Previously, `RefCountedPtr<>` and `WeakRefCountedPtr<>` incorrectly allowed
implicit casting of any type to any other type. This hadn't caused a
problem until recently, but now that it has, we need to fix it. I have
fixed this by changing these smart pointer types to allow type
conversions only when the type used is convertible to the type of the
smart pointer. This means that if `Subclass` inherits from `Base`, then
we can set a `RefCountedPtr<BaseClass>` to a value of type
`RefCountedPtr<Subclass>`, but we cannot do the reverse.
We had been (ab)using this bug to make it more convenient to deal with
down-casting in subclasses of ref-counted types. For example, because
`Resolver` inherits from `InternallyRefCounted<Resolver>`, calling
`Ref()` on a subclass of `Resolver` will return `RefCountedPtr<Resolver>`
rather than returning the subclass's type. The ability to implicitly
convert to the subclass type made this a bit easier to deal with. Now
that that ability is gone, we need a different way of dealing with that
problem.
I considered several ways of dealing with this, but none of them are
quite as ergonomic as I would ideally like. For now, I've settled on
requiring callers to explicitly down-cast as needed, although I have
provided some utility functions to make this slightly easier:
- `RefCounted<>`, `InternallyRefCounted<>`, and `DualRefCounted<>` all
provide a templated `RefAsSubclass<>()` method that will return a new
ref as a subclass. The type used with `RefAsSubclass()` must be a
subclass of the type passed to `RefCounted<>`, `InternallyRefCounted<>`,
or `DualRefCounted<>`.
- In addition, `DualRefCounted<>` provides a templated `WeakRefAsSubclass<T>()`
method. This is the same as `RefAsSubclass()`, except that it returns
a weak ref instead of a strong ref.
- In `RefCountedPtr<>`, I have added a new `Ref()` method that takes
debug tracing parameters. This can be used instead of calling `Ref()`
on the underlying object in cases where the caller already has a
`RefCountedPtr<>` and is calling `Ref()` only to specify the debug
tracing parameters. Using this method on `RefCountedPtr<>` is more
ergonomic, because the smart pointer is already using the right
subclass, so no down-casting is needed.
- In `WeakRefCountedPtr<>`, I have added a new `WeakRef()` method that
takes debug tracing parameters. This is the same as the new `Ref()`
method on `RefCountedPtr<>`.
- In both `RefCountedPtr<>` and `WeakRefCountedPtr<>`, I have added a
templated `TakeAsSubclass<>()` method that takes the ref out of the
smart pointer and returns a new smart pointer of the down-casted type.
Just as with the `RefAsSubclass()` method above, the type used with
`TakeAsSubclass()` must be a subclass of the type passed to
`RefCountedPtr<>` or `WeakRefCountedPtr<>`.
Note that I have *not* provided an `AsSubclass<>()` variant of the
`RefIfNonZero()` methods. Those methods are used relatively rarely, so
it's not as important for them to be quite so ergonomic. Callers of
these methods that need to down-cast can use
`RefIfNonZero().TakeAsSubclass<>()`.
PiperOrigin-RevId: 592327447
The support already exists in RefCounted and DualRefcounted, so expose similar API for InternallyRefCounted class
Closes#34869
COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/34869 from anicr7:orphanable_ref_if_nonzero f57c64dc62
PiperOrigin-RevId: 588514955
This adds the directory reloader implementation of the CrlProvider. This
will periodically reload CRL files in a directory per [gRFC
A69](https://github.com/grpc/proposal/pull/382)
Included in this is the following:
* A public API to create the `DirectoryReloaderCrlProvider`
* A basic directory interface in gprpp and platform specific impls for
getting the list of files in a directory (unfortunately prior C++17,
there is no std::filesystem, so we have to have platform specific impls)
* The implementation of `DirectoryReloaderCrlProvider` takes an
event_engine and a directory interface. This allows us to test using the
fuzzing event engine for time mocking, and to implement a test directory
interface so we avoid having to make temporary directories and files in
the tests. This is notably not in `include`, and the
`CreateDirectoryReloaderCrlProvider` is the only way to construct one
from the public API, so we don't expose the event engine and directory
details to the user.
---------
Co-authored-by: gtcooke94 <gtcooke94@users.noreply.github.com>
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Add some basic metrics to work serializer, keep them process wide for
now (though it may be interesting to get these into channelz in the
future).
Collected are:
- time spent running a work serializer when it starts
- time spent actually executing work when the work serializer runs
- number of items executed each run
A high disparity between the first two indicates our dispatching
mechanism is adding large amounts of latency (perhaps due to thread
starvation like effects).
A high value for any of these indicate contention on the serializer.
It's likely a future iteration on these will select different metrics -
I'm not *entirely* sure which will be useful in production analysis yet.
I'm using `std::chrono::steady_clock` here for precision (nanoseconds)
with a compact representation (better than timespec) and a robust &
portable api - I think it's appropriate for metrics, but wouldn't use it
much beyond that at this point.
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---------
Co-authored-by: Mark D. Roth <roth@google.com>
Co-authored-by: markdroth <markdroth@users.noreply.github.com>
Co-authored-by: ctiller <ctiller@users.noreply.github.com>
- add debug-only `WorkSerializer::IsRunningInWorkSerializer()` method
and use it in client_channel to verify that subchannels are destroyed in
the `WorkSerializer`
- note: this mechanism uses `std:🧵:id`, so I had to exclude
work_serializer.cc from the core_banned_constructs check
- fix `WorkSerializer::Run()` to unref the callback before releasing
ownership of the `WorkSerializer`, so that any refs captured by the
`std::function<>` will be released before releasing ownership
- fix the WRR timer callback to hop into the `WorkSerializer` to release
its ref to the picker, since that transitively releases refs to
subchannels
- fix subchannel connectivity state notifications to unref the watcher
inside the `WorkSerializer`, since the watcher often transitively holds
refs to subchannels
The approach of doing a recursive function call to expand the if checks
for known metadata names was tripping up an optimization clang has to
collapse that if/then tree into an optimized tree search over the set of
known strings. By unrolling that loop (with a code generator) we start
to present a pattern that clang *can* recognize, and hopefully get some
more stable and faster code generation as a benefit.
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---------
Co-authored-by: ctiller <ctiller@users.noreply.github.com>
In order to help https://github.com/grpc/grpc/pull/32748, change the
test so that it tells us what the problem is in the logs.
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---------
Co-authored-by: ctiller <ctiller@users.noreply.github.com>
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Co-authored-by: ctiller <ctiller@users.noreply.github.com>
Earlier, we were simply using a 64 bit random number, but the spec
actually calls for UUIDv4.
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This is a big rewrite of global config.
It does a few things, all somewhat intertwined:
1. centralize the list of configuration we have to a yaml file that can
be parsed, and code generated from it
2. add an initialization and a reset stage so that config vars can be
centrally accessed very quickly without the need for caching them
3. makes the syntax more C++ like (less macros!)
4. (optionally) adds absl flags to the OSS build
This first round of changes is intended to keep the system where it is
without major changes. We pick up absl flags to match internal code and
remove one point of deviation - but importantly continue to read from
the environment variables. In doing so we don't force absl flags on our
customers - it's possible to configure grpc without the flags - but
instead allow users that do use absl flags to configure grpc using that
mechanism. Importantly this lets internal customers configure grpc the
same everywhere.
Future changes along this path will be two-fold:
1. Move documentation generation into the code generation step, so that
within the source of truth yaml file we can find all documentation and
data about a configuration knob - eliminating the chance of forgetting
to document something in all the right places.
2. Provide fuzzing over configurations. Currently most config variables
get stashed in static constants across the codebase. To fuzz over these
we'd need a way to reset those cached values between fuzzing rounds,
something that is terrifically difficult right now, but with these
changes should simply be a reset on `ConfigVars`.
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Co-authored-by: ctiller <ctiller@users.noreply.github.com>
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Craig Tiller
ericsalo
Mark D. Roth
Anirudh Ramachandra
Gregory Cooke
Yijie Ma
Romain Geissler @ Amadeus
AJ Heller
Yash Tibrewal
Jan Tattermusch
Esun Kim
Yijie Ma
Alisha Nanda
Vignesh Babu