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.
In TrafficCounter, a recent change makes the contract of the API (the
constructor) wrong and lead to issue with GlobalChannelTrafficCounter
where executor must be null.
Motivation:
TrafficCounter executor argument in constructor might be null, as
explained in the API, for some particular cases where no executor are
needed (relevant tasks being taken by the caller as in
GlobalChannelTrafficCounter).
A null pointer exception is raised while it should not since it is
legal.
Modifications:
Remove the 2 null checking for this particular attribute.
Note that when null, the attribute is not reached nor used (a null
checking condition later on is applied).
Result:
No more null exception raized while it should not.
This shall be made also to 4.0, 4.1 (present) and master. 3.10 is not
concerned.
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
Related: #3567
Motivation:
SslHandler.channelReadComplete() forgets to call
super.channelReadComplete(), which discards read bytes from the
cumulative buffer. As a result, the cumulative buffer can expand its
capacity unboundedly.
Modifications:
Call super.channelReadComplete() instead of calling
ctx.fireChannelReadComplete()
Result:
Fixes#3567
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:
LoggingHandlerTest sometimes failure due to unexpected log messages
logged due to the automatic reclaimation of thread-local objects.
Expectation failure on verify:
Appender.doAppend([DEBUG] Freed 3 thread-local buffer(s) from thread: nioEventLoopGroup-23-0): expected: 1, actual: 0
Appender.doAppend([DEBUG] Freed 9 thread-local buffer(s) from thread: nioEventLoopGroup-23-1): expected: 1, actual: 0
Appender.doAppend([DEBUG] Freed 2 thread-local buffer(s) from thread: nioEventLoopGroup-23-2): expected: 1, actual: 0
Appender.doAppend([DEBUG] Freed 4 thread-local buffer(s) from thread: nioEventLoopGroup-26-0): expected: 1, actual: 0
Appender.doAppend(matchesLog(expected: ".+CLOSE$", got: "[id: 0xembedded, embedded => embedded] CLOSE")): expected: 1, actual: 0
Modifications:
Add the mock appender to the related logger only
Result:
No more intermittent test failures
Related: #3368
Motivation:
ChunkedWriteHandler checks if the return value of
ChunkedInput.isEndOfInput() after calling ChunkedInput.close().
This makes ChunkedStream.isEndOfInput() trigger an IOException, which is
originally triggered by PushBackInputStream.read().
By contract, ChunkedInput.isEndOfInput() should not raise an IOException
even when the underlying stream is closed.
Modifications:
Add a boolean flag that keeps track of whether the underlying stream has
been closed or not, so that ChunkedStream.isEndOfInput() does not
propagate the IOException from PushBackInputStream.
Result:
Fixes#3368
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:
For some use cases X509ExtendedTrustManager is needed as it allows to also access the SslEngine during validation.
Modifications:
Add support for X509ExtendedTrustManager on java >= 7
Result:
It's now possible to use X509ExtendedTrustManager with OpenSslEngine
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:
There are new versions of the ALPN and NPN dependencies. There was also some backport misses in the pom file related to ALPN/NPN.
Modifications:
- Add new versions for ALPN/NPN dependencies.
- Backport missed pieces from pom.xml.
Result:
Updated version of ALPN/NPN versions.
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:
Current AbstractMemcacheObjectEncoder does unnecessary message type checking if the message is MemcacheMessage type.
Modifications:
Returns after encoding MemcacheMessage message.
Result:
Small performance improvement for this encoder.
(Ported @luciferous's changes against 3.10)
Motivation:
The current implementation of the encoder writes each character of the
String as a single byte to the buffer, however not all characters are
mappable to a single byte.
Modifications:
If a character is outside the ASCII range, it's converted to '?'.
Result:
A safer encoder for String to ASCII, which substitutes unmappable
characters with'?'.
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:
With the current implementation the client protocol preference list
takes precedence over the one of the server, since the select method
will return the first item, in the client list, that matches any of the
protocols supported by the server. This violates the recommendation of
http://tools.ietf.org/html/rfc7301#section-3.2.
It will also fail with the current implementation of Chrome, which
sends back Extension application_layer_protocol_negotiation, protocols:
[http/1.1, spdy/3.1, h2-14]
Modifications:
Changed the protocol negotiator to prefer server’s list. Added a test
case that demonstrates the issue and that is fixed with the
modifications of this commit.
Result:
Server’s preference list is used.
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:
While the LengthFieldBasedFrameDecoder supports a byte order the LengthFieldPrepender does not.
That means that I can simply add a LengthFieldBasedFrameDecoder with ByteOrder.LITTLE_ENDIAN to my pipeline
but have to write my own Encoder to write length fields in little endian byte order.
Modifications:
Added a constructor that takes a byte order and all other parameters.
All other constructors delegate to this one with ByteOrder.BIG_ENDIAN.
LengthFieldPrepender.encode() uses this byte order to write the length field.
Result:
LengthFieldPrepender will write the length field in the defined byte order.
Motivation:
When an error happens during loading the native library it may try to generate a new RuntimeException before the RuntimeException is loaded.
Modifications:
- Load RuntimeException as first
Result:
No more segfaults possible
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:
When setting nEventLoops to zero in the MultithreadedEventLoopGroup constructor
the EventLoopGroup chooses the number of EventLoops and Threads to use for you.
We want to make use of this behaviour internally and thus we would like to document
it as a part of the official API, so that we can rely on it.
Modifications:
Document the behaviour when setting nEventLoops to zero.
Fix several spelling / sloppiness mistakes in the documentation.
Result:
nEventLoops=0 is now documented as a part of the official API.
The quality of the documentation is improved.
Motivation:
On a system where ipv4 and ipv6 are supported a user may want to use -Djava.net.preferIPv4Stack=true to restrict it to use ipv4 only.
This is currently ignored with the epoll transport.
Modifications:
Respect java.net.preferIPv4Stack system property.
Result:
-Djava.net.preferIPv4Stack=true will have the effect the user is looking for.
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:
When remove0() is called multiple times for an DefaultAttribute it can cause corruption of the internal linked-list structure.
Modifications:
- Ensure remove0() can not cause corruption by null out prev and next references.
Result:
No more corruption possible
Related: #3478
Motivation:
DefaultNameResolver uses InetSocketAddress.getHostString() instead of
getHostName(). Because Netty uses the DefaultNameResolver by default and
getHostString() is available only since Java 7, a user cannot use Netty
on Java 6 anymore.
Modifications:
Use InetSocketAddress.getHostName() which is practically same and also
is available in Java 6.
Result:
Netty 4.1 runs on Java 6 again.
Related: #3476
Motivation:
Some users use TrafficCounter for other uses than we originally
intended, such as implementing their own traffic shaper. In such a
case, a user does not want to specify an AbstractTrafficShapingHandler.
Modifications:
- Add a new constructor that does not require an
AbstractTrafficShapingHandler, so that a user can use it without it.
- Simplify TrafficMonitoringTask
- Javadoc cleanup
Result:
We open the possibility of using TrafficCounter for other purposes than
just using it with AbstractTrafficShapingHandler. Eventually, we could
generalize it a little bit more, so that we can potentially use it for
other uses.
