Motivation:
StreamBufferingEncoder provides queueing so that MAX_CONCURRENT_STREAMS is not violated. However the stream id generation provided by Http2Connection.nextStreamId() only returns the next stream id that is expected on the connection and does not account for queueing. The codec should provide a way to generate the next stream id for a given endpoint that functions with or without queueing.
Modifications:
- Change Http2Connection.nextStreamId to Http2Connection.incrementAndGetNextStreamId
Result:
Http2Connection can generate the next stream id in queued and non-queued scenarios.
Fixes https://github.com/netty/netty/issues/4704
Motivation:
If validateHeaders is set in combination with the encoder/decoder it will be silently ignored. We should enforce the constraint that validateHeaders and encoder/decoder are mutually exclusive.
Modifications:
- Make sure either validateHeaders can be set or encoder/decoder.
Result:
AbstractHttp2ConnectionHandlerBuilder does not allow conflicting options to be set.
Motivation:
DefaultHttp2RemoteFlowController does not correctly account for the padding in the event frames are merged. This causes the internal stat of DefaultHttp2RemoteFlowController to become corrupt and can result in attempting to write frames when there are none.
Modifications:
- Update DefaultHttp2RemoteFlowController to account for frame sizes not necessarily adding together.
Result:
DefaultHttp2RemoteFlowController internal state does not become corrupt when padding is present.
Fixes https://github.com/netty/netty/issues/4573
Motivation:
Currently it's impossible to distinguish which
connection the corresponding logged message is
related to.
Modifications:
Http2FrameLogger is extended to support channel
id logging, usages in Inbound/Outbound Frame
Loggers are adjusted accordingly.
Result:
Logger outputs the channel id.
Motivation:
HttpConversionUtil.toHttp2Headers currently has a throws Exception as part of the signature. This comes from the signature of ByteProcessor.process, but is not necessary because the ByteProcessor used does not throw.
Modifications:
- Remove throws Exception from the signature of HttpConversionUtil.toHttp2Headers.
Result:
HttpConversionUtil.toHttp2Headers interface does not propagate a throws Exception when it is used.
Motivation:
- AbstractHttp2ConnectionHandlerBuilder.encoderEnforceMaxConcurrentStreams can be the primitive boolean
- SpdySession.StreamComparator should not be Serializable since SpdySession is not Serializable
Modifications:
Use boolean instead and remove Serializable
Result:
- Minor improvement for AbstractHttp2ConnectionHandlerBuilder
- StreamComparator is not Serializable any more
Motivation:
Javadoc reports errors about invalid docs.
Modifications:
Fix some errors reported by javadoc.
Result:
A lot of javadoc errors are fixed by this patch.
Motivation:
There are some wrong links and tags in javadoc.
Modifications:
Fix the wrong links and tags in javadoc.
Result:
These links will work correctly in javadoc.
Motivation:
If the stream window is negative UniformStreamByteDistributor may write data. This is prohibited by the RFC https://tools.ietf.org/html/rfc7540#section-6.9.2.
Modifications:
- UniformStreamByteDistributor should use StreamState.isWriteAllowed()
Result:
UniformStreamByteDistributor is more complaint with HTTP/2 RFC.
Fixes https://github.com/netty/netty/issues/4545
Motivation:
RemoteFlowController.streamWritten is not currently required. We should remove it to keep interfaces minimal.
Modifications:
- Remove RemoteFlowController.streamWritten
Result:
1 Less method in RemoteFlowController interface.
Fixes https://github.com/netty/netty/issues/4600
Motivation:
PriorityStreamByteDistributor is now obsolete and can be replaced by WeightedFairQueueByteDistributor.
Modifications:
- Remove PriorityStreamByteDistributor and use WeightedFairQueueByteDistributor by default.
Result:
PriorityStreamByteDistributor no longer has to be maintained and is replaced by a better algorithm.
Motivation:
DefaultHttp2RemoteFlowController.ListenerWritabilityMonitor no longer reliably detects when a stream's writability change occurs.
Modifications:
- Ensure writiability is reliabily reported by DefaultHttp2RemoteFlowController.ListenerWritabilityMonitor
- Fix infinite loop issue (https://github.com/netty/netty/issues/4588) detected when consolidating unit tests
Result:
Reliable stream writability change notification, and 1 less infinite loop in UniformStreamByteDistributor.
Fixes https://github.com/netty/netty/issues/4587
Related: #4572#4574
Motivation:
Consistency in our builder API design
Modifications:
- Add AbstractInboundHttp2ToHttpAdapterBuilder
- Replace the old 'Builder's with InboundHttp2ToHttpAdapterBuilder and
InboundHttp2ToHttpPriorityAdapterBuilder
Result:
Builder API consistency
Motivation:
PriorityStreamByteDistributor uses a homegrown algorithm which distributes bytes to nodes in the priority tree. PriorityStreamByteDistributor has no concept of goodput which may result in poor utilization of network resources. PriorityStreamByteDistributor also has performance issues related to the tree traversal approach and number of nodes that must be visited. There also exists some more proven algorithms from the resource scheduling domain which PriorityStreamByteDistributor does not employ.
Modifications:
- Introduce a new ByteDistributor which uses elements from weighted fair queue schedulers
Result:
StreamByteDistributor which is sensitive to priority and uses a more familiar distribution concept.
Fixes https://github.com/netty/netty/issues/4462
Related: #4572
Motivation:
- A user might want to extend Http2ConnectionHandler and define his/her
own static inner Builder class that extends
Http2ConnectionHandler.BuilderBase. This introduces potential
confusion because there's already Http2ConnectionHandler.Builder. Your
IDE will warn about this name duplication as well.
- BuilderBase exposes all setters with public modifier. A user's Builder
might not want to expose them to enforce it to certain configuration.
There's no way to hide them because it's public already and they are
final.
- BuilderBase.build(Http2ConnectionDecoder, Http2ConnectionEncoder)
ignores most properties exposed by BuilderBase, such as
validateHeaders, frameLogger and encoderEnforceMaxConcurrentStreams.
If any build() method ignores the properties exposed by the builder,
there's something wrong.
- A user's Builder that extends BuilderBase might want to require more
parameters in build(). There's no way to do that cleanly because
build() is public and final already.
Modifications:
- Make BuilderBase and Builder top-level so that there's no duplicate
name issue anymore.
- Add AbstractHttp2ConnectionHandlerBuilder
- Add Http2ConnectionHandlerBuilder
- Add HttpToHttp2ConnectionHandlerBuilder
- Make all builder methods in AbstractHttp2ConnectionHandlerBuilder
protected so that a subclass can choose which methods to expose
- Provide only a single build() method
- Add connection() and codec() so that a user can still specify
Http2Connection or Http2Connection(En|De)coder explicitly
- Implement proper state validation mechanism so that it is prevented
to invoke conflicting setters
Result:
Less confusing yet flexible builder API
Motivation:
Some times the user wants to set a Http2HeaderEncoder.SensitivityDetector when building a Http2ConnectionHandler.
Modifications:
Allow to set Http2HeaderEncoder.SensitivityDetector via builder.
Result:
More flexible building of Http2ConnectionHandler possible.
Motivation:
We already provide a NEVER_SENSITIVE instance,we should add ALWAYS_SENSITIVE as well.
Modifications:
Add ALWAYS_SENSITIVE instance which will always return true when check for sesitive.
Result:
User can reuse code.
Motivation:
Because we flow control HEADERS frames, it's possible that an intermediate error can result in a RST_STREAM frame being sent for a frame that the other endpoint is not yet aware of. This is a violation of the spec and will either result in spammy logs at the other endpoint or broken connections.
Modifications:
Modified the HTTP/2 handler so that it only sends RST_STREAM if it has sent at least one HEADERS frame to the remote endpoint for the stream.
Result:
Fixes#4465
Motivation:
The encoder is currently responsible for chunking frames when writing in order to conform to max frame size. The frame writer would be a better place for this since it could perform a reuse the same promise aggregator for all the write and could also perform a single allocation for all of the frame headers.
Modifications:
Modified `DefaultHttp2FrameWriter` to perform the chunking and modified the contract in the `Http2FrameWriter` interface. Modified `DefaultHttp2ConnectionEncoder` to send give all allocated bytes to the writer.
Result:
Fixes#3966
Motivation:
The UniformStreamByteDistributor currently processes all zero-length frames, regardless of add order. This means that we would always send HEADERS for all streams, possibly taking away bandwidth for streams that actually have data.
Modifications:
Empty frames are now treated the same as any other frame except that the algorithm will pop off the any empty frames at the head of the queue.
Result:
Empty frames require no extra processing.
Motivation:
DefaultHeaders creates an array of size 16 for all headers. This may waste a good deal of memory if applications only have a small number of headers. This memory may be critical when the number of connections grows large.
Modifications:
- Make the size of the array for DefaultHeaders configurable
Result:
Applications can control the size of the DefaultHeaders array and save memory.
Motivation:
The current priority algorithm can yield poor per-stream goodput when either the number of streams is high or the connection window is small. When all priorities are the same (i.e. priority is disabled), we should be able to do better.
Modifications:
Added a new UniformStreamByteDistributor that ignores priority entirely and manages a queue of streams. Each stream is allocated a minimum of 1KiB on each iteration.
Result:
Improved goodput when priority is not used.
Motivation:
The `DefaultHttp2RemoteFlowController` does not correctly determine `hasFrame` when updating the stream state for the distributor. Adding a check to enforce `hasFrame` when `streamableBytes > 0` causes several test failures.
Modifications:
Modified `DefaultHttp2RemoteFlowController` to simplify the writing logic and to correct the bookkeeping for `hasFrame`.
Result:
The distributors are always called with valid arguments.
Motivation:
The twitter hpack project does not have the support that it used to have. See discussion here: https://github.com/netty/netty/issues/4403.
Modifications:
Created a new module in Netty and copied the latest from twitter hpack master.
Result:
Netty no longer depends on twitter hpack.
Motivation:
Recently a bug was found in DefaultHttp2Headers where the state of the headers could be corrupted due to the extra tracking to make pseudo headers first during iteration. Unit tests did not catch this bug.
Modifications:
- Update unit tests to cover more methods
Result:
Unit tests for DefaultHttp2Headers have better code coverage.
Motivation:
For many HTTP/2 applications (such as gRPC) it is necessary to autorefill the connection window in order to prevent application-level deadlocking.
Consider an application with 2 streams, A and B. A receives a stream of messages and the application pops off one message at a time and makes a request on stream B. However, if receiving of data on A has caused the connection window to collapse, B will not be able to receive any data and the application will deadlock. The only way (currently) to get around this is 1) use multiple connections, or 2) manually refill the connection window. Both are undesirable and could needlessly complicate the application code.
Modifications:
Add a configuration option to DefaultHttp2LocalFlowController, allowing it to autorefill the connection window.
Result:
Applications can configure HTTP/2 to avoid inter-stream deadlocking.
Motivation:
PriorityStreamByteDistributor saves exception state and attempts to reset state. This could be simplified by just throwing a connection error and closing the connection. PriorityStreamByteDistributor also does not handle or detect re-entry in the distribute method.
Motivation:
- PriorityStreamByteDistributor propagate an INTERNAL_ERROR if an exception occurs during writing
- PriorityStreamByteDistributor to handle re-entry on the write method
Result:
PriorityStreamByteDistributor exception code state simplified, and re-entry is detected.
Motivation:
Http2ConnectionHandler verifies if the first frame after the preface is
a SETTINGS frame. However, it does not reject the SETTING ack frame
which is not expected actually.
Modifications:
Reject a SETTINGS-ack frame as well
Result:
When the first frame is a SETTINGS-ack frame, connection does not
proceed to further frame handling. (simplicity)
Motivation:
The HTTP/2 RFC (https://tools.ietf.org/html/rfc7540#section-8.1.2) indicates that header names consist of ASCII characters. We currently use ByteString to represent HTTP/2 header names. The HTTP/2 RFC (https://tools.ietf.org/html/rfc7540#section-10.3) also eludes to header values inheriting the same validity characteristics as HTTP/1.x. Using AsciiString for the value type of HTTP/2 headers would allow for re-use of predefined HTTP/1.x values, and make comparisons more intuitive. The Headers<T> interface could also be expanded to allow for easier use of header types which do not have the same Key and Value type.
Motivation:
- Change Headers<T> to Headers<K, V>
- Change Http2Headers<ByteString> to Http2Headers<CharSequence, CharSequence>
- Remove ByteString. Having AsciiString extend ByteString complicates equality comparisons when the hash code algorithm is no longer shared.
Result:
Http2Header types are more representative of the HTTP/2 RFC, and relationship between HTTP/2 header name/values more directly relates to HTTP/1.x header names/values.
Motivation:
Http2ConnectionHandler.BaseBuilder is constructing objects which have 'close' methods, but is not calling these methods in the event of an exception.
Modifications:
- Objects which implement 'close' should have this method called if an exception is thrown and the build operation can not complete normally.
Result:
Objects are closed even if the build process encounters an error.
Motivation:
Remove encoderMaxConcurrentStreams(...) and use the default settings. Also throw an exception if server mode is used.
Modifications:
- Remove encoderMaxConcurrentStreams(...) method
- Throw exception if server mode is used and trying to enforce conncurrent streams.
Result:
Correctly support settings stuff via builder
Motivation:
We had an unused paramter on a method, we should just remove it to keep code clean.
Modifications:
- Remove parameter
- Fix typo in javadoc
Result:
Cleanup done.
Motivation:
DefaultHttp2ConnectionDecoder writes a ACK when receiving a ping frame and sends the same data buffer it received. The data buffer is also passed to the listener, but the indexes are shared between the send and the listener. We should ensure the indexes are independent for these two operations.
Modifications:
- Call slice on the buffer that is being sent
Result:
Listener now has access to a buffer that will not appear to be already consumed.
Motivation:
Using the builder pattern for Http2ConnectionHandler (and subclasses) would be advantageous for the following reasons:
1. Provides the consistent construction afforded by the builder pattern for 'optional' arguments. Users can specify these options 1 time in the builder and then re-use the builder after this.
2. Enforces that the Http2ConnectionHandler's internals (decoder Http2FrameListener) are initialized after construction.
Modifications:
- Add an extensible builder which can be used to build Http2ConnectionHandler objects
- Update classes which inherit from Http2ConnectionHandler
Result:
It is easier to specify options and construct Http2ConnectionHandler objects.
Motivation:
It is often the case that implementations of Http2FrameListener will want to send responses when data is read. The Http2FrameListener needs access to the Http2ConnectionHandler (or the encoder contained within) to be able to send responses. However the Http2ConnectionHandler requires a Http2FrameListener instance to be passed in during construction time. This creates a cyclic dependency which can make it difficult to cleanly accomplish this relationship.
Modifications:
- Add Http2ConnectionDecoder.frameListener(..) method to set the frame listener. This will allow the listener to be set after construction.
Result:
Classes which inherit from Http2ConnectionHandler can more cleanly set the Http2FrameListener.
Motivation:
For implementations that want to manage flow control down to the stream level it is useful to be notified when stream writability changes.
Modifications:
- Add writabilityChanged to Http2RemoteFlowController.Listener
- Add isWritable to Http2RemoteFlowController
Result:
The Http2RemoteFlowController provides notification when writability of a stream changes.
Motivation:
The DefaultHttp2RemoteFlowController has become very large and is getting difficult to understand and maintain. It is also desirable for some applications to be able to disable the priority algorithm altogether for performance reasons.
Modifications:
Abstract the stream byte assignment logic (renamed allocation->assignment for clarity) behind an interface `StreamByteAssigner` with a single implementation `PriorityStreamByteAssigner`.
Result:
Goes some way towards supporting #4246
Motivation:
DefaultHttp2RemoteFlowController's allocation algorithm may not allocate all bytes that are available in the connection window. If the 'fair share' based upon weight is not fully used by sibling nodes it was not correctly re-distributed to other sibilings which may be able to utilize part / all of that share.
Modifications:
- Add a unit test which demonstrates the issue.
- Modify the allocation algorithm to ensure all available bytes are allocated.
Result:
Fixes https://github.com/netty/netty/issues/4266
Motiviation:
The http2 spec https://tools.ietf.org/html/rfc7540#section-8.1.2.3 states that the :authority header should be copied into the HOST header when converting from HTTP/2 to HTTP/1.x. We currently have an extension header to preserve the authority.
Modifications:
- Remove AUTHORITY extension header
- HTTP/2 :authority should map to HOST header when converting to HTTP/1.x.
Result:
More spec compliant.
Motivation:
Buffer leak in StreamBufferingEncoderTest
Modifications:
- Make sure buffers are released in StreamBufferingEncoderTest
Result:
Fixes https://github.com/netty/netty/issues/4230
Motivation:
Http2LifecycleManager.onException takes a Throwable as a paramter and not an Exception. There are also onConnectionError and onStreamError methods in the codec. We should rename this method to onError for consistency and clarity.
Modifications:
- Rename Http2LifecycleManager.onException to Http2LifecycleManager.onError
Result:
More consistent and clarified interface.
Motivation:
DefaultHttp2RemoteFlowController attempts to write as many bytes as possible to transition the channel to not writable, and then relies on notification of channelWritabilityChange to continue writing. However the amount of bytes written by DefaultHttp2RemoteFlowController may not be the same number of bytes that is actually written to the channel due to other ChannelHandlers (SslHandler, compression, etc...) in the pipeline. This means there is a potential for the DefaultHttp2RemoteFlowController to be waiting for a channel writaiblity change event that will never come, and thus not write all queued data.
Modifications:
- DefaultHttp2RemoteFlowController should write pending bytes until there are no more, or until the channel is not writable.
Result:
DefaultHttp2RemoteFlowController will write all pending data.
Fixes https://github.com/netty/netty/issues/4242
Motivation:
We currently set the flow controller ChannelHandlerContexts to null when the channel becomes inactive. This is bad :)
Modifications:
Just remove that code in Http2ConnectionHandler
Result:
Fixes#4240
Motivation:
HttpConversionUtil.toHttp2Headers does not convert urlencoded uri to http2 path properly.
Modifications:
Use getRawPath(), getRawQuery(), getRawFragment() in java.net.URI when converts to http2 path
Result:
HttpConversionUtil.toHttp2Headers does not urldecode uri unproperly.
Motivation:
Http2CodecUtils has some static variables which are defined as Strings instead of CharSequence. One of these defines is used as a header name and should be AsciiString.
Modifications:
- Change the String defines in Http2CodecUtils to CharSequence
Result:
Types are more consistently using CharSequence and adding the upgrade header will require less work.
Motivation:
The DefaultHttp2Headers code is throwing a IllegalArgumentException if an invalid character is detected. This is being ignored by the HTTP/2 codec instead of generating a GOAWAY.
Modifications:
- Throw a Http2Exception of type PROTOCOL_ERROR in accordance with https://tools.ietf.org/html/rfc7540#section-8.1.2.6
- Update examples which were building invalid headers
Result:
More compliant with https://tools.ietf.org/html/rfc7540#section-8.1.2.6
Motivation:
The HTTP/2 spec states that the ping frame length must be 8 and is otherwise an error https://tools.ietf.org/html/rfc7540#section-6.7. The DefaultHttp2FrameReader enforces this, but the DefaultHttp2FrameWriter allows invalid frames to be written. We should not allow invalid ping frames to be written to the network.
Modifications:
- DefaultHttp2FrameWriter checks the frame size to be 8, or throws an exception
Result:
Fixes https://github.com/netty/netty/issues/3721
Motivation:
Currently there is a HttpConversionUtil.addHttp2ToHttpHeaders which requires a FullHttpMessage, but this may not always be available. There is no interface that can be used with just Http2Headers and HttpHeaders.
Modifications:
- add an overload for HttpConversionUtil.addHttp2ToHttpHeaders which does not take FullHttpMessage
Result:
An overload for HttpConversionUtil.addHttp2ToHttpHeaders exists which does not require FullHttpMessage.
Motivation:
The HTTP/2 codec has a few static buffers sent over the network which are allocated on the heap. This results in a copy operation when the buffer is sent out on the network.
Modifications:
- Ensure these static buffers are allocated using direct memory.
Result:
No copy operation necessary when writing static buffers to network.
Motivaion:
The HttpHeaders and DefaultHttpHeaders have methods deprecated due to being removed in future releases, but no replacement method to use in the current release. The deprecation policy should not be so aggressive as to not provide any non-deprecated method to use.
Modifications:
- Remove deprecated annotations and javadocs from methods which are the best we can do in terms of matching the master's api for 4.1
Result:
There should be non-deprecated methods available for HttpHeaders in 4.1.
Motivation:
The HTTP/2 header name validation was removed, and does not currently exist.
Modifications:
- Header name validation for HTTP/2 should be restored and set to the default mode of operation.
Result:
HTTP/2 header names are validated according to https://tools.ietf.org/html/rfc7540
Motivation:
The javadoc comments on Http2Headers.iterator() are incorrect.
Modifications:
- Correct and clarify the javadoc for Http2Headers.iterator()
Result:
Javadoc for Http2Headers.iterator() is more correct.
Motivation:
InboundHttp2ToHttpAdapterTest.bootstrapEnv does not wait for the serverConnectedChannel to be initialized before returning. Some methods rely only this behavior and throw a NPE because it may not be set.
Modifications:
- Add a CountDownLatch to ensure the serverConnectedChannel is initialized
Result:
No more NPE.
Motivation:
The SimplePromiseAggregator.setFailure allows a failure to occur before newPromise is called, but tryFailure doesn't. These methods should be consistent.
Modifications:
- tryFailure should use the same logic as setFailure
Result:
Consistent failure routines.
Motivation:
DefaultPropertyKey.index is currently private and accessed outside the class's scope.
Modifications:
- Change access level to package private
Result:
No chance of synthetic method generation for accessing this field
Motivation:
The latches in InboundHttp2ToHttpAdapterTest were volatile and reset during the tests. This resulted in race conditions and sometimes the tests would be waiting on old latches that were not the same latches being counted down when messages were received.
Modifications:
- Remove volatile latches from tests
Result:
More reliable tests with less race conditions.
Motivation:
There currently exists http.HttpUtil, http2.HttpUtil, and http.HttpHeaderUtil. Having 2 HttpUtil methods can be confusing and the utilty methods in the http package could be consolidated.
Modifications:
- Rename http2.HttpUtil to http2.HttpConversionUtil
- Move http.HttpHeaderUtil methods into http.HttpUtil
Result:
Consolidated utilities whose names don't overlap.
Fixes https://github.com/netty/netty/issues/4120
Motivation:
ByteToMessageDecoder may call decode after channelInactive is called. This will lead to a NPE.
Modifications:
- Call super.channelInactive() before we process the event in Http2ConnectionHandler
Result:
No more NPE in decode.
Motivation:
Commit 0d8ce23c83 failed to fix the Host header processing. Host is not a URI but is instead defined in https://tools.ietf.org/html/rfc3986#section-3.2.2 as host = IP-literal / IPv4address / reg-name
Modifications:
- Host should not be treated as a URI.
- We should be more explicit about required fields, and unexpected input by throwing exceptions.
Result:
Translation from HTTP/1.x to HTTP/2 is more correct.
Motivation:
If a SimpleChannelPromiseAggregator is failed before any new promises are generated, the failure is not propegated through to the aggregated promise.
Modifications:
- Failures should be allowed to occur even if no new promises have been generated
Result:
Failures are always allowed.
Motivation:
If any streams are still active the graceful shutdown code will wait until they are all closed before the connection is closed. In some situations this event may never occur, and thus a timeout should be supported so the socket can be closed even if all streams haven't been closed.
Modifications:
- Add a configurable timeout for when the graceful shutdown process is attempted.
- Update unit tests to be faster, and use this graceful timeout
Result:
Local endpoint can protect from local or remote issues which prevent the channel from being closed during the graceful shutdown process.
Motivation:
DefaultHttp2ConnectionEncoder.FlowControlledHeaders and DefaultHttp2ConnectionEncoder.FlowControlledData have private constructors which may result in static factory methods being generated to construct instances of these classes.
Modifications:
- Make constructors public for these private classes
Result:
Accessor for inner class constructor more correct and no possibiliy of synthetic method generation.
Motivation:
A degradation in performance has been observed from the 4.0 branch as documented in https://github.com/netty/netty/issues/3962.
Modifications:
- Simplify Headers class hierarchy.
- Restore the DefaultHeaders to be based upon DefaultHttpHeaders from 4.0.
- Make various other modifications that are causing hot spots.
Result:
Performance is now on par with 4.0.
Motivation:
The Http2ConnectionHandler was writing pending bytes, but was not flushing. This may result in deadlock.
Modifications:
- Http2ConnectionHandler must writePendingBytes and also flush.
Result:
Data is now flushed after writabilityChange writes more data to underlying layers.
Motivation:
We noticed that the headers implementation in Netty for HTTP/2 uses quite a lot of memory
and that also at least the performance of randomly accessing a header is quite poor. The main
concern however was memory usage, as profiling has shown that a DefaultHttp2Headers
not only use a lot of memory it also wastes a lot due to the underlying hashmaps having
to be resized potentially several times as new headers are being inserted.
This is tracked as issue #3600.
Modifications:
We redesigned the DefaultHeaders to simply take a Map object in its constructor and
reimplemented the class using only the Map primitives. That way the implementation
is very concise and hopefully easy to understand and it allows each concrete headers
implementation to provide its own map or to even use a different headers implementation
for processing requests and writing responses i.e. incoming headers need to provide
fast random access while outgoing headers need fast insertion and fast iteration. The
new implementation can support this with hardly any code changes. It also comes
with the advantage that if the Netty project decides to add a third party collections library
as a dependency, one can simply plug in one of those very fast and memory efficient map
implementations and get faster and smaller headers for free.
For now, we are using the JDK's TreeMap for HTTP and HTTP/2 default headers.
Result:
- Significantly fewer lines of code in the implementation. While the total commit is still
roughly 400 lines less, the actual implementation is a lot less. I just added some more
tests and microbenchmarks.
- Overall performance is up. The current implementation should be significantly faster
for insertion and retrieval. However, it is slower when it comes to iteration. There is simply
no way a TreeMap can have the same iteration performance as a linked list (as used in the
current headers implementation). That's totally fine though, because when looking at the
benchmark results @ejona86 pointed out that the performance of the headers is completely
dominated by insertion, that is insertion is so significantly faster in the new implementation
that it does make up for several times the iteration speed. You can't iterate what you haven't
inserted. I am demonstrating that in this spreadsheet [1]. (Actually, iteration performance is
only down for HTTP, it's significantly improved for HTTP/2).
- Memory is down. The implementation with TreeMap uses on avg ~30% less memory. It also does not
produce any garbage while being resized. In load tests for GRPC we have seen a memory reduction
of up to 1.2KB per RPC. I summarized the memory improvements in this spreadsheet [1]. The data
was generated by [2] using JOL.
- While it was my original intend to only improve the memory usage for HTTP/2, it should be similarly
improved for HTTP, SPDY and STOMP as they all share a common implementation.
[1] https://docs.google.com/spreadsheets/d/1ck3RQklyzEcCLlyJoqDXPCWRGVUuS-ArZf0etSXLVDQ/edit#gid=0
[2] https://gist.github.com/buchgr/4458a8bdb51dd58c82b4
Motivation:
The DataCompressionHttp2Test was exiting prematurely leading to unit test failures.
Modifications:
- Fix the race condition so the test does not evaluate final conditions until all expected events occur
Result:
Unit test no longer fails
Motivation:
When looking through the logs for entries pertaining to a specific stream, it's difficult because header entries use the syntax "streamId:<id>" but all other entries use "streamId=<id>". We should make all of the entries consistent.
Modifications:
Changed header entries to use "streamId=<id>" to match the other entries.
Result:
Easier HTTP/2 log navigation.
Motivation:
We should support XXXCollections methods for all primitive map types.
Modifications:
Removed PrimitiveCollections and added a template for XXXCollections.
Result:
Fixes#4001
Motivation:
It would be useful to support the Java `Map` interface in our primitive maps.
Modifications:
Renamed current methods to "pXXX", where p is short for "primitive". Made the template for all primitive maps extend the appropriate Map interface.
Result:
Fixes#3970
Motivation:
HttpToHttp2ConnectionHandler only converts FullHttpMessage to HTTP/2 Frames. This does not support other use cases such as adding a HttpContentCompressor to the pipeline, which writes HttpMessage and HttpContent.
Additionally HttpToHttp2ConnectionHandler ignores converting and sending HTTP trailing headers, which is a bug as the HTTP/2 spec states that they should be sent.
Modifications:
Update HttpToHttp2ConnectionHandler to support converting HttpMessage and HttpContent to HTTP/2 Frames.
Additionally, include an extra call to writeHeaders if the message includes trailing headers
Result:
One can now write HttpMessage and HttpContent (http chunking) down the pipeline and they will be converted to HTTP/2 Frames. If any trailing headers exist, they will be converted and sent as well.
Motivation:
The bufferingNewStreamFailsAfterGoAwayReceived method currently causes an NPE.
Modifications:
Fixed the test so that a valid ByteBuf is passed in.
Result:
The test no longer throws an NPE.
Motivation:
It is currently assumed that all usages of the HTTP/2 codec will be from the same event loop context. If the methods are used outside of the assumed thread context then unexpected behavior is observed. This assumption should be more clearly communicated and enforced in key areas.
Modifications:
- The flow controller interfaces have assert statements and updated javadocs indicating the assumptions.
Result:
Interfaces more clearly indicate thread context limitations.
Motivation:
The CompressorHttp2ConnectionEncoder is attempting to attach a property to streams before the exist.
Modifications:
- Allow the super class to create the streams before attempting to attach a property to the stream.
Result:
CompressorHttp2ConnectionEncoder is able to set the property and access the compressor.
Motivation:
See #3783
Modifications:
- The DefaultHttp2RemoteFlowController should use Channel.isWritable() before attempting to do any write operations.
- The Flow controller methods should no longer take ChannelHandlerContext. The concept of flow control is tied to a connection and we do not support 1 flow controller keeping track of multiple ChannelHandlerContext.
Result:
Writes are delayed until isWritable() is true. Flow controller interface methods are more clear as to ChannelHandlerContext restrictions.
Motivation:
The MAX_HEADER_LIST_SIZE of SETTINGS is represented by
unsigned 32-bit value and this value isn't limited in RFC7540.
But in current implementation, its stored to int variable so
over 2^31-1 value is recognized as minus and handled as
PROTOCOL_ERROR.
Modifications:
If a value of MAX_HEADER_LIST_SIZE is larger than 2^31-1, its
handled as 2^31-1
Result:
Over 2^31-1 MAX_HEADER_LIST_SIZE is became acceptable
Motivation:
Slicing a mutable CompositeByteBuf is not the appropriate mechanism to use to track and release buffers that have been written to a channel.
In particular buffers passed over an Embedded or LocalChannel are retained after the ChannelPromise is completed and listening to the
promise to consolidate a CompositeBuffer breaks slices taken from the composite as the offset indices have changed.
In addition CoalescingBufferQueue handles taking arbitrarily sized slices of a sequence of buffers more efficiently.
Modifications:
Convert FlowControlledData to use a CoalescingBufferQueue to handle merging data writes.
Result:
HTTP2 works over LocalChannel and code is considerably simpler.
Motivation:
Sometimes people use a data frame with length 0 to end a stream(such as jetty http2-server). So it is possible that data.readableBytes and padding are all 0 for a data frame, and cause an IllegalArgumentException when calling flowController.consumeBytes.
Modifications:
Return false when numBytes == 0 instead of throwing IllegalArgumentException.
Result:
Fix IllegalArgumentException.
Motivation:
The problem is described in https://github.com/grpc/grpc-java/issues/605. Basically, when using `StreamBufferingEncoder` there is a chance of creating zombie streams that never get closed.
Modifications:
Change `Http2ConnectionHandler`'s `channelInactive` handling logic to shutdown the encoder/decoder before shutting down the active streams.
Result:
Fixes https://github.com/grpc/grpc-java/issues/605
Motivation:
Http2ConnectionHandler missed to forward channelReadComplete(...) events.
Modifications:
Ensure we notify the next handler in the pipeline via ctx.fireChannelReadComplete().
Result:
Correctly forwarding of event.
Motivation:
The Http2FrameListener requires that the Http2FrameReader accumulate ByteBuf objects. There is currently no way to limit the amount of bytes that is accumulated.
Motiviation:
- DefaultHttp2FrameReader supports maxHeaderSize which will fail fast as soon as the maximum size is exceeded.
- DefaultHttp2HeadersDecoder will respect the return value of endHeaderBlock() and fail if the max size is exceeded.
Result:
Frames which carry header data now respect a maximum number of bytes that can be accumulated.
Motivation:
If server sends SETTINGS with ENABLE_PUSH, its handled as
PROTOCOL_ERROR in spite of the value. But the value specified to
0 may be allowed in RFC7540.
Modifications:
Check whether ENABLE_PUSH sent from a server is 0 or not.
Result:
When server specifies ENABLE_PUSH to 0 explicitly, client doesn't
handle it as PROTOCOL_ERROR.
Motivation:
NPE doesn't cause the tests to fail but should get fixed.
Modifications:
Modified the StreamBufferingEncoderTest to mock the ctx to return a promise.
Result:
Fixes#3905
Motivation:
Coalescing many small writes into a larger DATA frame reduces framing overheads on the wire and reduces the number of calls to Http2FrameListeners on the remote side.
Delaying the write of WINDOW_UPDATE until flush allows for more consumed bytes to be returned as the aggregate of consumed bytes is returned and not the amount consumed when the threshold was crossed.
Modifications:
- Remote flow controller no longer immediately writes bytes when a flow-controlled payload is enqueued. Sequential data payloads are now merged into a single CompositeByteBuf which are written when 'writePendingBytes' is called.
- Listener added to remote flow-controller which observes written bytes per stream.
- Local flow-controller no longer immediately writes WINDOW_UPDATE when the ratio threshold is crossed. Now an explicit call to 'writeWindowUpdates' triggers the WINDOW_UPDATE for all streams who's ratio is exceeded at that time. This results in
fewer window updates being sent and more bytes being returned.
- Http2ConnectionHandler.flush triggers 'writeWindowUpdates' on the local flow-controller followed by 'writePendingBytes' on the remote flow-controller so WINDOW_UPDATES preceed DATA frames on the wire.
Result:
- Better throughput for writing many small DATA chunks followed by a flush, saving 9-bytes per coalesced frame.
- Fewer WINDOW_UPDATES being written and more flow-control bytes returned to remote side more quickly, thereby improving throughput.
Motivation:
Bootstrap of the HTTP/2 can take a lot of paths and a lot of things can go wrong in the initial handshakes leading up to establishment of HTTP/2 between client and server. There have been many times where handshakes have failed silently, leading to very cryptic errors that are hard to debug.
Modifications:
Changed the HTTP/2 handler and decoder to ensure that the very first data on the wire (WRT HTTP/2) is SETTINGS/preface+SETTINGS. When this is not the case, a connection error is thrown with the bytes that were found instead.
Result:
Fixes#3880
Related: #3814
Motivation:
To implement the support for an upgrade from cleartext HTTP/1.1
connection to cleartext HTTP/2 (h2c) connection, a user usually uses
HttpServerUpgradeHandler.
It does its job, but it requires a user to instantiate the UpgradeCodecs
for all supported protocols upfront. It means redundancy for the
connections that are not upgraded.
Modifications:
- Change the constructor of HttpServerUpgradeHandler
- Accept UpgraceCodecFactory instead of UpgradeCodecs
- The default constructor of HttpServerUpgradeHandler sets the
maxContentLength to 0 now, which shouldn't be a problem because a
usual upgrade request is a GET.
- Update the examples accordingly
Result:
A user can instantiate Http2ServerUpgradeCodec and its related objects
(Http2Connection, Http2FrameReader/Writer, Http2FrameListener, etc) only
when necessary.
Motivation:
Our HTTP/2 implementation sometimes uses hard-coded handler names when
adding/removing a handler to/from a pipeline. It's not really a good
idea because it can easily result in name clashes. Unless there is a
good reason, we need to use the reference to the handlers
Modifications:
- Allow null as a handler name for Http2Client/ServerUpgradeCodec
- Use null as the default upgrade handler name
- Do not use handler name strings in some test cases and examples
Result:
Fixes#3815
Related: #3871
Motivation:
StreamBufferingEncoderTest does not release when writeGoAway() is
called.
Modifications:
Release the buffer in mock object arguments
Result:
No buffer leak
