subscriber: add `Subscribe::boxed` method #2026

hawkw · 2022-03-25T20:36:07Z

Motivation

PR #2023 made the impl Subscribe for boxed dyn Subscribe 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 subscriber's type, it's necessary to add a type annotation like
this:

let boxed_subscriber: Box<dyn Subscribe<_> + Send + Sync + 'static>
    = Box::new(some_subscriber);

Because the trait object includes Send + Sync + 'static, this is a bit
wordy to type out.

Solution

This commit adds a Subscribe::boxed method that takes Self and boxes
it as a type-erased dyn Subscribe trait object. This can then be
chained after a a chain of subscriber builder methods. Because the
boxed method explicitly returns a dyn Subscribe + ... trait
object, it's not necessary to use a wordy type annotation when
using this method.

## Motivation PR #2023 made the `impl Subscribe` for boxed `dyn Subscribe` 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 subscriber's type, it's necessary to add a type annotation like this: ```rust let boxed_subscriber: Box<dyn Subscribe<_> + Send + Sync + 'static> = Box::new(some_subscriber); ``` Because the trait object includes `Send + Sync + 'static`, this is a bit wordy to type out. ## Solution This commit adds a `Subscribe::boxed` method that takes `Self` and boxes it as a type-erased `dyn Subscribe` trait object. This can then be chained after a a chain of subscriber builder methods. Because the `boxed` method _explicitly_ returns a `dyn Subscribe + ...` trait object, it's not necessary to use a wordy type annotation when using this method.

## 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.

@TimoFreiberg

# 0.3.10 (Apr 1, 2022) This release adds several new features, including a `Filter` implementation and new builder API for `EnvFilter`, support for using a `Vec<L> where L: Layer` as a `Layer`, and a number of smaller API improvements to make working with dynamic and reloadable layers easier. ### Added - **registry**: Implement `Filter` for `EnvFilter`, allowing it to be used with per-layer filtering ([#1983]) - **registry**: `Filter::on_new_span`, `Filter::on_enter`, `Filter::on_exit`, `Filter::on_close` and `Filter::on_record` callbacks to allow `Filter`s to track span states internally ([#1973], [#2017], [#2031]) - **registry**: `Filtered::filter` and `Filtered::filter_mut` accessors ([#1959]) - **registry**: `Filtered::inner` and `Filtered::inner_mut` accessors to borrow the wrapped `Layer` ([#2034]) - **layer**: Implement `Layer` for `Vec<L: Layer>`, to allow composing together a dynamically sized list of `Layer`s ([#2027]) - **layer**: `Layer::boxed` method to make type-erasing `Layer`s easier ([#2026]) - **fmt**: `fmt::Layer::writer` and `fmt::Layer::writer_mut` accessors ([#2034]) - **fmt**: `fmt::Layer::set_ansi` method to allow changing the ANSI formatting configuration at runtime ([#2034]) - **env-filter**: `EnvFilter::builder` to configure a new `EnvFilter` prior to parsing it ([#2035]) - Several documentation fixes and improvements ([#1972], [#1971], [#2023], [#2023]) ### Fixed - **fmt**: `fmt::Layer`'s auto traits no longer depend on the `Subscriber` type parameter's auto traits ([2025]) - **env-filter**: Fixed missing help text when the `ansi` feature is disabled ([#2029]) Thanks to new contributors @TimoFreiberg and @wagenet, as well as @CAD97 for contributing to this release! [#1983]: #1983 [#1973]: #1973 [#2017]: #2017 [#2031]: #2031 [#1959]: #1959 [#2034]: #2034 [#2027]: #2027 [#2026]: #2026 [#2035]: #2035 [#1972]: #1972 [#1971]: #1971 [#2023]: #2023

@TimoFreiberg

# 0.3.10 (Apr 1, 2022) This release adds several new features, including a `Filter` implementation and new builder API for `EnvFilter`, support for using a `Vec<L> where L: Layer` as a `Layer`, and a number of smaller API improvements to make working with dynamic and reloadable layers easier. ### Added - **registry**: Implement `Filter` for `EnvFilter`, allowing it to be used with per-layer filtering ([#1983]) - **registry**: `Filter::on_new_span`, `Filter::on_enter`, `Filter::on_exit`, `Filter::on_close` and `Filter::on_record` callbacks to allow `Filter`s to track span states internally ([#1973], [#2017], [#2031]) - **registry**: `Filtered::filter` and `Filtered::filter_mut` accessors ([#1959]) - **registry**: `Filtered::inner` and `Filtered::inner_mut` accessors to borrow the wrapped `Layer` ([#2034]) - **layer**: Implement `Layer` for `Vec<L: Layer>`, to allow composing together a dynamically sized list of `Layer`s ([#2027]) - **layer**: `Layer::boxed` method to make type-erasing `Layer`s easier ([#2026]) - **fmt**: `fmt::Layer::writer` and `fmt::Layer::writer_mut` accessors ([#2034]) - **fmt**: `fmt::Layer::set_ansi` method to allow changing the ANSI formatting configuration at runtime ([#2034]) - **env-filter**: `EnvFilter::builder` to configure a new `EnvFilter` prior to parsing it ([#2035]) - Several documentation fixes and improvements ([#1972], [#1971], [#2023], [#2023]) ### Fixed - **fmt**: `fmt::Layer`'s auto traits no longer depend on the `Subscriber` type parameter's auto traits ([2025]) - **env-filter**: Fixed missing help text when the `ansi` feature is disabled ([#2029]) Thanks to new contributors @TimoFreiberg and @wagenet, as well as @CAD97 for contributing to this release! [#1983]: #1983 [#1973]: #1973 [#2017]: #2017 [#2031]: #2031 [#1959]: #1959 [#2034]: #2034 [#2027]: #2027 [#2026]: #2026 [#2035]: #2035 [#1972]: #1972 [#1971]: #1971 [#2023]: #2023

@TimoFreiberg

# 0.3.10 (Apr 1, 2022) This release adds several new features, including a `Filter` implementation and new builder API for `EnvFilter`, support for using a `Vec<L> where L: Layer` as a `Layer`, and a number of smaller API improvements to make working with dynamic and reloadable layers easier. ### Added - **registry**: Implement `Filter` for `EnvFilter`, allowing it to be used with per-layer filtering ([#1983]) - **registry**: `Filter::on_new_span`, `Filter::on_enter`, `Filter::on_exit`, `Filter::on_close` and `Filter::on_record` callbacks to allow `Filter`s to track span states internally ([#1973], [#2017], [#2031]) - **registry**: `Filtered::filter` and `Filtered::filter_mut` accessors ([#1959]) - **registry**: `Filtered::inner` and `Filtered::inner_mut` accessors to borrow the wrapped `Layer` ([#2034]) - **layer**: Implement `Layer` for `Vec<L: Layer>`, to allow composing together a dynamically sized list of `Layer`s ([#2027]) - **layer**: `Layer::boxed` method to make type-erasing `Layer`s easier ([#2026]) - **fmt**: `fmt::Layer::writer` and `fmt::Layer::writer_mut` accessors ([#2034]) - **fmt**: `fmt::Layer::set_ansi` method to allow changing the ANSI formatting configuration at runtime ([#2034]) - **env-filter**: `EnvFilter::builder` to configure a new `EnvFilter` prior to parsing it ([#2035]) - Several documentation fixes and improvements ([#1972], [#1971], [#2023], [#2023]) ### Fixed - **fmt**: `fmt::Layer`'s auto traits no longer depend on the `Subscriber` type parameter's auto traits ([2025]) - **env-filter**: Fixed missing help text when the `ansi` feature is disabled ([#2029]) Thanks to new contributors @TimoFreiberg and @wagenet, as well as @CAD97 for contributing to this release! [#1983]: #1983 [#1973]: #1973 [#2017]: #2017 [#2031]: #2031 [#1959]: #1959 [#2034]: #2034 [#2027]: #2027 [#2026]: #2026 [#2035]: #2035 [#1972]: #1972 [#1971]: #1971 [#2023]: #2023

@TimoFreiberg

# 0.3.10 (Apr 1, 2022) This release adds several new features, including a `Filter` implementation and new builder API for `EnvFilter`, support for using a `Vec<L> where L: Layer` as a `Layer`, and a number of smaller API improvements to make working with dynamic and reloadable layers easier. ### Added - **registry**: Implement `Filter` for `EnvFilter`, allowing it to be used with per-layer filtering ([#1983]) - **registry**: `Filter::on_new_span`, `Filter::on_enter`, `Filter::on_exit`, `Filter::on_close` and `Filter::on_record` callbacks to allow `Filter`s to track span states internally ([#1973], [#2017], [#2031]) - **registry**: `Filtered::filter` and `Filtered::filter_mut` accessors ([#1959]) - **registry**: `Filtered::inner` and `Filtered::inner_mut` accessors to borrow the wrapped `Layer` ([#2034]) - **layer**: Implement `Layer` for `Vec<L: Layer>`, to allow composing together a dynamically sized list of `Layer`s ([#2027]) - **layer**: `Layer::boxed` method to make type-erasing `Layer`s easier ([#2026]) - **fmt**: `fmt::Layer::writer` and `fmt::Layer::writer_mut` accessors ([#2034]) - **fmt**: `fmt::Layer::set_ansi` method to allow changing the ANSI formatting configuration at runtime ([#2034]) - **env-filter**: `EnvFilter::builder` to configure a new `EnvFilter` prior to parsing it ([#2035]) - Several documentation fixes and improvements ([#1972], [#1971], [#2023], [#2023]) ### Fixed - **fmt**: `fmt::Layer`'s auto traits no longer depend on the `Subscriber` type parameter's auto traits ([2025]) - **env-filter**: Fixed missing help text when the `ansi` feature is disabled ([#2029]) Thanks to new contributors @TimoFreiberg and @wagenet, as well as @CAD97 for contributing to this release! [#1983]: #1983 [#1973]: #1973 [#2017]: #2017 [#2031]: #2031 [#1959]: #1959 [#2034]: #2034 [#2027]: #2027 [#2026]: #2026 [#2035]: #2035 [#1972]: #1972 [#1971]: #1971 [#2023]: #2023

@TimoFreiberg

# 0.3.10 (Apr 1, 2022) This release adds several new features, including a `Filter` implementation and new builder API for `EnvFilter`, support for using a `Vec<L> where L: Layer` as a `Layer`, and a number of smaller API improvements to make working with dynamic and reloadable layers easier. ### Added - **registry**: Implement `Filter` for `EnvFilter`, allowing it to be used with per-layer filtering ([#1983]) - **registry**: `Filter::on_new_span`, `Filter::on_enter`, `Filter::on_exit`, `Filter::on_close` and `Filter::on_record` callbacks to allow `Filter`s to track span states internally ([#1973], [#2017], [#2031]) - **registry**: `Filtered::filter` and `Filtered::filter_mut` accessors ([#1959]) - **registry**: `Filtered::inner` and `Filtered::inner_mut` accessors to borrow the wrapped `Layer` ([#2034]) - **layer**: Implement `Layer` for `Vec<L: Layer>`, to allow composing together a dynamically sized list of `Layer`s ([#2027]) - **layer**: `Layer::boxed` method to make type-erasing `Layer`s easier ([#2026]) - **fmt**: `fmt::Layer::writer` and `fmt::Layer::writer_mut` accessors ([#2034]) - **fmt**: `fmt::Layer::set_ansi` method to allow changing the ANSI formatting configuration at runtime ([#2034]) - **env-filter**: `EnvFilter::builder` to configure a new `EnvFilter` prior to parsing it ([#2035]) - Several documentation fixes and improvements ([#1972], [#1971], [#2023], [#2023]) ### Fixed - **fmt**: `fmt::Layer`'s auto traits no longer depend on the `Subscriber` type parameter's auto traits ([#2025]) - **env-filter**: Fixed missing help text when the `ansi` feature is disabled ([#2029]) Thanks to new contributors @TimoFreiberg and @wagenet, as well as @CAD97 for contributing to this release! [#1983]: #1983 [#1973]: #1973 [#2017]: #2017 [#2031]: #2031 [#1959]: #1959 [#2034]: #2034 [#2027]: #2027 [#2026]: #2026 [#2035]: #2035 [#1972]: #1972 [#1971]: #1971 [#2023]: #2023 [#2025]: #2025 [#2029]: #2029

## Motivation PR tokio-rs#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.

@TimoFreiberg

# 0.3.10 (Apr 1, 2022) This release adds several new features, including a `Filter` implementation and new builder API for `EnvFilter`, support for using a `Vec<L> where L: Layer` as a `Layer`, and a number of smaller API improvements to make working with dynamic and reloadable layers easier. ### Added - **registry**: Implement `Filter` for `EnvFilter`, allowing it to be used with per-layer filtering ([tokio-rs#1983]) - **registry**: `Filter::on_new_span`, `Filter::on_enter`, `Filter::on_exit`, `Filter::on_close` and `Filter::on_record` callbacks to allow `Filter`s to track span states internally ([tokio-rs#1973], [tokio-rs#2017], [tokio-rs#2031]) - **registry**: `Filtered::filter` and `Filtered::filter_mut` accessors ([tokio-rs#1959]) - **registry**: `Filtered::inner` and `Filtered::inner_mut` accessors to borrow the wrapped `Layer` ([tokio-rs#2034]) - **layer**: Implement `Layer` for `Vec<L: Layer>`, to allow composing together a dynamically sized list of `Layer`s ([tokio-rs#2027]) - **layer**: `Layer::boxed` method to make type-erasing `Layer`s easier ([tokio-rs#2026]) - **fmt**: `fmt::Layer::writer` and `fmt::Layer::writer_mut` accessors ([tokio-rs#2034]) - **fmt**: `fmt::Layer::set_ansi` method to allow changing the ANSI formatting configuration at runtime ([tokio-rs#2034]) - **env-filter**: `EnvFilter::builder` to configure a new `EnvFilter` prior to parsing it ([tokio-rs#2035]) - Several documentation fixes and improvements ([tokio-rs#1972], [tokio-rs#1971], [tokio-rs#2023], [tokio-rs#2023]) ### Fixed - **fmt**: `fmt::Layer`'s auto traits no longer depend on the `Subscriber` type parameter's auto traits ([tokio-rs#2025]) - **env-filter**: Fixed missing help text when the `ansi` feature is disabled ([tokio-rs#2029]) Thanks to new contributors @TimoFreiberg and @wagenet, as well as @CAD97 for contributing to this release! [tokio-rs#1983]: tokio-rs#1983 [tokio-rs#1973]: tokio-rs#1973 [tokio-rs#2017]: tokio-rs#2017 [tokio-rs#2031]: tokio-rs#2031 [tokio-rs#1959]: tokio-rs#1959 [tokio-rs#2034]: tokio-rs#2034 [tokio-rs#2027]: tokio-rs#2027 [tokio-rs#2026]: tokio-rs#2026 [tokio-rs#2035]: tokio-rs#2035 [tokio-rs#1972]: tokio-rs#1972 [tokio-rs#1971]: tokio-rs#1971 [tokio-rs#2023]: tokio-rs#2023 [tokio-rs#2025]: tokio-rs#2025 [tokio-rs#2029]: tokio-rs#2029

hawkw requested review from davidbarsky and a team as code owners March 25, 2022 20:36

hawkw enabled auto-merge (squash) March 25, 2022 23:27

davidbarsky approved these changes Mar 26, 2022

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hawkw merged commit ba0b940 into master Mar 26, 2022

hawkw deleted the eliza/boxed-combinator branch March 26, 2022 02:07

hawkw mentioned this pull request Mar 29, 2022

backport boxed layer improvements ('n' stuff) #2033

Merged

hawkw mentioned this pull request Apr 1, 2022

subscriber: prepare to release v0.3.10 #2041

Merged

jaudiger mentioned this pull request Apr 5, 2022

Failed to add console layer to tracing subscriber under certain circumstance tokio-rs/console#268

Closed

davidbarsky mentioned this pull request Sep 26, 2023

chore: backport roughly a year's worth of changes #2728

Merged

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subscriber: add `Subscribe::boxed` method #2026

subscriber: add `Subscribe::boxed` method #2026

hawkw commented Mar 25, 2022

subscriber: add Subscribe::boxed method #2026

subscriber: add Subscribe::boxed method #2026

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hawkw commented Mar 25, 2022

Motivation

Solution

subscriber: add `Subscribe::boxed` method #2026

subscriber: add `Subscribe::boxed` method #2026