Motivation:
If an exclusive dependency change stream B should be an exclusive dependency of stream A is requested and stream B is already a child of stream A...then we will add B to B's own children map and create a circular link in the priority tree. This leads to an infinite recursive loop and a stack overflow exception.
Modifications:
-when removeAllChildren is called it should not remove the exclusive dependency.
-unit test to ensure this case is covered.
Result:
No more circular link in the priority tree.
Motivation:
The usage and code within AsciiString has exceeded the original design scope for this class. Its usage as a binary string is confusing and on the verge of violating interface assumptions in some spots.
Modifications:
- ByteString will be created as a base class to AsciiString. All of the generic byte handling processing will live in ByteString and all the special character encoding will live in AsciiString.
Results:
The AsciiString interface will be clarified. Users of AsciiString can now be clear of the limitations the class imposes while users of the ByteString class don't have to live with those limitations.
Motivation:
Due to a recent flurry of cleanup and fixes, we no longer need the stream removal policy to protect against recently removed streams. We should get rid of it.
Modifications:
Removed Http2StreamRemovalPolicy and everywhere it's used.
Result:
Fixes#3448
Motivation:
The DefaultHttp2Connection is not checking for RuntimeExceptions when invoking Http2Connection.Listener methods. This is a problem for a few reasons: 1. The state of DefaultHttp2Connection will be corrupted if a listener throws a RuntimeException. 2. If the first listener throws then no other listeners will be notified, which may further corrupt state that is updated as a result of listeners being notified.
Modifications:
- Document that RuntimeExceptions are not supported for Http2Connection.Listener methods, and will be logged as an error.
- Update DefaultHttp2Connection to handle and exception for each listener that is notified, and be sure that 1 listener throwing an exception does not prevent others from being notified.
Result:
More robust DefaultHttp2Connection.
Motivation:
Now that we have a CharObjectHashMap, we should change Http2Settings to use it.
Modifications:
Changed Http2Settings to extend CharObjectHashMap rather than IntObjectHashMap.
Result:
Http2Settings uses less memory to store keys.
Motivation:
We've removed access to the activeStreams collection, we should do the same for the children of a stream to provide a consistent interface.
Modifications:
Moved Http2StreamVisitor to a top-level interface. Removed unnecessary child operations from the Http2Stream interface so that we no longer require a map structure.
Result:
Cleaner and more consistent interface for iterating over child streams.
Motivation:
The Http2Connection interface exposes an activeStreams() method which allows direct iteration over the underlying collection. There are a few places that make copies of this collection to avoid modification while iterating, and a few places that do not make copies. The copy operation can be expensive on hot code paths and also we are not consistently iterating over the activeStreams collection.
Modifications:
- The Http2Connection interface should reduce the exposure of the underlying collection and just expose what is necessary for the interface to function. This is just a means to iterate over the collection.
- The DefaultHttp2Connection should use this new interface and protect it's internal state while iteration is occurring.
Result:
Reduction in surface area of the Http2Connection interface. Consistent iteration of the set of active streams. Concurrent modification exceptions are handled in 1 encapsulated spot.
Motivation:
1) The current implementation doesn't allow for HEADERS, DATA, PING, PRIORITY and SETTINGS
frames to be sent after GOAWAY.
2) When receiving or sending a GOAWAY frame, all streams with ids greater than the lastStreamId
of the GOAWAY frame should be closed. That's not happening.
Modifications:
1) Allow sending of HEADERS and DATA frames after GOAWAY for streams with ids < lastStreamId.
2) Always allow sending PING, PRIORITY AND SETTINGS frames.
3) Allow sending multiple GOAWAY frames with decreasing lastStreamIds.
4) After receiving or sending a GOAWAY frame, close all streams with ids > lastStreamId.
Result:
The GOAWAY handling is more correct.
Motivation:
There are methods to manipulate the prioritzable count for streams which have the '0' postfix which are designed to be used during recursion. However these methods are calling out to an external method without the '0' during the recursive process. This is doing uneccessary conditional checks during recursion.
Modifications:
Change the decrementPrioritizableForTree to decrementPrioritizableForTree0 while in recursive method.
Change the incrementPrioritizableForTree to incrementPrioritizableForTree0 while in recursive method.
Result:
Less overhead during recursive calls.
Motiviation:
The interface provided by Http2LifecycleManager is not clear as to how the writeXXX methods should behave. The implementation of this interface from the Http2ConnectionHandler's perspecitve is unclear what writeXXX means in this context.
Modifications:
- Method names in Http2LifecycleManager and Http2ConnectionHandler should be renamed and comments should clarify the interfaces.
Results:
Http2LifecycleManager is more clear and Http2ConnectionHandler's implementation makes sense w.r.t to return values.
Motivation:
The HTTP/2 headers code should be using binary string (currently AsciiString) objects instead of String objects. The DefaultHttp2HeadersEncoder was still using String for sensitiveHeaders.
Modifications:
- Remove the usage of String from DefaultHttp2HeadersEncoder.
- Introduce an interface to determine if a header name/value is sensitive or not to 1. prevent necessarily creating/copying sets. 2. Allow the name/value to be considered when checking if sensitive.
Result:
No more String in DefaultHttp2HeadersEncoder and less required set creation/operations.
Motivation:
The spec requires that a RST_STREAM received on an IDLE stream results in a connection error. This is not happening.
Modifications:
Check for this condition when a RST_STREAM is received in DefaultHttp2ConnectionDecoder.
Result:
More spec compliant. Fixes https://github.com/netty/netty/issues/3573.
Motivation:
The DefaultHttp2ConnectionDecoder has the setPriority call after the Http2FrameListener is notified of the change. The setPriority call has additional verification logic and may even create the dependency stream and so it must be before the Http2FrameListener is notified.
Modifications:
The DefaultHttp2ConnectionDecoder should treat the setPriority call in the same for the HEADERS and PRIORITY frame (call it before notifying the listener).
Result:
Http2FrameListener should see correct state when a HEADERS frame has a stream dependency that has not yet been created yet. Fixes https://github.com/netty/netty/issues/3572.
Motivation:
We are allocating a hash map for every HTTP2 Stream to store it's children.
Most streams are leafs in the priority tree and don't have children.
Modification:
- Only allocate children when we actually use them.
- Make EmptyIntObjectMap not throw a UnsupportedOperationException on remove, but return null instead (as is stated in it's javadoc).
Result:
Fewer unnecessary allocations.
Motivation:
In a simple load test that creates and closes several 10k streams per second
I have seen Iterator objects using roughly 1.6% of the total committed heap.
Modifications:
Use an ArrayList instead of a LinkedHashSet to store the connection listeners.
That way we can iterate over the list without creating an iterator every time.
Result:
Zero Iterator allocations due to notifying connection listeners.
Motivation:
The Http2Settings class currently disallows setting non-standard settings, which violates the spec.
Modifications:
Updated Http2Settings to permit arbitrary settings. Also adjusting the default initial capacity to allow setting all of the standard settings without reallocation.
Result:
Fixes#3560
Motivation:
The HTTP/2 specification allows for closed (and streams in any state) to exist in the priority tree. The current code removes streams from the priority tree as soon as they are closed (subject to the removal policy). This may lead to undesired distribution of resources from the peer's perspective.
Modifications:
- We should only remove streams from the priority tree when they have no descendant streams in a viable state.
- We should track when tree edges change or nodes are removed if inviable nodes can then be removed.
Result:
Priority tree doesn't remove closed streams until descendant are all closed, or there are no descendants.
Motivation:
We're currently using Math.ceil which isn't necessary. We should exchange for a lighter weight operation.
Modifications:
Changing the logic to just ensure that we allocate at least one byte to the child rather than always performing a ceil.
Result:
Slight performance improvement in the priority algorithm.
Motivation:
The Connection.Listener GOAWAY event handler currently provides no additional information, requiring applications to hack in other ways to get at the error code and debug message.
Modifications:
Modified the Connection.Listener interface to pass on the error code and message that triggered the GOAWAY.
Result:
Application can now use Connection.Listener for all GOAWAY processing.
Motivation:
It currently takes a builder for the encoder and decoder, which makes it difficult to decorate them.
Modifications:
Removed the builders from the interfaces entirely. Left the builder for the decoder impl but removed it from the encoder since it's constructor only takes 2 parameters. Also added decorator base classes for the encoder and decoder and made the CompressorHttp2ConnectionEncoder extend the decorator.
Result:
Fixes#3530
Motivation:
The DefaultHttp2RemoteFlowController's priority algorithm doesn't really need to sort the children by weight since it already fairly distributes data based on weight.
Modifications:
Removing the sorting in the priority algorithm and updating one test to allow a small bit of variability in the results.
Result:
Slight improvement on the performance of the priority algorithm.
Motivation:
The encoder/decoder currently do not handle streams which have previously existed but no longer exist because they were closed. The specification requires supporting this.
Modifications:
- encoder/decoder should tolerate the frame or the dependent frame not existing in the streams map due to the fact that it may have previously existed.
Result:
encoder/decoder are more compliant with the specification.
Motivation:
The DefaultHttp2ConnectionDecoder class is calling verifyPrefaceReceived() for almost every frame event at all times.
The Http2ConnectionHandler class is calling readClientPrefaceString() on every decode event.
Modifications:
- DefaultHttp2ConnectionDecoder should not have to continuously call verifyPrefaceReceived() because it transitions boolean state 1 time for each connection.
- Http2ConnectionHandler should not have to continuously call readClientPrefaceString() because it transitions boolean state 1 time for each connection.
Result:
- Less conditional checks for the mainstream usage of the connection.
Motivation:
The current DefaultHttp2RemoteFlowController's writePendingBytes currently operates in 2 passes. The first allocates bytes and optionally writes some frames. The second pass just loops across all active streams and writes all remaining bytes.
If streams can be removed/added as a side effect of writing (EOS or error) then we need to take more care when the write actually occurs. Moving all of the writes to the second loop (across active streams) is simpler since we can just make a copy of the list and not worry about any restructuring of the priority tree that may result.
Modifications:
Modified DefaultHttp2RemoteFlowController.writePendingBytes to only allocate bytes on the first pass and then write any allocated bytes on the second pass.
Result:
Side effects resulting from writing should no longer impact the flow control algorithm.
Motivation:
A microbenchmark will be useful to get a baseline for performance.
Modifications:
- Introduce a new microbenchmark which tests the Http2DefaultFrameWriter.
- Allow benchmarks to run without thread context switching between JMH and Netty.
Result:
Microbenchmark exists to test performance.
Motivation:
The Http2ConnectionHandler writeRstStream method allows RST_STREAM frames to be sent when we do not know about the stream and after a RST_STREAM frame has already been sent. This may lead to sending frames when we should not according to the HTTP/2 spec. There is also the potential to notify the closeListener multiple times if the closeStream method is called multiple times.
Modifications:
- Prevent RST_STREAM from being sent if we don't know about the stream, or if we already sent the RST_STREAM.
- Prevent the closeListener from being notified multiple times.
Result:
More robust writeRstStream logic in boundary conditions.
Motivation:
There was a new draft for HTTP/2. We should support the new draft.
Modifications:
- Review the HTTP/2 draft 17 specification, and update code to reflect changes.
Result:
Support for HTTP/2 draft 17.
Motivation:
- In FlowState.write(...) we are currently swalloing an exception.
- In my previous commit I introduced a compiler warning by not making
a local variabe final.
Modifications:
- Have FlowState.cancel() take a Throwable.
- Make the variable final.
Result:
No more swallowed exceptions and warnings.
Motivation:
- The encoder and decoder should be closed right after the handler releases its resources.
- The clientPrefaceString is allocated in the constructor but releases in handlerRemoved.
If the handler is never added to the pipeline, the clientPrefaceString will never be
released.
Modifications:
- Call encoder.close() and decoder.close() on channelInactive.
- Release the clientPrefaceString on handlerRemoved.
Result:
- The encoder and decoder get closed right after the handler's resources are freed.
- It's easier to verify that the clientPrefaceString will also get released.
Motivation:
The Http2FrameLogger is currently using the internal logging classes. We should change this so that it's using the public classes and then converts internally.
Modifications:
Modified Http2FrameLogger and the examples to use the public LogLevel class.
Result:
Fixes#2512
Motivation:
The current documentation for Endpoint methods referring to concurrent streams and the SETTINGS_MAX_CONCURRENT_STREAMS setting are a bit confusing.
Modifications:
Renamed a few of the methods and added more clear documentation.
Result:
Fixes#3451
Motivation:
There are two writeRstStream methods in the DefaultHttp2ConnectionEncoder.
One of the two is neither used nor part of the Http2FrameWriter interface.
Modifications:
Delete the method.
Result:
Fewer lines of dead code.
Motivation:
For every write of a flow controlled frame (HEADERS, DATA) we are allocating
a Frame object that is not necessary anymore as it does not maintain any
state, besides the payload.
Modifications:
Remove the Frame class and directly add the payload to the pending write queue.
Result:
One few object allocation per write of a flow controlled frame.
Motivation:
The logger was always performing a hex dump of the ByteBufs regarless whether or not the log would take place.
Modifications:
Fixed the logger to avoid serializing the ByteBufs and calling the varargs method if logging is not enabled.
Result:
The loggers should run MUCH faster when disabled.
Motivation:
If HEADERS or DATA frames are pending due to a too small flow control
window, a frame with the END_STREAM flag set will wrongfully cancel
all pending frames (including itself).
Also see grpc/grpc-java#145
Modifications:
The transition of the stream state to CLOSE / HALF_CLOSE due to a
set END_STREAM flag is delayed until the frame with the flag is
actually written to the Channel.
Result:
Flow control works correctly. Frames with END_STREAM flag will no
longer cancel their preceding frames.
Motivation:
HttpToHttp2ConnectionHandlerTest was accidentally modified with a
debugging value for WAIT_TIME_SECONDS.
Modifications:
Reverted the change.
Result:
original wait time restored.
Motivation:
The Http2DefaultFrameWriter copies all contents into a buffer (or uses a CompositeBuffer in 1 case) and then writes that buffer to the socket. There is an opportunity to avoid the copy operations and write directly to the socket.
Modifications:
- Http2DefaultFrameWriter should avoid copy operations where possible.
- The Http2FrameWriter interface should be clarified to indicate that ByteBuf objects will be released.
Result:
Hopefully less allocation/copy leads to memory and throughput performance benefit.
Motivation:
Http2Stream has several methods that provide state information. We need
to simplify how state is used and consolidate as many of these fields as
possible.
Modifications:
Since we already have a concept of a stream being active or inactive,
I'm now separating the deactivation of a stream from the act of closing
it. The reason for this is the case of sending a frame with
endOfStream=true. In this case we want to close the stream immediately
in order to disallow further writing, but we don't want to mark the
stream as inactive until the write has completed since the inactive
event triggers the flow controller to cancel any pending writes on the
stream.
With deactivation separated out, we are able to eliminate most of the
additional state methods with the exception of `isResetSent`. This is
still required because we need to ignore inbound frames in this case (as
per the spec), since the remote endpoint may not yet know that the
stream has been closed.
Result:
Fixes#3382
Motivation:
Previously flow-controller had to know the implementation details of each frame type in order to write it correctly. That concern is more correctly handled by the encoder. By encapsulating the payload types to be flow-controlled it will be easier to add support for extension types later. This change also fixes#3353.
Modifications:
Add interface FlowControlled which is now delivered to flow-controller.
Implement this interface for HEADERS and DATA
Refactor and improve tests for flow-control.
Result:
Flow control semantics are more cleanly separated for data encoding and implementation is simpler overall.
Motivation:
A downstream consumer of Netty failed as emitting zero-length http2 data frames in a unit test resulted in assertion errors in Http2LocalFlowController. Since zero-length frames are valid, an assertion that http2 data frame length must be positive is invalid.
Modifications:
Assertions of data length in Http2LocalFlowController now permit zero.
Result:
Those running netty with assertions on can now emit zero length http2 data frames.
Motivation:
Commit eb0e127ee9 was designed for the 4.1 branch. The 5.0 branch had a few additional classes which required updates to get the new timeMillis methods for all the header classes.
Modifications:
Update the *Headers interfaces/classes that were not updated in the 4.1 branch.
Result:
All *Headers interfaces support set/add timeMillis methods.
Motivation:
HttpToHttp2ConnectionHandler is awaiting on a future and a latch that may be competed before the buffers actually get released. This test is attempting to validate that the buffer's refCnt() is 0 but there is no mechanism to wait on for a buffer's release() method to be called.
Modifications:
Remove the buffer refCnt() check. The leak profile is designed to pick these up.
Result:
Unit tests that no longer have a race condition.
Motivation:
The stress tests have been observed to fail on the CI server. The average run time of the stress tests has recently been 26+ seconds. Our timeout is currently set to 30 seconds.
Modifications:
Increase the timeout for the stress test so when the leak profile is active we will have more time to complete the test (with the additional overhead).
Result:
Stress tests fail less frequently (hopefully not at all).
Motivation:
Clinker provides a Sonar tool which detects potential bugs or problems in the code. These problems were reported here http://clinker.netty.io/sonar/drilldown/issues/io.netty:netty-parent:master?
Modifications:
Make the recommended changes as reported by Sonar
Result:
Better or more standard code. Less Sonar problem reports for HTTP/2 codec.
Motivation:
The Http2ConnectionRoundtripTest.noMoreStreamIdsShouldSendGoAway unit test had a race condition where it would sometimes receive a SETINGS_ACK message that was not anticipated. This caused the test to fail because of bad test code.
Modifications:
The bad unit test should be updated to handle the message exchange for a good connection setup, and then the GO_AWAY frame.
Result:
Http2ConnectionRoundtripTest.noMoreStreamIdsShouldSendGoAway should no longer sporadically fail.
Motivation:
The terminology used with inbound/outbound is a little confusing since
it's not discussed in the spec. We should switch to using local/remote
instead. Also there is some asymmetry between the inbound/outbound
interfaces which could probably be cleaned up.
Modifications:
Changing the interface names and making a common Http2FlowController
interface for most of the methods.
Result:
The HTTP/2 flow control interfaces should be more clear.
Motivation:
The inbound flow control code was returning too many bytes to the connection window. This was resulting in GO_AWAYs being generated by peers with the error code indicating a flow control issue. Bytes were being returned to the connection window before the call to returnProcessedBytes. All of the state representing the connection window was not updated when a local settings event occurred.
Modifications:
The DefaultHttp2InboundFlowController will be updated to correct the above defects.
The unit tests will be updated to reflect the changes.
Result:
Inbound flow control algorithm does not cause peers to send flow control errors for the above mentioned cases.
Motivation:
We use 3 (!) libraries to build mock objects - easymock, mockito, jmock.
Mockito and jMock pulls in the different versions of Hamcrest, and it
conflicts with the version pulled by jUnit.
Modifications:
- Replace mockito-all with mockito-core to avoid pulling in outdated
jUnit and Hamcrest
- Exclude junit-dep when pulling in jmock-junit4, because it pulls an
outdated Hamcrest version
- Pull in the hamcrest-library version used by jUnit explicitly
Result:
No more dependency hell that results in NoSuchMethodError during the
tests
Motivation:
The Http2SecurityUtil class lists a few ciphers that are explicitly prohibited by the HTTP/2 specification because of their characteristics.
Modifications:
Remove the ciphers that are prohibited.
Results:
Cipher suite used for HTTP/2 codec is compatible with HTTP/2 spec.
Motivation:
The DefaultHttp2FrameWriter has an exception generated but is missing the throw keyword.
Modifications:
Insert the missing throw keyword.
Result:
Exception thrown when it was intended to be thrown.
Motivation:
The DefaultHttp2InboundFlowController uses processedBytes to determine
when to send the WINDOW_UPDATE, but uses window to determine the delta
to send in the request. This is incorrect since we shouldn't be
requesting bytes that haven't been processed.
Modifications:
Changed DefaultHttp2InboundFlowController to use processedBytes in the
calculation of the delta to send in the WINDOW_UPDATE request.
Result:
Inbound flow control only asks for bytes that have been processed in
WINDOW_UPDATE.
Related: #3157
Motivation:
It should be convenient to have an easy way to classify an
HttpResponseStatus based on the first digit of the HTTP status code, as
defined in the RFC 2616:
- Information 1xx
- Success 2xx
- Redirection 3xx
- Client Error 4xx
- Server Error 5xx
Modification:
- Add HttpStatusClass
- Add HttpResponseStatus.codeClass() that returns the class of the HTTP
status code
- Remove HttpResponseStatus.isInformational()
Result:
It's easier to determine the class of an HTTP status
Motivation:
The HTTP/2 compressor does not release the input buffer when compression is done. This results in buffer leaks.
Modifications:
- Release the buffer in the HTTP/2 compressor
- Update tests to reflect the correct state
Result:
1 less buffer leak.
Motivation:
The interface for HTTP/2 onDataRead states that buffers will be released by the codec. The decompressor and compressor methods are not releasing buffers created during the decompression/compression process.
Modifications:
After onDataRead calls the decompressor and compressor classes will release the data buffer.
Result:
HTTP/2 compressor/decompressors are consistent with onDataRead interface assumptions.
Motivation:
Some of the comments in HTTP/2 Frame Listener interface are misleading.
Modifications:
Clarify comments in Http2FrameListener.
Result:
Http2FrameListener onDataRead comments are clarified.
Motivation:
When DefaultHttp2FrameReader has read a settings frame, the settings
will be passed along the pipeline. This allows a client to hold off
sending data until it has received a settings frame. But for a server it
will always have received a settings frame and the usefulness of this
forwarding of settings is less useful. This also causes a debug message
to be logged on the server side if there is no channel handler to handle
the settings:
[nioEventLoopGroup-1-1] DEBUG io.netty.channel.DefaultChannelPipeline -
Discarded inbound message {INITIAL_WINDOW_SIZE=131072,
MAX_FRAME_SIZE=16384} that reached at the tail of the pipeline. Please
check your pipeline configuration.
Modifications:
Added a builder for the InboundHttp2ToHttpAdapter and
InboundHttp2PriortyAdapter and a new parameter named 'propagateSettings'
to their constructors.
Result:
It is now possible to control whether settings should be passed along
the pipeline or not.
Motivation:
Found performance issues via FindBugs and PMD.
Modifications:
- Removed unnecessary boxing/unboxing operations in DefaultTextHeaders.convertToInt(CharSequence) and DefaultTextHeaders.convertToLong(CharSequence). A boxed primitive is created from a string, just to extract the unboxed primitive value.
- Added a static modifier for DefaultHttp2Connection.ParentChangedEvent class. This class is an inner class, but does not use its embedded reference to the object which created it. This reference makes the instances of the class larger, and may keep the reference to the creator object alive longer than necessary.
- Added a static compiled Pattern to avoid compile it each time it is used when we need to replace some part of authority.
- Improved using of StringBuilders.
Result:
Performance improvements.
Motivation:
The HTTP/2 codec currently does not expose the boundaries of the initial settings. This could be useful for applications to define their own initial settings.
Modifications:
Add new static final variables to Http2CodecUtil and make Http2Settings use these in the bounds checks.
Result:
Applications can use the max (or min) variables to initialize their settings.
Motivation:
When the inbound flow controller recognizes that the flow control window
has been violated on a stream (not connection-wide), it throws a
connection error.
Modifications:
Changed the DefaultHttp2InboundFlowController to properly throw
connection error if the connection window is violated and stream error
if a stream window is violated.
Result:
inbound flow control throws the correct error for window violations.
Motivation:
The current name of the class which converts from HTTP objects to HTTP/2 frames contains the text Http2ToHttp. This is misleading and opposite of what is being done.
Modifications:
Rename this class name to be HttpToHttp2.
Result:
Class names that more clearly identify what they do.
Motivation:
The current decompression frame listener currently opts-out of application level flow control. The application should still be able to control flow control even if decompression is in use.
Modifications:
- DecompressorFrameListener will maintain how many compressed bytes, decompressed bytes, and processed by the listener bytes. A ratio will be used to translate these values into application level flow control amount.
Result:
HTTP/2 decompressor delegates the application level flow control to the listener processing the decompressed data.
Motivation:
Currently when an exception occurs during a listener.onDataRead
callback, we return all bytes as processed. However, the listener may
choose to return bytes via the InboundFlowState object rather than
returning the integer. If the listener returns a few bytes and then
throws, we will attempt to return too many bytes.
Modifications:
Added InboundFlowState.unProcessedBytes() to indicate how many
unprocessed bytes are outstanding.
Updated DefaultHttp2ConnectionDecoder to compare the unprocessed bytes
before and after the listener.onDataRead callback when an exception was
encountered. If there is a difference, it is subtracted off the total
processed bytes to be returned to the flow controller.
Result:
HTTP/2 data frame delivery properly accounts for processed bytes through
an exception.
Motivation:
The current priority algorithm uses 2 different mechanisms to iterate the priority tree and send the results of the allocation. The current algorithm also uses a two step phase where the priority tree is traversed and allocation amounts are calculated and then all active streams are traversed to send for any streams that may or may not have been allocated bytes.
Modifications:
- DefaultHttp2OutboundFlowController will allocate and send (when possible) in the same looping structure.
- The recursive method will send only for the children instead of itself and its children which should simplify the recursion.
Result:
Hopefully simplified recursive algorithm where the tree iteration determines who needs to send and less iteration after the recursive calls complete.
Currently the DefaultHttp2InboundFlowController only supports the
ability to turn on and off "window maintenance" for a stream. This is
insufficient for true application-level flow control that may only want
to return a few bytes to flow control at a time.
Modifications:
Removing "window maintenance" interface from
DefaultHttp2InboundFlowController in favor of the new interface.
Created the Http2InboundFlowState interface which extends Http2FlowState
to add the ability to return bytes for a specific stream.
Changed the onDataRead method to return an integer number of bytes that
will be immediately returned to flow control, to support use cases that
want to opt-out of application-level inbound flow control.
Updated DefaultHttp2InboundFlowController to use 2 windows per stream.
The first, "window", is the actual flow control window that is
decremented as soon as data is received. The second "processedWindow"
is a delayed view of "window" that is only decremented after the
application returns the processed bytes. It is processedWindow that is
used when determining when to send a WINDOW_UPDATE to restore part of
the inbound flow control window for the stream/connection.
Result:
The HTTP/2 inbound flow control interfaces support application-level
flow control.
Motivation:
Too many warnings from IntelliJ IDEA code inspector, PMD and FindBugs.
Modifications:
- Removed unnecessary casts, braces, modifiers, imports, throws on methods, etc.
- Added static modifiers where it is possible.
- Fixed incorrect links in javadoc.
Result:
Better code.
Motivation:
The outbound flow controller logic does not properly reset the allocated
bytes between successive invocations of the priority algorithm.
Modifications:
Updated the priority algorithm to reset the allocated bytes for each
stream.
Result:
Each call to the priority algorithm now starts with zero allocated bytes
for each stream.
Motivation:
I came across an issue when I was adding/setting headers and mistakenly
used an upper case header name. When using the http2 example that ships
with Netty this was not an issue. But when working with a browser that
supports http2, in my case I was using Firefox Nightly, I'm guessing
that it interprets the response as invalid in accordance with the
specifiction
https://tools.ietf.org/html/draft-ietf-httpbis-http2-14#section-8.1.2
"However, header field names MUST be converted to lowercase prior
to their encoding in HTTP/2. A request or response containing
uppercase header field names MUST be treated as malformed"
This PR suggests converting to lowercase to be the default.
Modifications:
Added a no-args constructor that defaults to forcing the key/name to
lowercase, and providing a second constructor to override this behaviour
if desired.
Result:
It is now possible to specify a header like this:
Http2Headers headers = new DefaultHttp2Headers(true)
.status(new AsciiString("200"))
.set(new AsciiString("Testing-Uppercase"), new AsciiString("some value"));
And the header written to the client will then become:
testing-uppercase:"some value"
Motivation:
The HTTP/2 codec currently does not provide an interface to compress data. There is an analogous case to this in the HTTP codec and it is expected to be used commonly enough that it will be beneficial to have the feature in the http2-codec.
Modifications:
- Add a class which extends DefaultHttp2ConnectionEncoder and provides hooks to an EmbeddedChannel
- Add a compressor element to the Http2Stream interface
- Update unit tests to utilize the new feature
Result:
HTTP/2 codec supports data compression.
Motivation:
The current logic in DefaultHttp2OutboundFlowController for handling the
case of a stream shutdown results in a Http2Exception (not a
Http2StreamException). This results in a GO_AWAY being sent for what
really could just be a stream-specific error.
Modifications:
Modified DefaultHttp2OutboundFlowController to set a stream exception
rather than a connection-wide exception. Also using the error code of
INTERNAL_ERROR rather than STREAM_CLOSED, since it's more appropriate
for this case.
Result:
Should not be triggering GO_AWAY when a stream closes prematurely.
Motivation:
Currently due to flow control, HEADERS frames can be written
out-of-order WRT DATA frames.
Modifications:
When data is written, we preserve the future as the lastWriteFuture in
the outbound flow controller. The encoder then uses the lastWriteFuture
such that headers are only written after the lastWriteFuture completes.
Result:
HEADERS/DATA write order is correctly preserved.
Motivation:
The HTTP/2 specification indicates that when converting from HTTP/2 to HTTP/1.x and non-ascii characters are detected that an error should be thrown.
Modifications:
- The ASCII validation is already done but the exception that is raised is not properly converted to a RST_STREAM error.
Result:
- If HTTP/2 to HTTP/1.x translation layer is in use and a non-ascii header is received then a RST_STREAM frame should be sent in response.
Motivation:
The DefaultOutboundFlowController was attempting to write frames with a negative length. This resulted in attempting to allocate a buffer of negative size and thus an exception.
Modifications:
- Don't allow DefaultOutboundFlowController to write negative length buffers.
Result:
No more negative length writes which resulted in IllegalArgumentExceptions.
Motivation:
x-gzip and x-deflate are not standard header values, and thus should be
removed from HttpHeaderValues, which is meant to provide the standard
values only.
Modifications:
- Remove X_DEFLATE and X_GZIP from HttpHeaderValues
- Move X_DEFLATE and X_GZIP to HttpContentDecompressor and
DelegatingDecompressorFrameListener
- We have slight code duplication here, but it does less harm than
having non-standard constant.
Result:
HttpHeaderValues contains only standard header values.
Related: 4ce994dd4f
Motivation:
In 4.1, we were not able to change the type of the HTTP header name and
value constants from String to AsciiString due to backward compatibility
reasons.
Instead of breaking backward compatibility in 4.1, we introduced new
types called HttpHeaderNames and HttpHeaderValues which provides the
AsciiString version of the constants, and then deprecated
HttpHeaders.Names/Values.
We should make the same changes while deleting the deprecated classes
activaly.
Modifications:
- Remove HttpHeaders.Names/Values and RtspHeaders
- Add HttpHeaderNames/Values and RtspHeaderNames/Values
- Make HttpHeaderValues.WEBSOCKET lowercased because it's actually
lowercased in all WebSocket versions but the oldest one
- Do not use AsciiString.equalsIgnoreCase(CharSeq, CharSeq) if one of
the parameters are AsciiString
- Avoid using AsciiString.toString() repetitively
- Change the parameter type of some methods from String to
CharSequence
Result:
A user who upgraded from 4.0 to 4.1 first and removed the references to
the deprecated classes and methods can easily upgrade from 4.1 to 5.0.
Motivation:
If the http2 encoder has exhausted all available stream IDs a GOAWAY frame is not sent. Once the encoder detects the a new stream ID has rolled over past the last stream ID a GOAWAY should be sent as recommended in section [5.1.1](https://tools.ietf.org/html/draft-ietf-httpbis-http2-14#section-5.1.1).
Modifications:
-This condition is already detected but it just needs to result in a GOAWAY being sent.
-Add a subclass of Http2Exception so the encoder can detect this special case.
-Add a unit test which checks that the GOAWAY is sent/received.
Result:
Encoder attempting to use the first 'rolled over' stream id results in a GOAWAY being sent.
Motivation:
- There are still various inspector warnings to fix.
- ValueConverter.convert() methods need to end with the type name like
other methods in Headers, such as setInt() and addInt(), for more
consistency
Modifications:
- Fix all inspector warnings
- Rename ValueConverter.convert() to convert<type>()
Result:
- Cleaner code
- Consistency
Motivation:
Headers within netty do not cleanly share a common class hierarchy. As a result some header types support some operations
and don't support others. The consolidation of the class hierarchy will allow for maintenance and scalability for new codec.
The existing hierarchy also has a few short comings such as it is not clear when data conversions are happening. This
could result unintentionally getting back a collection or iterator where a conversion on each entry must happen.
The current headers algorithm also prepends all elements which means to find the first element or return a collection
in insertion order often requires a complete traversal followed by a collections.reverse call.
Modifications:
-Provide a generic base class which provides all the implementation for headers in netty
-Provide an extension to this class which allows for name type conversions to happen (to accommodate legacy CharSequence to String conversions)
-Update the headers interface to clarify when conversions will happen.
-Update the headers data structure so that appends are done to avoid unnecessary iteration or collection reversal.
Result:
-More unified class hierarchy for headers in netty
-Improved headers data structure and algorithms
-headers API more clearly identify when conversions are required.
Motivation:
There should be a unit test for when the stream ID wraps around and is 'too large' or negative.
The lack of unit test masked an issue where this was not being throw.
Modifications:
Add a unit test to cover the case where creating a remote and local stream where stream id is 'too large'
Result:
Unit test scope increases.
Motivation:
Currently when receiving DATA/HEADERS frames, we throw Http2Exception (a
connection error) instead of Http2StreamException (stream error). This
is incorrect according to the HTTP/2 spec.
Modifications:
Updated various places in the encoder and decoder that were out of spec
WRT connection/state checking.
Result:
Stream state verification is properly handled.
Motivation:
Twitter hpack has upgraded to 0.9.1, we should upgrade to the latest.
Modifications:
Updated the parent pom to specify the dependency version. Updated the
http2 pom to use the version specified by the parent.
Result:
HTTP/2 updated to the latest hpack release.
Motiviation:
The HTTP/2 server example is not using the outbound flow control. It is instead using a FrameWriter directly.
This can lead to flow control errors and other comm. related errors
Modifications:
-Force server example to use outbound flow controller
Result:
-Server example should use follow flow control rules.
Motivation:
InboundHttp2ToHttpAdapterTest swaps non-volatile CountDownLatches in
handlers, which seems to cause a race condition that can lead to missing
messages.
Modifications:
Make CountDownLatch variables in InboundHttp2ToHttpAdapterTest volatile.
Result:
InboundHttp2ToHttpAdapterTest should be more stable.
Motivation:
The current GOAWAY methods are in each endpoint and are a little
confusing since their called connection.<endpoint>.goAwayReceived().
Modifications:
Moving GOAWAY methods to connection with more clear names
goAwaySent/goAwayReceived.
Result:
The GOAWAY method names are more clear.
Motivation:
There is a NPE due to the order of builder initialization in the class.
Modifications:
-Correct the ordering of initialization and building to avoid NPE.
Result:
No more NPE in construction.
Motivation:
This was lost in recent changes, just adding it back in.
Modifications:
Added listener() accessor to Http2ConnectionDecoder and the default
impl.
Result:
The Http2FrameListener can be obtained from the decoder.
Motivation:
Currently, Http2LifecycleManager implements the exception handling logic
which makes it difficult to extend or modify the exception handling
behavior. Simply overriding exceptionCaught() will only affect one of
the many possible exception paths. We need to reorganize the exception
handling code to centralize the exception handling logic into a single
place that can easily be extended by subclasses of
Http2ConnectionHandler.
Modifications:
Made Http2LifecycleManager an interface, implemented directly by
Http2ConnectionHandler. This adds a circular dependency between the
handler and the encoder/decoder, so I added builders for them that allow
the constructor of Http2ConnectionHandler to set itself as the lifecycle
manager and build them.
Changed Http2LifecycleManager.onHttpException to just
onException(Throwable) to simplify the interface. This method is now the
central control point for all exceptions. Subclasses now only need to
override onException() to intercept any exception encountered by the
handler.
Result:
HTTP/2 has more extensible exception handling, that is less likely to
see exceptions vanish into the ether.
Motivation:
Some tests occasionally appear unstable, throwing a
org.mockito.exceptions.misusing.UnfinishedStubbingException. Mockito
stubbing does not work properly in multi-threaded environments, so any
stubbing has to be done before the threads are started.
Modifications:
Modified tests to perform any custom stubbing before the client/server
bootstrap logic executes.
Result:
HTTP/2 tests should be more stable.
Motivation:
Some tests do not properly assert that all requests have been
sent/received, so the failures messages may be misleading.
Modifications:
Adding missing asserts to HTTP/2 tests for awaiting requests and
responses.
Result:
HTTP/2 tests properly assert message counts.
Motiviation:
PR https://github.com/netty/netty/pull/2948 missed a collection to synchronize in the HTTP/2 unit tests.
Modifications:
synchronize the collection that was missed
Result:
Missed collection is syncronized and initial size is corrected
The HTTP/2 tests have been unstable, in particular the
Http2ConnectionRoundtripTest.
Modifications:
Modified fields in Http2TestUtil to be volatile.
Result:
Tests should (hopefully) be more stable.
Motivation:
HTTP/2 codec does not properly test exception passed to
exceptionCaught() for instanceof Http2Exception (since the exception
will always be wrapped in a PipelineException), so it will never
properly handle Http2Exceptions in the pipeline.
Also if any streams are present, the connection close logic will execute
twice when a pipeline exception. This is because the exception logic
calls ctx.close() which then triggers the handleInActive() logic to
execute. This clears all of the remaining streams and then attempts to
run the closeListener logic (which has already been run).
Modifications:
Changed exceptionCaught logic to properly extract Http2Exception from
the PipelineException. Also added logic to the closeListener so that is
only run once.
Changed Http2CodecUtil.toHttp2Exception() to avoid NPE when creating
an exception with cause.getMessage().
Refactored Http2ConnectionHandler to more cleanly separate inbound and
outbound flows (Http2ConnectionDecoder/Http2ConnectionEncoder).
Added a test for verifying that a pipeline exception closes the
connection.
Result:
Exception handling logic is tidied up.
Motivation:
The HTTP/2 unit tests are collecting responses read events which are happening in a multithreaded environment.
These collections are currently not synchronized or thread safe and are resulting in verification failures.
Modifications:
-Modify unit tests that use collections to store results for verifiction to be thread safe
Result:
Tests should not fail because of syncrhonization issues while verifying expected results.
Motivation:
The HTTP/2 codec has some duplication and the read/write interfaces are not cleanly exposed to users of the codec.
Modifications:
-Restructure the AbstractHttp2ConnectionHandler class to be able to extend write behavior before the outbound flow control gets the data
-Add Http2InboundConnectionHandler and Http2OutboundConnectionHandler interfaces and restructure external codec interface around these concepts
Result:
HTTP/2 codec provides a cleaner external interface which is easy to extend for read/write events.
Motivation:
The HTTP tranlsation layer uses a FullHttpMessage object after it has been fired up the pipeline.
Although the content ByteBuf is not used by default it is still not ideal to use a releasable object
after it has potentially been released.
Modifications:
-InboundHttp2ToHttpAdapter ordering issues will be corrected
Result:
Safer access to releasable objects in the HTTP/2 to HTTP translation layer.
