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//! A `Subscriber` for formatting and logging `tracing` data. //! //! ## Overview //! //! [`tracing`] is a framework for instrumenting Rust programs with context-aware, //! structured, event-based diagnostic information. This crate provides an //! implementation of the [`Subscriber`] trait that records `tracing`'s `Event`s //! and `Span`s by formatting them as text and logging them to stdout. //! //! ## Usage //! //! First, add this to your `Cargo.toml` file: //! //! ```toml //! [dependencies] //! tracing-subscriber = "0.2" //! ``` //! //! *Compiler support: requires rustc 1.39+* //! //! Add the following to your executable to initialize the default subscriber: //! ```rust //! use tracing_subscriber; //! //! tracing_subscriber::fmt::init(); //! ``` //! //! ## Filtering Events with Environment Variables //! //! The default collector installed by `init` enables you to filter events //! at runtime using environment variables (using the [`EnvFilter`]). //! //! The filter syntax is a superset of the [`env_logger`] syntax. //! //! For example: //! - Setting `RUST_LOG=debug` enables all `Span`s and `Event`s //! set to the log level `DEBUG` or higher //! - Setting `RUST_LOG=my_crate=trace` enables `Span`s and `Event`s //! in `my_crate` at all log levels //! //! **Note**: This should **not** be called by libraries. Libraries should use //! [`tracing`] to publish `tracing` `Event`s. //! //! ## Configuration //! //! You can configure a subscriber instead of using the defaults with //! the following functions: //! //! ### Subscriber //! //! The [`FmtSubscriber`] formats and records `tracing` events as line-oriented logs. //! You can create one by calling: //! //! ```rust //! let collector = tracing_subscriber::fmt() //! // ... add configuration //! .finish(); //! ``` //! //! You can find the configuration methods for [`FmtSubscriber`] in //! [`SubscriberBuilder`]. //! //! ### Formatters //! //! The output format used by the layer and subscriber in this module is //! represented by implementing the [`FormatEvent`] trait, and can be //! customized. This module provides a number of formatter implementations: //! //! * [`format::Full`]: The default formatter. This emits human-readable, //! single-line logs for each event that occurs, with the current span context //! displayed before the formatted representation of the event. //! //! For example: //! <pre><font color="#4E9A06"><b> Finished</b></font> dev [unoptimized + debuginfo] target(s) in 1.59s //! <font color="#4E9A06"><b> Running</b></font> `target/debug/examples/fmt` //! <font color="#AAAAAA">Oct 24 12:55:47.814 </font><font color="#4E9A06"> INFO</font> fmt: preparing to shave yaks number_of_yaks=3 //! <font color="#AAAAAA">Oct 24 12:55:47.814 </font><font color="#4E9A06"> INFO</font> <b>shaving_yaks{</b>yaks=3<b>}</b>: fmt::yak_shave: shaving yaks //! <font color="#AAAAAA">Oct 24 12:55:47.814 </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b>yaks=3<b>}</b>:<b>shave{</b>yak=1<b>}</b>: fmt::yak_shave: hello! I'm gonna shave a yak excitement="yay!" //! <font color="#AAAAAA">Oct 24 12:55:47.814 </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b>yaks=3<b>}</b>:<b>shave{</b>yak=1<b>}</b>: fmt::yak_shave: yak shaved successfully //! <font color="#AAAAAA">Oct 24 12:55:47.814 </font><font color="#3465A4">DEBUG</font> <b>shaving_yaks{</b>yaks=3<b>}</b>: yak_events: yak=1 shaved=true //! <font color="#AAAAAA">Oct 24 12:55:47.814 </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b>yaks=3<b>}</b>: fmt::yak_shave: yaks_shaved=1 //! <font color="#AAAAAA">Oct 24 12:55:47.815 </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b>yaks=3<b>}</b>:<b>shave{</b>yak=2<b>}</b>: fmt::yak_shave: hello! I'm gonna shave a yak excitement="yay!" //! <font color="#AAAAAA">Oct 24 12:55:47.815 </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b>yaks=3<b>}</b>:<b>shave{</b>yak=2<b>}</b>: fmt::yak_shave: yak shaved successfully //! <font color="#AAAAAA">Oct 24 12:55:47.815 </font><font color="#3465A4">DEBUG</font> <b>shaving_yaks{</b>yaks=3<b>}</b>: yak_events: yak=2 shaved=true //! <font color="#AAAAAA">Oct 24 12:55:47.815 </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b>yaks=3<b>}</b>: fmt::yak_shave: yaks_shaved=2 //! <font color="#AAAAAA">Oct 24 12:55:47.815 </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b>yaks=3<b>}</b>:<b>shave{</b>yak=3<b>}</b>: fmt::yak_shave: hello! I'm gonna shave a yak excitement="yay!" //! <font color="#AAAAAA">Oct 24 12:55:47.815 </font><font color="#C4A000"> WARN</font> <b>shaving_yaks{</b>yaks=3<b>}</b>:<b>shave{</b>yak=3<b>}</b>: fmt::yak_shave: could not locate yak //! <font color="#AAAAAA">Oct 24 12:55:47.815 </font><font color="#3465A4">DEBUG</font> <b>shaving_yaks{</b>yaks=3<b>}</b>: yak_events: yak=3 shaved=false //! <font color="#AAAAAA">Oct 24 12:55:47.815 </font><font color="#CC0000">ERROR</font> <b>shaving_yaks{</b>yaks=3<b>}</b>: fmt::yak_shave: failed to shave yak yak=3 error=missing yak //! <font color="#AAAAAA">Oct 24 12:55:47.815 </font><font color="#75507B">TRACE</font> <b>shaving_yaks{</b>yaks=3<b>}</b>: fmt::yak_shave: yaks_shaved=2 //! <font color="#AAAAAA">Oct 24 12:55:47.815 </font><font color="#4E9A06"> INFO</font> fmt: yak shaving completed all_yaks_shaved=false //! </pre> //! //! * [`format::Pretty`]: Emits excessively pretty, multi-line logs, optimized //! for human readability. This is primarily intended to be used in local //! development and debugging, or for command-line applications, where //! automated analysis and compact storage of logs is less of a priority than //! readability and visual appeal. //! //! For example: //! <pre><font color="#4E9A06"><b> Finished</b></font> dev [unoptimized + debuginfo] target(s) in 1.61s //! <font color="#4E9A06"><b> Running</b></font> `target/debug/examples/fmt-pretty` //! Oct 24 12:57:29.386 <font color="#4E9A06"><b>fmt_pretty</b></font><font color="#4E9A06">: preparing to shave yaks, </font><font color="#4E9A06"><b>number_of_yaks</b></font><font color="#4E9A06">: 3</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt-pretty.rs:16<font color="#AAAAAA"><i> on</i></font> main //! //! Oct 24 12:57:29.386 <font color="#4E9A06"><b>fmt_pretty::yak_shave</b></font><font color="#4E9A06">: shaving yaks</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:38<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#75507B"><b>fmt_pretty::yak_shave</b></font><font color="#75507B">: hello! I'm gonna shave a yak, </font><font color="#75507B"><b>excitement</b></font><font color="#75507B">: "yay!"</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:14<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shave</b> <font color="#AAAAAA"><i>with</i></font> <b>yak</b>: 1 //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#75507B"><b>fmt_pretty::yak_shave</b></font><font color="#75507B">: yak shaved successfully</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:22<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shave</b> <font color="#AAAAAA"><i>with</i></font> <b>yak</b>: 1 //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#3465A4"><b>yak_events</b></font><font color="#3465A4">: </font><font color="#3465A4"><b>yak</b></font><font color="#3465A4">: 1, </font><font color="#3465A4"><b>shaved</b></font><font color="#3465A4">: true</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:43<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#75507B"><b>fmt_pretty::yak_shave</b></font><font color="#75507B">: </font><font color="#75507B"><b>yaks_shaved</b></font><font color="#75507B">: 1</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:52<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#75507B"><b>fmt_pretty::yak_shave</b></font><font color="#75507B">: hello! I'm gonna shave a yak, </font><font color="#75507B"><b>excitement</b></font><font color="#75507B">: "yay!"</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:14<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shave</b> <font color="#AAAAAA"><i>with</i></font> <b>yak</b>: 2 //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#75507B"><b>fmt_pretty::yak_shave</b></font><font color="#75507B">: yak shaved successfully</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:22<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shave</b> <font color="#AAAAAA"><i>with</i></font> <b>yak</b>: 2 //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#3465A4"><b>yak_events</b></font><font color="#3465A4">: </font><font color="#3465A4"><b>yak</b></font><font color="#3465A4">: 2, </font><font color="#3465A4"><b>shaved</b></font><font color="#3465A4">: true</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:43<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#75507B"><b>fmt_pretty::yak_shave</b></font><font color="#75507B">: </font><font color="#75507B"><b>yaks_shaved</b></font><font color="#75507B">: 2</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:52<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#75507B"><b>fmt_pretty::yak_shave</b></font><font color="#75507B">: hello! I'm gonna shave a yak, </font><font color="#75507B"><b>excitement</b></font><font color="#75507B">: "yay!"</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:14<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shave</b> <font color="#AAAAAA"><i>with</i></font> <b>yak</b>: 3 //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#C4A000"><b>fmt_pretty::yak_shave</b></font><font color="#C4A000">: could not locate yak</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:16<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shave</b> <font color="#AAAAAA"><i>with</i></font> <b>yak</b>: 3 //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#3465A4"><b>yak_events</b></font><font color="#3465A4">: </font><font color="#3465A4"><b>yak</b></font><font color="#3465A4">: 3, </font><font color="#3465A4"><b>shaved</b></font><font color="#3465A4">: false</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:43<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#CC0000"><b>fmt_pretty::yak_shave</b></font><font color="#CC0000">: failed to shave yak, </font><font color="#CC0000"><b>yak</b></font><font color="#CC0000">: 3, </font><font color="#CC0000"><b>error</b></font><font color="#CC0000">: missing yak</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:48<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#75507B"><b>fmt_pretty::yak_shave</b></font><font color="#75507B">: </font><font color="#75507B"><b>yaks_shaved</b></font><font color="#75507B">: 2</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt/yak_shave.rs:52<font color="#AAAAAA"><i> on</i></font> main //! <font color="#AAAAAA"><i>in</i></font> fmt_pretty::yak_shave::<b>shaving_yaks</b> <font color="#AAAAAA"><i>with</i></font> <b>yaks</b>: 3 //! //! Oct 24 12:57:29.387 <font color="#4E9A06"><b>fmt_pretty</b></font><font color="#4E9A06">: yak shaving completed, </font><font color="#4E9A06"><b>all_yaks_shaved</b></font><font color="#4E9A06">: false</font> //! <font color="#AAAAAA"><i>at</i></font> examples/examples/fmt-pretty.rs:19<font color="#AAAAAA"><i> on</i></font> main //! </pre> //! //! * [`format::Json`]: Outputs newline-delimited JSON logs. This is intended //! for production use with systems where structured logs are consumed as JSON //! by analysis and viewing tools. The JSON output, as seen below, is *not* //! optimized for human readability. //! //! For example: //! <pre><font color="#4E9A06"><b> Finished</b></font> dev [unoptimized + debuginfo] target(s) in 1.58s //! <font color="#4E9A06"><b> Running</b></font> `target/debug/examples/fmt-json` //! {"timestamp":"Oct 24 13:00:00.873","level":"INFO","fields":{"message":"preparing to shave yaks","number_of_yaks":3},"target":"fmt_json"} //! {"timestamp":"Oct 24 13:00:00.874","level":"INFO","fields":{"message":"shaving yaks"},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"}]} //! {"timestamp":"Oct 24 13:00:00.874","level":"TRACE","fields":{"message":"hello! I'm gonna shave a yak","excitement":"yay!"},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"},{"yak":"1","name":"shave"}]} //! {"timestamp":"Oct 24 13:00:00.874","level":"TRACE","fields":{"message":"yak shaved successfully"},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"},{"yak":"1","name":"shave"}]} //! {"timestamp":"Oct 24 13:00:00.874","level":"DEBUG","fields":{"yak":1,"shaved":true},"target":"yak_events","spans":[{"yaks":3,"name":"shaving_yaks"}]} //! {"timestamp":"Oct 24 13:00:00.874","level":"TRACE","fields":{"yaks_shaved":1},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"}]} //! {"timestamp":"Oct 24 13:00:00.874","level":"TRACE","fields":{"message":"hello! I'm gonna shave a yak","excitement":"yay!"},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"},{"yak":"2","name":"shave"}]} //! {"timestamp":"Oct 24 13:00:00.874","level":"TRACE","fields":{"message":"yak shaved successfully"},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"},{"yak":"2","name":"shave"}]} //! {"timestamp":"Oct 24 13:00:00.874","level":"DEBUG","fields":{"yak":2,"shaved":true},"target":"yak_events","spans":[{"yaks":3,"name":"shaving_yaks"}]} //! {"timestamp":"Oct 24 13:00:00.874","level":"TRACE","fields":{"yaks_shaved":2},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"}]} //! {"timestamp":"Oct 24 13:00:00.874","level":"TRACE","fields":{"message":"hello! I'm gonna shave a yak","excitement":"yay!"},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"},{"yak":"3","name":"shave"}]} //! {"timestamp":"Oct 24 13:00:00.875","level":"WARN","fields":{"message":"could not locate yak"},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"},{"yak":"3","name":"shave"}]} //! {"timestamp":"Oct 24 13:00:00.875","level":"DEBUG","fields":{"yak":3,"shaved":false},"target":"yak_events","spans":[{"yaks":3,"name":"shaving_yaks"}]} //! {"timestamp":"Oct 24 13:00:00.875","level":"ERROR","fields":{"message":"failed to shave yak","yak":3,"error":"missing yak"},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"}]} //! {"timestamp":"Oct 24 13:00:00.875","level":"TRACE","fields":{"yaks_shaved":2},"target":"fmt_json::yak_shave","spans":[{"yaks":3,"name":"shaving_yaks"}]} //! {"timestamp":"Oct 24 13:00:00.875","level":"INFO","fields":{"message":"yak shaving completed","all_yaks_shaved":false},"target":"fmt_json"} //! </pre> //! //! ### Filters //! //! If you want to filter the `tracing` `Events` based on environment //! variables, you can use the [`EnvFilter`] as follows: //! //! ```rust //! use tracing_subscriber::EnvFilter; //! //! let filter = EnvFilter::from_default_env(); //! ``` //! //! As mentioned above, the [`EnvFilter`] allows `Span`s and `Event`s to //! be filtered at runtime by setting the `RUST_LOG` environment variable. //! //! You can find the other available [`filter`]s in the documentation. //! //! ### Using Your Subscriber //! //! Finally, once you have configured your `Subscriber`, you need to //! configure your executable to use it. //! //! A subscriber can be installed globally using: //! ```rust //! use tracing; //! use tracing_subscriber::FmtSubscriber; //! //! let subscriber = FmtSubscriber::new(); //! //! tracing::subscriber::set_global_default(subscriber) //! .map_err(|_err| eprintln!("Unable to set global default subscriber")); //! // Note this will only fail if you try to set the global default //! // subscriber multiple times //! ``` //! //! ### Composing Layers //! //! Composing an [`EnvFilter`] `Layer` and a [format `Layer`](../fmt/struct.Layer.html): //! //! ```rust //! use tracing_subscriber::{fmt, EnvFilter}; //! use tracing_subscriber::prelude::*; //! //! let fmt_layer = fmt::layer() //! .with_target(false); //! let filter_layer = EnvFilter::try_from_default_env() //! .or_else(|_| EnvFilter::try_new("info")) //! .unwrap(); //! //! tracing_subscriber::registry() //! .with(filter_layer) //! .with(fmt_layer) //! .init(); //! ``` //! //! [`EnvFilter`]: ../filter/struct.EnvFilter.html //! [`env_logger`]: https://docs.rs/env_logger/ //! [`filter`]: ../filter/index.html //! [`SubscriberBuilder`]: ./struct.SubscriberBuilder.html //! [`FmtSubscriber`]: ./struct.Subscriber.html //! [`Subscriber`]: //! https://docs.rs/tracing/latest/tracing/trait.Subscriber.html //! [`tracing`]: https://crates.io/crates/tracing use std::{any::TypeId, error::Error, io}; use tracing_core::{span, subscriber::Interest, Event, Metadata}; mod fmt_layer; pub mod format; pub mod time; pub mod writer; #[allow(deprecated)] pub use fmt_layer::LayerBuilder; pub use fmt_layer::{FmtContext, FormattedFields, Layer}; use crate::layer::Layer as _; use crate::{ filter::LevelFilter, layer, registry::{LookupSpan, Registry}, }; #[doc(inline)] pub use self::{ format::{format, FormatEvent, FormatFields}, time::time, writer::{MakeWriter, TestWriter}, }; /// A `Subscriber` that logs formatted representations of `tracing` events. /// /// This consists of an inner `Formatter` wrapped in a layer that performs filtering. #[derive(Debug)] pub struct Subscriber< N = format::DefaultFields, E = format::Format<format::Full>, F = LevelFilter, W = fn() -> io::Stdout, > { inner: layer::Layered<F, Formatter<N, E, W>>, } /// A `Subscriber` that logs formatted representations of `tracing` events. /// This type only logs formatted events; it does not perform any filtering. pub type Formatter< N = format::DefaultFields, E = format::Format<format::Full>, W = fn() -> io::Stdout, > = layer::Layered<fmt_layer::Layer<Registry, N, E, W>, Registry>; /// Configures and constructs `Subscriber`s. #[derive(Debug)] pub struct SubscriberBuilder< N = format::DefaultFields, E = format::Format<format::Full>, F = LevelFilter, W = fn() -> io::Stdout, > { filter: F, inner: Layer<Registry, N, E, W>, } /// Returns a new [`SubscriberBuilder`] for configuring a [formatting subscriber]. /// /// This is essentially shorthand for [`SubscriberBuilder::default()]`. /// /// # Examples /// /// Using [`init`] to set the default subscriber: /// /// ```rust /// tracing_subscriber::fmt().init(); /// ``` /// /// Configuring the output format: /// /// ```rust /// /// tracing_subscriber::fmt() /// // Configure formatting settings. /// .with_target(false) /// .with_timer(tracing_subscriber::fmt::time::uptime()) /// .with_level(true) /// // Set the collector as the default. /// .init(); /// ``` /// /// [`try_init`] returns an error if the default subscriber could not be set: /// /// ```rust /// use std::error::Error; /// /// fn init_subscriber() -> Result<(), Box<dyn Error + Send + Sync + 'static>> { /// tracing_subscriber::fmt() /// // Configure the collector to emit logs in JSON format. /// .json() /// // Configure the collector to flatten event fields in the output JSON objects. /// .flatten_event(true) /// // Set the collector as the default, returning an error if this fails. /// .try_init()?; /// /// Ok(()) /// } /// ``` /// /// Rather than setting the subscriber as the default, [`finish`] _returns_ the /// constructed subscriber, which may then be passed to other functions: /// /// ```rust /// let subscriber = tracing_subscriber::fmt() /// .with_max_level(tracing::Level::DEBUG) /// .compact() /// .finish(); /// /// tracing::subscriber::with_default(subscriber, || { /// // the subscriber will only be set as the default /// // inside this closure... /// }) /// ``` /// /// [`SubscriberBuilder`]: struct.SubscriberBuilder.html /// [formatting subscriber]: struct.Subscriber.html /// [`SubscriberBuilder::default()`]: struct.SubscriberBuilder.html#method.default /// [`init`]: struct.SubscriberBuilder.html#method.init /// [`try_init`]: struct.SubscriberBuilder.html#method.try_init /// [`finish`]: struct.SubscriberBuilder.html#method.finish pub fn fmt() -> SubscriberBuilder { SubscriberBuilder::default() } /// Returns a new [formatting layer] that can be [composed] with other layers to /// construct a [`Subscriber`]. /// /// This is a shorthand for the equivalent [`Layer::default`] function. /// /// [formatting layer]: struct.Layer.html /// [composed]: ../layer/index.html /// [`Layer::default`]: struct.Layer.html#method.default pub fn layer<S>() -> Layer<S> { Layer::default() } impl Subscriber { /// The maximum [verbosity level] that is enabled by a `Subscriber` by /// default. /// /// This can be overridden with the [`SubscriberBuilder::with_max_level`] method. /// /// [verbosity level]: https://docs.rs/tracing-core/0.1.5/tracing_core/struct.Level.html /// [`SubscriberBuilder::with_max_level`]: struct.SubscriberBuilder.html#method.with_max_level pub const DEFAULT_MAX_LEVEL: LevelFilter = LevelFilter::INFO; /// Returns a new `SubscriberBuilder` for configuring a format subscriber. pub fn builder() -> SubscriberBuilder { SubscriberBuilder::default() } /// Returns a new format subscriber with the default configuration. pub fn new() -> Self { Default::default() } } impl Default for Subscriber { fn default() -> Self { SubscriberBuilder::default().finish() } } // === impl Subscriber === impl<N, E, F, W> tracing_core::Subscriber for Subscriber<N, E, F, W> where N: for<'writer> FormatFields<'writer> + 'static, E: FormatEvent<Registry, N> + 'static, F: layer::Layer<Formatter<N, E, W>> + 'static, W: MakeWriter + 'static, layer::Layered<F, Formatter<N, E, W>>: tracing_core::Subscriber, fmt_layer::Layer<Registry, N, E, W>: layer::Layer<Registry>, { #[inline] fn register_callsite(&self, meta: &'static Metadata<'static>) -> Interest { self.inner.register_callsite(meta) } #[inline] fn enabled(&self, meta: &Metadata<'_>) -> bool { self.inner.enabled(meta) } #[inline] fn new_span(&self, attrs: &span::Attributes<'_>) -> span::Id { self.inner.new_span(attrs) } #[inline] fn record(&self, span: &span::Id, values: &span::Record<'_>) { self.inner.record(span, values) } #[inline] fn record_follows_from(&self, span: &span::Id, follows: &span::Id) { self.inner.record_follows_from(span, follows) } #[inline] fn event(&self, event: &Event<'_>) { self.inner.event(event); } #[inline] fn enter(&self, id: &span::Id) { // TODO: add on_enter hook self.inner.enter(id); } #[inline] fn exit(&self, id: &span::Id) { self.inner.exit(id); } #[inline] fn current_span(&self) -> span::Current { self.inner.current_span() } #[inline] fn clone_span(&self, id: &span::Id) -> span::Id { self.inner.clone_span(id) } #[inline] fn try_close(&self, id: span::Id) -> bool { self.inner.try_close(id) } #[inline] fn max_level_hint(&self) -> Option<tracing_core::LevelFilter> { self.inner.max_level_hint() } unsafe fn downcast_raw(&self, id: TypeId) -> Option<*const ()> { if id == TypeId::of::<Self>() { Some(self as *const Self as *const ()) } else { self.inner.downcast_raw(id) } } } impl<'a, N, E, F, W> LookupSpan<'a> for Subscriber<N, E, F, W> where layer::Layered<F, Formatter<N, E, W>>: LookupSpan<'a>, { type Data = <layer::Layered<F, Formatter<N, E, W>> as LookupSpan<'a>>::Data; fn span_data(&'a self, id: &span::Id) -> Option<Self::Data> { self.inner.span_data(id) } } // ===== impl SubscriberBuilder ===== impl Default for SubscriberBuilder { fn default() -> Self { SubscriberBuilder { filter: Subscriber::DEFAULT_MAX_LEVEL, inner: Default::default(), } } } impl<N, E, F, W> SubscriberBuilder<N, E, F, W> where N: for<'writer> FormatFields<'writer> + 'static, E: FormatEvent<Registry, N> + 'static, W: MakeWriter + 'static, F: layer::Layer<Formatter<N, E, W>> + Send + Sync + 'static, fmt_layer::Layer<Registry, N, E, W>: layer::Layer<Registry> + Send + Sync + 'static, { /// Finish the builder, returning a new `FmtSubscriber`. pub fn finish(self) -> Subscriber<N, E, F, W> { let subscriber = self.inner.with_subscriber(Registry::default()); Subscriber { inner: self.filter.with_subscriber(subscriber), } } /// Install this Subscriber as the global default if one is /// not already set. /// /// If the `tracing-log` feature is enabled, this will also install /// the LogTracer to convert `Log` records into `tracing` `Event`s. /// /// # Errors /// Returns an Error if the initialization was unsuccessful, likely /// because a global subscriber was already installed by another /// call to `try_init`. pub fn try_init(self) -> Result<(), Box<dyn Error + Send + Sync + 'static>> { use crate::util::SubscriberInitExt; self.finish().try_init()?; Ok(()) } /// Install this Subscriber as the global default. /// /// If the `tracing-log` feature is enabled, this will also install /// the LogTracer to convert `Log` records into `tracing` `Event`s. /// /// # Panics /// Panics if the initialization was unsuccessful, likely because a /// global subscriber was already installed by another call to `try_init`. pub fn init(self) { self.try_init() .expect("Unable to install global subscriber") } } impl<N, E, F, W> Into<tracing_core::Dispatch> for SubscriberBuilder<N, E, F, W> where N: for<'writer> FormatFields<'writer> + 'static, E: FormatEvent<Registry, N> + 'static, W: MakeWriter + 'static, F: layer::Layer<Formatter<N, E, W>> + Send + Sync + 'static, fmt_layer::Layer<Registry, N, E, W>: layer::Layer<Registry> + Send + Sync + 'static, { fn into(self) -> tracing_core::Dispatch { tracing_core::Dispatch::new(self.finish()) } } impl<N, L, T, F, W> SubscriberBuilder<N, format::Format<L, T>, F, W> where N: for<'writer> FormatFields<'writer> + 'static, { /// Use the given [`timer`] for log message timestamps. /// /// See [`time`] for the provided timer implementations. /// /// Note that using the `chrono` feature flag enables the /// additional time formatters [`ChronoUtc`] and [`ChronoLocal`]. /// /// [`time`]: ./time/index.html /// [`timer`]: ./time/trait.FormatTime.html /// [`ChronoUtc`]: ./time/struct.ChronoUtc.html /// [`ChronoLocal`]: ./time/struct.ChronoLocal.html pub fn with_timer<T2>(self, timer: T2) -> SubscriberBuilder<N, format::Format<L, T2>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.with_timer(timer), } } /// Do not emit timestamps with log messages. pub fn without_time(self) -> SubscriberBuilder<N, format::Format<L, ()>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.without_time(), } } /// Configures how synthesized events are emitted at points in the [span /// lifecycle][lifecycle]. /// /// The following options are available: /// /// - `FmtSpan::NONE`: No events will be synthesized when spans are /// created, entered, exited, or closed. Data from spans will still be /// included as the context for formatted events. This is the default. /// - `FmtSpan::ACTIVE`: Events will be synthesized when spans are entered /// or exited. /// - `FmtSpan::CLOSE`: An event will be synthesized when a span closes. If /// [timestamps are enabled][time] for this formatter, the generated /// event will contain fields with the span's _busy time_ (the total /// time for which it was entered) and _idle time_ (the total time that /// the span existed but was not entered). /// - `FmtSpan::FULL`: Events will be synthesized whenever a span is /// created, entered, exited, or closed. If timestamps are enabled, the /// close event will contain the span's busy and idle time, as /// described above. /// /// Note that the generated events will only be part of the log output by /// this formatter; they will not be recorded by other `Subscriber`s or by /// `Layer`s added to this subscriber. /// /// [lifecycle]: https://docs.rs/tracing/latest/tracing/span/index.html#the-span-lifecycle /// [time]: #method.without_time pub fn with_span_events(self, kind: format::FmtSpan) -> Self { SubscriberBuilder { filter: self.filter, inner: self.inner.with_span_events(kind), } } /// Enable ANSI encoding for formatted events. #[cfg(feature = "ansi")] #[cfg_attr(docsrs, doc(cfg(feature = "ansi")))] pub fn with_ansi(self, ansi: bool) -> SubscriberBuilder<N, format::Format<L, T>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.with_ansi(ansi), } } /// Sets whether or not an event's target is displayed. pub fn with_target( self, display_target: bool, ) -> SubscriberBuilder<N, format::Format<L, T>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.with_target(display_target), } } /// Sets whether or not an event's level is displayed. pub fn with_level( self, display_level: bool, ) -> SubscriberBuilder<N, format::Format<L, T>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.with_level(display_level), } } /// Sets whether or not the [name] of the current thread is displayed /// when formatting events /// /// [name]: https://doc.rust-lang.org/stable/std/thread/index.html#naming-threads pub fn with_thread_names( self, display_thread_names: bool, ) -> SubscriberBuilder<N, format::Format<L, T>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.with_thread_names(display_thread_names), } } /// Sets whether or not the [thread ID] of the current thread is displayed /// when formatting events /// /// [thread ID]: https://doc.rust-lang.org/stable/std/thread/struct.ThreadId.html pub fn with_thread_ids( self, display_thread_ids: bool, ) -> SubscriberBuilder<N, format::Format<L, T>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.with_thread_ids(display_thread_ids), } } /// Sets the subscriber being built to use a less verbose formatter. /// /// See [`format::Compact`]. pub fn compact(self) -> SubscriberBuilder<N, format::Format<format::Compact, T>, F, W> where N: for<'writer> FormatFields<'writer> + 'static, { SubscriberBuilder { filter: self.filter, inner: self.inner.compact(), } } /// Sets the subscriber being built to use an [excessively pretty, human-readable formatter](crate::fmt::format::Pretty). #[cfg(feature = "ansi")] #[cfg_attr(docsrs, doc(cfg(feature = "ansi")))] pub fn pretty( self, ) -> SubscriberBuilder<format::Pretty, format::Format<format::Pretty, T>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.pretty(), } } /// Sets the subscriber being built to use a JSON formatter. /// /// See [`format::Json`](../fmt/format/struct.Json.html) #[cfg(feature = "json")] #[cfg_attr(docsrs, doc(cfg(feature = "json")))] pub fn json( self, ) -> SubscriberBuilder<format::JsonFields, format::Format<format::Json, T>, F, W> where N: for<'writer> FormatFields<'writer> + 'static, { SubscriberBuilder { filter: self.filter, inner: self.inner.json(), } } } #[cfg(feature = "json")] #[cfg_attr(docsrs, doc(cfg(feature = "json")))] impl<T, F, W> SubscriberBuilder<format::JsonFields, format::Format<format::Json, T>, F, W> { /// Sets the json subscriber being built to flatten event metadata. /// /// See [`format::Json`](../fmt/format/struct.Json.html) pub fn flatten_event( self, flatten_event: bool, ) -> SubscriberBuilder<format::JsonFields, format::Format<format::Json, T>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.flatten_event(flatten_event), } } /// Sets whether or not the JSON subscriber being built will include the current span /// in formatted events. /// /// See [`format::Json`](../fmt/format/struct.Json.html) pub fn with_current_span( self, display_current_span: bool, ) -> SubscriberBuilder<format::JsonFields, format::Format<format::Json, T>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.with_current_span(display_current_span), } } /// Sets whether or not the JSON subscriber being built will include a list (from /// root to leaf) of all currently entered spans in formatted events. /// /// See [`format::Json`](../fmt/format/struct.Json.html) pub fn with_span_list( self, display_span_list: bool, ) -> SubscriberBuilder<format::JsonFields, format::Format<format::Json, T>, F, W> { SubscriberBuilder { filter: self.filter, inner: self.inner.with_span_list(display_span_list), } } } #[cfg(feature = "env-filter")] #[cfg_attr(docsrs, doc(cfg(feature = "env-filter")))] impl<N, E, W> SubscriberBuilder<N, E, crate::EnvFilter, W> where Formatter<N, E, W>: tracing_core::Subscriber + 'static, { /// Configures the subscriber being built to allow filter reloading at /// runtime. pub fn with_filter_reloading( self, ) -> SubscriberBuilder<N, E, crate::reload::Layer<crate::EnvFilter, Formatter<N, E, W>>, W> { let (filter, _) = crate::reload::Layer::new(self.filter); SubscriberBuilder { filter, inner: self.inner, } } } #[cfg(feature = "env-filter")] #[cfg_attr(docsrs, doc(cfg(feature = "env-filter")))] impl<N, E, W> SubscriberBuilder<N, E, crate::reload::Layer<crate::EnvFilter, Formatter<N, E, W>>, W> where Formatter<N, E, W>: tracing_core::Subscriber + 'static, { /// Returns a `Handle` that may be used to reload the constructed subscriber's /// filter. pub fn reload_handle(&self) -> crate::reload::Handle<crate::EnvFilter, Formatter<N, E, W>> { self.filter.handle() } } impl<N, E, F, W> SubscriberBuilder<N, E, F, W> { /// Sets the Visitor that the subscriber being built will use to record /// fields. /// /// For example: /// ```rust /// use tracing_subscriber::fmt::format; /// use tracing_subscriber::prelude::*; /// /// let formatter = /// // Construct a custom formatter for `Debug` fields /// format::debug_fn(|writer, field, value| write!(writer, "{}: {:?}", field, value)) /// // Use the `tracing_subscriber::MakeFmtExt` trait to wrap the /// // formatter so that a delimiter is added between fields. /// .delimited(", "); /// /// let subscriber = tracing_subscriber::fmt() /// .fmt_fields(formatter) /// .finish(); /// # drop(subscriber) /// ``` pub fn fmt_fields<N2>(self, fmt_fields: N2) -> SubscriberBuilder<N2, E, F, W> where N2: for<'writer> FormatFields<'writer> + 'static, { SubscriberBuilder { filter: self.filter, inner: self.inner.fmt_fields(fmt_fields), } } /// Sets the [`EnvFilter`] that the subscriber will use to determine if /// a span or event is enabled. /// /// Note that this method requires the "env-filter" feature flag to be enabled. /// /// If a filter was previously set, or a maximum level was set by the /// [`with_max_level`] method, that value is replaced by the new filter. /// /// # Examples /// /// Setting a filter based on the value of the `RUST_LOG` environment /// variable: /// ```rust /// use tracing_subscriber::{fmt, EnvFilter}; /// /// fmt() /// .with_env_filter(EnvFilter::from_default_env()) /// .init(); /// ``` /// /// Setting a filter based on a pre-set filter directive string: /// ```rust /// use tracing_subscriber::fmt; /// /// fmt() /// .with_env_filter("my_crate=info,my_crate::my_mod=debug,[my_span]=trace") /// .init(); /// ``` /// /// Adding additional directives to a filter constructed from an env var: /// ```rust /// use tracing_subscriber::{fmt, filter::{EnvFilter, LevelFilter}}; /// /// # fn filter() -> Result<(), Box<dyn std::error::Error + Send + Sync + 'static>> { /// let filter = EnvFilter::try_from_env("MY_CUSTOM_FILTER_ENV_VAR")? /// // Set the base level when not matched by other directives to WARN. /// .add_directive(LevelFilter::WARN.into()) /// // Set the max level for `my_crate::my_mod` to DEBUG, overriding /// // any directives parsed from the env variable. /// .add_directive("my_crate::my_mod=debug".parse()?); /// /// fmt() /// .with_env_filter(filter) /// .try_init()?; /// # Ok(())} /// ``` /// [`EnvFilter`]: ../filter/struct.EnvFilter.html /// [`with_max_level`]: #method.with_max_level #[cfg(feature = "env-filter")] #[cfg_attr(docsrs, doc(cfg(feature = "env-filter")))] pub fn with_env_filter( self, filter: impl Into<crate::EnvFilter>, ) -> SubscriberBuilder<N, E, crate::EnvFilter, W> where Formatter<N, E, W>: tracing_core::Subscriber + 'static, { let filter = filter.into(); SubscriberBuilder { filter, inner: self.inner, } } /// Sets the maximum [verbosity level] that will be enabled by the /// subscriber. /// /// If the max level has already been set, or a [`EnvFilter`] was added by /// [`with_filter`], this replaces that configuration with the new /// maximum level. /// /// # Examples /// /// Enable up to the `DEBUG` verbosity level: /// ```rust /// use tracing_subscriber::fmt; /// use tracing::Level; /// /// fmt() /// .with_max_level(Level::DEBUG) /// .init(); /// ``` /// This subscriber won't record any spans or events! /// ```rust /// use tracing_subscriber::{fmt, filter::LevelFilter}; /// /// let subscriber = fmt() /// .with_max_level(LevelFilter::OFF) /// .finish(); /// ``` /// [verbosity level]: https://docs.rs/tracing-core/0.1.5/tracing_core/struct.Level.html /// [`EnvFilter`]: ../filter/struct.EnvFilter.html /// [`with_filter`]: #method.with_filter pub fn with_max_level( self, filter: impl Into<LevelFilter>, ) -> SubscriberBuilder<N, E, LevelFilter, W> { let filter = filter.into(); SubscriberBuilder { filter, inner: self.inner, } } /// Sets the function that the subscriber being built should use to format /// events that occur. pub fn event_format<E2>(self, fmt_event: E2) -> SubscriberBuilder<N, E2, F, W> where E2: FormatEvent<Registry, N> + 'static, N: for<'writer> FormatFields<'writer> + 'static, W: MakeWriter + 'static, { SubscriberBuilder { filter: self.filter, inner: self.inner.event_format(fmt_event), } } /// Sets whether or not spans inherit their parents' field values (disabled /// by default). #[deprecated(since = "0.2.0", note = "this no longer does anything")] pub fn inherit_fields(self, inherit_fields: bool) -> Self { let _ = inherit_fields; self } /// Sets the function that the subscriber being built should use to format /// events that occur. #[deprecated(since = "0.2.0", note = "renamed to `event_format`.")] pub fn on_event<E2>(self, fmt_event: E2) -> SubscriberBuilder<N, E2, F, W> where E2: FormatEvent<Registry, N> + 'static, N: for<'writer> FormatFields<'writer> + 'static, W: MakeWriter + 'static, { self.event_format(fmt_event) } /// Sets the [`MakeWriter`] that the subscriber being built will use to write events. /// /// # Examples /// /// Using `stderr` rather than `stdout`: /// /// ```rust /// use tracing_subscriber::fmt; /// use std::io; /// /// fmt() /// .with_writer(io::stderr) /// .init(); /// ``` /// /// [`MakeWriter`]: trait.MakeWriter.html pub fn with_writer<W2>(self, make_writer: W2) -> SubscriberBuilder<N, E, F, W2> where W2: MakeWriter + 'static, { SubscriberBuilder { filter: self.filter, inner: self.inner.with_writer(make_writer), } } /// Configures the subscriber to support [`libtest`'s output capturing][capturing] when used in /// unit tests. /// /// See [`TestWriter`] for additional details. /// /// # Examples /// /// Using [`TestWriter`] to let `cargo test` capture test output. Note that we do not install it /// globally as it may cause conflicts. /// /// ```rust /// use tracing_subscriber::fmt; /// use tracing::subscriber; /// /// subscriber::set_default( /// fmt() /// .with_test_writer() /// .finish() /// ); /// ``` /// /// [capturing]: /// https://doc.rust-lang.org/book/ch11-02-running-tests.html#showing-function-output /// [`TestWriter`]: writer/struct.TestWriter.html pub fn with_test_writer(self) -> SubscriberBuilder<N, E, F, TestWriter> { SubscriberBuilder { filter: self.filter, inner: self.inner.with_writer(TestWriter::default()), } } } /// Install a global tracing subscriber that listens for events and /// filters based on the value of the [`RUST_LOG` environment variable], /// if one is not already set. /// /// If the `tracing-log` feature is enabled, this will also install /// the [`LogTracer`] to convert `log` records into `tracing` `Event`s. /// /// This is shorthand for /// /// ```rust /// # fn doc() -> Result<(), Box<dyn std::error::Error + Send + Sync + 'static>> { /// tracing_subscriber::fmt().try_init() /// # } /// ``` /// /// /// # Errors /// /// Returns an Error if the initialization was unsuccessful, /// likely because a global subscriber was already installed by another /// call to `try_init`. /// /// [`LogTracer`]: /// https://docs.rs/tracing-log/0.1.0/tracing_log/struct.LogTracer.html /// [`RUST_LOG` environment variable]: /// ../filter/struct.EnvFilter.html#associatedconstant.DEFAULT_ENV pub fn try_init() -> Result<(), Box<dyn Error + Send + Sync + 'static>> { let builder = Subscriber::builder(); #[cfg(feature = "env-filter")] let builder = builder.with_env_filter(crate::EnvFilter::from_default_env()); builder.try_init() } /// Install a global tracing subscriber that listens for events and /// filters based on the value of the [`RUST_LOG` environment variable]. /// /// If the `tracing-log` feature is enabled, this will also install /// the LogTracer to convert `Log` records into `tracing` `Event`s. /// /// This is shorthand for /// /// ```rust /// tracing_subscriber::fmt().init() /// ``` /// /// # Panics /// Panics if the initialization was unsuccessful, likely because a /// global subscriber was already installed by another call to `try_init`. /// /// [`RUST_LOG` environment variable]: /// ../filter/struct.EnvFilter.html#associatedconstant.DEFAULT_ENV pub fn init() { try_init().expect("Unable to install global subscriber") } #[cfg(test)] mod test { use crate::{ filter::LevelFilter, fmt::{ format::{self, Format}, time, writer::MakeWriter, Subscriber, }, }; use std::{ io, sync::{Mutex, MutexGuard, TryLockError}, }; use tracing_core::dispatcher::Dispatch; pub(crate) struct MockWriter<'a> { buf: &'a Mutex<Vec<u8>>, } impl<'a> MockWriter<'a> { pub(crate) fn new(buf: &'a Mutex<Vec<u8>>) -> Self { Self { buf } } pub(crate) fn map_error<Guard>(err: TryLockError<Guard>) -> io::Error { match err { TryLockError::WouldBlock => io::Error::from(io::ErrorKind::WouldBlock), TryLockError::Poisoned(_) => io::Error::from(io::ErrorKind::Other), } } pub(crate) fn buf(&self) -> io::Result<MutexGuard<'a, Vec<u8>>> { self.buf.try_lock().map_err(Self::map_error) } } impl<'a> io::Write for MockWriter<'a> { fn write(&mut self, buf: &[u8]) -> io::Result<usize> { self.buf()?.write(buf) } fn flush(&mut self) -> io::Result<()> { self.buf()?.flush() } } pub(crate) struct MockMakeWriter<'a> { buf: &'a Mutex<Vec<u8>>, } impl<'a> MockMakeWriter<'a> { pub(crate) fn new(buf: &'a Mutex<Vec<u8>>) -> Self { Self { buf } } } impl<'a> MakeWriter for MockMakeWriter<'a> { type Writer = MockWriter<'a>; fn make_writer(&self) -> Self::Writer { MockWriter::new(self.buf) } } #[test] fn impls() { let f = Format::default().with_timer(time::Uptime::default()); let subscriber = Subscriber::builder().event_format(f).finish(); let _dispatch = Dispatch::new(subscriber); let f = format::Format::default(); let subscriber = Subscriber::builder().event_format(f).finish(); let _dispatch = Dispatch::new(subscriber); let f = format::Format::default().compact(); let subscriber = Subscriber::builder().event_format(f).finish(); let _dispatch = Dispatch::new(subscriber); } #[test] fn subscriber_downcasts() { let subscriber = Subscriber::builder().finish(); let dispatch = Dispatch::new(subscriber); assert!(dispatch.downcast_ref::<Subscriber>().is_some()); } #[test] fn subscriber_downcasts_to_parts() { let subscriber = Subscriber::new(); let dispatch = Dispatch::new(subscriber); assert!(dispatch.downcast_ref::<format::DefaultFields>().is_some()); assert!(dispatch.downcast_ref::<LevelFilter>().is_some()); assert!(dispatch.downcast_ref::<format::Format>().is_some()) } #[test] fn is_lookup_span() { fn assert_lookup_span<T: for<'a> crate::registry::LookupSpan<'a>>(_: T) {} let subscriber = Subscriber::new(); assert_lookup_span(subscriber) } }