backport boxed layer improvements ('n' stuff) #2033
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
## Motivation Remove unused dev-dependencies, and update documentation examples to use `std::future`.
... instead of `#[path = ""]` importing it everywhere. Make sure to use a diff review tool that understands file renaming 😅 (GitHub's diff view does.) ## Motivation Transparency: I want to use the mocking functionality in the development of a tracing component out-of-tree. Additionally, this reduces the use of `#[path] mod` and file multiple-inclusion, which aren't that great of a practice. ## Solution The tracing test support module was already well self-contained, due to being `#[path] mod` used in multiple places. As such, extracting it to its own crate is rather mechanical, with no surprising blockers. We additionally move the tracing-futures support module contents into tracing_mock, for convenience. The one function which relies on tokio-test is made optional. It's a reasonable result for this functionality to stay unpublished, and only used inside the repo, but pulling it out into a directly reusable chunk instead of abusing the module system to reuse it via multiple-inclusion is an improvement to code structure and modularization.
## Motivation It took me several reads to understand why holding a guard over an await was bad because my brain is naturally synchronous and could only think about `my_async_function` and `some_other_async_function` ## Solution Rather than just iterating "this is bad" use that opportunity to introduce why. Remind the user that this is being executed concurrently to other tasks Co-authored-by: Eliza Weisman <eliza@buoyant.io>
Currently, there is an `impl<S: Subscriber> Layer for Box<dyn Layer<S> + Send + Sync>` intended to allow type-erasing a subscriber. This change improves the documentation on runtime configuration of layers to include an example of using `Box` to type-erase a layer. Signed-off-by: Eliza Weisman <eliza@buoyant.io>
RustDoc didn't actually parse the link to the `Layer` impl for `Box<dyn Layer<S> + Send + Sync>` because the link URL contained unescaped spaces. Therefore, the link reference was treated as normal text rather than as a link reference. This commit replaces the link ref with the escaped version, which works correctly. My bad!
Depends on #2023 ## Motivation Currently, `FmtLayer` holds a `PhantomData<S>` with the `Subscriber` type it wraps. This is unfortunate because it means that the layer's auto traits such as `Send`, `Sync`, and `'static` (as well as `UnwindSafe`, `Unpin`, etc) depend on the `Subscriber` type's auto traits...but the layer will never actually _store_ a value of type `S`. While all `Subscriber` will be `Send + Sync + 'static` in practice, the `PhantomData` means that functions returning a boxed `FmtLayer` must unnecessarily bound the subscriber type parameter. ## Solution This commit changes the `PhantomData` to `PhantomData<fn(S)>`, solving the problem. Signed-off-by: Eliza Weisman <eliza@buoyant.io>
## Motivation PR #2023 made the `impl Layer` for boxed `dyn Layer` trait objects actually be useful. One minor annoyance when working with boxed trait objects is that, in some cases, in order to use `Box::new` to erase a `Layer`'s type, it's necessary to add a type annotation like this: ```rust let boxed_layer: Box<dyn Layer<_> + Send + Sync + 'static> = Box::new(some_layer); ``` Because the trait object includes `Send + Sync + 'static`, this is a bit wordy to type out. ## Solution This commit adds a `Layer::boxed` method that takes `Self` and boxes it as a type-erased `dyn Layer` trait object. This can then be chained after a a chain of layer builder methods. Because the `boxed` method _explicitly_ returns a `dyn Layer<_> + ...` trait object, it's not necessary to use a wordy type annotation when using this method.
…nsi_term (#2029) ## Motivation EnvFilter with ansi_term will say something like the following when statically disabled filters are present: ``` warning: some trace filter directives would enable traces ... = note: the static max level is `LEVEL` = help: to enable LEVEL logging, ... ``` Without the ansi_term feature, it instead says something like the following: ``` warning: some trace filter directives would enable traces ... note: the static max level is `LEVEL` note: to enable LEVEL logging, ... ``` This is due to a simple error in cfg'd code that ignores the requested prefix and always uses `note:` when `not(feature = "ansi_term")`. ## Solution Use the unused `prefix` variable to do what it does when `feature = "ansi_term"`. The output without ansi_term is now ``` warning: some trace filter directives would enable traces ... note: the static max level is `LEVEL` help: to enable LEVEL logging, ... ```
davidbarsky
approved these changes
Mar 29, 2022
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
this branch backports the following commits to v0.1.x:
EnvFIlter's filter disabled help say help without ansi_term (LetEnvFilter's filter disabled help say "help" without ansi_term #2029)Layer::boxedmethod (subscriber: addSubscribe::boxedmethod #2026)FmtLayer's auto traits inheritingS's (subscriber: makeFmtSubscriber's auto traits not depend onC#2024)Layerimpl forBoxLayers (subscriber: make boxed subscribers not useless #2023)tracing-lokito "Related Crates" section (docs: Addtracing-lokito "Related Crates" section #2012)Note that I did not backport #2028 and #2030, because the the missing methods
they added are not missing on v0.1.x. Also, #2023 was changed to just include the
documentation change, because the
v0.1.ximpl already had correct bounds.