Motivation:
We can just implement the interfaces directly and so reduce object creation in DefaultHttp2RemoteFlowController.
Modifications:
Directly implement the interfaces.
Result:
Less object creation.
Motivation:
When part of a HTTP/2 StreamChannel the Http2StreamChannel.isOpen() / isActive() should report false within a call to a ChannelInboundHandlers channelInactive() method.
Modifications:
Fullfill promise before call fireChannelInactive()
Result:
Correctly update state / promise before notify handlers. Fixes [#7638]
Motivation:
With HTTP1, it's very easy to check if a header is present and has a
given value: you can simply invoke
io.netty.handler.codec.http.HttpHeaders#contains(java.lang.CharSequence, java.lang.CharSequence, boolean)
It is not possible to do the same with HTTP2. You have to get the list
of all headers (returned as String) and then iterate over it invoking
String#equals or String#equalsIgnoreCase
Modifications:
I've added io.netty.handler.codec.http2.Http2Headers#contains and
implemented it in DefaultHttp2Headers, EmptyHttp2Headers and ReadOnlyHttp2Headers.
Result:
You can use AsciiString constants to check if a header is present in a
consice and efficient manner.
Motivation:
Usually when using netty exceptions which happen for outbound operations should not be fired through the pipeline but only the ChannelPromise should be failed.
Modifications:
- Change Http2LifecycleManager.onError(...) to take also an boolean that indicate if the error was caused by an outbound operation
- Channel Http2ConnectionHandler.on*Error(...) methods to also take this boolean
- Change Http2FrameCodec to only fire exceptions through the pipeline if these are not outbound operations related
- Add unit test.
Result:
More consistent error handling when using Http2FrameCodec and Http2MultiplexCodec.
Motivation:
Http2MultiplexCodec swallows Http2PingFrames without releasing the payload, resulting in a memory leak.
Modification:
Send unhandled frames down the pipeline for consumption/disposal by another InboundChannelHandler.
Result:
Fixes#7607.
Motivation:
Usages of HttpResponseStatus may result in more object allocation then necessary due to not looking for cached objects and the AsciiString parsing method not being used due to CharSequence method being used instead.
Modifications:
- HttpResponseDecoder should attempt to get the HttpResponseStatus from cache instead of allocating a new object
- HttpResponseStatus#parseLine(CharSequence) should check if the type is AsciiString and redirect to the AsciiString parsing method which may not require an additional toString call
- HttpResponseStatus#parseLine(AsciiString) can be optimized and doesn't require and may not require object allocation
Result:
Less allocations when dealing with HttpResponseStatus.
Motivation:
When we cancel the flowcontrolled writes we did create a new StreamException for each write that was enqueued. Creating Exceptions is very expensive due of filling the stacktrace.
Modifications:
Only create the StreamException once and reuse the same for all the flowcontrolled writes (per stream).
Result:
Less expensive to cancel flowcontrolled writes.
Motivation:
Http2FrameCodec increases the initialWindowSize when the user attempts to increase the connection flow control window. The initialWindowSize should only be touched as a result of a SETTINGS frame, and otherwise may result in flow control getting out of sync with our peer.
Modifications:
- Http2FrameCodec shouldn't update the initialWindowSize when a WindowUpdateFrame is written on the connection channel
Result:
More correct WindowUpdate processing.
Motivation:
HPackDecoder works on entire header block, we shouldn't encounter
incomplete header fields. If we do we should treat it as
a decoding error and according to the specification:
A decoding error in a header block MUST be treated as
a connection error (Section 5.4.1) of type COMPRESSION_ERROR.
Modifications:
* Check final state in HpackDecoder once we've decoded all the data.
Result:
* Throw a connection error if we receive incomplete header fields
* H2spec 4.3 tests all passes
Motivation:
Http2FrameStream#CONNECTION_STREAM is required to identify the
connection stream. However this leads to inconsistent usage from a user
perspective. When a user creates a Http2Frame for a non-connection
stream, the Http2MultiplexCodec automatically sets the stream, and the
user is never exposed to the Http2FrameStream object. However when the
user writes a Http2Frame for a connection stream they are required to
set the Http2FrameStream object. We can remove the Http2FrameStream#CONNECTION_STREAM
and keep the Http2FrameStream object internal, and therefore consistent
between the connection and non-connection use cases.
Modifications:
- Remove Http2FrameStream#CONNECTION_STREAM
- Update Http2FrameCodec to handle Http2Frame#stream() which returns
null
Result:
More consistent usage on http2 parent channel and http2 child channel.
Motivation:
HpackDecoder#addHeader takes in the streamId as a parameter but no longer uses it.
Modifications:
- Remove the streamId parameter from HpackDecoder#addHeader
Result:
Less unused parameters in HpackDecoder.
Motivation:
According to the HTTP/2 Spec:
SETTINGS_MAX_HEADER_LIST_SIZE (0x6): This advisory setting informs a
peer of the maximum size of header list that the sender is
prepared to accept, in octets. The value is based on the
uncompressed size of header fields, including the length of the
name and value in octets plus an overhead of 32 octets for each
header field.
We were accounting for the 32 bytes when encoding in HpackEncoder,
but not when decoding in HPackDecoder.
Modifications:
- Add 32 bytes to the header list length for each entry when decoding
with HPackDecoder.
Result:
- We account for the 32 bytes overhead by header entry in HPackDecoder
Motivation:
Currently the remote flow controller limits the maximum amount of pending data to Integer.MAX_VALUE. The overflow handling is also not very graceful in that it may lead to infinite loops, or otherwise no progress being made.
Modifications:
- StreamByteDistributor and RemoteFlowController should support pending bytes of type long.
Result:
Fixes https://github.com/netty/netty/issues/4283
Motivation:
http/2 counts header sizes somewhat inconsistently. Sometimes, headers
which are substantively less than the header list size will be measured
as longer than the header list size.
Modifications:
Keep better track of the nameLength of a given name, so that we don't
accidentally end up reusing a nameLength.
Result:
More consistent measurement of header list size.
Fixes#7511.
H2C upgrades should be ineligible for flow control
Motivation:
When the h2c upgrade request is too big, the Http2FrameCodec complains
it's too big for flow control reasons, even though it's ineligible for
flow control.
Modifications:
Specially mark upgrade streams and make Http2FrameCodec know not to try
to flow control on those streams.
Result:
Servers won't barf when they receive an upgrade request with a fat
payload.
[Fixes#7280]
Motivation:
Http2ConnectionHandler uses ctx.fireUserEvent to propagate the Http2ConnectionPrefaceAndSettingsFrameWrittenEvent through the pipeline. This will propagate the event to the next inbound handler in the pipeline. If the user extends Http2ConnectionHandler the Http2ConnectionPrefaceAndSettingsFrameWrittenEvent may be missed and initialization dependent upon this event will not be run.
Modifications:
- Http2ConnectionHandler should use userEventTriggered instead of ctx.fireUserEvent
Result:
Classes that extend Http2ConnectionHandler will see the Http2ConnectionPrefaceAndSettingsFrameWrittenEvent user event.
Motivation:
HttpConversionUtil#toHttp2Headers has special code to filter the TE header name. However this filtering code may result in adding the <TE, TRAILERS> tuple in scenarios that are not appropriate. For example if a value containing trailers is seen it will be added, but the value could not actually be equal to trailers. Also CSV values are not supported.
Modifications:
- Account for CSV header values
- Account for the value containing 'trailers' but not actually being equal to 'trailers'
Result:
More robust parsing of the TE header.
Modifications:
HttpConversionUtil#toLowercaseMap requires an intermediate List to be allocated. This can be avoided with the recently added value iterator methods.
Modifications:
- Use HttpHeaders#valueCharSequenceIterator instead of getAll
Result:
Less intermediate object allocation and copying.
Motivation:
DefaultHttp2FrameWriter#writeData allocates a DataFrameHeader for each write operation. DataFrameHeader maintains internal state and allocates multiple slices of a buffer which is a maximum of 30 bytes. This 30 byte buffer may not always be necessary and the additional slice operations can utilize retainedSlice to take advantage of pooled objects. We can also save computation and object allocations if there is no padding which is a common case in practice.
Modifications:
- Remove DataFrameHeader
- Add a fast path for padding == 0
Result:
Less object allocation in DefaultHttp2FrameWriter
Motivation:
AbstractByteBuf#readSlice relied upon the bounds checking of the slice operation in order to detect index out of bounds conditions. However the slice bounds checking operation allows for the slice to go beyond the writer index, and this is out of bounds for a read operation.
Modifications:
- AbstractByteBuf#readSlice and AbstractByteBuf#readRetainedSlice should ensure the desired amount of bytes are readable before taking a slice
Result:
No reading of undefined data in AbstractByteBuf#readSlice and AbstractByteBuf#readRetainedSlice.
Motivation:
Netty could handle "connection" or "te" headers more gently when
converting from http/1.1 to http/2 headers. Http/2 headers don't
support single-hop headers, so when we convert from http/1.1 to http/2,
we should drop all single-hop headers. This includes headers like
"transfer-encoding" and "connection", but also the headers that
"connection" points to, since "connection" can be used to designate
other headers as single-hop headers. For the "te" header, we can more
permissively convert it by just dropping non-conforming headers (ie
non-"trailers" headers) which is what we do for all other headers when
we convert.
Modifications:
Add a new blacklist to the http/1.1 to http/2 conversion, which is
constructed from the values of the "connection" header, and stop
throwing an exception when a "te" header is passed with a non-"trailers"
value. Instead, drop all values except for "trailers". Add unit tests
for "connection" and "te" headers when converting from http/1.1 to http/2.
Result:
This will improve the h2c upgrade request, and also conversions from
http/1.1 to http/2. This will simplify implementing spec-compliant
http/2 servers that want to share code between their http/1.1 and http/2
implementations.
[Fixes#7355]
Motivation:
HTTP/2 allows writes of 0 length data frames. However in some cases EMPTY_BUFFER is used instead of the actual buffer that was written. This may mask writes of released buffers or otherwise invalid buffer objects. It is also possible that if the buffer is invalid AbstractCoalescingBufferQueue will not release the aggregated buffer nor fail the associated promise.
Modifications:
- DefaultHttp2FrameCodec should take care to fail the promise, even if releasing the data throws
- AbstractCoalescingBufferQueue should release any aggregated data and fail the associated promise if something goes wrong during aggregation
Result:
More correct handling of invalid buffers in HTTP/2 code.
Motivation:
If a child channel's read is triggered outside the parent channel's read
loop then it is possible a WINDOW_UPDATE will be written, but not
flushed.
If a child channel's beginRead processes data from the inboundBuffer and
then readPending is set to false, which will result in data not being
delivered if in the parent's read loop and more data is attempted to be
delievered to that child channel.
Modifications:
- The child channel must force a flush if a frame is written as a result
of reading a frame, and this is not in the parent channel's read loop
- The child channel must allow a transition from dequeueing from
beginRead into the parent channel's read loop to deliver more data
Result:
The child channel flushes data when reading outside the parent's read
loop, and has frames delivered more reliably.
Motivation:
Http2StreamFrameToHttpObjectCodec was not properly encoding and
decoding 100-Continue HttpResponse/Http2SettingsFrame properly. It was
encoding 100-Continue FullHttpResponse as an Http2SettingFrame with
endStream=true, causing the child channel to terminate. It was not
decoding 100-Continue Http2SettingsFrame (endStream=false) as
FullHttpResponse. This should be fixed as it would cause http2 child
stream to prematurely close, and could cause HttpObjectAggregator to
fail if it's in the pipeline.
Modification:
- Fixed encode() to properly encode 100-Continue FullHttpResponse as
Http2SettingsFrame with endStream=false
- Reject 100-Continue HttpResponse that are NOT FullHttpResponse
- Fixed decode() to properly decode 100-Continue Http2SettingsFrame
(endStream=false) as a FullHttpResponse
- made Http2StreamFrameToHttpObjectCodec sharable so that it can b used
among child streams within the same Http2MultiplexCodec
Result:
Now Http2StreamFrameToHttpObjectCodec should be properly handling
100-Continue responses.
Motivation:
Previously client Http2ConnectionHandler trigger a user event
immediately when the HTTP/2 connection preface is sent. Any attempt to
immediately send a new request could cause the server to terminate the
connection, as it might not have received the SETTINGS frame from the
client. Per RFC7540 Section 3.5, the preface "MUST be followed by a
SETTINGS frame (Section 6.5), which MAY be empty."
(https://tools.ietf.org/html/rfc7540#section-3.5)
This event could be made more meaningful if it also indicates that the
initial client SETTINGS frame has been sent to signal that the channel
is ready to send new requests.
Modification:
- Renamed event to Http2ConnectionPrefaceAndSettingsFrameWrittenEvent.
- Modified Http2ConnectionHandler to trigger the user event only if it
is a client and it has sent both the preface and SETTINGS frame.
Result:
It is now safe to use the event as an indicator that the HTTP/2
connection is ready to send new requests.
Motivation:
Objects of java.util.TreeMap or java.util.TreeSet will become
non-Serializable if instantiated with Comparators, which are not also
Serializable. This can result in unexpected and difficult-to-diagnose
bugs.
Modifications:
Implements Serializable for all classes, which implements Comparator.
Result:
Proper Comparators which will not force collections to
non-Serializable mode.
Motivation:
Without a 'serialVersionUID' field, any change to a class will make
previously serialized versions unreadable.
Modifications:
Add missed 'serialVersionUID' field for all Serializable
classes.
Result:
Proper deserialization of previously serialized objects.
Motivation:
Http2ServerDowngrader is specifically built for server channels where
inbound Http2StreamFrames are converted into HttpRequests, and outbound
HttpResponses are converted into Http2StreamFrames. It can be easily
made to be more generic to work with client channels where inbound
Http2StreamFrames are converted into HttpResponses, and outbound
HttpRequests are converted into Http2StreamFrames.
Modification:
- Renamed Http2ServerDowngrader to a more general
Http2StreamFrameToHttpObjectCodec
- Made it take in an "isServer" parameter to determine whether encoding
inbound Http2StreamFrames should create HttpRequests (for server) or
HttpResponses (for client)
- Norman fixed a leak in the unit test. Thanks! :-)
Result:
Now Http2StreamFrameToHttpObjectCodec can be used to translate
Http2StreamFrame to HttpObject for both server and client.
Motivation:
We changed Http2ConnectionHandler to expect the upgrade method to be
called *after* we send the preface (ie add the handler to the pipeline)
but we forgot to change the Http2ClientUpgradeCodec to match the new
policy. This meant that client-side h2c upgrades failed.
Modifications:
Reverse sending the preface and calling the upgrade method to match the
new policy.
Result:
Clients can initiate h2c upgrades successfully.
Motiviation:
At the moment an NPE is thrown if someone tries to use the InboundHttp2ToHttpAdapter.
Modifications:
- Ensure the status was null in "InboundHttp2ToHttpAdapter::onPushPromiseRead" before calling "HttpConversionUtil.parseStatus" methods.
- Fix setting status to OK in "InboundHttp2ToHttpAdapter::onPushPromiseRead".
Result:
Fixes [#7214].
Motivation:
The Headers interface supports an interface to get all the headers values corresponding to a particular name. This API returns a List which requires intermediate storage and increases GC pressure.
Modifications:
- Add a method which returns an iterator over all the values for a specific name
Result:
Ability to iterator over values for a specific name with no intermediate collection.
Motivation:
We missed to mark the Http2StreamChannel as writable in some cases which could lead to the situation that a Channel never becomes writable. Also when a Http2StreamChannel was created we always marked it non-writable at the beginning which means if the user will only start writing once the Channel becomes writable it will never happen as it only became writable after the first header was written.
Modifications:
- Correctly handle updates for writability in all cases
- Change unit tests to cover this.
Result:
Fixes [#7179].
Motiviation:
At the moment an NPE is thrown if someone tries to use the Http2ServerUpgradeCodec with Http2FrameCodec and Http2MultiplexCodec.
Modifications:
- Ensure the handler was added to the pipeline before calling on*Upgrade(...) methods.
- Add tests
- Fix adding of handlers after upgrade.
Result:
Fixes [#7173].
Motivation:
In `Http2StreamChannelId` a `hashCode()` is not consistent with `equals()`.
Modifications:
Make a `Http2StreamChannelId.hashCode()` consistent with `equals()`.
Result:
Faster hash map's operations where the Http2StreamChannelId as keys.
Motivation:
In `DefaultHttp2GoAwayFrame.equals()` a content compared twice: explicitly and in the `super` method.
Modifications:
Remove explicit content comparision.
Make `hashCode()` consistent with `equals()`.
Result:
A `DefaultHttp2GoAwayFrame.equals()` work faster.
Motivation:
We must not add the inboundStreamHandler for outbound streams creates by Http2MultiplexCodec as the user will specify a handler via Http2StreamChannelBootstrap.
Modifications:
- Check if the stream is for outbound and if so not add the inboundStreamHandler to the pipeline
- Update tests so this is covered.
Result:
Fixes [#7178]
Motivation:
When using Http2FrameCodec / Http2MultiplexCodec with HttpServerUpgradeHandler reference count exception will be triggered.
Modifications:
- Correctly retain before calling InboundHttpToHttp2Adapter.handle
- Add unit test
Result:
Fixes [#7172].
Motivation:
The construction `new AsciiString(string.substring(...))` can be replaced with the `new AsciiString(string, start, length)` to avoid extra allocation.
Modifications:
Apply the described replacement in `HttpConversionUtil#setHttp2Authority`.
Result:
Less allocations.
Motivation:
The `AsciiString#toString` method calculate string value and cache it into field. If an `AsciiString` created from the `String` value, we can avoid rebuilding strings if we cache them immediately when creating `AsciiString`. It would be useful for constants strings, which already stored in the JVMs string table, or in cases where an unavoidable `#toString `method call is assumed.
Modifications:
- Add new static method `AsciiString#cache(String)` which save string value into cache field.
- Apply a "benign" data race in the `#hashCode` and `#toString` methods.
Result:
Less memory usage in some `AsciiString` use cases.
Motivation:
We should call promise.setUncancellable() in DefaultHttp2StreamChannel.Unsafe impl to detect if the operation was cancelled.
Modifications:
Add promise.setUncancellable() calls
Result:
More correct handling of cancelled promises
Motivation:
Our http2 child channel implementation was not 100 % complete and had a few bugs. Beside this the performance overhead was non-trivial.
Modifications:
There are a lot of modifications, the most important....
* Http2FrameCodec extends Http2ConnectionHandler and Http2MultiplexCodec extends Http2FrameCodec to reduce performance heads and inter-dependencies on handlers in the pipeline
* Correctly handle outbound flow control for child channels
* Support unknow frame types in Http2FrameCodec and Http2MultiplexCodec
* Use a consistent way how to create Http2ConnectionHandler, Http2FrameCodec and Http2MultiplexCodec (via a builder)
* Remove Http2Codec and Http2CodecBuilder as the user should just use Http2MultipleCodec and Http2MultiplexCodecBuilder now
* Smart handling of flushes from child channels to reduce overhead
* Reduce object allocations
* child channels always use the same EventLoop as the parent Channel to reduce overhead and simplify implementation.
* Not extend AbstractChannel for the child channel implementation to reduce overhead in terms of performance and memory usage
* Remove Http2FrameStream.managedState(...) as the user of the child channel api should just use Channel.attr(...)
Result:
Http2MultiplexCodec (and so child channels) and Http2FrameCodec are more correct, faster and more feature complete.
Motivation:
This PR (unfortunately) does 4 things:
1) Add outbound flow control to the Http2MultiplexCodec:
The HTTP/2 child channel API should interact with HTTP/2 outbound/remote flow control. That is,
if a H2 stream used up all its flow control window, the corresponding child channel should be
marked unwritable and a writability-changed event should be fired. Similarly, a unwritable
child channel should be marked writable and a writability-event should be fired, once a
WINDOW_UPDATE frame has been received. The changes are (mostly) contained in ChannelOutboundBuffer,
AbstractHttp2StreamChannel and Http2MultiplexCodec.
2) Introduce a Http2Stream2 object, that is used instead of stream identifiers on stream frames. A
Http2Stream2 object allows an application to attach state to it, and so a application handler
no longer needs to maintain stream state (i.e. in a map(id -> state)) himself.
3) Remove stream state events, which are no longer necessary due to the introduction of Http2Stream2.
Also those stream state events have been found hard and complex to work with, when porting gRPC
to the Http2FrameCodec.
4) Add support for HTTP/2 frames that have not yet been implemented, like PING and SETTINGS. Also add
a Http2FrameCodecBuilder that exposes options from the Http2ConnectionHandler API that couldn't else
be used with the frame codec, like buffering outbound streams, window update ratio, frame logger, etc.
Modifications:
1) A child channel's writability and a H2 stream's outbound flow control window interact, as described
in the motivation. A channel handler is free to ignore the channel's writability, in which case the
parent channel is reponsible for buffering writes until a WINDOW_UPDATE is received.
The connection-level flow control window is ignored for now. That is, a child channel's writability
is only affected by the stream-level flow control window. So a child channel could be marked writable,
even though the connection-level flow control window is zero.
2) Modify Http2StreamFrame and the Http2FrameCodec to take a Http2Stream2 object intstead of a primitive
integer. Introduce a special Http2ChannelDuplexHandler that has newStream() and forEachActiveStream()
methods. It's recommended for a user to extend from this handler, to use those advanced features.
3) As explained in the documentation, a new inbound stream active can be detected by checking if the
Http2Stream2.managedState() of a Http2HeadersFrame is null. An outbound stream active can be detected
by adding a listener to the ChannelPromise of the write of the first Http2HeadersFrame. A stream
closed event can be listened to by adding a listener to the Http2Stream2.closeFuture().
4) Add a simple Http2FrameCodecBuilder and implement the missing frame types.
Result:
1) The Http2MultiplexCodec supports outbound flow control.
2) The Http2FrameCodec API makes it easy for a user to manage custom stream specific state and to create
new outbound streams.
3) The Http2FrameCodec API is much cleaner and easier to work with. Hacks like the ChannelCarryingHeadersFrame
are no longer necessary.
4) The Http2FrameCodec now also supports PING and SETTINGS frames. The Http2FrameCodecBuilder allows the Http2FrameCodec
to use some of the rich features of the Http2ConnectionHandler API.
Motivation:
The javadocs of Http2RemoteFlowController.isWritable(...) are incorrect.
Modifications:
Update javadocs to reflect reality.
Result:
Correct javadocs.
Motivation:
The labels identifying the frame types in Http2FrameLogger are not always correct.
Modification:
- Correct the string labels to indicate the right frame type in Http2FrameLogger
Result:
Logs are more correct.
Motivation:
In Http2ConnectionHandler we call flush(...) in channelReadComplete(...) to ensure we update the flow-controller and write stuff to the remote peer. We should better flip the order and so may be able to pick up more bytes.
Modifications:
Change order of calls.
Result:
Better performance
Motivation:
When we use pipeline.replace and we still had ongoing inbound, then
there will be some problem that inbound message would go to wrong
handlers. So we add handler first, and remove self after add, so that
the next handler will be the correct one.
Modifications:
Uses remove after addAfter instead of replace.
Result:
Fixed#6881
Motivation:
Http2FrameCodec should use Http2Settings.defaultSettings() when no Http2Settings were specified by the user.
Modifications:
Replace new Http2Settings() with Http2Settings.defaultSettings()
Result:
Use correct Http2Settings by default when using Http2FrameCodec in all cases.
