Motivation:
If we don't need the scheduled future, then it will be one less complication when we change Netty Future to no longer extend JDK Future.
It would also result in fewer elements in our API.
Modification:
There was only one real use of ScheduledFuture in our code, in Cache.
This has been changed to wrap an ordinary future with a deadline for implementing the Delayed interface.
All other places were effectively overspecifying by relying on ScheduledFuture.
A few places were also specifying JDK Futures - these have been changed to specify Netty Futures.
Result:
Reduced dependency on the ScheduledFuture interfaces.
Motivation:
The need of cascade from a Future to a Promise exists. We should add some default implementation for it.
Modifications:
- Merge PromiseNotifier into Futures
- Add default cascadeTo(...) methods to Future
- Add tests to FuturesTest
- Replace usage of PromiseNotifier with Future.cascadeTo
- Use combination of map(...) and cascadeTo(...) in *Bootstrap to reduce code duplication
Result:
Provide default implementation of cascadeTo.
Motivation:
We should just add `executor()` to the `ChannelOutboundInvoker` interface and override this method in `Channel` to return `EventLoop`.
Modifications:
- Add `executor()` method to `ChannelOutboundInvoker`
- Let `Channel` override this method and return `EventLoop`.
- Adjust all usages of `eventLoop()`
- Add some default implementations
Result:
API cleanup
Motivation:
At the moment the outbound operations of ChannelHandler take a Promise as argument. This Promise needs to be carried forward to the next handler in the pipeline until it hits the transport. This is API choice has a few quirks which we should aim to remove:
- There is a difference between if you add a FutureListener to the Promise or the Future that is returned by the outbound method in terms of the ordering of execution of the listeners. Sometimes we add the listener to the promise while in reality we usually always want to add it to the future to ensure the listerns are executed in the "correct order".
- It is quite easy to "loose" a promise by forgetting to use the right method which also takes a promise
- We have no idea what EventExecutor is used for the passed in Promise which may invalid our assumption of threading.
While changing the method signature of the outbound operations of the ChannelHandler is a good step forward we should also take care of just remove all the methods from ChannelOutboundInvoker (and its sub-types) that take a Promise and just always use the methods that return a Future only.
Modifications:
- Change the signature of the methods that took a Promise to not take one anymore and just return a Future
- Remove all operations for ChannelOutboundInvoker that take a Promise.
- Adjust all code to cope with the API changes
Result:
Cleaner API which is easier to reason about and easier to use.
Motivation:
The generics for the existing futures, promises, and listeners are too complicated.
This complication comes from the existence of `ChannelPromise` and `ChannelFuture`, which forces listeners to care about the particular _type_ of future being listened on.
Modification:
* Add a `FutureContextListener` which can take a context object as an additional argument. This allows our listeners to have the channel piped through to them, so they don't need to rely on the `ChannelFuture.channel()` method.
* Make the `FutureListener`, along with the `FutureContextListener` sibling, the default listener API, retiring the `GenericFutureListener` since we no longer need to abstract over the type of the future.
* Change all uses of `ChannelPromise` to `Promise<Void>`.
* Change all uses of `ChannelFuture` to `Future<Void>`.
* Change all uses of `GenericFutureListener` to either `FutureListener` or `FutureContextListener` as needed.
* Remove `ChannelFutureListener` and `GenericFutureListener`.
* Introduce a `ChannelFutureListeners` enum to house the constants that previously lived in `ChannelFutureListener`. These constants now implement `FutureContextListener` and take the `Channel` as a context.
* Remove `ChannelPromise` and `ChannelFuture` — all usages now rely on the plain `Future` and `Promise` APIs.
* Add static factory methods to `DefaultPromise` that allow us to create promises that are initialised as successful or failed.
* Remove `CompleteFuture`, `SucceededFuture`, `FailedFuture`, `CompleteChannelFuture`, `SucceededChannelFuture`, and `FailedChannelFuture`.
* Remove `ChannelPromiseNotifier`.
Result:
Cleaner generics and more straight forward code.
Motivation:
At the moment all methods in `ChannelHandler` declare `throws Exception` as part of their method signature. While this is fine for methods that handle inbound events it is quite confusing for methods that handle outbound events. This comes due the fact that these methods also take a `ChannelPromise` which actually need to be fullfilled to signal back either success or failure. Define `throws...` for these methods is confusing at best. We should just always require the implementation to use the passed in promise to signal back success or failure. Doing so also clears up semantics in general. Due the fact that we can't "forbid" throwing `RuntimeException` we still need to handle this in some way tho. In this case we should just consider it a "bug" and so log it and close the `Channel` in question. The user should never have an exception "escape" their implementation and just use the promise. This also clears up the ownership of the passed in message etc.
As `flush(ChannelHandlerContext)` and `read(ChannelHandlerContext)` don't take a `ChannelPromise` as argument this also means that these methods can never produce an error. This makes kind of sense as these really are just "signals" for the underlying transports to do something. For `RuntimeException` the same rule is used as for other outbound event handling methods, which is logging and closing the `Channel`.
Motifications:
- Remove `throws Exception` from signature
- Adjust code to not throw and just notify the promise directly
- Adjust unit tests
Result:
Much cleaner API and semantics.
Motivation:
JUnit 5 is more expressive, extensible, and composable in many ways, and it's better able to run tests in parallel.
Modifications:
Use JUnit5 in tests
Result:
Related to https://github.com/netty/netty/issues/10757
Motivation:
HTTP is a plaintext protocol which means that someone may be able
to eavesdrop the data. To prevent this, HTTPS should be used whenever
possible. However, maintaining using https:// in all URLs may be
difficult. The nohttp tool can help here. The tool scans all the files
in a repository and reports where http:// is used.
Modifications:
- Added nohttp (via checkstyle) into the build process.
- Suppressed findings for the websites
that don't support HTTPS or that are not reachable
Result:
- Prevent using HTTP in the future.
- Encourage users to use HTTPS when they follow the links they found in
the code.
Motivation:
In next major version of netty users should use ChannelHandler everywhere. We should ensure we do the same
Modifications:
Replace usage of deprecated classes / interfaces with ChannelHandler
Result:
Use non-deprecated code
Motivation:
Sometimes it is beneficial to be able to set a parent Channel in EmbeddedChannel if the handler that should be tested depend on the parent.
Modifications:
- Add another constructor which allows to specify a parent
- Add unit tests
Result:
Fixes https://github.com/netty/netty/issues/9228.
Motivation
The optimization in #8988 didn't correctly handle the specific case
where the channel hasDisconnect == false, and a
ChannelOutboundHandlerAdapter subclass overrides only the close(ctx,
promise) method without also overriding the disconnect(ctx, promise)
method.
Modifications
Adjust AbstractChannelHandler.disconnect(...) method to divert to
close(...) in !hasDisconnect case before computing target context for
the event.
Result
Fixes#9092
Motivation:
In 42742e233f we already added default methods to Channel*Handler and deprecated the Adapter classes to simplify the class hierarchy. With this change we go even further and merge everything into just ChannelHandler. This simplifies things even more in terms of class-hierarchy.
Modifications:
- Merge ChannelInboundHandler | ChannelOutboundHandler into ChannelHandler
- Adjust code to just use ChannelHandler
- Deprecate old interfaces.
Result:
Cleaner and simpler code in terms of class-hierarchy.
Motivation:
As we now us java8 as minimum java version we can deprecate ChannelInboundHandlerAdapter / ChannelOutboundHandlerAdapter and just move the default implementations into the interfaces. This makes things a bit more flexible for the end-user and also simplifies the class-hierarchy.
Modifications:
- Mark ChannelInboundHandlerAdapter and ChannelOutboundHandlerAdapter as deprecated
- Add default implementations to ChannelInboundHandler / ChannelOutboundHandler
- Refactor our code to not use ChannelInboundHandlerAdapter / ChannelOutboundHandlerAdapter anymore
Result:
Cleanup class-hierarchy and make things a bit more flexible.
Motivation:
We can use lambdas instead of anonymous inner class to improve readablity
Modification:
Replace anonymous inner class with lambda
Result:
Cleaner code that uses Java8 features
Motivation:
We can use the diamond operator these days.
Modification:
Use diamond operator whenever possible.
Result:
More modern code and less boiler-plate.
Motivation:
When a user called ctx.close() and used the EmbeddedChannel we did not correctly run all pending tasks which means channelInactive was never called.
Modifications:
Ensure we run all pending tasks after all operations that may change the Channel state and are part of the Channel.Unsafe impl.
Result:
Fixes [#6894].
Motivation:
Some ChannelOptions must be set before the Channel is really registered to have the desired effect.
Modifications:
Add another constructor argument which allows to not register the EmbeddedChannel to its EventLoop until the user calls register().
Result:
More flexible usage of EmbeddedChannel. Also Fixes [#6968].
the implicit #fireChannelReadComplete() in EmbeddedChannel#writeInbound().
Motivation
We use EmbeddedChannels to implement a ProxyChannel of some sorts that shovels
messages between a source and a destination Channel. The latter are real network
channels (such as Epoll) and they may or may not be managed in a ChannelPool. We
could fuse both ends directly together but the EmbeddedChannel provides a nice
disposable section of a ChannelPipeline that can be used to instrument the messages
that are passing through the proxy portion.
The ideal flow looks abount like this:
source#channelRead() -> proxy#writeOutbound() -> destination#write()
source#channelReadComplete() -> proxy#flushOutbound() -> destination#flush()
destination#channelRead() -> proxy#writeInbound() -> source#write()
destination#channelReadComplete() -> proxy#flushInbound() -> source#flush()
The problem is that #writeOutbound() and #writeInbound() emit surplus #flush()
and #fireChannelReadComplete() events which in turn yield to surplus #flush()
calls on both ends of the pipeline.
Modifications
Introduce a new set of write methods that reain the same sematics as the #write()
method and #flushOutbound() and #flushInbound().
Result
It's possible to implement the above ideal flow.
Fix for EmbeddedChannel#ensureOpen() and Unit Tests for it
Some PR stuff.
Motivation:
The LateListener logic is prone to infinite loops and relies on being processed in the EventExecutor's thread for synchronization, but this EventExecutor may not be constant. An infinite loop can occur if the EventExecutor's execute method does not introduce a context switch in LateListener.run. The EventExecutor can be changed by classes which inherit from DefaultPromise. For example the DefaultChannelPromise will return w/e EventLoop the channel is registered to, but this EventLoop can change (re-registration).
Modifications:
- Remove the LateListener concept and instead use a single Object to maintain the listeners while still preserving notification order
- Make the result member variable an atomic variable so it can be outside the synchronized(this) blocks
- Cleanup/simplify existing state management code
Result:
Fixes https://github.com/netty/netty/issues/5185
Motivation:
We need to ensure we run all pending tasks before doing any flush in writeOutbound(...) to ensure all pending tasks are run first. Also we should remove the assert of the future and just add a listener to it so it is processed later if needed. This is true as a user may schedule a write for later execution.
Modifications:
- Remove assert of future in writeOutbound(...)
- Correctly run pending tasks before doing the flush and also before doing the close of the channel.
- Add unit tests to proof the defect is fixed.
Result:
Correclty handle the situation of delayed writes.
Motivation:
Often the user uses EmbeddedChannel within unit tests where the only "important" thing is to know if any pending messages were in the buffer and then release these.
We should provide methods for this so the user not need to manually loop through these and release.
Modifications:
Add methods to easily handle releasing of messages.
Result:
Less boiler-plate code for the user to write.
Motivation:
At the moment EmbeddedChannel always handle close() and disconnect() the same way which also means that ChannelOutboundHandler.disconnect(...) will never called. We should allow to specify if these are handle different or not to make the use of EmbeddedChannel more flexible.
Modifications:
Add 2 other constructors which allow to specify if disconnect / close are handled the same way or differently.
Result:
More flexible usage of EmbeddedChannel possible.
Motivation:
EmbeddedChannelId#hashCode() and equals() do not behave correctly if an
instance is serialized and then deserialized. Additionally,
EmbeddedChannel does not allow use of any other type of ChannelId, and
EmbeddedChannelId is (mostly) a singleton instance. This creates a
problem for unit tests that construct multiple EmbeddedChannels and
expect each channel to have a unique ID.
Modifications:
EmbeddedChannelId is modified so equals() will return true and
hashCode() will return the same value for any instance of the class.
EmbeddedChannel is modified to allow a ChannelId to be specified when
the channel is constructed. Tests added for both changes.
Result:
EmbeddedChannelId now behaves correctly when deserialized, and
EmbeddedChannels can now have unique IDs.
Motivation:
We missed to run all pending tasks when EmbeddedChannel.close(...) or disconnect(...) was called. Because of this channelInactive(...) / channelUnregistered(...) of the handlers were never called.
Modifications:
Correctly run all pending tasks and cancel all not ready scheduled tasks when close or disconnect was called.
Result:
Correctly run tasks on close / disconnect and have channelInactive(...) / channelUnregistered(...) called.
Motivation:
While cherry-picked 11f9e9084b I changed the EmbeddedChannel implementation to not allow no ChannelHandlers when constructing it.
This was done by mistake.
Modifications:
Revert change and add unit test.
Result:
Restore old behavior.
Motivation:
Currently in EmbeddedChannel we add the ChannelHandlers before the Channel is registered which leads to have the handlerAdded(...) callback
be called from outside the EventLoop and also prevent the user to obtain a reference to the EventLoop in the callback itself.
Modifications:
Delay adding ChannelHandlers until EmbeddedChannel is registered.
Result:
Correctly call handlerAdded(...) after EmbeddedChannel is registered.
Motivation:
At the moment when EmbeddedChannel is used and a ChannelHandler tries to schedule and task it will throw an UnsupportedOperationException. This makes it impossible to test these handlers or even reuse them with EmbeddedChannel.
Modifications:
- Factor out reusable scheduling code into AbstractSchedulingEventExecutor
- Let EmbeddedEventLoop and SingleThreadEventExecutor extend AbstractSchedulingEventExecutor
- add EmbbededChannel.runScheduledPendingTasks() which allows to run all scheduled tasks that are ready
Result:
Embeddedchannel is now usable even with ChannelHandler that try to schedule tasks.
Motivation:
Because of an incorrect logic in teh EmbeddedChannel constructor it is not possible to use EmbeddedChannel with a ChannelInitializer as constructor argument. This is because it adds the internal LastInboundHandler to its ChannelPipeline before it register itself to the EventLoop.
Modifications:
First register self to EventLoop before add LastInboundHandler to the ChannelPipeline.
Result:
It's now possible to use EmbeddedChannel with ChannelInitializer.
Chris Vest
Norman Maurer
Riley Park
Artem Smotrakov
Nick Hill
田欧
kezhenxu94
Nikolay Fedorovskikh
Roger Kapsi
Scott Mitchell
Richard DiCroce
Norman Maurer