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This backports PR #991 to v0.1.x. This is primarily necessary for the MSRV bump, since some dependencies no longer compile on Rust 1.40.0. This has already been approved on `master`, in PR #991, so it should be fine to ship. ## Motivation This will avoid breaking CI on new releases of clippy. It also makes the code a little easier to read. ## Solution - Convert `match val { pat => true, _ => false }` to `matches!(val, pat)` - Remove unnecessary closures - Convert `self: &mut Self` to `&mut self` This bumps the MSRV to 1.42.0 for `matches!`. The latest version of rust is 1.46.0, so as per https://github.com/tokio-rs/tracing#supported-rust-versions this is not considered a breaking change. I didn't fix the following warning because the fix was not trivial/needed a decision: ``` warning: you are deriving `Ord` but have implemented `PartialOrd` explicitly --> tracing-subscriber/src/filter/env/field.rs:16:32 | 16 | #[derive(Debug, Eq, PartialEq, Ord)] | ^^^ | = note: `#[warn(clippy::derive_ord_xor_partial_ord)]` on by default note: `PartialOrd` implemented here --> tracing-subscriber/src/filter/env/field.rs:98:1 | 98 | / impl PartialOrd for Match { 99 | | fn partial_cmp(&self, other: &Self) -> Option<Ordering> { 100 | | // Ordering for `Match` directives is based first on _whether_ a value 101 | | // is matched or not. This is semantically meaningful --- we would ... | 121 | | } 122 | | } | |_^ = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#derive_ord_xor_partial_ord ``` As a side note, this found a bug in clippy 😆 https://github.com/rust-lang/rust-clippy/issues/6089
122 lines
4.9 KiB
Markdown
122 lines
4.9 KiB
Markdown
![Tracing — Structured, application-level diagnostics][splash]
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[splash]: https://raw.githubusercontent.com/tokio-rs/tracing/master/assets/splash.svg
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# tracing-core
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Core primitives for application-level tracing.
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[![Crates.io][crates-badge]][crates-url]
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[![Documentation][docs-badge]][docs-url]
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[![Documentation (master)][docs-master-badge]][docs-master-url]
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[![MIT licensed][mit-badge]][mit-url]
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[![Build Status][actions-badge]][actions-url]
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[![Discord chat][discord-badge]][discord-url]
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[Documentation][docs-url] | [Chat][discord-url]
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[crates-badge]: https://img.shields.io/crates/v/tracing-core.svg
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[crates-url]: https://crates.io/crates/tracing-core/0.1.17
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[docs-badge]: https://docs.rs/tracing-core/badge.svg
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[docs-url]: https://docs.rs/tracing-core/0.1.17
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[docs-master-badge]: https://img.shields.io/badge/docs-master-blue
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[docs-master-url]: https://tracing-rs.netlify.com/tracing_core
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[mit-badge]: https://img.shields.io/badge/license-MIT-blue.svg
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[mit-url]: LICENSE
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[actions-badge]: https://github.com/tokio-rs/tracing/workflows/CI/badge.svg
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[actions-url]:https://github.com/tokio-rs/tracing/actions?query=workflow%3ACI
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[discord-badge]: https://img.shields.io/discord/500028886025895936?logo=discord&label=discord&logoColor=white
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[discord-url]: https://discord.gg/EeF3cQw
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## Overview
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[`tracing`] is a framework for instrumenting Rust programs to collect
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structured, event-based diagnostic information. This crate defines the core
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primitives of `tracing`.
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The crate provides:
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* [`span::Id`] identifies a span within the execution of a program.
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* [`Event`] represents a single event within a trace.
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* [`Subscriber`], the trait implemented to collect trace data.
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* [`Metadata`] and [`Callsite`] provide information describing spans and
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events.
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* [`Field`], [`FieldSet`], [`Value`], and [`ValueSet`] represent the
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structured data attached to spans and events.
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* [`Dispatch`] allows spans and events to be dispatched to `Subscriber`s.
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In addition, it defines the global callsite registry and per-thread current
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dispatcher which other components of the tracing system rely on.
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*Compiler support: [requires `rustc` 1.42+][msrv]*
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[msrv]: #supported-rust-versions
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## Usage
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Application authors will typically not use this crate directly. Instead, they
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will use the [`tracing`] crate, which provides a much more fully-featured
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API. However, this crate's API will change very infrequently, so it may be used
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when dependencies must be very stable.
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`Subscriber` implementations may depend on `tracing-core` rather than `tracing`,
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as the additional APIs provided by `tracing` are primarily useful for
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instrumenting libraries and applications, and are generally not necessary for
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`Subscriber` implementations.
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### Crate Feature Flags
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The following crate feature flags are available:
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* `std`: Depend on the Rust standard library (enabled by default).
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`no_std` users may disable this feature with `default-features = false`:
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```toml
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[dependencies]
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tracing-core = { version = "0.1.17", default-features = false }
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```
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**Note**:`tracing-core`'s `no_std` support requires `liballoc`.
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[`tracing`]: ../tracing
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[`span::Id`]: https://docs.rs/tracing-core/0.1.17/tracing_core/span/struct.Id.html
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[`Event`]: https://docs.rs/tracing-core/0.1.17/tracing_core/event/struct.Event.html
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[`Subscriber`]: https://docs.rs/tracing-core/0.1.17/tracing_core/subscriber/trait.Subscriber.html
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[`Metadata`]: https://docs.rs/tracing-core/0.1.17/tracing_core/metadata/struct.Metadata.html
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[`Callsite`]: https://docs.rs/tracing-core/0.1.17/tracing_core/callsite/trait.Callsite.html
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[`Field`]: https://docs.rs/tracing-core/0.1.17/tracing_core/field/struct.Field.html
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[`FieldSet`]: https://docs.rs/tracing-core/0.1.17/tracing_core/field/struct.FieldSet.html
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[`Value`]: https://docs.rs/tracing-core/0.1.17/tracing_core/field/trait.Value.html
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[`ValueSet`]: https://docs.rs/tracing-core/0.1.17/tracing_core/field/struct.ValueSet.html
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[`Dispatch`]: https://docs.rs/tracing-core/0.1.17/tracing_core/dispatcher/struct.Dispatch.html
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## Supported Rust Versions
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Tracing is built against the latest stable release. The minimum supported
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version is 1.42. The current Tracing version is not guaranteed to build on Rust
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versions earlier than the minimum supported version.
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Tracing follows the same compiler support policies as the rest of the Tokio
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project. The current stable Rust compiler and the three most recent minor
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versions before it will always be supported. For example, if the current stable
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compiler version is 1.45, the minimum supported version will not be increased
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past 1.42, three minor versions prior. Increasing the minimum supported compiler
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version is not considered a semver breaking change as long as doing so complies
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with this policy.
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## License
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This project is licensed under the [MIT license](LICENSE).
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### Contribution
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Unless you explicitly state otherwise, any contribution intentionally submitted
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for inclusion in Tokio by you, shall be licensed as MIT, without any additional
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terms or conditions.
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