry.getValue)
if (time < cleanupTime) {
iterator.remove()
deleteBroadcastFile(file)
}
}
}
private def deleteBroadcastFile(file: File) {
try {
if (file.exists) {
if (file.delete()) {
logInfo("Deleted broadcast file: %s".format(file))
} else {
logWarning("Could not delete broadcast file: %s".format(file))
}
}
} catch {
case e: Exception =>
logError("Exception while deleting broadcast file: %s".format(file), e)
}
}
}
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