io.netty.handler.codec.http2.Http2MultiplexHandler Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including
all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and
Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* Copyright 2019 The Netty Project
*
* The Netty Project 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 io.netty.handler.codec.http2;
import io.netty.buffer.ByteBuf;
import io.netty.channel.Channel;
import io.netty.channel.ChannelConfig;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoop;
import io.netty.channel.ServerChannel;
import io.netty.handler.codec.http2.Http2FrameCodec.DefaultHttp2FrameStream;
import io.netty.util.ReferenceCounted;
import io.netty.util.internal.ObjectUtil;
import io.netty.util.internal.UnstableApi;
import java.util.ArrayDeque;
import java.util.Queue;
import static io.netty.handler.codec.http2.Http2Error.INTERNAL_ERROR;
import static io.netty.handler.codec.http2.Http2Exception.connectionError;
/**
* An HTTP/2 handler that creates child channels for each stream. This handler must be used in combination
* with {@link Http2FrameCodec}.
*
* When a new stream is created, a new {@link Channel} is created for it. Applications send and
* receive {@link Http2StreamFrame}s on the created channel. {@link ByteBuf}s cannot be processed by the channel;
* all writes that reach the head of the pipeline must be an instance of {@link Http2StreamFrame}. Writes that reach
* the head of the pipeline are processed directly by this handler and cannot be intercepted.
*
*
The child channel will be notified of user events that impact the stream, such as {@link
* Http2GoAwayFrame} and {@link Http2ResetFrame}, as soon as they occur. Although {@code
* Http2GoAwayFrame} and {@code Http2ResetFrame} signify that the remote is ignoring further
* communication, closing of the channel is delayed until any inbound queue is drained with {@link
* Channel#read()}, which follows the default behavior of channels in Netty. Applications are
* free to close the channel in response to such events if they don't have use for any queued
* messages. Any connection level events like {@link Http2SettingsFrame} and {@link Http2GoAwayFrame}
* will be processed internally and also propagated down the pipeline for other handlers to act on.
*
*
Outbound streams are supported via the {@link Http2StreamChannelBootstrap}.
*
*
{@link ChannelConfig#setMaxMessagesPerRead(int)} and {@link ChannelConfig#setAutoRead(boolean)} are supported.
*
*
Reference Counting
*
* Some {@link Http2StreamFrame}s implement the {@link ReferenceCounted} interface, as they carry
* reference counted objects (e.g. {@link ByteBuf}s). The multiplex codec will call {@link ReferenceCounted#retain()}
* before propagating a reference counted object through the pipeline, and thus an application handler needs to release
* such an object after having consumed it. For more information on reference counting take a look at
* https://netty.io/wiki/reference-counted-objects.html
*
* Channel Events
*
* A child channel becomes active as soon as it is registered to an {@link EventLoop}. Therefore, an active channel
* does not map to an active HTTP/2 stream immediately. Only once a {@link Http2HeadersFrame} has been successfully sent
* or received, does the channel map to an active HTTP/2 stream. In case it is not possible to open a new HTTP/2 stream
* (i.e. due to the maximum number of active streams being exceeded), the child channel receives an exception
* indicating the cause and is closed immediately thereafter.
*
* Writability and Flow Control
*
* A child channel observes outbound/remote flow control via the channel's writability. A channel only becomes writable
* when it maps to an active HTTP/2 stream . A child channel does not know about the connection-level flow control
* window. {@link ChannelHandler}s are free to ignore the channel's writability, in which case the excessive writes will
* be buffered by the parent channel. It's important to note that only {@link Http2DataFrame}s are subject to
* HTTP/2 flow control.
*/
@UnstableApi
public final class Http2MultiplexHandler extends Http2ChannelDuplexHandler {
static final ChannelFutureListener CHILD_CHANNEL_REGISTRATION_LISTENER = new ChannelFutureListener() {
@Override
public void operationComplete(ChannelFuture future) {
registerDone(future);
}
};
private final ChannelHandler inboundStreamHandler;
private final ChannelHandler upgradeStreamHandler;
private final Queue readCompletePendingQueue =
new MaxCapacityQueue(new ArrayDeque(8),
// Choose 100 which is what is used most of the times as default.
Http2CodecUtil.SMALLEST_MAX_CONCURRENT_STREAMS);
private boolean parentReadInProgress;
private int idCount;
// Need to be volatile as accessed from within the Http2MultiplexHandlerStreamChannel in a multi-threaded fashion.
private volatile ChannelHandlerContext ctx;
/**
* Creates a new instance
*
* @param inboundStreamHandler the {@link ChannelHandler} that will be added to the {@link ChannelPipeline} of
* the {@link Channel}s created for new inbound streams.
*/
public Http2MultiplexHandler(ChannelHandler inboundStreamHandler) {
this(inboundStreamHandler, null);
}
/**
* Creates a new instance
*
* @param inboundStreamHandler the {@link ChannelHandler} that will be added to the {@link ChannelPipeline} of
* the {@link Channel}s created for new inbound streams.
* @param upgradeStreamHandler the {@link ChannelHandler} that will be added to the {@link ChannelPipeline} of the
* upgraded {@link Channel}.
*/
public Http2MultiplexHandler(ChannelHandler inboundStreamHandler, ChannelHandler upgradeStreamHandler) {
this.inboundStreamHandler = ObjectUtil.checkNotNull(inboundStreamHandler, "inboundStreamHandler");
this.upgradeStreamHandler = upgradeStreamHandler;
}
static void registerDone(ChannelFuture future) {
// Handle any errors that occurred on the local thread while registering. Even though
// failures can happen after this point, they will be handled by the channel by closing the
// childChannel.
if (!future.isSuccess()) {
Channel childChannel = future.channel();
if (childChannel.isRegistered()) {
childChannel.close();
} else {
childChannel.unsafe().closeForcibly();
}
}
}
@Override
protected void handlerAdded0(ChannelHandlerContext ctx) {
if (ctx.executor() != ctx.channel().eventLoop()) {
throw new IllegalStateException("EventExecutor must be EventLoop of Channel");
}
this.ctx = ctx;
}
@Override
protected void handlerRemoved0(ChannelHandlerContext ctx) {
readCompletePendingQueue.clear();
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
parentReadInProgress = true;
if (msg instanceof Http2StreamFrame) {
if (msg instanceof Http2WindowUpdateFrame) {
// We dont want to propagate update frames to the user
return;
}
Http2StreamFrame streamFrame = (Http2StreamFrame) msg;
DefaultHttp2FrameStream s =
(DefaultHttp2FrameStream) streamFrame.stream();
AbstractHttp2StreamChannel channel = (AbstractHttp2StreamChannel) s.attachment;
if (msg instanceof Http2ResetFrame) {
// Reset frames needs to be propagated via user events as these are not flow-controlled and so
// must not be controlled by suppressing channel.read() on the child channel.
channel.pipeline().fireUserEventTriggered(msg);
// RST frames will also trigger closing of the streams which then will call
// AbstractHttp2StreamChannel.streamClosed()
} else {
channel.fireChildRead(streamFrame);
}
return;
}
if (msg instanceof Http2GoAwayFrame) {
// goaway frames will also trigger closing of the streams which then will call
// AbstractHttp2StreamChannel.streamClosed()
onHttp2GoAwayFrame(ctx, (Http2GoAwayFrame) msg);
}
// Send everything down the pipeline
ctx.fireChannelRead(msg);
}
@Override
public void channelWritabilityChanged(final ChannelHandlerContext ctx) throws Exception {
if (ctx.channel().isWritable()) {
// While the writability state may change during iterating of the streams we just set all of the streams
// to writable to not affect fairness. These will be "limited" by their own watermarks in any case.
forEachActiveStream(AbstractHttp2StreamChannel.WRITABLE_VISITOR);
}
ctx.fireChannelWritabilityChanged();
}
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
if (evt instanceof Http2FrameStreamEvent) {
Http2FrameStreamEvent event = (Http2FrameStreamEvent) evt;
DefaultHttp2FrameStream stream = (DefaultHttp2FrameStream) event.stream();
if (event.type() == Http2FrameStreamEvent.Type.State) {
switch (stream.state()) {
case HALF_CLOSED_LOCAL:
if (stream.id() != Http2CodecUtil.HTTP_UPGRADE_STREAM_ID) {
// Ignore everything which was not caused by an upgrade
break;
}
// fall-through
case HALF_CLOSED_REMOTE:
// fall-through
case OPEN:
if (stream.attachment != null) {
// ignore if child channel was already created.
break;
}
final AbstractHttp2StreamChannel ch;
// We need to handle upgrades special when on the client side.
if (stream.id() == Http2CodecUtil.HTTP_UPGRADE_STREAM_ID && !isServer(ctx)) {
// We must have an upgrade handler or else we can't handle the stream
if (upgradeStreamHandler == null) {
throw connectionError(INTERNAL_ERROR,
"Client is misconfigured for upgrade requests");
}
ch = new Http2MultiplexHandlerStreamChannel(stream, upgradeStreamHandler);
ch.closeOutbound();
} else {
ch = new Http2MultiplexHandlerStreamChannel(stream, inboundStreamHandler);
}
ChannelFuture future = ctx.channel().eventLoop().register(ch);
if (future.isDone()) {
registerDone(future);
} else {
future.addListener(CHILD_CHANNEL_REGISTRATION_LISTENER);
}
break;
case CLOSED:
AbstractHttp2StreamChannel channel = (AbstractHttp2StreamChannel) stream.attachment;
if (channel != null) {
channel.streamClosed();
}
break;
default:
// ignore for now
break;
}
}
return;
}
ctx.fireUserEventTriggered(evt);
}
// TODO: This is most likely not the best way to expose this, need to think more about it.
Http2StreamChannel newOutboundStream() {
return new Http2MultiplexHandlerStreamChannel((DefaultHttp2FrameStream) newStream(), null);
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
if (cause instanceof Http2FrameStreamException) {
Http2FrameStreamException exception = (Http2FrameStreamException) cause;
Http2FrameStream stream = exception.stream();
AbstractHttp2StreamChannel childChannel = (AbstractHttp2StreamChannel)
((DefaultHttp2FrameStream) stream).attachment;
try {
childChannel.pipeline().fireExceptionCaught(cause.getCause());
} finally {
childChannel.unsafe().closeForcibly();
}
return;
}
ctx.fireExceptionCaught(cause);
}
private static boolean isServer(ChannelHandlerContext ctx) {
return ctx.channel().parent() instanceof ServerChannel;
}
private void onHttp2GoAwayFrame(ChannelHandlerContext ctx, final Http2GoAwayFrame goAwayFrame) {
try {
final boolean server = isServer(ctx);
forEachActiveStream(new Http2FrameStreamVisitor() {
@Override
public boolean visit(Http2FrameStream stream) {
final int streamId = stream.id();
if (streamId > goAwayFrame.lastStreamId() && Http2CodecUtil.isStreamIdValid(streamId, server)) {
final AbstractHttp2StreamChannel childChannel = (AbstractHttp2StreamChannel)
((DefaultHttp2FrameStream) stream).attachment;
childChannel.pipeline().fireUserEventTriggered(goAwayFrame.retainedDuplicate());
}
return true;
}
});
} catch (Http2Exception e) {
ctx.fireExceptionCaught(e);
ctx.close();
}
}
/**
* Notifies any child streams of the read completion.
*/
@Override
public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
processPendingReadCompleteQueue();
ctx.fireChannelReadComplete();
}
private void processPendingReadCompleteQueue() {
parentReadInProgress = true;
// If we have many child channel we can optimize for the case when multiple call flush() in
// channelReadComplete(...) callbacks and only do it once as otherwise we will end-up with multiple
// write calls on the socket which is expensive.
AbstractHttp2StreamChannel childChannel = readCompletePendingQueue.poll();
if (childChannel != null) {
try {
do {
childChannel.fireChildReadComplete();
childChannel = readCompletePendingQueue.poll();
} while (childChannel != null);
} finally {
parentReadInProgress = false;
readCompletePendingQueue.clear();
ctx.flush();
}
} else {
parentReadInProgress = false;
}
}
private final class Http2MultiplexHandlerStreamChannel extends AbstractHttp2StreamChannel {
Http2MultiplexHandlerStreamChannel(DefaultHttp2FrameStream stream, ChannelHandler inboundHandler) {
super(stream, ++idCount, inboundHandler);
}
@Override
protected boolean isParentReadInProgress() {
return parentReadInProgress;
}
@Override
protected void addChannelToReadCompletePendingQueue() {
// If there is no space left in the queue, just keep on processing everything that is already
// stored there and try again.
while (!readCompletePendingQueue.offer(this)) {
processPendingReadCompleteQueue();
}
}
@Override
protected ChannelHandlerContext parentContext() {
return ctx;
}
}
}
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