Motivation:
SwiftNIO periodically drops support for older Swift versions. Now that
5.7 has been released, 5.4 will be dropped.
Modifications:
- Remove 5.4 specific Package.swift and docker-compose
- Update the 5.7 docker-compose to use the released 5.7 and move from
focal (2004) to jammy (2204)
- Remove unused swiftformat from Dockerfile
- Update tools version in syscall wrapper tests to 5.5
- Update docs
Results:
Minimum Swift version is 5.5
Motivation:
The node.js HTTP parser library that we use has been unmaintained for some time. We should move to the maintained replacement, which is llhttp. This patch will update our dependency and bring us over to the new library, as well as make any changes we need.
Modifications:
This patch comes in 4 parts, each contained in a separate commit in the PR.
The first commit drops the existing http_parser code and updates some of the repo state for using llhttp.
The second commit rewrites the update script to bring in llhttp instead of http_parser.
The third runs the actual script. You can skip reviewing this except to sanity check the outcome.
The fourth commit updates the NIO code and the tests to get everything working.
In general the substance of the product modifications was minimal. The logic around keeping track of where we are in the buffer and how upgrades work has changed a bit, so that required some fiddling. I also had to add an error reporting path for the delegates to be able to throw specific errors that llhttp no longer checks for. Finally, I removed two tests that were a little overzealous and that llhttp does not police.
Result:
Back on the supported path.
Motivation
Testing versions of NIO code that involve interfacing with Swift
Concurrency is currently a difficult business. In particular,
EmbeddedChannel is not available in Swift concurrency, making it
difficult to write tests where you fully control the I/O.
To that end, we should provide a variation of EmbeddedChannel that makes
testing these things possible.
Modifications
Provide an implementation of NIOAsyncTestingChannel.
Results
Users can write tests confidently with async/await.
* initial adoption of DocC based documentaiton
motivation: use DocC for docs
change:
* add DocC catalog to NIO target, as the "landing page"
* remove jazzy doc generation script
* add Package.swift with tools-version 5.6 so that DocC can be used, and add a dependency on the DocC plugin
* udpate soundness script
* * add packge.swift files for older vrsions
* adjust waning-as-error and enable-test-discovery to the different permutations
* fixup
* remove jazzy
Co-authored-by: Cory Benfield <lukasa@apple.com>
* Drop support for 5.2 and 5.3
As outlined in a [Swift forums post in November ’21](https://forums.swift.org/t/swiftnio-swift-version-support/53232), SwiftNIO will only support the latest non-patch Swift release and the 2 immediately prior non-patch versions.
In this commit we drop support for Swift 5.2 and 5.3. We update CI for Swift 5.4 to run on bionic instead of focal to ensure that we still test bionic.
* Added Versions paragraph to Security document
* Apply suggestions from code review
Co-authored-by: Cory Benfield <lukasa@apple.com>
Co-authored-by: Cory Benfield <lukasa@apple.com>
We regressed allocs in nightly, probably for a Swift bug. Fixing it is
tracked in #2070, for now we're going to raise the limits so CI isn't
moaning all the time.
### Motivation:
In my previous PR https://github.com/apple/swift-nio/pull/2010, I was able to decrease the allocations for both `scheduleTask` and `execute` by 1 already. Gladly, there are no more allocations left to remove from `execute` now; however, `scheduleTask` still provides a couple of allocations that we can try to get rid of.
### Modifications:
This PR removes two allocations inside `Scheduled` where we were using the passed in `EventLoopPromise` to call the `cancellationTask` once the `EventLoopFuture` of the promise fails. This requires two allocations inside `whenFailure` and inside `_whenComplete`. However, since we are passing the `cancellationTask` to `Scheduled` anyhow and `Scheduled` is also the one that is failing the promise from the `cancel()` method. We can just go ahead and store the `cancellationTask` inside `Scheduled` and call it from the `cancel()` method directly instead of going through the future.
Importantly, here is that the `cancellationTask` is not allowed to retain the `ScheduledTask.task` otherwise we would change the semantics and retain the `ScheduledTask.task` longer than necessary. My previous PR https://github.com/apple/swift-nio/pull/2010, already implemented the work to get rid of the retain from the `cancellationTask` closure. So we are good to go ahead and store the `cancellationTask` inside `Scheduled` now
### Result:
`scheduleTask` requires two fewer allocations
### Motivation:
In my previous PR https://github.com/apple/swift-nio/pull/2009, I added baseline performance and allocation tests around `scheduleTask` and `execute`. After analysing, the various allocations that happen when scheduling a task there were only a few that could be optimized away potentially.
### Modifications:
This PR converts the `ScheduledTask` class to a struct which will reduce the number of allocations for scheduling tasks by 1. The only thing that needs to be worked around when converting to a struct is giving it an identity so that we can implement `Equatable` conformance properly. I explored two options. First, using an `ObjectIdentifier` passed to the init. Second, using an atomic counter per EventLoop. I went with the latter since the former requires an additional allocation in the case of calling `execute`
### Result:
`scheduleTask` and `execute` require one less allocation
### Motivation:
In issue https://github.com/apple/swift-nio/issues/1316, we see a large number of allocations to happen when scheduling tasks. This can definitely be optimized. This PR adds a number of baseline allocation and performance tests for both `scheduleTask` and `execute`. In the next PRs, I am going to try a few optimizations to reduce the number of allocations.
### Modifications:
Added baseline performance and allocation tests for `scheduleTask` and `execute`
Motivation:
In February, @weissi noticed that the nightly builds of Swift could no
longer compile the unit tests. We disabled them at that time and
reported an upstream bug, https://bugs.swift.org/browse/SR-14268. This
is not an ideal situation, but the Swift core team has provided a
workaround we can use to re-enable the tests.
Modifications:
Provide free functions that wrap some specific extension methods that
are called in unit tests, and amend the call sites to use them.
Result:
We can re-enable the nightly tests.
Motivation:
Xcode 13 GM shipped with a Swift overlay for libsystem in macOS that
marked free's first argument as non-nullable. This leads to an awkward
breakage for us, because we're trying to hold a reference to free as a
function pointer, and to do that we had an explicit type annotation.
We'd like to keep NIO compiling in Xcode 13 GM.
Modifications:
- Defined the free function as a thunk that passes through to the
underlying OS free call, but takes its first argument as non-nullable.
Result:
Should compile on the Xcode 13 GM again.
Motivation:
To justify performance changes we need to measure the code being
changed. We believe that `HTTPHeaders.subscript(canonicalForm:)` is a
little slow.
Modifications:
- Add allocation and performance tests for fetching header values in
their canonical form
Results:
More benchmarks!
* Fix doc generation and jazzy version
From: https://github.com/apple/swift-nio-extras/pull/141
motivation: fix ci
changes:
* only install ruby and jazzy on focal since jazzy id not supported onlder versions of ubuntu
* fix doc generations script adjusting it to latest source-kittent syntax
* Always install ruby: we need it for generating a test manifest
Make Swift 5.2 the minimum requirement, dropping support for Swift 5.0 and 5.1.
Motivation:
Whenever we have problems, Swift 5.0 and 5.1 seem to be the culprits. Dropping support for these very old versions will require less maintenance and free up our time to work on new features.
Modifications:
Set the tools version in Package.swift to 5.2
Remove CI configurations for 5.0 and 5.1
Update the various readmes to reflect that this change will be rolled out in NIO 2.30.0
Result:
Swift 5.2 is the minimum version of Swift required to use NIO.
Motivation:
Peter thinks that result-erasing maps should not allocate, and we have
special code paths in the code to try to make Void -> Void maps not
allocate. Sadly, both code paths currently do allocate.
Per our rules for not trying to make optimizations without data, we
should start measuing these closures so we can make optimizations.
Modifications:
- Added an alloc couter test for result-erasing maps.
Result:
Alloc counter test suitable for any fix of #1697.
motivation: update syntax for release images
changes: replace use of "base_image" with "ubuntu_version" and "swift_version" pair, which the intended way to use release images
Motivation:
5.0 is several years old now, and while we still support it there is
beginning to be some conflict with performance optimizations for newer
Swift versions. We should stop counting the allocation counts on this
version now: we no longer care as much about regressions.
Modifications:
- Stop setting alloc counter limits on 5.0
- Remove the script that tries to add them back.
Result:
No longer measure allocs on 5.0
Motivation:
Sometimes it's useful to know the kernel & Swift versions that CI uses.
Modifications:
Print the versions in the soundness check.
Result:
More info.
Co-authored-by: Cory Benfield <lukasa@apple.com>
Motivation:
We alloc quite a lot with our implementations of flatMapThrowing and flatMapErrorThrowing.
While we don't use Futures a lot in NIO itself a lot of our users, depend quite a bit on them. Let's make their code faster.
Modifications:
Create a Promise and use _whenComplete directly instead of going through another flatMap method
Result:
In my testing I see a reduction of 3 allocs per invocation 🎉
Motivation:
With the registration ID refactoring (#1801) we'll now have the third
reimplementation of integer bit packing. Three is one too many, let's
make it generic.
Modifications:
Introduce generic integer bit packing and use it for _UInt56/24.
Result:
- Less bit packing code.
- Will simplify #1801
Motivation:
Due to https://bugs.swift.org/browse/SR-14516 , we sometimes get
allocating (!?) `subscript.read` accessors in the CircularBuffer.first
depending on the `Element` type...
Modifications:
Implement `CircularBuffer.first` instead of inheriting it from
Collection.
Result:
Fewer allocs in some cases.
Motivation:
The Swift compiler can still not compile NIO's tests on main, so I'm
proposing this sad workaround for
https://bugs.swift.org/browse/SR-14268 .
Modifications:
Don't compile (or run) tests on `main` :(
Result:
May get a green tick.
Motivation:
Usually, we add a more or less random number of slack allocations to
make sure the tests don't spuriously fail. This makes it quite costly to
support new Swift versions.
Modifications:
Add a script which can spit you out the right allocation limits
including slack.
Result:
Easier to support new Swift versions
Motivation:
Any version of ChannelHandler removal that does not have a
ChannelHandlerContext already in hand is currently excessively
expensive. This is because it allocates a promise and a callback for
finding the context, despite already having a promise in hand for users
to complete.
We can remove a pair of allocations here by jumping to the event loop
directly and then running our operations synchronously.
Modifications:
- Rewrite removeHandler(name:promise:) and removeHandler(_:promise:) to
jump directly to the event loops and then work synchronously.
Result:
Cheaper code
Motivation:
Allocation counter tests are good, and we aren't measuring this today.
Modifications:
- Wrote some add/remove tests that use different remove functions.
Result:
Better insight into performance.
Motivation:
We recently added a synchronous view of the `ChannelPipline` so that
callers can avoid allocating futures when they know they're on the right
event loop. We also offer convenience APIs to configure the pipeline for
particular use cases, like an HTTP/1 server but we don't have
synchronous versions of these APIs yet. We should have parity
between as synchronous and asyncronous APIs where feasible.
Modifications:
- Add synchronous helpers to configure HTTP1 client and server pipelines
Result:
Callers to synchronously configure HTTP1 client and server pipelines.
Motivation:
We added synchronous pipeline operations to allow the caller to save
allocations when they know they are already on the correct event loop.
However, we missed a trick! In some cases the caller cannot guarantee
they are on the correct event loop and must use an asynchronous method
instead. If that method returns a void future and is called on the event
loop, then we can perform the operation synchronously and return a
cached void future.
Modifications:
- Add API to `EventLoop` for creating a 'completed' future with a
`Result` (similar to `EventLoopPromise.completeWith`)
- Add an equivalent for making completed void futures
- Use these when asynchronously adding handlers and the caller is
already on the right event loop.
Result:
- Fewer allocations on the happiest of happy paths when adding handlers
asynchronously to a pipeline.
* Add synchronous channel options
Motivation:
The functions for getting and setting channel options are currently
asynchronous. This ensures that options are set and retrieved safely.
However, in some cases the caller knows they are on the correct event
loop but still has to pay the cost of allocating a future to either get
or set an option.
Modifications:
- Add a 'NIOSynchronousChannelOptions' protocol for getting and setting
options
- Add a customisation point to 'Channel' to return 'NIOSynchronousChannelOptions'.
- Default implementation returns nil so as to not break API.
- Add implementations for 'EmbeddedChannel' and 'BaseSocketChannel'
- Allocation tests for getting and setting autoRead
Results:
Options can be get and set synchronously.
Motivation:
`ChannelPipeline` is explicitly thread-safe, any of the operations may
be called from outside of the channel's event loop. However, there are
often cases where it is known that the caller be on the right event
loop, and an asynchronous API is unnecessary.
In some cases -- such as when a pipeline is configured dynamically and
handlers are added from the 'channelRead' implementation of one handler
-- it forces the caller to write code that they might not actually need:
such as buffering events which may happen before the future completes.
This is unnecessary complexity when the caller knows that they must
already be on an event loop.
Modifications:
- Add a 'SynchronousOperations' view to the 'ChannelPipeline' which is
available to callers via 'syncOperations'.
- Supported operations include: adding a handler, adding multiple
handlers, retrieving a context via various predicates and retrieving a
handler of a given type.
- Some of the operations in 'ChannelPipeline' were refactored to have an
explicitly synchronous version, asynchronous versions complete their
promise based on the result of these calls.
- Various minor documentation fixes and addition of 'self' where it was
not used explicitly.
Result:
Users can perform synchronous operations on the 'ChannelPipeline' if
they know they are on the right event loop.
Motivation:
After chatting to the Swift perf team, they thought it may be a good
idea to align all functions in our performance tests which may make the
micro benchmarks more stable.
Modifications:
Align all functions/blocks.
Result:
Hopefully more stable micro benchmarks.
George Barnett