/
AbstractProtocolDecoder.scala
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/
AbstractProtocolDecoder.scala
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/*
* JBoss, Home of Professional Open Source
* Copyright 2010 Red Hat Inc. and/or its affiliates and other
* contributors as indicated by the @author tags. All rights reserved.
* See the copyright.txt in the distribution for a full listing of
* individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.infinispan.server.core
import org.infinispan.Cache
import Operation._
import java.util.concurrent.TimeUnit
import transport._
import java.io.StreamCorruptedException
import transport.ExtendedChannelBuffer._
import org.jboss.netty.buffer.ChannelBuffer
import org.jboss.netty.channel._
import DecoderState._
import org.infinispan.util.ClusterIdGenerator
import logging.Log
import java.lang.StringBuilder
import org.jboss.netty.handler.codec.replay.ReplayingDecoder
/**
* Common abstract decoder for Memcached and Hot Rod protocols.
*
* @author Galder Zamarreño
* @since 4.1
*/
abstract class AbstractProtocolDecoder[K, V <: CacheValue](transport: NettyTransport)
extends ReplayingDecoder[DecoderState](DECODE_HEADER, true) with Log {
import AbstractProtocolDecoder._
type SuitableParameters <: RequestParameters
type SuitableHeader <: RequestHeader
var versionGenerator: ClusterIdGenerator = _
private val isTrace = isTraceEnabled
protected var header: SuitableHeader = null.asInstanceOf[SuitableHeader]
protected var params: SuitableParameters = null.asInstanceOf[SuitableParameters]
protected var key: K = null.asInstanceOf[K]
protected var rawValue: Array[Byte] = null.asInstanceOf[Array[Byte]]
protected var cache: Cache[K, V] = null
override def decode(ctx: ChannelHandlerContext, ch: Channel, buffer: ChannelBuffer, state: DecoderState): AnyRef = {
val ch = ctx.getChannel
try {
if (isTrace) // To aid debugging
trace("Decode using instance @%x", System.identityHashCode(this))
state match {
case DECODE_HEADER => decodeHeader(ch, buffer, state)
case DECODE_KEY => decodeKey(ch, buffer, state)
case DECODE_PARAMETERS => decodeParameters(ch, buffer, state)
case DECODE_VALUE => decodeValue(ch, buffer, state)
}
} catch {
case e: Exception => {
val (serverException, isClientError) = createServerException(e, buffer)
// If decode returns an exception, decode won't be called again so,
// we need to fire the exception explicitly so that requests can
// carry on being processed on same connection after a client error
if (isClientError) {
Channels.fireExceptionCaught(ch, serverException)
null
} else {
throw serverException
}
}
case t: Throwable => throw t
}
}
private def decodeHeader(ch: Channel, buffer: ChannelBuffer, state: DecoderState): AnyRef = {
header = createHeader
val endOfOp = readHeader(buffer, header)
if (endOfOp == None) {
// Something went wrong reading the header, so get more bytes.
// It can happen with Hot Rod if the header is completely corrupted
return null
}
cache = getCache
if (endOfOp.get) {
header.op match {
case StatsRequest => writeResponse(ch, createStatsResponse)
case _ => customDecodeHeader(ch, buffer)
}
} else {
checkpointTo(DECODE_KEY)
}
}
private def decodeKey(ch: Channel, buffer: ChannelBuffer, state: DecoderState): AnyRef = {
header.op match {
// Get, put and remove are the most typical operations, so they're first
case GetRequest => writeResponse(ch, get(buffer))
case PutRequest => handleModification(ch, buffer)
case RemoveRequest => handleModification(ch, buffer)
case GetWithVersionRequest => writeResponse(ch, get(buffer))
case PutIfAbsentRequest | ReplaceRequest | ReplaceIfUnmodifiedRequest =>
handleModification(ch, buffer)
case _ => customDecodeKey(ch, buffer)
}
}
def handleModification(ch: Channel, buf: ChannelBuffer): AnyRef = {
val (k, endOfOp) = readKey(buf)
key = k
if (endOfOp) {
// If it's the end of the operation, it can only be a remove
writeResponse(ch, remove)
} else {
checkpointTo(DECODE_PARAMETERS)
}
}
private def decodeParameters(ch: Channel, buffer: ChannelBuffer, state: DecoderState): AnyRef = {
val endOfOp = readParameters(ch, buffer)
if (!endOfOp && params.valueLength > 0) {
// Create value holder and checkpoint only if there's more to read
rawValue = new Array[Byte](params.valueLength)
checkpointTo(DECODE_VALUE)
} else if (params.valueLength == 0){
rawValue = Array.empty
decodeValue(ch, buffer, state)
} else {
decodeValue(ch, buffer, state)
}
}
private def decodeValue(ch: Channel, buffer: ChannelBuffer, state: DecoderState): AnyRef = {
val ret = header.op match {
case PutRequest | PutIfAbsentRequest | ReplaceRequest | ReplaceIfUnmodifiedRequest => {
readValue(buffer)
header.op match {
case PutRequest => put
case PutIfAbsentRequest => putIfAbsent
case ReplaceRequest => replace
case ReplaceIfUnmodifiedRequest => replaceIfUmodified
}
}
case RemoveRequest => remove
case _ => customDecodeValue(ch, buffer)
}
writeResponse(ch, ret)
}
override def decodeLast(ctx: ChannelHandlerContext, ch: Channel, buffer: ChannelBuffer, state: DecoderState): AnyRef = null // no-op
protected def writeResponse(ch: Channel, response: AnyRef): AnyRef = {
try {
if (response != null) {
if (isTrace) trace("Write response %s", response)
response match {
// We only expect Lists of ChannelBuffer instances, so don't worry about type erasure
case l: List[ChannelBuffer] => l.foreach(ch.write(_))
case a: Array[Byte] => ch.write(wrappedBuffer(a))
case sb: StringBuilder => ch.write(wrappedBuffer(sb.toString.getBytes))
case s: String => ch.write(wrappedBuffer(s.getBytes))
case _ => ch.write(response)
}
}
null
} finally {
resetParams
}
}
private def resetParams: AnyRef = {
checkpointTo(DECODE_HEADER)
// Reset parameters to avoid leaking previous params
// into a request that has no params
params = null.asInstanceOf[SuitableParameters]
rawValue = null.asInstanceOf[Array[Byte]] // Clear reference to value
null
}
private def put: AnyRef = {
val v = createValue(generateVersion(cache))
// Get an optimised cache in case we can make the operation more efficient
val prev = getOptimizedCache(cache).put(key, v,
toMillis(params.lifespan), DefaultTimeUnit,
toMillis(params.maxIdle), DefaultTimeUnit)
createSuccessResponse(prev)
}
protected def getOptimizedCache(c: Cache[K, V]): Cache[K, V] = c
private def putIfAbsent: AnyRef = {
var prev = cache.get(key)
if (prev == null) { // Generate new version only if key not present
val v = createValue(generateVersion(cache))
prev = cache.putIfAbsent(key, v,
toMillis(params.lifespan), DefaultTimeUnit,
toMillis(params.maxIdle), DefaultTimeUnit)
}
if (prev == null)
createSuccessResponse(prev)
else
createNotExecutedResponse(prev)
}
private def replace: AnyRef = {
var prev = cache.get(key)
if (prev != null) { // Generate new version only if key present
val v = createValue(generateVersion(cache))
prev = cache.replace(key, v,
toMillis(params.lifespan), DefaultTimeUnit,
toMillis(params.maxIdle), DefaultTimeUnit)
}
if (prev != null)
createSuccessResponse(prev)
else
createNotExecutedResponse(prev)
}
private def replaceIfUmodified: AnyRef = {
val prev = cache.get(key)
if (prev != null) {
if (prev.version == params.streamVersion) {
// Generate new version only if key present and version has not changed, otherwise it's wasteful
val v = createValue(generateVersion(cache))
val replaced = cache.replace(key, prev, v,
toMillis(params.lifespan), DefaultTimeUnit,
toMillis(params.maxIdle), DefaultTimeUnit)
if (replaced)
createSuccessResponse(prev)
else
createNotExecutedResponse(prev)
} else {
createNotExecutedResponse(prev)
}
} else createNotExistResponse
}
private def remove: AnyRef = {
val prev = cache.remove(key)
if (prev != null)
createSuccessResponse(prev)
else
createNotExistResponse
}
protected def get(buffer: ChannelBuffer): AnyRef =
createGetResponse(key, cache.get(readKey(buffer)._1))
override def exceptionCaught(ctx: ChannelHandlerContext, e: ExceptionEvent) {
val ch = ctx.getChannel
val cause = e.getCause
// Log it just in case the channel is closed or similar
debug(cause, "Exception caught")
val errorResponse = createErrorResponse(cause)
if (errorResponse != null) {
errorResponse match {
case a: Array[Byte] => ch.write(wrappedBuffer(a))
case sb: StringBuilder => ch.write(wrappedBuffer(sb.toString.getBytes))
case null => // ignore
case _ => ch.write(errorResponse)
}
}
// After writing back an error, reset params and revert to initial state
resetParams
}
override def channelOpen(ctx: ChannelHandlerContext, e: ChannelStateEvent) {
transport.acceptedChannels.add(e.getChannel)
super.channelOpen(ctx, e)
}
def checkpointTo(state: DecoderState): AnyRef = {
checkpoint(state)
null // For netty's decoder that mandates a return
}
protected def createHeader: SuitableHeader
protected def readHeader(b: ChannelBuffer, header: SuitableHeader): Option[Boolean]
protected def getCache: Cache[K, V]
/**
* Returns the key read along with a boolean indicating whether the
* end of the operation was found or not. This allows client to
* differentiate between extra parameters or pipelined sequence of
* operations.
*/
protected def readKey(b: ChannelBuffer): (K, Boolean)
protected def readParameters(ch: Channel, b: ChannelBuffer): Boolean
protected def readValue(b: ChannelBuffer)
protected def createValue(nextVersion: Long): V
protected def createSuccessResponse(prev: V): AnyRef
protected def createNotExecutedResponse(prev: V): AnyRef
protected def createNotExistResponse: AnyRef
protected def createGetResponse(k: K, v: V): AnyRef
protected def createMultiGetResponse(pairs: Map[K, V]): AnyRef
protected def createErrorResponse(t: Throwable): AnyRef
protected def createStatsResponse: AnyRef
protected def customDecodeHeader(ch: Channel, buffer: ChannelBuffer): AnyRef
protected def customDecodeKey(ch: Channel, buffer: ChannelBuffer): AnyRef
protected def customDecodeValue(ch: Channel, buffer: ChannelBuffer): AnyRef
protected def createServerException(e: Exception, b: ChannelBuffer): (Exception, Boolean)
protected def generateVersion(cache: Cache[K, V]): Long = {
val rpcManager = cache.getAdvancedCache.getRpcManager
versionGenerator.newVersion(rpcManager != null)
}
/**
* Transforms lifespan pass as seconds into milliseconds
* following this rule:
*
* If lifespan is bigger than number of seconds in 30 days,
* then it is considered unix time. After converting it to
* milliseconds, we substract the current time in and the
* result is returned.
*
* Otherwise it's just considered number of seconds from
* now and it's returned in milliseconds unit.
*/
protected def toMillis(lifespan: Int): Long = {
if (lifespan > SecondsInAMonth) {
val unixTimeExpiry = TimeUnit.SECONDS.toMillis(lifespan) - System.currentTimeMillis
if (unixTimeExpiry < 0) 0 else unixTimeExpiry
} else {
TimeUnit.SECONDS.toMillis(lifespan)
}
}
override def writeComplete(ctx: ChannelHandlerContext, e: WriteCompletionEvent) {
transport.updateTotalBytesWritten(e)
ctx.sendUpstream(e)
}
override def messageReceived(ctx: ChannelHandlerContext, e: MessageEvent) {
transport.updateTotalBytesRead(e)
super.messageReceived(ctx, e)
}
}
object AbstractProtocolDecoder extends Log {
private val SecondsInAMonth = 60 * 60 * 24 * 30
private val DefaultTimeUnit = TimeUnit.MILLISECONDS
}
class RequestHeader {
var op: Enumeration#Value = _
override def toString = {
new StringBuilder().append("RequestHeader").append("{")
.append("op=").append(op)
.append("}").toString
}
}
class RequestParameters(val valueLength: Int, val lifespan: Int, val maxIdle: Int, val streamVersion: Long) {
override def toString = {
new StringBuilder().append("RequestParameters").append("{")
.append("valueLength=").append(valueLength)
.append(", lifespan=").append(lifespan)
.append(", maxIdle=").append(maxIdle)
.append(", streamVersion=").append(streamVersion)
.append("}").toString
}
}
class UnknownOperationException(reason: String) extends StreamCorruptedException(reason)