/*************************************************************************
* Copyright 2009-2012 Eucalyptus Systems, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 3 of the License.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*
* Please contact Eucalyptus Systems, Inc., 6755 Hollister Ave., Goleta
* CA 93117, USA or visit http://www.eucalyptus.com/licenses/ if you need
* additional information or have any questions.
*
* This file may incorporate work covered under the following copyright
* and permission notice:
*
* Software License Agreement (BSD License)
*
* Copyright (c) 2008, Regents of the University of California
* All rights reserved.
*
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*
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************************************************************************/
package com.eucalyptus.objectstorage.pipeline.handlers;
import java.util.ArrayList;
import org.apache.log4j.Logger;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.handler.codec.http.DefaultHttpChunk;
import org.jboss.netty.handler.codec.http.HttpHeaders;
import com.eucalyptus.http.MappingHttpRequest;
import com.eucalyptus.objectstorage.exceptions.s3.MissingContentLengthException;
import com.google.common.base.Strings;
/**
* Aggregates the HTTP request such that it can move forward in the pipeline. Will aggregate up to the specified buffer size and then make the
* aggregated event available via 'poll'
*
* Expected usage: new instance per channel, to aggregate the data up from and then pass it on. Subsequent chunks are then rejected and no processing
* is done because they can be passed up directly. Example: offer(mappingHttpRequestEvent) => true poll() => null offer(DefaultHttpChunkEvent) => true
* poll() => null offer(DefaultHttpChunkEvent) => true poll() => AggregatedMessageEvent offer(DefaultHttpChunkEvent) => false
* offer(DefaultHttpChunkEvent) => false in this case, poll() will continue to return the aggregated message, but with no new content. use hardReset()
* to reset and use again if needed
*
* In the case where poll() is not called between offer() calls, offer will return false if the threshold is passed, the caller must call poll() to
* get the current aggregated amount. This keeps memory usage limited.
*
*
* This aggregator operates on a single channel, is not intended for multiple threads, should use multiple instances for multiple channels
*/
public class HttpThresholdBufferingAggregator {
private static Logger LOG = Logger.getLogger(HttpThresholdBufferingAggregator.class);
private final static int DEFAULT_BUFFER_SIZE = 128 * 1024; // 128k default size
/**
* Represents the aggregated event. The initial message event plus the aggregated content buffer.
*/
public static class AggregatedMessageEvent {
public AggregatedMessageEvent(MessageEvent initial, ChannelBuffer initialContent) {
this.messageEvent = initial;
this.lastReceived = false;
this.contentBuffers = new ArrayList<ChannelBuffer>(3); // usually no more than a few are needed
this.contentBuffers.add(initialContent);
}
public MessageEvent getMessageEvent() {
return messageEvent;
}
/**
* May be invoked repeatedly, but will result in distinct copies of the aggregated buffer for each call. Use carefully to avoid memory issues
*
* @return
*/
public ChannelBuffer getAggregatedContentBuffer() {
return ChannelBuffers.copiedBuffer(this.contentBuffers.toArray(new ChannelBuffer[this.contentBuffers.size()]));
}
public void addContentBuffer(ChannelBuffer nextContentBuffer, boolean isLast) {
this.contentBuffers.add(nextContentBuffer);
this.lastReceived = isLast;
}
public int getAggregationCount() {
return this.contentBuffers.size();
}
public long getCurrentAggregatedSize() {
long size = 0;
for (ChannelBuffer b : this.contentBuffers) {
size += b.readableBytes();
}
return size;
}
public boolean isLastReceived() {
return this.lastReceived;
}
private MessageEvent messageEvent;
private ArrayList<ChannelBuffer> contentBuffers;
private boolean lastReceived;
}
private int maxBufferingSize; // The size after which the message will be passed along
private volatile AggregatedMessageEvent currentEvent;
public HttpThresholdBufferingAggregator() {
this.maxBufferingSize = DEFAULT_BUFFER_SIZE;
}
public HttpThresholdBufferingAggregator(int bufferSize) {
this.maxBufferingSize = bufferSize;
}
/**
* Returns the event to send upstream if one is ready, otherwise returns null
*
* @return
*/
public AggregatedMessageEvent poll() {
if (this.currentEvent != null && (this.currentEvent.isLastReceived() || this.currentEvent.getCurrentAggregatedSize() >= this.maxBufferingSize)) {
LOG.trace("Poll returning event: " + this.currentEvent.toString() + " data: " + this.currentEvent.getAggregatedContentBuffer().toString());
return this.currentEvent;
} else {
LOG.trace("Poll returning null");
return null;
}
}
/**
* Flushes and resets this instance. Will discard all pending data
*/
public void hardReset() {
LOG.trace("HardReset invoked");
this.currentEvent = null;
}
/**
* Handles the filtering, returns true if accepted, false if not accepted. Reasons for not accepting: 1. Message itself is larger than threshold 2.
* Message is a chunk, but no preceding request has been processed 3. The message was aggregated and returned causing reset, similar to #2.
* Subsequent chunks will be rejected 4. There is a pending aggregation, but a MappingHttpRequest event is offered
*
* @param event
* @return
*/
public boolean offer(final MessageEvent event) throws Exception {
if (event.getMessage() instanceof MappingHttpRequest && this.currentEvent == null) {
return offerRequest(event);
} else if (event.getMessage() instanceof DefaultHttpChunk && this.currentEvent != null) {
return offerChunk((DefaultHttpChunk) event.getMessage());
} else {
// Reject the data
return false;
}
}
protected boolean offerRequest(MessageEvent event) throws Exception {
if (!(event.getMessage() instanceof MappingHttpRequest) || this.currentEvent != null) {
return false; // reject, wrong type or pending already
}
MappingHttpRequest httpRequest = (MappingHttpRequest) event.getMessage();
if (Strings.isNullOrEmpty(httpRequest.getHeader(HttpHeaders.Names.CONTENT_LENGTH))) {
throw new MissingContentLengthException();
}
try {
long contentLength = Long.parseLong(httpRequest.getHeader(HttpHeaders.Names.CONTENT_LENGTH));
} catch (NumberFormatException e) {
LOG.error("Client specified content-length in invalid format, not a integer", e);
throw new MissingContentLengthException(null, "Content-Length not valid integer");
}
// First chunk, or full message
if (this.currentEvent == null && httpRequest.isChunked() && httpRequest.getContent().readableBytes() < this.maxBufferingSize) {
// Long message, less than threshold, start aggregating.
this.currentEvent = new AggregatedMessageEvent(event, httpRequest.getContent());
return true;
} else {
// Message is big enough or is not chunked so no follow-ups expected
return false;
}
}
protected boolean offerChunk(final DefaultHttpChunk httpChunk) throws Exception {
if (this.currentEvent == null || this.currentEvent.getCurrentAggregatedSize() > this.maxBufferingSize) {
// reject because either not ready, or already exceeded the threshold and poll() not yet called
return false;
}
// Buffer content
this.currentEvent.addContentBuffer(httpChunk.getContent(), httpChunk.isLast());
return true;
}
}