diff options
Diffstat (limited to 'vendor/tracing/src')
| -rw-r--r-- | vendor/tracing/src/dispatcher.rs | 145 | ||||
| -rw-r--r-- | vendor/tracing/src/field.rs | 170 | ||||
| -rw-r--r-- | vendor/tracing/src/instrument.rs | 370 | ||||
| -rw-r--r-- | vendor/tracing/src/level_filters.rs | 94 | ||||
| -rw-r--r-- | vendor/tracing/src/lib.rs | 1107 | ||||
| -rw-r--r-- | vendor/tracing/src/macros.rs | 2504 | ||||
| -rw-r--r-- | vendor/tracing/src/span.rs | 1617 | ||||
| -rw-r--r-- | vendor/tracing/src/stdlib.rs | 55 | ||||
| -rw-r--r-- | vendor/tracing/src/subscriber.rs | 68 |
9 files changed, 6130 insertions, 0 deletions
diff --git a/vendor/tracing/src/dispatcher.rs b/vendor/tracing/src/dispatcher.rs new file mode 100644 index 000000000..8817ac033 --- /dev/null +++ b/vendor/tracing/src/dispatcher.rs @@ -0,0 +1,145 @@ +//! Dispatches trace events to [`Subscriber`]s. +//! +//! The _dispatcher_ is the component of the tracing system which is responsible +//! for forwarding trace data from the instrumentation points that generate it +//! to the subscriber that collects it. +//! +//! # Using the Trace Dispatcher +//! +//! Every thread in a program using `tracing` has a _default subscriber_. When +//! events occur, or spans are created, they are dispatched to the thread's +//! current subscriber. +//! +//! ## Setting the Default Subscriber +//! +//! By default, the current subscriber is an empty implementation that does +//! nothing. To use a subscriber implementation, it must be set as the default. +//! There are two methods for doing so: [`with_default`] and +//! [`set_global_default`]. `with_default` sets the default subscriber for the +//! duration of a scope, while `set_global_default` sets a default subscriber +//! for the entire process. +//! +//! To use either of these functions, we must first wrap our subscriber in a +//! [`Dispatch`], a cloneable, type-erased reference to a subscriber. For +//! example: +//! ```rust +//! # pub struct FooSubscriber; +//! # use tracing_core::{ +//! # dispatcher, Event, Metadata, +//! # span::{Attributes, Id, Record} +//! # }; +//! # impl tracing_core::Subscriber for FooSubscriber { +//! # fn new_span(&self, _: &Attributes) -> Id { Id::from_u64(0) } +//! # fn record(&self, _: &Id, _: &Record) {} +//! # fn event(&self, _: &Event) {} +//! # fn record_follows_from(&self, _: &Id, _: &Id) {} +//! # fn enabled(&self, _: &Metadata) -> bool { false } +//! # fn enter(&self, _: &Id) {} +//! # fn exit(&self, _: &Id) {} +//! # } +//! # impl FooSubscriber { fn new() -> Self { FooSubscriber } } +//! use dispatcher::Dispatch; +//! +//! let my_subscriber = FooSubscriber::new(); +//! let my_dispatch = Dispatch::new(my_subscriber); +//! ``` +//! Then, we can use [`with_default`] to set our `Dispatch` as the default for +//! the duration of a block: +//! ```rust +//! # pub struct FooSubscriber; +//! # use tracing_core::{ +//! # dispatcher, Event, Metadata, +//! # span::{Attributes, Id, Record} +//! # }; +//! # impl tracing_core::Subscriber for FooSubscriber { +//! # fn new_span(&self, _: &Attributes) -> Id { Id::from_u64(0) } +//! # fn record(&self, _: &Id, _: &Record) {} +//! # fn event(&self, _: &Event) {} +//! # fn record_follows_from(&self, _: &Id, _: &Id) {} +//! # fn enabled(&self, _: &Metadata) -> bool { false } +//! # fn enter(&self, _: &Id) {} +//! # fn exit(&self, _: &Id) {} +//! # } +//! # impl FooSubscriber { fn new() -> Self { FooSubscriber } } +//! # let my_subscriber = FooSubscriber::new(); +//! # let my_dispatch = dispatcher::Dispatch::new(my_subscriber); +//! // no default subscriber +//! +//! # #[cfg(feature = "std")] +//! dispatcher::with_default(&my_dispatch, || { +//! // my_subscriber is the default +//! }); +//! +//! // no default subscriber again +//! ``` +//! It's important to note that `with_default` will not propagate the current +//! thread's default subscriber to any threads spawned within the `with_default` +//! block. To propagate the default subscriber to new threads, either use +//! `with_default` from the new thread, or use `set_global_default`. +//! +//! As an alternative to `with_default`, we can use [`set_global_default`] to +//! set a `Dispatch` as the default for all threads, for the lifetime of the +//! program. For example: +//! ```rust +//! # pub struct FooSubscriber; +//! # use tracing_core::{ +//! # dispatcher, Event, Metadata, +//! # span::{Attributes, Id, Record} +//! # }; +//! # impl tracing_core::Subscriber for FooSubscriber { +//! # fn new_span(&self, _: &Attributes) -> Id { Id::from_u64(0) } +//! # fn record(&self, _: &Id, _: &Record) {} +//! # fn event(&self, _: &Event) {} +//! # fn record_follows_from(&self, _: &Id, _: &Id) {} +//! # fn enabled(&self, _: &Metadata) -> bool { false } +//! # fn enter(&self, _: &Id) {} +//! # fn exit(&self, _: &Id) {} +//! # } +//! # impl FooSubscriber { fn new() -> Self { FooSubscriber } } +//! # let my_subscriber = FooSubscriber::new(); +//! # let my_dispatch = dispatcher::Dispatch::new(my_subscriber); +//! // no default subscriber +//! +//! dispatcher::set_global_default(my_dispatch) +//! // `set_global_default` will return an error if the global default +//! // subscriber has already been set. +//! .expect("global default was already set!"); +//! +//! // `my_subscriber` is now the default +//! ``` +//! +//! <pre class="ignore" style="white-space:normal;font:inherit;"> +//! <strong>Note</strong>: The thread-local scoped dispatcher (<code>with_default</code>) +//! requires the Rust standard library. <code>no_std</code> users should +//! use <a href="fn.set_global_default.html"><code>set_global_default</code></a> +//! instead. +//! </pre> +//! +//! ## Accessing the Default Subscriber +//! +//! A thread's current default subscriber can be accessed using the +//! [`get_default`] function, which executes a closure with a reference to the +//! currently default `Dispatch`. This is used primarily by `tracing` +//! instrumentation. +//! +//! [`Subscriber`]: crate::Subscriber +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +pub use tracing_core::dispatcher::set_default; +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +pub use tracing_core::dispatcher::with_default; +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +pub use tracing_core::dispatcher::DefaultGuard; +pub use tracing_core::dispatcher::{ + get_default, set_global_default, Dispatch, SetGlobalDefaultError, +}; + +/// Private API for internal use by tracing's macros. +/// +/// This function is *not* considered part of `tracing`'s public API, and has no +/// stability guarantees. If you use it, and it breaks or disappears entirely, +/// don't say we didn;'t warn you. +#[doc(hidden)] +pub use tracing_core::dispatcher::has_been_set; diff --git a/vendor/tracing/src/field.rs b/vendor/tracing/src/field.rs new file mode 100644 index 000000000..b3f9fbdfc --- /dev/null +++ b/vendor/tracing/src/field.rs @@ -0,0 +1,170 @@ +//! `Span` and `Event` key-value data. +//! +//! Spans and events may be annotated with key-value data, referred to as known +//! as _fields_. These fields consist of a mapping from a key (corresponding to +//! a `&str` but represented internally as an array index) to a [`Value`]. +//! +//! # `Value`s and `Subscriber`s +//! +//! `Subscriber`s consume `Value`s as fields attached to [span]s or [`Event`]s. +//! The set of field keys on a given span or is defined on its [`Metadata`]. +//! When a span is created, it provides [`Attributes`] to the `Subscriber`'s +//! [`new_span`] method, containing any fields whose values were provided when +//! the span was created; and may call the `Subscriber`'s [`record`] method +//! with additional [`Record`]s if values are added for more of its fields. +//! Similarly, the [`Event`] type passed to the subscriber's [`event`] method +//! will contain any fields attached to each event. +//! +//! `tracing` represents values as either one of a set of Rust primitives +//! (`i64`, `u64`, `f64`, `bool`, and `&str`) or using a `fmt::Display` or +//! `fmt::Debug` implementation. `Subscriber`s are provided these primitive +//! value types as `dyn Value` trait objects. +//! +//! These trait objects can be formatted using `fmt::Debug`, but may also be +//! recorded as typed data by calling the [`Value::record`] method on these +//! trait objects with a _visitor_ implementing the [`Visit`] trait. This trait +//! represents the behavior used to record values of various types. For example, +//! an implementation of `Visit` might record integers by incrementing counters +//! for their field names rather than printing them. +//! +//! +//! # Using `valuable` +//! +//! `tracing`'s [`Value`] trait is intentionally minimalist: it supports only a small +//! number of Rust primitives as typed values, and only permits recording +//! user-defined types with their [`fmt::Debug`] or [`fmt::Display`] +//! implementations. However, there are some cases where it may be useful to record +//! nested values (such as arrays, `Vec`s, or `HashMap`s containing values), or +//! user-defined `struct` and `enum` types without having to format them as +//! unstructured text. +//! +//! To address `Value`'s limitations, `tracing` offers experimental support for +//! the [`valuable`] crate, which provides object-safe inspection of structured +//! values. User-defined types can implement the [`valuable::Valuable`] trait, +//! and be recorded as a `tracing` field by calling their [`as_value`] method. +//! If the [`Subscriber`] also supports the `valuable` crate, it can +//! then visit those types fields as structured values using `valuable`. +//! +//! <pre class="ignore" style="white-space:normal;font:inherit;"> +//! <strong>Note</strong>: <code>valuable</code> support is an +//! <a href = "../index.html#unstable-features">unstable feature</a>. See +//! the documentation on unstable features for details on how to enable it. +//! </pre> +//! +//! For example: +//! ```ignore +//! // Derive `Valuable` for our types: +//! use valuable::Valuable; +//! +//! #[derive(Clone, Debug, Valuable)] +//! struct User { +//! name: String, +//! age: u32, +//! address: Address, +//! } +//! +//! #[derive(Clone, Debug, Valuable)] +//! struct Address { +//! country: String, +//! city: String, +//! street: String, +//! } +//! +//! let user = User { +//! name: "Arwen Undomiel".to_string(), +//! age: 3000, +//! address: Address { +//! country: "Middle Earth".to_string(), +//! city: "Rivendell".to_string(), +//! street: "leafy lane".to_string(), +//! }, +//! }; +//! +//! // Recording `user` as a `valuable::Value` will allow the `tracing` subscriber +//! // to traverse its fields as a nested, typed structure: +//! tracing::info!(current_user = user.as_value()); +//! ``` +//! +//! Alternatively, the [`valuable()`] function may be used to convert a type +//! implementing [`Valuable`] into a `tracing` field value. +//! +//! When the `valuable` feature is enabled, the [`Visit`] trait will include an +//! optional [`record_value`] method. `Visit` implementations that wish to +//! record `valuable` values can implement this method with custom behavior. +//! If a visitor does not implement `record_value`, the [`valuable::Value`] will +//! be forwarded to the visitor's [`record_debug`] method. +//! +//! [`fmt::Debug`]: std::fmt::Debug +//! [`fmt::Display`]: std::fmt::Debug +//! [`valuable`]: https://crates.io/crates/valuable +//! [`valuable::Valuable`]: https://docs.rs/valuable/latest/valuable/trait.Valuable.html +//! [`as_value`]: https://docs.rs/valuable/latest/valuable/trait.Valuable.html#tymethod.as_value +//! [`valuable::Value`]: https://docs.rs/valuable/latest/valuable/enum.Value.html +//! [`Subscriber`]: crate::Subscriber +//! [`record_value`]: Visit::record_value +//! [`record_debug`]: Visit::record_debug +//! [span]: mod@crate::span +//! [`Event`]: crate::event::Event +//! [`Metadata`]: crate::Metadata +//! [`Attributes`]: crate::span::Attributes +//! [`Record`]: crate::span::Record +//! [`new_span`]: crate::Subscriber::new_span +//! [`record`]: crate::Subscriber::record +//! [`event`]: crate::Subscriber::event +pub use tracing_core::field::*; + +use crate::Metadata; + +/// Trait implemented to allow a type to be used as a field key. +/// +/// <pre class="ignore" style="white-space:normal;font:inherit;"> +/// <strong>Note</strong>: Although this is implemented for both the +/// <a href="./struct.Field.html"><code>Field</code></a> type <em>and</em> any +/// type that can be borrowed as an <code>&str</code>, only <code>Field</code> +/// allows <em>O</em>(1) access. +/// Indexing a field with a string results in an iterative search that performs +/// string comparisons. Thus, if possible, once the key for a field is known, it +/// should be used whenever possible. +/// </pre> +pub trait AsField: crate::sealed::Sealed { + /// Attempts to convert `&self` into a `Field` with the specified `metadata`. + /// + /// If `metadata` defines this field, then the field is returned. Otherwise, + /// this returns `None`. + fn as_field(&self, metadata: &Metadata<'_>) -> Option<Field>; +} + +// ===== impl AsField ===== + +impl AsField for Field { + #[inline] + fn as_field(&self, metadata: &Metadata<'_>) -> Option<Field> { + if self.callsite() == metadata.callsite() { + Some(self.clone()) + } else { + None + } + } +} + +impl<'a> AsField for &'a Field { + #[inline] + fn as_field(&self, metadata: &Metadata<'_>) -> Option<Field> { + if self.callsite() == metadata.callsite() { + Some((*self).clone()) + } else { + None + } + } +} + +impl AsField for str { + #[inline] + fn as_field(&self, metadata: &Metadata<'_>) -> Option<Field> { + metadata.fields().field(&self) + } +} + +impl crate::sealed::Sealed for Field {} +impl<'a> crate::sealed::Sealed for &'a Field {} +impl crate::sealed::Sealed for str {} diff --git a/vendor/tracing/src/instrument.rs b/vendor/tracing/src/instrument.rs new file mode 100644 index 000000000..46e5f579c --- /dev/null +++ b/vendor/tracing/src/instrument.rs @@ -0,0 +1,370 @@ +use crate::stdlib::pin::Pin; +use crate::stdlib::task::{Context, Poll}; +use crate::stdlib::{future::Future, marker::Sized}; +use crate::{ + dispatcher::{self, Dispatch}, + span::Span, +}; +use pin_project_lite::pin_project; + +/// Attaches spans to a [`std::future::Future`]. +/// +/// Extension trait allowing futures to be +/// instrumented with a `tracing` [span]. +/// +/// [span]: super::Span +pub trait Instrument: Sized { + /// Instruments this type with the provided [`Span`], returning an + /// `Instrumented` wrapper. + /// + /// The attached [`Span`] will be [entered] every time the instrumented + /// [`Future`] is polled. + /// + /// # Examples + /// + /// Instrumenting a future: + /// + /// ```rust + /// use tracing::Instrument; + /// + /// # async fn doc() { + /// let my_future = async { + /// // ... + /// }; + /// + /// my_future + /// .instrument(tracing::info_span!("my_future")) + /// .await + /// # } + /// ``` + /// + /// The [`Span::or_current`] combinator can be used in combination with + /// `instrument` to ensure that the [current span] is attached to the + /// future if the span passed to `instrument` is [disabled]: + /// + /// ``` + /// use tracing::Instrument; + /// # mod tokio { + /// # pub(super) fn spawn(_: impl std::future::Future) {} + /// # } + /// + /// let my_future = async { + /// // ... + /// }; + /// + /// let outer_span = tracing::info_span!("outer").entered(); + /// + /// // If the "my_future" span is enabled, then the spawned task will + /// // be within both "my_future" *and* "outer", since "outer" is + /// // "my_future"'s parent. However, if "my_future" is disabled, + /// // the spawned task will *not* be in any span. + /// tokio::spawn( + /// my_future + /// .instrument(tracing::debug_span!("my_future")) + /// ); + /// + /// // Using `Span::or_current` ensures the spawned task is instrumented + /// // with the current span, if the new span passed to `instrument` is + /// // not enabled. This means that if the "my_future" span is disabled, + /// // the spawned task will still be instrumented with the "outer" span: + /// # let my_future = async {}; + /// tokio::spawn( + /// my_future + /// .instrument(tracing::debug_span!("my_future").or_current()) + /// ); + /// ``` + /// + /// [entered]: super::Span::enter() + /// [`Span::or_current`]: super::Span::or_current() + /// [current span]: super::Span::current() + /// [disabled]: super::Span::is_disabled() + /// [`Future`]: std::future::Future + fn instrument(self, span: Span) -> Instrumented<Self> { + Instrumented { inner: self, span } + } + + /// Instruments this type with the [current] [`Span`], returning an + /// `Instrumented` wrapper. + /// + /// The attached [`Span`] will be [entered] every time the instrumented + /// [`Future`] is polled. + /// + /// This can be used to propagate the current span when spawning a new future. + /// + /// # Examples + /// + /// ```rust + /// use tracing::Instrument; + /// + /// # mod tokio { + /// # pub(super) fn spawn(_: impl std::future::Future) {} + /// # } + /// # async fn doc() { + /// let span = tracing::info_span!("my_span"); + /// let _enter = span.enter(); + /// + /// // ... + /// + /// let future = async { + /// tracing::debug!("this event will occur inside `my_span`"); + /// // ... + /// }; + /// tokio::spawn(future.in_current_span()); + /// # } + /// ``` + /// + /// [current]: super::Span::current() + /// [entered]: super::Span::enter() + /// [`Span`]: crate::Span + /// [`Future`]: std::future::Future + #[inline] + fn in_current_span(self) -> Instrumented<Self> { + self.instrument(Span::current()) + } +} + +/// Extension trait allowing futures to be instrumented with +/// a `tracing` [`Subscriber`](crate::Subscriber). +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +pub trait WithSubscriber: Sized { + /// Attaches the provided [`Subscriber`] to this type, returning a + /// [`WithDispatch`] wrapper. + /// + /// The attached [`Subscriber`] will be set as the [default] when the returned + /// [`Future`] is polled. + /// + /// # Examples + /// + /// ``` + /// # use tracing::subscriber::NoSubscriber as MySubscriber; + /// # use tracing::subscriber::NoSubscriber as MyOtherSubscriber; + /// # async fn docs() { + /// use tracing::instrument::WithSubscriber; + /// + /// // Set the default `Subscriber` + /// let _default = tracing::subscriber::set_default(MySubscriber::default()); + /// + /// tracing::info!("this event will be recorded by the default `Subscriber`"); + /// + /// // Create a different `Subscriber` and attach it to a future. + /// let other_subscriber = MyOtherSubscriber::default(); + /// let future = async { + /// tracing::info!("this event will be recorded by the other `Subscriber`"); + /// // ... + /// }; + /// + /// future + /// // Attach the other `Subscriber` to the future before awaiting it + /// .with_subscriber(other_subscriber) + /// .await; + /// + /// // Once the future has completed, we return to the default `Subscriber`. + /// tracing::info!("this event will be recorded by the default `Subscriber`"); + /// # } + /// ``` + /// + /// [`Subscriber`]: super::Subscriber + /// [default]: crate::dispatcher#setting-the-default-subscriber + /// [`Future`]: std::future::Future + fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> + where + S: Into<Dispatch>, + { + WithDispatch { + inner: self, + dispatcher: subscriber.into(), + } + } + + /// Attaches the current [default] [`Subscriber`] to this type, returning a + /// [`WithDispatch`] wrapper. + /// + /// The attached `Subscriber` will be set as the [default] when the returned + /// [`Future`] is polled. + /// + /// This can be used to propagate the current dispatcher context when + /// spawning a new future that may run on a different thread. + /// + /// # Examples + /// + /// ``` + /// # mod tokio { + /// # pub(super) fn spawn(_: impl std::future::Future) {} + /// # } + /// # use tracing::subscriber::NoSubscriber as MySubscriber; + /// # async fn docs() { + /// use tracing::instrument::WithSubscriber; + /// + /// // Using `set_default` (rather than `set_global_default`) sets the + /// // default `Subscriber` for *this* thread only. + /// let _default = tracing::subscriber::set_default(MySubscriber::default()); + /// + /// let future = async { + /// // ... + /// }; + /// + /// // If a multi-threaded async runtime is in use, this spawned task may + /// // run on a different thread, in a different default `Subscriber`'s context. + /// tokio::spawn(future); + /// + /// // However, calling `with_current_subscriber` on the future before + /// // spawning it, ensures that the current thread's default `Subscriber` is + /// // propagated to the spawned task, regardless of where it executes: + /// # let future = async { }; + /// tokio::spawn(future.with_current_subscriber()); + /// # } + /// ``` + /// [`Subscriber`]: super::Subscriber + /// [default]: crate::dispatcher#setting-the-default-subscriber + /// [`Future`]: std::future::Future + #[inline] + fn with_current_subscriber(self) -> WithDispatch<Self> { + WithDispatch { + inner: self, + dispatcher: crate::dispatcher::get_default(|default| default.clone()), + } + } +} + +pin_project! { + /// A [`Future`] that has been instrumented with a `tracing` [`Subscriber`]. + /// + /// This type is returned by the [`WithSubscriber`] extension trait. See that + /// trait's documentation for details. + /// + /// [`Future`]: std::future::Future + /// [`Subscriber`]: crate::Subscriber + #[derive(Clone, Debug)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + #[cfg_attr(docsrs, doc(cfg(feature = "std")))] + pub struct WithDispatch<T> { + #[pin] + inner: T, + dispatcher: Dispatch, + } +} + +pin_project! { + /// A [`Future`] that has been instrumented with a `tracing` [`Span`]. + /// + /// This type is returned by the [`Instrument`] extension trait. See that + /// trait's documentation for details. + /// + /// [`Future`]: std::future::Future + /// [`Span`]: crate::Span + #[derive(Debug, Clone)] + #[must_use = "futures do nothing unless you `.await` or poll them"] + pub struct Instrumented<T> { + #[pin] + inner: T, + span: Span, + } +} + +// === impl Instrumented === + +impl<T: Future> Future for Instrumented<T> { + type Output = T::Output; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = self.project(); + let _enter = this.span.enter(); + this.inner.poll(cx) + } +} + +impl<T: Sized> Instrument for T {} + +impl<T> Instrumented<T> { + /// Borrows the `Span` that this type is instrumented by. + pub fn span(&self) -> &Span { + &self.span + } + + /// Mutably borrows the `Span` that this type is instrumented by. + pub fn span_mut(&mut self) -> &mut Span { + &mut self.span + } + + /// Borrows the wrapped type. + pub fn inner(&self) -> &T { + &self.inner + } + + /// Mutably borrows the wrapped type. + pub fn inner_mut(&mut self) -> &mut T { + &mut self.inner + } + + /// Get a pinned reference to the wrapped type. + pub fn inner_pin_ref(self: Pin<&Self>) -> Pin<&T> { + self.project_ref().inner + } + + /// Get a pinned mutable reference to the wrapped type. + pub fn inner_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T> { + self.project().inner + } + + /// Consumes the `Instrumented`, returning the wrapped type. + /// + /// Note that this drops the span. + pub fn into_inner(self) -> T { + self.inner + } +} + +// === impl WithDispatch === + +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +impl<T: Future> Future for WithDispatch<T> { + type Output = T::Output; + + fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let this = self.project(); + let dispatcher = this.dispatcher; + let future = this.inner; + let _default = dispatcher::set_default(dispatcher); + future.poll(cx) + } +} + +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +impl<T: Sized> WithSubscriber for T {} + +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +impl<T> WithDispatch<T> { + /// Borrows the [`Dispatch`] that is entered when this type is polled. + pub fn dispatcher(&self) -> &Dispatch { + &self.dispatcher + } + + /// Borrows the wrapped type. + pub fn inner(&self) -> &T { + &self.inner + } + + /// Mutably borrows the wrapped type. + pub fn inner_mut(&mut self) -> &mut T { + &mut self.inner + } + + /// Get a pinned reference to the wrapped type. + pub fn inner_pin_ref(self: Pin<&Self>) -> Pin<&T> { + self.project_ref().inner + } + + /// Get a pinned mutable reference to the wrapped type. + pub fn inner_pin_mut(self: Pin<&mut Self>) -> Pin<&mut T> { + self.project().inner + } + + /// Consumes the `Instrumented`, returning the wrapped type. + /// + /// Note that this drops the span. + pub fn into_inner(self) -> T { + self.inner + } +} diff --git a/vendor/tracing/src/level_filters.rs b/vendor/tracing/src/level_filters.rs new file mode 100644 index 000000000..44f5e5f57 --- /dev/null +++ b/vendor/tracing/src/level_filters.rs @@ -0,0 +1,94 @@ +//! Trace verbosity level filtering. +//! +//! # Compile time filters +//! +//! Trace verbosity levels can be statically disabled at compile time via Cargo +//! features, similar to the [`log` crate]. Trace instrumentation at disabled +//! levels will be skipped and will not even be present in the resulting binary +//! unless the verbosity level is specified dynamically. This level is +//! configured separately for release and debug builds. The features are: +//! +//! * `max_level_off` +//! * `max_level_error` +//! * `max_level_warn` +//! * `max_level_info` +//! * `max_level_debug` +//! * `max_level_trace` +//! * `release_max_level_off` +//! * `release_max_level_error` +//! * `release_max_level_warn` +//! * `release_max_level_info` +//! * `release_max_level_debug` +//! * `release_max_level_trace` +//! +//! These features control the value of the `STATIC_MAX_LEVEL` constant. The +//! instrumentation macros macros check this value before recording an event or +//! constructing a span. By default, no levels are disabled. +//! +//! For example, a crate can disable trace level instrumentation in debug builds +//! and trace, debug, and info level instrumentation in release builds with the +//! following configuration: +//! +//! ```toml +//! [dependencies] +//! tracing = { version = "0.1", features = ["max_level_debug", "release_max_level_warn"] } +//! ``` +//! ## Notes +//! +//! Please note that `tracing`'s static max level features do *not* control the +//! [`log`] records that may be emitted when [`tracing`'s "log" feature flag][f] is +//! enabled. This is to allow `tracing` to be disabled entirely at compile time +//! while still emitting `log` records --- such as when a library using +//! `tracing` is used by an application using `log` that doesn't want to +//! generate any `tracing`-related code, but does want to collect `log` records. +//! +//! This means that if the "log" feature is in use, some code may be generated +//! for `log` records emitted by disabled `tracing` events. If this is not +//! desirable, `log` records may be disabled separately using [`log`'s static +//! max level features][`log` crate]. +//! +//! [`log`]: https://docs.rs/log/ +//! [`log` crate]: https://docs.rs/log/latest/log/#compile-time-filters +//! [f]: https://docs.rs/tracing/latest/tracing/#emitting-log-records +pub use tracing_core::{metadata::ParseLevelFilterError, LevelFilter}; + +/// The statically configured maximum trace level. +/// +/// See the [module-level documentation] for information on how to configure +/// this. +/// +/// This value is checked by the `event!` and `span!` macros. Code that +/// manually constructs events or spans via the `Event::record` function or +/// `Span` constructors should compare the level against this value to +/// determine if those spans or events are enabled. +/// +/// [module-level documentation]: super#compile-time-filters +pub const STATIC_MAX_LEVEL: LevelFilter = MAX_LEVEL; + +cfg_if::cfg_if! { + if #[cfg(all(not(debug_assertions), feature = "release_max_level_off"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::OFF; + } else if #[cfg(all(not(debug_assertions), feature = "release_max_level_error"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::ERROR; + } else if #[cfg(all(not(debug_assertions), feature = "release_max_level_warn"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::WARN; + } else if #[cfg(all(not(debug_assertions), feature = "release_max_level_info"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::INFO; + } else if #[cfg(all(not(debug_assertions), feature = "release_max_level_debug"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::DEBUG; + } else if #[cfg(all(not(debug_assertions), feature = "release_max_level_trace"))] { + const MAX_LEVEL: LevelFilter = LevelFilter::TRACE; + } else if #[cfg(feature = "max_level_off")] { + const MAX_LEVEL: LevelFilter = LevelFilter::OFF; + } else if #[cfg(feature = "max_level_error")] { + const MAX_LEVEL: LevelFilter = LevelFilter::ERROR; + } else if #[cfg(feature = "max_level_warn")] { + const MAX_LEVEL: LevelFilter = LevelFilter::WARN; + } else if #[cfg(feature = "max_level_info")] { + const MAX_LEVEL: LevelFilter = LevelFilter::INFO; + } else if #[cfg(feature = "max_level_debug")] { + const MAX_LEVEL: LevelFilter = LevelFilter::DEBUG; + } else { + const MAX_LEVEL: LevelFilter = LevelFilter::TRACE; + } +} diff --git a/vendor/tracing/src/lib.rs b/vendor/tracing/src/lib.rs new file mode 100644 index 000000000..4743eba20 --- /dev/null +++ b/vendor/tracing/src/lib.rs @@ -0,0 +1,1107 @@ +//! A scoped, structured logging and diagnostics system. +//! +//! # Overview +//! +//! `tracing` is a framework for instrumenting Rust programs to collect +//! structured, event-based diagnostic information. +//! +//! In asynchronous systems like Tokio, interpreting traditional log messages can +//! often be quite challenging. Since individual tasks are multiplexed on the same +//! thread, associated events and log lines are intermixed making it difficult to +//! trace the logic flow. `tracing` expands upon logging-style diagnostics by +//! allowing libraries and applications to record structured events with additional +//! information about *temporality* and *causality* — unlike a log message, a span +//! in `tracing` has a beginning and end time, may be entered and exited by the +//! flow of execution, and may exist within a nested tree of similar spans. In +//! addition, `tracing` spans are *structured*, with the ability to record typed +//! data as well as textual messages. +//! +//! The `tracing` crate provides the APIs necessary for instrumenting libraries +//! and applications to emit trace data. +//! +//! *Compiler support: [requires `rustc` 1.49+][msrv]* +//! +//! [msrv]: #supported-rust-versions +//! # Core Concepts +//! +//! The core of `tracing`'s API is composed of _spans_, _events_ and +//! _subscribers_. We'll cover these in turn. +//! +//! ## Spans +//! +//! To record the flow of execution through a program, `tracing` introduces the +//! concept of [spans]. Unlike a log line that represents a _moment in +//! time_, a span represents a _period of time_ with a beginning and an end. When a +//! program begins executing in a context or performing a unit of work, it +//! _enters_ that context's span, and when it stops executing in that context, +//! it _exits_ the span. The span in which a thread is currently executing is +//! referred to as that thread's _current_ span. +//! +//! For example: +//! ``` +//! use tracing::{span, Level}; +//! # fn main() { +//! let span = span!(Level::TRACE, "my_span"); +//! // `enter` returns a RAII guard which, when dropped, exits the span. this +//! // indicates that we are in the span for the current lexical scope. +//! let _enter = span.enter(); +//! // perform some work in the context of `my_span`... +//! # } +//!``` +//! +//! The [`span` module][span]'s documentation provides further details on how to +//! use spans. +//! +//! <div class="example-wrap" style="display:inline-block"><pre class="compile_fail" style="white-space:normal;font:inherit;"> +//! +//! **Warning**: In asynchronous code that uses async/await syntax, +//! `Span::enter` may produce incorrect traces if the returned drop +//! guard is held across an await point. See +//! [the method documentation][Span#in-asynchronous-code] for details. +//! +//! </pre></div> +//! +//! ## Events +//! +//! An [`Event`] represents a _moment_ in time. It signifies something that +//! happened while a trace was being recorded. `Event`s are comparable to the log +//! records emitted by unstructured logging code, but unlike a typical log line, +//! an `Event` may occur within the context of a span. +//! +//! For example: +//! ``` +//! use tracing::{event, span, Level}; +//! +//! # fn main() { +//! // records an event outside of any span context: +//! event!(Level::INFO, "something happened"); +//! +//! let span = span!(Level::INFO, "my_span"); +//! let _guard = span.enter(); +//! +//! // records an event within "my_span". +//! event!(Level::DEBUG, "something happened inside my_span"); +//! # } +//!``` +//! +//! In general, events should be used to represent points in time _within_ a +//! span — a request returned with a given status code, _n_ new items were +//! taken from a queue, and so on. +//! +//! The [`Event` struct][`Event`] documentation provides further details on using +//! events. +//! +//! ## Subscribers +//! +//! As `Span`s and `Event`s occur, they are recorded or aggregated by +//! implementations of the [`Subscriber`] trait. `Subscriber`s are notified +//! when an `Event` takes place and when a `Span` is entered or exited. These +//! notifications are represented by the following `Subscriber` trait methods: +//! +//! + [`event`][Subscriber::event], called when an `Event` takes place, +//! + [`enter`], called when execution enters a `Span`, +//! + [`exit`], called when execution exits a `Span` +//! +//! In addition, subscribers may implement the [`enabled`] function to _filter_ +//! the notifications they receive based on [metadata] describing each `Span` +//! or `Event`. If a call to `Subscriber::enabled` returns `false` for a given +//! set of metadata, that `Subscriber` will *not* be notified about the +//! corresponding `Span` or `Event`. For performance reasons, if no currently +//! active subscribers express interest in a given set of metadata by returning +//! `true`, then the corresponding `Span` or `Event` will never be constructed. +//! +//! # Usage +//! +//! First, add this to your `Cargo.toml`: +//! +//! ```toml +//! [dependencies] +//! tracing = "0.1" +//! ``` +//! +//! ## Recording Spans and Events +//! +//! Spans and events are recorded using macros. +//! +//! ### Spans +//! +//! The [`span!`] macro expands to a [`Span` struct][`Span`] which is used to +//! record a span. The [`Span::enter`] method on that struct records that the +//! span has been entered, and returns a [RAII] guard object, which will exit +//! the span when dropped. +//! +//! For example: +//! +//! ```rust +//! use tracing::{span, Level}; +//! # fn main() { +//! // Construct a new span named "my span" with trace log level. +//! let span = span!(Level::TRACE, "my span"); +//! +//! // Enter the span, returning a guard object. +//! let _enter = span.enter(); +//! +//! // Any trace events that occur before the guard is dropped will occur +//! // within the span. +//! +//! // Dropping the guard will exit the span. +//! # } +//! ``` +//! +//! The [`#[instrument]`][instrument] attribute provides an easy way to +//! add `tracing` spans to functions. A function annotated with `#[instrument]` +//! will create and enter a span with that function's name every time the +//! function is called, with arguments to that function will be recorded as +//! fields using `fmt::Debug`. +//! +//! For example: +//! ```ignore +//! # // this doctest is ignored because we don't have a way to say +//! # // that it should only be run with cfg(feature = "attributes") +//! use tracing::{Level, event, instrument}; +//! +//! #[instrument] +//! pub fn my_function(my_arg: usize) { +//! // This event will be recorded inside a span named `my_function` with the +//! // field `my_arg`. +//! event!(Level::INFO, "inside my_function!"); +//! // ... +//! } +//! # fn main() {} +//! ``` +//! +//! For functions which don't have built-in tracing support and can't have +//! the `#[instrument]` attribute applied (such as from an external crate), +//! the [`Span` struct][`Span`] has a [`in_scope()` method][`in_scope`] +//! which can be used to easily wrap synchonous code in a span. +//! +//! For example: +//! ```rust +//! use tracing::info_span; +//! +//! # fn doc() -> Result<(), ()> { +//! # mod serde_json { +//! # pub(crate) fn from_slice(buf: &[u8]) -> Result<(), ()> { Ok(()) } +//! # } +//! # let buf: [u8; 0] = []; +//! let json = info_span!("json.parse").in_scope(|| serde_json::from_slice(&buf))?; +//! # let _ = json; // suppress unused variable warning +//! # Ok(()) +//! # } +//! ``` +//! +//! You can find more examples showing how to use this crate [here][examples]. +//! +//! [RAII]: https://github.com/rust-unofficial/patterns/blob/master/patterns/behavioural/RAII.md +//! [examples]: https://github.com/tokio-rs/tracing/tree/master/examples +//! +//! ### Events +//! +//! [`Event`]s are recorded using the [`event!`] macro: +//! +//! ```rust +//! # fn main() { +//! use tracing::{event, Level}; +//! event!(Level::INFO, "something has happened!"); +//! # } +//! ``` +//! +//! ## Using the Macros +//! +//! The [`span!`] and [`event!`] macros as well as the `#[instrument]` attribute +//! use fairly similar syntax, with some exceptions. +//! +//! ### Configuring Attributes +//! +//! Both macros require a [`Level`] specifying the verbosity of the span or +//! event. Optionally, the [target] and [parent span] may be overridden. If the +//! target and parent span are not overridden, they will default to the +//! module path where the macro was invoked and the current span (as determined +//! by the subscriber), respectively. +//! +//! For example: +//! +//! ``` +//! # use tracing::{span, event, Level}; +//! # fn main() { +//! span!(target: "app_spans", Level::TRACE, "my span"); +//! event!(target: "app_events", Level::INFO, "something has happened!"); +//! # } +//! ``` +//! ``` +//! # use tracing::{span, event, Level}; +//! # fn main() { +//! let span = span!(Level::TRACE, "my span"); +//! event!(parent: &span, Level::INFO, "something has happened!"); +//! # } +//! ``` +//! +//! The span macros also take a string literal after the level, to set the name +//! of the span. +//! +//! ### Recording Fields +//! +//! Structured fields on spans and events are specified using the syntax +//! `field_name = field_value`. Fields are separated by commas. +//! +//! ``` +//! # use tracing::{event, Level}; +//! # fn main() { +//! // records an event with two fields: +//! // - "answer", with the value 42 +//! // - "question", with the value "life, the universe and everything" +//! event!(Level::INFO, answer = 42, question = "life, the universe, and everything"); +//! # } +//! ``` +//! +//! As shorthand, local variables may be used as field values without an +//! assignment, similar to [struct initializers]. For example: +//! +//! ``` +//! # use tracing::{span, Level}; +//! # fn main() { +//! let user = "ferris"; +//! +//! span!(Level::TRACE, "login", user); +//! // is equivalent to: +//! span!(Level::TRACE, "login", user = user); +//! # } +//!``` +//! +//! Field names can include dots, but should not be terminated by them: +//! ``` +//! # use tracing::{span, Level}; +//! # fn main() { +//! let user = "ferris"; +//! let email = "ferris@rust-lang.org"; +//! span!(Level::TRACE, "login", user, user.email = email); +//! # } +//!``` +//! +//! Since field names can include dots, fields on local structs can be used +//! using the local variable shorthand: +//! ``` +//! # use tracing::{span, Level}; +//! # fn main() { +//! # struct User { +//! # name: &'static str, +//! # email: &'static str, +//! # } +//! let user = User { +//! name: "ferris", +//! email: "ferris@rust-lang.org", +//! }; +//! // the span will have the fields `user.name = "ferris"` and +//! // `user.email = "ferris@rust-lang.org"`. +//! span!(Level::TRACE, "login", user.name, user.email); +//! # } +//!``` +//! +//! Fields with names that are not Rust identifiers, or with names that are Rust reserved words, +//! may be created using quoted string literals. However, this may not be used with the local +//! variable shorthand. +//! ``` +//! # use tracing::{span, Level}; +//! # fn main() { +//! // records an event with fields whose names are not Rust identifiers +//! // - "guid:x-request-id", containing a `:`, with the value "abcdef" +//! // - "type", which is a reserved word, with the value "request" +//! span!(Level::TRACE, "api", "guid:x-request-id" = "abcdef", "type" = "request"); +//! # } +//!``` +//! +//! The `?` sigil is shorthand that specifies a field should be recorded using +//! its [`fmt::Debug`] implementation: +//! ``` +//! # use tracing::{event, Level}; +//! # fn main() { +//! #[derive(Debug)] +//! struct MyStruct { +//! field: &'static str, +//! } +//! +//! let my_struct = MyStruct { +//! field: "Hello world!" +//! }; +//! +//! // `my_struct` will be recorded using its `fmt::Debug` implementation. +//! event!(Level::TRACE, greeting = ?my_struct); +//! // is equivalent to: +//! event!(Level::TRACE, greeting = tracing::field::debug(&my_struct)); +//! # } +//! ``` +//! +//! The `%` sigil operates similarly, but indicates that the value should be +//! recorded using its [`fmt::Display`] implementation: +//! ``` +//! # use tracing::{event, Level}; +//! # fn main() { +//! # #[derive(Debug)] +//! # struct MyStruct { +//! # field: &'static str, +//! # } +//! # +//! # let my_struct = MyStruct { +//! # field: "Hello world!" +//! # }; +//! // `my_struct.field` will be recorded using its `fmt::Display` implementation. +//! event!(Level::TRACE, greeting = %my_struct.field); +//! // is equivalent to: +//! event!(Level::TRACE, greeting = tracing::field::display(&my_struct.field)); +//! # } +//! ``` +//! +//! The `%` and `?` sigils may also be used with local variable shorthand: +//! +//! ``` +//! # use tracing::{event, Level}; +//! # fn main() { +//! # #[derive(Debug)] +//! # struct MyStruct { +//! # field: &'static str, +//! # } +//! # +//! # let my_struct = MyStruct { +//! # field: "Hello world!" +//! # }; +//! // `my_struct.field` will be recorded using its `fmt::Display` implementation. +//! event!(Level::TRACE, %my_struct.field); +//! # } +//! ``` +//! +//! Additionally, a span may declare fields with the special value [`Empty`], +//! which indicates that that the value for that field does not currently exist +//! but may be recorded later. For example: +//! +//! ``` +//! use tracing::{trace_span, field}; +//! +//! // Create a span with two fields: `greeting`, with the value "hello world", and +//! // `parting`, without a value. +//! let span = trace_span!("my_span", greeting = "hello world", parting = field::Empty); +//! +//! // ... +//! +//! // Now, record a value for parting as well. +//! span.record("parting", &"goodbye world!"); +//! ``` +//! +//! Note that a span may have up to 32 fields. The following will not compile: +//! +//! ```rust,compile_fail +//! # use tracing::Level; +//! # fn main() { +//! let bad_span = span!( +//! Level::TRACE, +//! "too many fields!", +//! a = 1, b = 2, c = 3, d = 4, e = 5, f = 6, g = 7, h = 8, i = 9, +//! j = 10, k = 11, l = 12, m = 13, n = 14, o = 15, p = 16, q = 17, +//! r = 18, s = 19, t = 20, u = 21, v = 22, w = 23, x = 24, y = 25, +//! z = 26, aa = 27, bb = 28, cc = 29, dd = 30, ee = 31, ff = 32, gg = 33 +//! ); +//! # } +//! ``` +//! +//! Finally, events may also include human-readable messages, in the form of a +//! [format string][fmt] and (optional) arguments, **after** the event's +//! key-value fields. If a format string and arguments are provided, +//! they will implicitly create a new field named `message` whose value is the +//! provided set of format arguments. +//! +//! For example: +//! +//! ``` +//! # use tracing::{event, Level}; +//! # fn main() { +//! let question = "the ultimate question of life, the universe, and everything"; +//! let answer = 42; +//! // records an event with the following fields: +//! // - `question.answer` with the value 42, +//! // - `question.tricky` with the value `true`, +//! // - "message", with the value "the answer to the ultimate question of life, the +//! // universe, and everything is 42." +//! event!( +//! Level::DEBUG, +//! question.answer = answer, +//! question.tricky = true, +//! "the answer to {} is {}.", question, answer +//! ); +//! # } +//! ``` +//! +//! Specifying a formatted message in this manner does not allocate by default. +//! +//! [struct initializers]: https://doc.rust-lang.org/book/ch05-01-defining-structs.html#using-the-field-init-shorthand-when-variables-and-fields-have-the-same-name +//! [target]: Metadata::target +//! [parent span]: span::Attributes::parent +//! [determined contextually]: span::Attributes::is_contextual +//! [`fmt::Debug`]: std::fmt::Debug +//! [`fmt::Display`]: std::fmt::Display +//! [fmt]: std::fmt#usage +//! [`Empty`]: field::Empty +//! +//! ### Shorthand Macros +//! +//! `tracing` also offers a number of macros with preset verbosity levels. +//! The [`trace!`], [`debug!`], [`info!`], [`warn!`], and [`error!`] behave +//! similarly to the [`event!`] macro, but with the [`Level`] argument already +//! specified, while the corresponding [`trace_span!`], [`debug_span!`], +//! [`info_span!`], [`warn_span!`], and [`error_span!`] macros are the same, +//! but for the [`span!`] macro. +//! +//! These are intended both as a shorthand, and for compatibility with the [`log`] +//! crate (see the next section). +//! +//! [`span!`]: span! +//! [`event!`]: event! +//! [`trace!`]: trace! +//! [`debug!`]: debug! +//! [`info!`]: info! +//! [`warn!`]: warn! +//! [`error!`]: error! +//! [`trace_span!`]: trace_span! +//! [`debug_span!`]: debug_span! +//! [`info_span!`]: info_span! +//! [`warn_span!`]: warn_span! +//! [`error_span!`]: error_span! +//! +//! ### For `log` Users +//! +//! Users of the [`log`] crate should note that `tracing` exposes a set of +//! macros for creating `Event`s (`trace!`, `debug!`, `info!`, `warn!`, and +//! `error!`) which may be invoked with the same syntax as the similarly-named +//! macros from the `log` crate. Often, the process of converting a project to +//! use `tracing` can begin with a simple drop-in replacement. +//! +//! Let's consider the `log` crate's yak-shaving example: +//! +//! ```rust,ignore +//! use std::{error::Error, io}; +//! use tracing::{debug, error, info, span, warn, Level}; +//! +//! // the `#[tracing::instrument]` attribute creates and enters a span +//! // every time the instrumented function is called. The span is named after the +//! // the function or method. Parameters passed to the function are recorded as fields. +//! #[tracing::instrument] +//! pub fn shave(yak: usize) -> Result<(), Box<dyn Error + 'static>> { +//! // this creates an event at the DEBUG level with two fields: +//! // - `excitement`, with the key "excitement" and the value "yay!" +//! // - `message`, with the key "message" and the value "hello! I'm gonna shave a yak." +//! // +//! // unlike other fields, `message`'s shorthand initialization is just the string itself. +//! debug!(excitement = "yay!", "hello! I'm gonna shave a yak."); +//! if yak == 3 { +//! warn!("could not locate yak!"); +//! // note that this is intended to demonstrate `tracing`'s features, not idiomatic +//! // error handling! in a library or application, you should consider returning +//! // a dedicated `YakError`. libraries like snafu or thiserror make this easy. +//! return Err(io::Error::new(io::ErrorKind::Other, "shaving yak failed!").into()); +//! } else { +//! debug!("yak shaved successfully"); +//! } +//! Ok(()) +//! } +//! +//! pub fn shave_all(yaks: usize) -> usize { +//! // Constructs a new span named "shaving_yaks" at the TRACE level, +//! // and a field whose key is "yaks". This is equivalent to writing: +//! // +//! // let span = span!(Level::TRACE, "shaving_yaks", yaks = yaks); +//! // +//! // local variables (`yaks`) can be used as field values +//! // without an assignment, similar to struct initializers. +//! let _span = span!(Level::TRACE, "shaving_yaks", yaks).entered(); +//! +//! info!("shaving yaks"); +//! +//! let mut yaks_shaved = 0; +//! for yak in 1..=yaks { +//! let res = shave(yak); +//! debug!(yak, shaved = res.is_ok()); +//! +//! if let Err(ref error) = res { +//! // Like spans, events can also use the field initialization shorthand. +//! // In this instance, `yak` is the field being initalized. +//! error!(yak, error = error.as_ref(), "failed to shave yak!"); +//! } else { +//! yaks_shaved += 1; +//! } +//! debug!(yaks_shaved); +//! } +//! +//! yaks_shaved +//! } +//! ``` +//! +//! ## In libraries +//! +//! Libraries should link only to the `tracing` crate, and use the provided +//! macros to record whatever information will be useful to downstream +//! consumers. +//! +//! ## In executables +//! +//! In order to record trace events, executables have to use a `Subscriber` +//! implementation compatible with `tracing`. A `Subscriber` implements a +//! way of collecting trace data, such as by logging it to standard output. +//! +//! This library does not contain any `Subscriber` implementations; these are +//! provided by [other crates](#related-crates). +//! +//! The simplest way to use a subscriber is to call the [`set_global_default`] +//! function: +//! +//! ``` +//! extern crate tracing; +//! # pub struct FooSubscriber; +//! # use tracing::{span::{Id, Attributes, Record}, Metadata}; +//! # impl tracing::Subscriber for FooSubscriber { +//! # fn new_span(&self, _: &Attributes) -> Id { Id::from_u64(0) } +//! # fn record(&self, _: &Id, _: &Record) {} +//! # fn event(&self, _: &tracing::Event) {} +//! # fn record_follows_from(&self, _: &Id, _: &Id) {} +//! # fn enabled(&self, _: &Metadata) -> bool { false } +//! # fn enter(&self, _: &Id) {} +//! # fn exit(&self, _: &Id) {} +//! # } +//! # impl FooSubscriber { +//! # fn new() -> Self { FooSubscriber } +//! # } +//! # fn main() { +//! +//! let my_subscriber = FooSubscriber::new(); +//! tracing::subscriber::set_global_default(my_subscriber) +//! .expect("setting tracing default failed"); +//! # } +//! ``` +//! +//! <pre class="compile_fail" style="white-space:normal;font:inherit;"> +//! <strong>Warning</strong>: In general, libraries should <em>not</em> call +//! <code>set_global_default()</code>! Doing so will cause conflicts when +//! executables that depend on the library try to set the default later. +//! </pre> +//! +//! This subscriber will be used as the default in all threads for the +//! remainder of the duration of the program, similar to setting the logger +//! in the `log` crate. +//! +//! In addition, the default subscriber can be set through using the +//! [`with_default`] function. This follows the `tokio` pattern of using +//! closures to represent executing code in a context that is exited at the end +//! of the closure. For example: +//! +//! ```rust +//! # pub struct FooSubscriber; +//! # use tracing::{span::{Id, Attributes, Record}, Metadata}; +//! # impl tracing::Subscriber for FooSubscriber { +//! # fn new_span(&self, _: &Attributes) -> Id { Id::from_u64(0) } +//! # fn record(&self, _: &Id, _: &Record) {} +//! # fn event(&self, _: &tracing::Event) {} +//! # fn record_follows_from(&self, _: &Id, _: &Id) {} +//! # fn enabled(&self, _: &Metadata) -> bool { false } +//! # fn enter(&self, _: &Id) {} +//! # fn exit(&self, _: &Id) {} +//! # } +//! # impl FooSubscriber { +//! # fn new() -> Self { FooSubscriber } +//! # } +//! # fn main() { +//! +//! let my_subscriber = FooSubscriber::new(); +//! # #[cfg(feature = "std")] +//! tracing::subscriber::with_default(my_subscriber, || { +//! // Any trace events generated in this closure or by functions it calls +//! // will be collected by `my_subscriber`. +//! }) +//! # } +//! ``` +//! +//! This approach allows trace data to be collected by multiple subscribers +//! within different contexts in the program. Note that the override only applies to the +//! currently executing thread; other threads will not see the change from with_default. +//! +//! Any trace events generated outside the context of a subscriber will not be collected. +//! +//! Once a subscriber has been set, instrumentation points may be added to the +//! executable using the `tracing` crate's macros. +//! +//! ## `log` Compatibility +//! +//! The [`log`] crate provides a simple, lightweight logging facade for Rust. +//! While `tracing` builds upon `log`'s foundation with richer structured +//! diagnostic data, `log`'s simplicity and ubiquity make it the "lowest common +//! denominator" for text-based logging in Rust — a vast majority of Rust +//! libraries and applications either emit or consume `log` records. Therefore, +//! `tracing` provides multiple forms of interoperability with `log`: `tracing` +//! instrumentation can emit `log` records, and a compatibility layer enables +//! `tracing` [`Subscriber`]s to consume `log` records as `tracing` [`Event`]s. +//! +//! ### Emitting `log` Records +//! +//! This crate provides two feature flags, "log" and "log-always", which will +//! cause [spans] and [events] to emit `log` records. When the "log" feature is +//! enabled, if no `tracing` `Subscriber` is active, invoking an event macro or +//! creating a span with fields will emit a `log` record. This is intended +//! primarily for use in libraries which wish to emit diagnostics that can be +//! consumed by applications using `tracing` *or* `log`, without paying the +//! additional overhead of emitting both forms of diagnostics when `tracing` is +//! in use. +//! +//! Enabling the "log-always" feature will cause `log` records to be emitted +//! even if a `tracing` `Subscriber` _is_ set. This is intended to be used in +//! applications where a `log` `Logger` is being used to record a textual log, +//! and `tracing` is used only to record other forms of diagnostics (such as +//! metrics, profiling, or distributed tracing data). Unlike the "log" feature, +//! libraries generally should **not** enable the "log-always" feature, as doing +//! so will prevent applications from being able to opt out of the `log` records. +//! +//! See [here][flags] for more details on this crate's feature flags. +//! +//! The generated `log` records' messages will be a string representation of the +//! span or event's fields, and all additional information recorded by `log` +//! (target, verbosity level, module path, file, and line number) will also be +//! populated. Additionally, `log` records are also generated when spans are +//! entered, exited, and closed. Since these additional span lifecycle logs have +//! the potential to be very verbose, and don't include additional fields, they +//! will always be emitted at the `Trace` level, rather than inheriting the +//! level of the span that generated them. Furthermore, they are are categorized +//! under a separate `log` target, "tracing::span" (and its sub-target, +//! "tracing::span::active", for the logs on entering and exiting a span), which +//! may be enabled or disabled separately from other `log` records emitted by +//! `tracing`. +//! +//! ### Consuming `log` Records +//! +//! The [`tracing-log`] crate provides a compatibility layer which +//! allows a `tracing` [`Subscriber`] to consume `log` records as though they +//! were `tracing` [events]. This allows applications using `tracing` to record +//! the logs emitted by dependencies using `log` as events within the context of +//! the application's trace tree. See [that crate's documentation][log-tracer] +//! for details. +//! +//! [log-tracer]: https://docs.rs/tracing-log/latest/tracing_log/#convert-log-records-to-tracing-events +//! +//! ## Related Crates +//! +//! In addition to `tracing` and `tracing-core`, the [`tokio-rs/tracing`] repository +//! contains several additional crates designed to be used with the `tracing` ecosystem. +//! This includes a collection of `Subscriber` implementations, as well as utility +//! and adapter crates to assist in writing `Subscriber`s and instrumenting +//! applications. +//! +//! In particular, the following crates are likely to be of interest: +//! +//! - [`tracing-futures`] provides a compatibility layer with the `futures` +//! crate, allowing spans to be attached to `Future`s, `Stream`s, and `Executor`s. +//! - [`tracing-subscriber`] provides `Subscriber` implementations and +//! utilities for working with `Subscriber`s. This includes a [`FmtSubscriber`] +//! `FmtSubscriber` for logging formatted trace data to stdout, with similar +//! filtering and formatting to the [`env_logger`] crate. +//! - [`tracing-log`] provides a compatibility layer with the [`log`] crate, +//! allowing log messages to be recorded as `tracing` `Event`s within the +//! trace tree. This is useful when a project using `tracing` have +//! dependencies which use `log`. Note that if you're using +//! `tracing-subscriber`'s `FmtSubscriber`, you don't need to depend on +//! `tracing-log` directly. +//! - [`tracing-appender`] provides utilities for outputting tracing data, +//! including a file appender and non blocking writer. +//! +//! Additionally, there are also several third-party crates which are not +//! maintained by the `tokio` project. These include: +//! +//! - [`tracing-timing`] implements inter-event timing metrics on top of `tracing`. +//! It provides a subscriber that records the time elapsed between pairs of +//! `tracing` events and generates histograms. +//! - [`tracing-opentelemetry`] provides a subscriber for emitting traces to +//! [OpenTelemetry]-compatible distributed tracing systems. +//! - [`tracing-honeycomb`] Provides a layer that reports traces spanning multiple machines to [honeycomb.io]. Backed by [`tracing-distributed`]. +//! - [`tracing-distributed`] Provides a generic implementation of a layer that reports traces spanning multiple machines to some backend. +//! - [`tracing-actix-web`] provides `tracing` integration for the `actix-web` web framework. +//! - [`tracing-actix`] provides `tracing` integration for the `actix` actor +//! framework. +//! - [`tracing-gelf`] implements a subscriber for exporting traces in Greylog +//! GELF format. +//! - [`tracing-coz`] provides integration with the [coz] causal profiler +//! (Linux-only). +//! - [`tracing-bunyan-formatter`] provides a layer implementation that reports events and spans +//! in [bunyan] format, enriched with timing information. +//! - [`tracing-wasm`] provides a `Subscriber`/`Layer` implementation that reports +//! events and spans via browser `console.log` and [User Timing API (`window.performance`)]. +//! - [`tide-tracing`] provides a [tide] middleware to trace all incoming requests and responses. +//! - [`test-log`] takes care of initializing `tracing` for tests, based on +//! environment variables with an `env_logger` compatible syntax. +//! - [`tracing-unwrap`] provides convenience methods to report failed unwraps +//! on `Result` or `Option` types to a `Subscriber`. +//! - [`diesel-tracing`] provides integration with [`diesel`] database connections. +//! - [`tracing-tracy`] provides a way to collect [Tracy] profiles in instrumented +//! applications. +//! - [`tracing-elastic-apm`] provides a layer for reporting traces to [Elastic APM]. +//! - [`tracing-etw`] provides a layer for emitting Windows [ETW] events. +//! - [`tracing-fluent-assertions`] provides a fluent assertions-style testing +//! framework for validating the behavior of `tracing` spans. +//! - [`sentry-tracing`] provides a layer for reporting events and traces to [Sentry]. +//! - [`tracing-forest`] provides a subscriber that preserves contextual coherence by +//! grouping together logs from the same spans during writing. +//! - [`tracing-loki`] provides a layer for shipping logs to [Grafana Loki]. +//! +//! If you're the maintainer of a `tracing` ecosystem crate not listed above, +//! please let us know! We'd love to add your project to the list! +//! +//! [`tracing-opentelemetry`]: https://crates.io/crates/tracing-opentelemetry +//! [OpenTelemetry]: https://opentelemetry.io/ +//! [`tracing-honeycomb`]: https://crates.io/crates/tracing-honeycomb +//! [`tracing-distributed`]: https://crates.io/crates/tracing-distributed +//! [honeycomb.io]: https://www.honeycomb.io/ +//! [`tracing-actix-web`]: https://crates.io/crates/tracing-actix-web +//! [`tracing-actix`]: https://crates.io/crates/tracing-actix +//! [`tracing-gelf`]: https://crates.io/crates/tracing-gelf +//! [`tracing-coz`]: https://crates.io/crates/tracing-coz +//! [coz]: https://github.com/plasma-umass/coz +//! [`tracing-bunyan-formatter`]: https://crates.io/crates/tracing-bunyan-formatter +//! [bunyan]: https://github.com/trentm/node-bunyan +//! [`tracing-wasm`]: https://docs.rs/tracing-wasm +//! [User Timing API (`window.performance`)]: https://developer.mozilla.org/en-US/docs/Web/API/User_Timing_API +//! [`tide-tracing`]: https://crates.io/crates/tide-tracing +//! [tide]: https://crates.io/crates/tide +//! [`test-log`]: https://crates.io/crates/test-log +//! [`tracing-unwrap`]: https://docs.rs/tracing-unwrap +//! [`diesel`]: https://crates.io/crates/diesel +//! [`diesel-tracing`]: https://crates.io/crates/diesel-tracing +//! [`tracing-tracy`]: https://crates.io/crates/tracing-tracy +//! [Tracy]: https://github.com/wolfpld/tracy +//! [`tracing-elastic-apm`]: https://crates.io/crates/tracing-elastic-apm +//! [Elastic APM]: https://www.elastic.co/apm +//! [`tracing-etw`]: https://github.com/microsoft/tracing-etw +//! [ETW]: https://docs.microsoft.com/en-us/windows/win32/etw/about-event-tracing +//! [`tracing-fluent-assertions`]: https://crates.io/crates/tracing-fluent-assertions +//! [`sentry-tracing`]: https://crates.io/crates/sentry-tracing +//! [Sentry]: https://sentry.io/welcome/ +//! [`tracing-forest`]: https://crates.io/crates/tracing-forest +//! [`tracing-loki`]: https://crates.io/crates/tracing-loki +//! [Grafana Loki]: https://grafana.com/oss/loki/ +//! +//! <pre class="ignore" style="white-space:normal;font:inherit;"> +//! <strong>Note</strong>: Some of these ecosystem crates are currently +//! unreleased and/or in earlier stages of development. They may be less stable +//! than <code>tracing</code> and <code>tracing-core</code>. +//! </pre> +//! +//! ## Crate Feature Flags +//! +//! The following crate [feature flags] are available: +//! +//! * A set of features controlling the [static verbosity level]. +//! * `log`: causes trace instrumentation points to emit [`log`] records as well +//! as trace events, if a default `tracing` subscriber has not been set. This +//! is intended for use in libraries whose users may be using either `tracing` +//! or `log`. +//! * `log-always`: Emit `log` records from all `tracing` spans and events, even +//! if a `tracing` subscriber has been set. This should be set only by +//! applications which intend to collect traces and logs separately; if an +//! adapter is used to convert `log` records into `tracing` events, this will +//! cause duplicate events to occur. +//! * `attributes`: Includes support for the `#[instrument]` attribute. +//! This is on by default, but does bring in the `syn` crate as a dependency, +//! which may add to the compile time of crates that do not already use it. +//! * `std`: Depend on the Rust standard library (enabled by default). +//! +//! `no_std` users may disable this feature with `default-features = false`: +//! +//! ```toml +//! [dependencies] +//! tracing = { version = "0.1.35", default-features = false } +//! ``` +//! +//! <pre class="ignore" style="white-space:normal;font:inherit;"> +//! <strong>Note</strong>: <code>tracing</code>'s <code>no_std</code> support +//! requires <code>liballoc</code>. +//! </pre> +//! +//! ### Unstable Features +//! +//! These feature flags enable **unstable** features. The public API may break in 0.1.x +//! releases. To enable these features, the `--cfg tracing_unstable` must be passed to +//! `rustc` when compiling. +//! +//! The following unstable feature flags are currently available: +//! +//! * `valuable`: Enables support for recording [field values] using the +//! [`valuable`] crate. +//! +//! #### Enabling Unstable Features +//! +//! The easiest way to set the `tracing_unstable` cfg is to use the `RUSTFLAGS` +//! env variable when running `cargo` commands: +//! +//! ```shell +//! RUSTFLAGS="--cfg tracing_unstable" cargo build +//! ``` +//! Alternatively, the following can be added to the `.cargo/config` file in a +//! project to automatically enable the cfg flag for that project: +//! +//! ```toml +//! [build] +//! rustflags = ["--cfg", "tracing_unstable"] +//! ``` +//! +//! [feature flags]: https://doc.rust-lang.org/cargo/reference/manifest.html#the-features-section +//! [field values]: crate::field +//! [`valuable`]: https://crates.io/crates/valuable +//! +//! ## Supported Rust Versions +//! +//! Tracing is built against the latest stable release. The minimum supported +//! version is 1.49. The current Tracing version is not guaranteed to build on +//! Rust versions earlier than the minimum supported version. +//! +//! Tracing follows the same compiler support policies as the rest of the Tokio +//! project. The current stable Rust compiler and the three most recent minor +//! versions before it will always be supported. For example, if the current +//! stable compiler version is 1.45, the minimum supported version will not be +//! increased past 1.42, three minor versions prior. Increasing the minimum +//! supported compiler version is not considered a semver breaking change as +//! long as doing so complies with this policy. +//! +//! [`log`]: https://docs.rs/log/0.4.6/log/ +//! [span]: mod@span +//! [spans]: mod@span +//! [`Span`]: span::Span +//! [`in_scope`]: span::Span::in_scope +//! [event]: Event +//! [events]: Event +//! [`Subscriber`]: subscriber::Subscriber +//! [Subscriber::event]: subscriber::Subscriber::event +//! [`enter`]: subscriber::Subscriber::enter +//! [`exit`]: subscriber::Subscriber::exit +//! [`enabled`]: subscriber::Subscriber::enabled +//! [metadata]: Metadata +//! [`field::display`]: field::display +//! [`field::debug`]: field::debug +//! [`set_global_default`]: subscriber::set_global_default +//! [`with_default`]: subscriber::with_default +//! [`tokio-rs/tracing`]: https://github.com/tokio-rs/tracing +//! [`tracing-futures`]: https://crates.io/crates/tracing-futures +//! [`tracing-subscriber`]: https://crates.io/crates/tracing-subscriber +//! [`tracing-log`]: https://crates.io/crates/tracing-log +//! [`tracing-timing`]: https://crates.io/crates/tracing-timing +//! [`tracing-appender`]: https://crates.io/crates/tracing-appender +//! [`env_logger`]: https://crates.io/crates/env_logger +//! [`FmtSubscriber`]: https://docs.rs/tracing-subscriber/latest/tracing_subscriber/fmt/struct.Subscriber.html +//! [static verbosity level]: level_filters#compile-time-filters +//! [instrument]: https://docs.rs/tracing-attributes/latest/tracing_attributes/attr.instrument.html +//! [flags]: #crate-feature-flags +#![cfg_attr(not(feature = "std"), no_std)] +#![cfg_attr(docsrs, feature(doc_cfg), deny(rustdoc::broken_intra_doc_links))] +#![doc(html_root_url = "https://docs.rs/tracing/0.1.35")] +#![doc( + html_logo_url = "https://raw.githubusercontent.com/tokio-rs/tracing/master/assets/logo-type.png", + issue_tracker_base_url = "https://github.com/tokio-rs/tracing/issues/" +)] +#![warn( + missing_debug_implementations, + missing_docs, + rust_2018_idioms, + unreachable_pub, + bad_style, + const_err, + dead_code, + improper_ctypes, + non_shorthand_field_patterns, + no_mangle_generic_items, + overflowing_literals, + path_statements, + patterns_in_fns_without_body, + private_in_public, + unconditional_recursion, + unused, + unused_allocation, + unused_comparisons, + unused_parens, + while_true +)] + +#[cfg(not(feature = "std"))] +extern crate alloc; + +// Somehow this `use` statement is necessary for us to re-export the `core` +// macros on Rust 1.26.0. I'm not sure how this makes it work, but it does. +#[allow(unused_imports)] +#[doc(hidden)] +use tracing_core::*; + +#[doc(inline)] +pub use self::instrument::Instrument; +pub use self::{dispatcher::Dispatch, event::Event, field::Value, subscriber::Subscriber}; + +#[doc(hidden)] +pub use self::span::Id; + +#[doc(hidden)] +pub use tracing_core::{ + callsite::{self, Callsite}, + metadata, +}; +pub use tracing_core::{event, Level, Metadata}; + +#[doc(inline)] +pub use self::span::Span; +#[cfg(feature = "attributes")] +#[cfg_attr(docsrs, doc(cfg(feature = "attributes")))] +#[doc(inline)] +pub use tracing_attributes::instrument; + +#[macro_use] +mod macros; + +pub mod dispatcher; +pub mod field; +/// Attach a span to a `std::future::Future`. +pub mod instrument; +pub mod level_filters; +pub mod span; +pub(crate) mod stdlib; +pub mod subscriber; + +#[doc(hidden)] +pub mod __macro_support { + pub use crate::callsite::Callsite; + use crate::{subscriber::Interest, Metadata}; + pub use core::concat; + + /// Callsite implementation used by macro-generated code. + /// + /// /!\ WARNING: This is *not* a stable API! /!\ + /// This type, and all code contained in the `__macro_support` module, is + /// a *private* API of `tracing`. It is exposed publicly because it is used + /// by the `tracing` macros, but it is not part of the stable versioned API. + /// Breaking changes to this module may occur in small-numbered versions + /// without warning. + pub use tracing_core::callsite::DefaultCallsite as MacroCallsite; + + /// /!\ WARNING: This is *not* a stable API! /!\ + /// This function, and all code contained in the `__macro_support` module, is + /// a *private* API of `tracing`. It is exposed publicly because it is used + /// by the `tracing` macros, but it is not part of the stable versioned API. + /// Breaking changes to this module may occur in small-numbered versions + /// without warning. + pub fn __is_enabled(meta: &Metadata<'static>, interest: Interest) -> bool { + interest.is_always() || crate::dispatcher::get_default(|default| default.enabled(meta)) + } + + /// /!\ WARNING: This is *not* a stable API! /!\ + /// This function, and all code contained in the `__macro_support` module, is + /// a *private* API of `tracing`. It is exposed publicly because it is used + /// by the `tracing` macros, but it is not part of the stable versioned API. + /// Breaking changes to this module may occur in small-numbered versions + /// without warning. + #[inline] + #[cfg(feature = "log")] + pub fn __disabled_span(meta: &'static Metadata<'static>) -> crate::Span { + crate::Span::new_disabled(meta) + } + + /// /!\ WARNING: This is *not* a stable API! /!\ + /// This function, and all code contained in the `__macro_support` module, is + /// a *private* API of `tracing`. It is exposed publicly because it is used + /// by the `tracing` macros, but it is not part of the stable versioned API. + /// Breaking changes to this module may occur in small-numbered versions + /// without warning. + #[inline] + #[cfg(not(feature = "log"))] + pub fn __disabled_span(_: &'static Metadata<'static>) -> crate::Span { + crate::Span::none() + } + + /// /!\ WARNING: This is *not* a stable API! /!\ + /// This function, and all code contained in the `__macro_support` module, is + /// a *private* API of `tracing`. It is exposed publicly because it is used + /// by the `tracing` macros, but it is not part of the stable versioned API. + /// Breaking changes to this module may occur in small-numbered versions + /// without warning. + #[cfg(feature = "log")] + pub fn __tracing_log( + meta: &Metadata<'static>, + logger: &'static dyn log::Log, + log_meta: log::Metadata<'_>, + values: &tracing_core::field::ValueSet<'_>, + ) { + logger.log( + &crate::log::Record::builder() + .file(meta.file()) + .module_path(meta.module_path()) + .line(meta.line()) + .metadata(log_meta) + .args(format_args!( + "{}", + crate::log::LogValueSet { + values, + is_first: true + } + )) + .build(), + ); + } +} + +#[cfg(feature = "log")] +#[doc(hidden)] +pub mod log { + use core::fmt; + pub use log::*; + use tracing_core::field::{Field, ValueSet, Visit}; + + /// Utility to format [`ValueSet`]s for logging. + pub(crate) struct LogValueSet<'a> { + pub(crate) values: &'a ValueSet<'a>, + pub(crate) is_first: bool, + } + + impl<'a> fmt::Display for LogValueSet<'a> { + #[inline] + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + struct LogVisitor<'a, 'b> { + f: &'a mut fmt::Formatter<'b>, + is_first: bool, + result: fmt::Result, + } + + impl Visit for LogVisitor<'_, '_> { + fn record_debug(&mut self, field: &Field, value: &dyn fmt::Debug) { + let res = if self.is_first { + self.is_first = false; + if field.name() == "message" { + write!(self.f, "{:?}", value) + } else { + write!(self.f, "{}={:?}", field.name(), value) + } + } else { + write!(self.f, " {}={:?}", field.name(), value) + }; + if let Err(err) = res { + self.result = self.result.and(Err(err)); + } + } + + fn record_str(&mut self, field: &Field, value: &str) { + if field.name() == "message" { + self.record_debug(field, &format_args!("{}", value)) + } else { + self.record_debug(field, &value) + } + } + } + + let mut visit = LogVisitor { + f, + is_first: self.is_first, + result: Ok(()), + }; + self.values.record(&mut visit); + visit.result + } + } +} + +mod sealed { + pub trait Sealed {} +} diff --git a/vendor/tracing/src/macros.rs b/vendor/tracing/src/macros.rs new file mode 100644 index 000000000..b134af6e8 --- /dev/null +++ b/vendor/tracing/src/macros.rs @@ -0,0 +1,2504 @@ +/// Constructs a new span. +/// +/// See [the top-level documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [lib]: crate#using-the-macros +/// +/// # Examples +/// +/// Creating a new span: +/// ``` +/// # use tracing::{span, Level}; +/// # fn main() { +/// let span = span!(Level::TRACE, "my span"); +/// let _enter = span.enter(); +/// // do work inside the span... +/// # } +/// ``` +#[macro_export] +macro_rules! span { + (target: $target:expr, parent: $parent:expr, $lvl:expr, $name:expr) => { + $crate::span!(target: $target, parent: $parent, $lvl, $name,) + }; + (target: $target:expr, parent: $parent:expr, $lvl:expr, $name:expr, $($fields:tt)*) => { + { + use $crate::__macro_support::Callsite as _; + static CALLSITE: $crate::callsite::DefaultCallsite = $crate::callsite2! { + name: $name, + kind: $crate::metadata::Kind::SPAN, + target: $target, + level: $lvl, + fields: $($fields)* + }; + let mut interest = $crate::subscriber::Interest::never(); + if $crate::level_enabled!($lvl) + && { interest = CALLSITE.interest(); !interest.is_never() } + && $crate::__macro_support::__is_enabled(CALLSITE.metadata(), interest) + { + let meta = CALLSITE.metadata(); + // span with explicit parent + $crate::Span::child_of( + $parent, + meta, + &$crate::valueset!(meta.fields(), $($fields)*), + ) + } else { + let span = $crate::__macro_support::__disabled_span(CALLSITE.metadata()); + $crate::if_log_enabled! { $lvl, { + span.record_all(&$crate::valueset!(CALLSITE.metadata().fields(), $($fields)*)); + }}; + span + } + } + }; + (target: $target:expr, $lvl:expr, $name:expr, $($fields:tt)*) => { + { + use $crate::__macro_support::Callsite as _; + static CALLSITE: $crate::callsite::DefaultCallsite = $crate::callsite2! { + name: $name, + kind: $crate::metadata::Kind::SPAN, + target: $target, + level: $lvl, + fields: $($fields)* + }; + let mut interest = $crate::subscriber::Interest::never(); + if $crate::level_enabled!($lvl) + && { interest = CALLSITE.interest(); !interest.is_never() } + && $crate::__macro_support::__is_enabled(CALLSITE.metadata(), interest) + { + let meta = CALLSITE.metadata(); + // span with contextual parent + $crate::Span::new( + meta, + &$crate::valueset!(meta.fields(), $($fields)*), + ) + } else { + let span = $crate::__macro_support::__disabled_span(CALLSITE.metadata()); + $crate::if_log_enabled! { $lvl, { + span.record_all(&$crate::valueset!(CALLSITE.metadata().fields(), $($fields)*)); + }}; + span + } + } + }; + (target: $target:expr, parent: $parent:expr, $lvl:expr, $name:expr) => { + $crate::span!(target: $target, parent: $parent, $lvl, $name,) + }; + (parent: $parent:expr, $lvl:expr, $name:expr, $($fields:tt)*) => { + $crate::span!( + target: module_path!(), + parent: $parent, + $lvl, + $name, + $($fields)* + ) + }; + (parent: $parent:expr, $lvl:expr, $name:expr) => { + $crate::span!( + target: module_path!(), + parent: $parent, + $lvl, + $name, + ) + }; + (target: $target:expr, $lvl:expr, $name:expr, $($fields:tt)*) => { + $crate::span!( + target: $target, + $lvl, + $name, + $($fields)* + ) + }; + (target: $target:expr, $lvl:expr, $name:expr) => { + $crate::span!(target: $target, $lvl, $name,) + }; + ($lvl:expr, $name:expr, $($fields:tt)*) => { + $crate::span!( + target: module_path!(), + $lvl, + $name, + $($fields)* + ) + }; + ($lvl:expr, $name:expr) => { + $crate::span!( + target: module_path!(), + $lvl, + $name, + ) + }; +} + +/// Constructs a span at the trace level. +/// +/// [Fields] and [attributes] are set using the same syntax as the [`span!`] +/// macro. +/// +/// See [the top-level documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [lib]: crate#using-the-macros +/// [attributes]: crate#configuring-attributes +/// [Fields]: crate#recording-fields +/// [`span!`]: crate::span! +/// +/// # Examples +/// +/// ```rust +/// # use tracing::{trace_span, span, Level}; +/// # fn main() { +/// trace_span!("my_span"); +/// // is equivalent to: +/// span!(Level::TRACE, "my_span"); +/// # } +/// ``` +/// +/// ```rust +/// # use tracing::{trace_span, span, Level}; +/// # fn main() { +/// let span = trace_span!("my span"); +/// span.in_scope(|| { +/// // do work inside the span... +/// }); +/// # } +/// ``` +#[macro_export] +macro_rules! trace_span { + (target: $target:expr, parent: $parent:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: $target, + parent: $parent, + $crate::Level::TRACE, + $name, + $($field)* + ) + }; + (target: $target:expr, parent: $parent:expr, $name:expr) => { + $crate::trace_span!(target: $target, parent: $parent, $name,) + }; + (parent: $parent:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: module_path!(), + parent: $parent, + $crate::Level::TRACE, + $name, + $($field)* + ) + }; + (parent: $parent:expr, $name:expr) => { + $crate::trace_span!(parent: $parent, $name,) + }; + (target: $target:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: $target, + $crate::Level::TRACE, + $name, + $($field)* + ) + }; + (target: $target:expr, $name:expr) => { + $crate::trace_span!(target: $target, $name,) + }; + ($name:expr, $($field:tt)*) => { + $crate::span!( + target: module_path!(), + $crate::Level::TRACE, + $name, + $($field)* + ) + }; + ($name:expr) => { $crate::trace_span!($name,) }; +} + +/// Constructs a span at the debug level. +/// +/// [Fields] and [attributes] are set using the same syntax as the [`span!`] +/// macro. +/// +/// See [the top-level documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [lib]: crate#using-the-macros +/// [attributes]: crate#configuring-attributes +/// [Fields]: crate#recording-fields +/// [`span!`]: crate::span! +/// +/// # Examples +/// +/// ```rust +/// # use tracing::{debug_span, span, Level}; +/// # fn main() { +/// debug_span!("my_span"); +/// // is equivalent to: +/// span!(Level::DEBUG, "my_span"); +/// # } +/// ``` +/// +/// ```rust +/// # use tracing::debug_span; +/// # fn main() { +/// let span = debug_span!("my span"); +/// span.in_scope(|| { +/// // do work inside the span... +/// }); +/// # } +/// ``` +#[macro_export] +macro_rules! debug_span { + (target: $target:expr, parent: $parent:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: $target, + parent: $parent, + $crate::Level::DEBUG, + $name, + $($field)* + ) + }; + (target: $target:expr, parent: $parent:expr, $name:expr) => { + $crate::debug_span!(target: $target, parent: $parent, $name,) + }; + (parent: $parent:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: module_path!(), + parent: $parent, + $crate::Level::DEBUG, + $name, + $($field)* + ) + }; + (parent: $parent:expr, $name:expr) => { + $crate::debug_span!(parent: $parent, $name,) + }; + (target: $target:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: $target, + $crate::Level::DEBUG, + $name, + $($field)* + ) + }; + (target: $target:expr, $name:expr) => { + $crate::debug_span!(target: $target, $name,) + }; + ($name:expr, $($field:tt)*) => { + $crate::span!( + target: module_path!(), + $crate::Level::DEBUG, + $name, + $($field)* + ) + }; + ($name:expr) => {$crate::debug_span!($name,)}; +} + +/// Constructs a span at the info level. +/// +/// [Fields] and [attributes] are set using the same syntax as the [`span!`] +/// macro. +/// +/// See [the top-level documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [lib]: crate#using-the-macros +/// [attributes]: crate#configuring-attributes +/// [Fields]: crate#recording-fields +/// [`span!`]: crate::span! +/// +/// # Examples +/// +/// ```rust +/// # use tracing::{span, info_span, Level}; +/// # fn main() { +/// info_span!("my_span"); +/// // is equivalent to: +/// span!(Level::INFO, "my_span"); +/// # } +/// ``` +/// +/// ```rust +/// # use tracing::info_span; +/// # fn main() { +/// let span = info_span!("my span"); +/// span.in_scope(|| { +/// // do work inside the span... +/// }); +/// # } +/// ``` +#[macro_export] +macro_rules! info_span { + (target: $target:expr, parent: $parent:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: $target, + parent: $parent, + $crate::Level::INFO, + $name, + $($field)* + ) + }; + (target: $target:expr, parent: $parent:expr, $name:expr) => { + $crate::info_span!(target: $target, parent: $parent, $name,) + }; + (parent: $parent:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: module_path!(), + parent: $parent, + $crate::Level::INFO, + $name, + $($field)* + ) + }; + (parent: $parent:expr, $name:expr) => { + $crate::info_span!(parent: $parent, $name,) + }; + (target: $target:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: $target, + $crate::Level::INFO, + $name, + $($field)* + ) + }; + (target: $target:expr, $name:expr) => { + $crate::info_span!(target: $target, $name,) + }; + ($name:expr, $($field:tt)*) => { + $crate::span!( + target: module_path!(), + $crate::Level::INFO, + $name, + $($field)* + ) + }; + ($name:expr) => {$crate::info_span!($name,)}; +} + +/// Constructs a span at the warn level. +/// +/// [Fields] and [attributes] are set using the same syntax as the [`span!`] +/// macro. +/// +/// See [the top-level documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [lib]: crate#using-the-macros +/// [attributes]: crate#configuring-attributes +/// [Fields]: crate#recording-fields +/// [`span!`]: crate::span! +/// +/// # Examples +/// +/// ```rust +/// # use tracing::{warn_span, span, Level}; +/// # fn main() { +/// warn_span!("my_span"); +/// // is equivalent to: +/// span!(Level::WARN, "my_span"); +/// # } +/// ``` +/// +/// ```rust +/// use tracing::warn_span; +/// # fn main() { +/// let span = warn_span!("my span"); +/// span.in_scope(|| { +/// // do work inside the span... +/// }); +/// # } +/// ``` +#[macro_export] +macro_rules! warn_span { + (target: $target:expr, parent: $parent:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: $target, + parent: $parent, + $crate::Level::WARN, + $name, + $($field)* + ) + }; + (target: $target:expr, parent: $parent:expr, $name:expr) => { + $crate::warn_span!(target: $target, parent: $parent, $name,) + }; + (parent: $parent:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: module_path!(), + parent: $parent, + $crate::Level::WARN, + $name, + $($field)* + ) + }; + (parent: $parent:expr, $name:expr) => { + $crate::warn_span!(parent: $parent, $name,) + }; + (target: $target:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: $target, + $crate::Level::WARN, + $name, + $($field)* + ) + }; + (target: $target:expr, $name:expr) => { + $crate::warn_span!(target: $target, $name,) + }; + ($name:expr, $($field:tt)*) => { + $crate::span!( + target: module_path!(), + $crate::Level::WARN, + $name, + $($field)* + ) + }; + ($name:expr) => {$crate::warn_span!($name,)}; +} +/// Constructs a span at the error level. +/// +/// [Fields] and [attributes] are set using the same syntax as the [`span!`] +/// macro. +/// +/// See [the top-level documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [lib]: crate#using-the-macros +/// [attributes]: crate#configuring-attributes +/// [Fields]: crate#recording-fields +/// [`span!`]: crate::span! +/// +/// # Examples +/// +/// ```rust +/// # use tracing::{span, error_span, Level}; +/// # fn main() { +/// error_span!("my_span"); +/// // is equivalent to: +/// span!(Level::ERROR, "my_span"); +/// # } +/// ``` +/// +/// ```rust +/// # use tracing::error_span; +/// # fn main() { +/// let span = error_span!("my span"); +/// span.in_scope(|| { +/// // do work inside the span... +/// }); +/// # } +/// ``` +#[macro_export] +macro_rules! error_span { + (target: $target:expr, parent: $parent:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: $target, + parent: $parent, + $crate::Level::ERROR, + $name, + $($field)* + ) + }; + (target: $target:expr, parent: $parent:expr, $name:expr) => { + $crate::error_span!(target: $target, parent: $parent, $name,) + }; + (parent: $parent:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: module_path!(), + parent: $parent, + $crate::Level::ERROR, + $name, + $($field)* + ) + }; + (parent: $parent:expr, $name:expr) => { + $crate::error_span!(parent: $parent, $name,) + }; + (target: $target:expr, $name:expr, $($field:tt)*) => { + $crate::span!( + target: $target, + $crate::Level::ERROR, + $name, + $($field)* + ) + }; + (target: $target:expr, $name:expr) => { + $crate::error_span!(target: $target, $name,) + }; + ($name:expr, $($field:tt)*) => { + $crate::span!( + target: module_path!(), + $crate::Level::ERROR, + $name, + $($field)* + ) + }; + ($name:expr) => {$crate::error_span!($name,)}; +} + +/// Constructs a new `Event`. +/// +/// The event macro is invoked with a `Level` and up to 32 key-value fields. +/// Optionally, a format string and arguments may follow the fields; this will +/// be used to construct an implicit field named "message". +/// +/// See [the top-level documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [lib]: crate#using-the-macros +/// +/// # Examples +/// +/// ```rust +/// use tracing::{event, Level}; +/// +/// # fn main() { +/// let data = (42, "forty-two"); +/// let private_data = "private"; +/// let error = "a bad error"; +/// +/// event!(Level::ERROR, %error, "Received error"); +/// event!( +/// target: "app_events", +/// Level::WARN, +/// private_data, +/// ?data, +/// "App warning: {}", +/// error +/// ); +/// event!(Level::INFO, the_answer = data.0); +/// # } +/// ``` +/// +// /// Note that *unlike `span!`*, `event!` requires a value for all fields. As +// /// events are recorded immediately when the macro is invoked, there is no +// /// opportunity for fields to be recorded later. A trailing comma on the final +// /// field is valid. +// /// +// /// For example, the following does not compile: +// /// ```rust,compile_fail +// /// # use tracing::{Level, event}; +// /// # fn main() { +// /// event!(Level::INFO, foo = 5, bad_field, bar = "hello") +// /// #} +// /// ``` +#[macro_export] +macro_rules! event { + (target: $target:expr, parent: $parent:expr, $lvl:expr, { $($fields:tt)* } )=> ({ + use $crate::__macro_support::Callsite as _; + static CALLSITE: $crate::callsite::DefaultCallsite = $crate::callsite2! { + name: $crate::__macro_support::concat!( + "event ", + file!(), + ":", + line!() + ), + kind: $crate::metadata::Kind::EVENT, + target: $target, + level: $lvl, + fields: $($fields)* + }; + + let enabled = $crate::level_enabled!($lvl) && { + let interest = CALLSITE.interest(); + !interest.is_never() && $crate::__macro_support::__is_enabled(CALLSITE.metadata(), interest) + }; + if enabled { + (|value_set: $crate::field::ValueSet| { + $crate::__tracing_log!( + $lvl, + CALLSITE, + &value_set + ); + let meta = CALLSITE.metadata(); + // event with explicit parent + $crate::Event::child_of( + $parent, + meta, + &value_set + ); + })($crate::valueset!(CALLSITE.metadata().fields(), $($fields)*)); + } else { + $crate::__tracing_log!( + $lvl, + CALLSITE, + &$crate::valueset!(CALLSITE.metadata().fields(), $($fields)*) + ); + } + }); + + (target: $target:expr, parent: $parent:expr, $lvl:expr, { $($fields:tt)* }, $($arg:tt)+ ) => ( + $crate::event!( + target: $target, + parent: $parent, + $lvl, + { message = format_args!($($arg)+), $($fields)* } + ) + ); + (target: $target:expr, parent: $parent:expr, $lvl:expr, $($k:ident).+ = $($fields:tt)* ) => ( + $crate::event!(target: $target, parent: $parent, $lvl, { $($k).+ = $($fields)* }) + ); + (target: $target:expr, parent: $parent:expr, $lvl:expr, $($arg:tt)+) => ( + $crate::event!(target: $target, parent: $parent, $lvl, { $($arg)+ }) + ); + (target: $target:expr, $lvl:expr, { $($fields:tt)* } )=> ({ + use $crate::__macro_support::Callsite as _; + static CALLSITE: $crate::callsite::DefaultCallsite = $crate::callsite2! { + name: $crate::__macro_support::concat!( + "event ", + file!(), + ":", + line!() + ), + kind: $crate::metadata::Kind::EVENT, + target: $target, + level: $lvl, + fields: $($fields)* + }; + let enabled = $crate::level_enabled!($lvl) && { + let interest = CALLSITE.interest(); + !interest.is_never() && $crate::__macro_support::__is_enabled(CALLSITE.metadata(), interest) + }; + if enabled { + (|value_set: $crate::field::ValueSet| { + let meta = CALLSITE.metadata(); + // event with contextual parent + $crate::Event::dispatch( + meta, + &value_set + ); + $crate::__tracing_log!( + $lvl, + CALLSITE, + &value_set + ); + })($crate::valueset!(CALLSITE.metadata().fields(), $($fields)*)); + } else { + $crate::__tracing_log!( + $lvl, + CALLSITE, + &$crate::valueset!(CALLSITE.metadata().fields(), $($fields)*) + ); + } + }); + (target: $target:expr, $lvl:expr, { $($fields:tt)* }, $($arg:tt)+ ) => ( + $crate::event!( + target: $target, + $lvl, + { message = format_args!($($arg)+), $($fields)* } + ) + ); + (target: $target:expr, $lvl:expr, $($k:ident).+ = $($fields:tt)* ) => ( + $crate::event!(target: $target, $lvl, { $($k).+ = $($fields)* }) + ); + (target: $target:expr, $lvl:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, $lvl, { $($arg)+ }) + ); + (parent: $parent:expr, $lvl:expr, { $($fields:tt)* }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $lvl, + { message = format_args!($($arg)+), $($fields)* } + ) + ); + (parent: $parent:expr, $lvl:expr, $($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $lvl, + { $($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, $lvl:expr, ?$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $lvl, + { ?$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, $lvl:expr, %$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $lvl, + { %$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, $lvl:expr, $($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $lvl, + { $($k).+, $($field)*} + ) + ); + (parent: $parent:expr, $lvl:expr, %$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $lvl, + { %$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, $lvl:expr, ?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $lvl, + { ?$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, $lvl:expr, $($arg:tt)+ ) => ( + $crate::event!(target: module_path!(), parent: $parent, $lvl, { $($arg)+ }) + ); + ( $lvl:expr, { $($fields:tt)* }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + $lvl, + { message = format_args!($($arg)+), $($fields)* } + ) + ); + ( $lvl:expr, { $($fields:tt)* }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + $lvl, + { message = format_args!($($arg)+), $($fields)* } + ) + ); + ($lvl:expr, $($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $lvl, + { $($k).+ = $($field)*} + ) + ); + ($lvl:expr, $($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $lvl, + { $($k).+, $($field)*} + ) + ); + ($lvl:expr, ?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $lvl, + { ?$($k).+, $($field)*} + ) + ); + ($lvl:expr, %$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $lvl, + { %$($k).+, $($field)*} + ) + ); + ($lvl:expr, ?$($k:ident).+) => ( + $crate::event!($lvl, ?$($k).+,) + ); + ($lvl:expr, %$($k:ident).+) => ( + $crate::event!($lvl, %$($k).+,) + ); + ($lvl:expr, $($k:ident).+) => ( + $crate::event!($lvl, $($k).+,) + ); + ( $lvl:expr, $($arg:tt)+ ) => ( + $crate::event!(target: module_path!(), $lvl, { $($arg)+ }) + ); +} + +/// Tests whether an event with the specified level and target would be enabled. +/// +/// This is similar to [`enabled!`], but queries the current subscriber specifically for +/// an event, whereas [`enabled!`] queries for an event _or_ span. +/// +/// See the documentation for [`enabled!]` for more details on using this macro. +/// See also [`span_enabled!`]. +/// +/// # Examples +/// +/// ```rust +/// # use tracing::{event_enabled, Level}; +/// if event_enabled!(target: "my_crate", Level::DEBUG) { +/// // some expensive work... +/// } +/// // simpler +/// if event_enabled!(Level::DEBUG) { +/// // some expensive work... +/// } +/// // with fields +/// if event_enabled!(Level::DEBUG, foo_field) { +/// // some expensive work... +/// } +/// ``` +/// +/// [`enabled!`]: crate::enabled +/// [`span_enabled!`]: crate::span_enabled +#[macro_export] +macro_rules! event_enabled { + ($($rest:tt)*)=> ( + $crate::enabled!(kind: $crate::metadata::Kind::EVENT, $($rest)*) + ) +} + +/// Tests whether a span with the specified level and target would be enabled. +/// +/// This is similar to [`enabled!`], but queries the current subscriber specifically for +/// an event, whereas [`enabled!`] queries for an event _or_ span. +/// +/// See the documentation for [`enabled!]` for more details on using this macro. +/// See also [`span_enabled!`]. +/// +/// # Examples +/// +/// ```rust +/// # use tracing::{span_enabled, Level}; +/// if span_enabled!(target: "my_crate", Level::DEBUG) { +/// // some expensive work... +/// } +/// // simpler +/// if span_enabled!(Level::DEBUG) { +/// // some expensive work... +/// } +/// // with fields +/// if span_enabled!(Level::DEBUG, foo_field) { +/// // some expensive work... +/// } +/// ``` +/// +/// [`enabled!`]: crate::enabled +/// [`span_enabled!`]: crate::span_enabled +#[macro_export] +macro_rules! span_enabled { + ($($rest:tt)*)=> ( + $crate::enabled!(kind: $crate::metadata::Kind::SPAN, $($rest)*) + ) +} + +/// Checks whether a span or event is [enabled] based on the provided [metadata]. +/// +/// [enabled]: crate::Subscriber::enabled +/// [metadata]: crate::Metadata +/// +/// This macro is a specialized tool: it is intended to be used prior +/// to an expensive computation required *just* for that event, but +/// *cannot* be done as part of an argument to that event, such as +/// when multiple events are emitted (e.g., iterating over a collection +/// and emitting an event for each item). +/// +/// # Usage +/// +/// [Subscribers] can make filtering decisions based all the data included in a +/// span or event's [`Metadata`]. This means that it is possible for `enabled!` +/// to return a _false positive_ (indicating that something would be enabled +/// when it actually would not be) or a _false negative_ (indicating that +/// something would be disabled when it would actually be enabled). +/// +/// [Subscribers]: crate::subscriber::Subscriber +/// [`Metadata`]: crate::metadata::Metadata +/// +/// This occurs when a subscriber is using a _more specific_ filter than the +/// metadata provided to the `enabled!` macro. Some situations that can result +/// in false positives or false negatives include: +/// +/// - If a subscriber is using a filter which may enable a span or event based +/// on field names, but `enabled!` is invoked without listing field names, +/// `enabled!` may return a false negative if a specific field name would +/// cause the subscriber to enable something that would otherwise be disabled. +/// - If a subscriber is using a filter which enables or disables specific events by +/// file path and line number, a particular event may be enabled/disabled +/// even if an `enabled!` invocation with the same level, target, and fields +/// indicated otherwise. +/// - The subscriber can choose to enable _only_ spans or _only_ events, which `enabled` +/// will not reflect. +/// +/// `enabled!()` requires a [level](crate::Level) argument, an optional `target:` +/// argument, and an optional set of field names. If the fields are not provided, +/// they are considered to be unknown. `enabled!` attempts to match the +/// syntax of `event!()` as closely as possible, which can be seen in the +/// examples below. +/// +/// # Examples +/// +/// If the current subscriber is interested in recording `DEBUG`-level spans and +/// events in the current file and module path, this will evaluate to true: +/// ```rust +/// use tracing::{enabled, Level}; +/// +/// if enabled!(Level::DEBUG) { +/// // some expensive work... +/// } +/// ``` +/// +/// If the current subscriber is interested in recording spans and events +/// in the current file and module path, with the target "my_crate", and at the +/// level `DEBUG`, this will evaluate to true: +/// ```rust +/// # use tracing::{enabled, Level}; +/// if enabled!(target: "my_crate", Level::DEBUG) { +/// // some expensive work... +/// } +/// ``` +/// +/// If the current subscriber is interested in recording spans and events +/// in the current file and module path, with the target "my_crate", at +/// the level `DEBUG`, and with a field named "hello", this will evaluate +/// to true: +/// +/// ```rust +/// # use tracing::{enabled, Level}; +/// if enabled!(target: "my_crate", Level::DEBUG, hello) { +/// // some expensive work... +/// } +/// ``` +/// +/// # Alternatives +/// +/// `enabled!` queries subscribers with [`Metadata`] where +/// [`is_event`] and [`is_span`] both return `false`. Alternatively, +/// use [`event_enabled!`] or [`span_enabled!`] to ensure one of these +/// returns true. +/// +/// +/// [`Metadata`]: crate::Metadata +/// [`is_event`]: crate::Metadata::is_event +/// [`is_span`]: crate::Metadata::is_span +/// [`enabled!`]: crate::enabled +/// [`span_enabled!`]: crate::span_enabled +#[macro_export] +macro_rules! enabled { + (kind: $kind:expr, target: $target:expr, $lvl:expr, { $($fields:tt)* } )=> ({ + if $crate::level_enabled!($lvl) { + use $crate::__macro_support::Callsite as _; + static CALLSITE: $crate::callsite::DefaultCallsite = $crate::callsite2! { + name: $crate::__macro_support::concat!( + "enabled ", + file!(), + ":", + line!() + ), + kind: $kind.hint(), + target: $target, + level: $lvl, + fields: $($fields)* + }; + let interest = CALLSITE.interest(); + if !interest.is_never() && $crate::__macro_support::__is_enabled(CALLSITE.metadata(), interest) { + let meta = CALLSITE.metadata(); + $crate::dispatcher::get_default(|current| current.enabled(meta)) + } else { + false + } + } else { + false + } + }); + // Just target and level + (kind: $kind:expr, target: $target:expr, $lvl:expr ) => ( + $crate::enabled!(kind: $kind, target: $target, $lvl, { }) + ); + (target: $target:expr, $lvl:expr ) => ( + $crate::enabled!(kind: $crate::metadata::Kind::HINT, target: $target, $lvl, { }) + ); + + // These four cases handle fields with no values + (kind: $kind:expr, target: $target:expr, $lvl:expr, $($field:tt)*) => ( + $crate::enabled!( + kind: $kind, + target: $target, + $lvl, + { $($field)*} + ) + ); + (target: $target:expr, $lvl:expr, $($field:tt)*) => ( + $crate::enabled!( + kind: $crate::metadata::Kind::HINT, + target: $target, + $lvl, + { $($field)*} + ) + ); + + // Level and field case + (kind: $kind:expr, $lvl:expr, $($field:tt)*) => ( + $crate::enabled!( + kind: $kind, + target: module_path!(), + $lvl, + { $($field)*} + ) + ); + + // Simplest `enabled!` case + (kind: $kind:expr, $lvl:expr) => ( + $crate::enabled!(kind: $kind, target: module_path!(), $lvl, { }) + ); + ($lvl:expr) => ( + $crate::enabled!(kind: $crate::metadata::Kind::HINT, target: module_path!(), $lvl, { }) + ); + + // Fallthrough from above + ($lvl:expr, $($field:tt)*) => ( + $crate::enabled!( + kind: $crate::metadata::Kind::HINT, + target: module_path!(), + $lvl, + { $($field)*} + ) + ); +} + +/// Constructs an event at the trace level. +/// +/// This functions similarly to the [`event!`] macro. See [the top-level +/// documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [`event!`]: crate::event! +/// [lib]: crate#using-the-macros +/// +/// # Examples +/// +/// ```rust +/// use tracing::trace; +/// # #[derive(Debug, Copy, Clone)] struct Position { x: f32, y: f32 } +/// # impl Position { +/// # const ORIGIN: Self = Self { x: 0.0, y: 0.0 }; +/// # fn dist(&self, other: Position) -> f32 { +/// # let x = (other.x - self.x).exp2(); let y = (self.y - other.y).exp2(); +/// # (x + y).sqrt() +/// # } +/// # } +/// # fn main() { +/// let pos = Position { x: 3.234, y: -1.223 }; +/// let origin_dist = pos.dist(Position::ORIGIN); +/// +/// trace!(position = ?pos, ?origin_dist); +/// trace!( +/// target: "app_events", +/// position = ?pos, +/// "x is {} and y is {}", +/// if pos.x >= 0.0 { "positive" } else { "negative" }, +/// if pos.y >= 0.0 { "positive" } else { "negative" } +/// ); +/// # } +/// ``` +#[macro_export] +macro_rules! trace { + (target: $target:expr, parent: $parent:expr, { $($field:tt)* }, $($arg:tt)* ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::TRACE, { $($field)* }, $($arg)*) + ); + (target: $target:expr, parent: $parent:expr, $($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::TRACE, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, ?$($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::TRACE, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, %$($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::TRACE, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::TRACE, {}, $($arg)+) + ); + (parent: $parent:expr, { $($field:tt)+ }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::TRACE, + { $($field)+ }, + $($arg)+ + ) + ); + (parent: $parent:expr, $($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::TRACE, + { $($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, ?$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::TRACE, + { ?$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, %$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::TRACE, + { %$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, $($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::TRACE, + { $($k).+, $($field)*} + ) + ); + (parent: $parent:expr, ?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::TRACE, + { ?$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, %$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::TRACE, + { %$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, $($arg:tt)+) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::TRACE, + {}, + $($arg)+ + ) + ); + (target: $target:expr, { $($field:tt)* }, $($arg:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::TRACE, { $($field)* }, $($arg)*) + ); + (target: $target:expr, $($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::TRACE, { $($k).+ $($field)* }) + ); + (target: $target:expr, ?$($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::TRACE, { ?$($k).+ $($field)* }) + ); + (target: $target:expr, %$($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::TRACE, { %$($k).+ $($field)* }) + ); + (target: $target:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, $crate::Level::TRACE, {}, $($arg)+) + ); + ({ $($field:tt)+ }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + $crate::Level::TRACE, + { $($field)+ }, + $($arg)+ + ) + ); + ($($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::TRACE, + { $($k).+ = $($field)*} + ) + ); + ($($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::TRACE, + { $($k).+, $($field)*} + ) + ); + (?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::TRACE, + { ?$($k).+, $($field)*} + ) + ); + (%$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::TRACE, + { %$($k).+, $($field)*} + ) + ); + (?$($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::TRACE, + { ?$($k).+ } + ) + ); + (%$($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::TRACE, + { %$($k).+ } + ) + ); + ($($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::TRACE, + { $($k).+ } + ) + ); + ($($arg:tt)+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::TRACE, + {}, + $($arg)+ + ) + ); +} + +/// Constructs an event at the debug level. +/// +/// This functions similarly to the [`event!`] macro. See [the top-level +/// documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [`event!`]: crate::event! +/// [lib]: crate#using-the-macros +/// +/// # Examples +/// +/// ```rust +/// use tracing::debug; +/// # fn main() { +/// # #[derive(Debug)] struct Position { x: f32, y: f32 } +/// +/// let pos = Position { x: 3.234, y: -1.223 }; +/// +/// debug!(?pos.x, ?pos.y); +/// debug!(target: "app_events", position = ?pos, "New position"); +/// # } +/// ``` +#[macro_export] +macro_rules! debug { + (target: $target:expr, parent: $parent:expr, { $($field:tt)* }, $($arg:tt)* ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::DEBUG, { $($field)* }, $($arg)*) + ); + (target: $target:expr, parent: $parent:expr, $($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::DEBUG, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, ?$($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::DEBUG, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, %$($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::DEBUG, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::DEBUG, {}, $($arg)+) + ); + (parent: $parent:expr, { $($field:tt)+ }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::DEBUG, + { $($field)+ }, + $($arg)+ + ) + ); + (parent: $parent:expr, $($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::DEBUG, + { $($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, ?$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::DEBUG, + { ?$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, %$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::DEBUG, + { %$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, $($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::DEBUG, + { $($k).+, $($field)*} + ) + ); + (parent: $parent:expr, ?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::DEBUG, + { ?$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, %$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::DEBUG, + { %$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, $($arg:tt)+) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::DEBUG, + {}, + $($arg)+ + ) + ); + (target: $target:expr, { $($field:tt)* }, $($arg:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::DEBUG, { $($field)* }, $($arg)*) + ); + (target: $target:expr, $($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::DEBUG, { $($k).+ $($field)* }) + ); + (target: $target:expr, ?$($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::DEBUG, { ?$($k).+ $($field)* }) + ); + (target: $target:expr, %$($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::DEBUG, { %$($k).+ $($field)* }) + ); + (target: $target:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, $crate::Level::DEBUG, {}, $($arg)+) + ); + ({ $($field:tt)+ }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + { $($field)+ }, + $($arg)+ + ) + ); + ($($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + { $($k).+ = $($field)*} + ) + ); + (?$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + { ?$($k).+ = $($field)*} + ) + ); + (%$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + { %$($k).+ = $($field)*} + ) + ); + ($($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + { $($k).+, $($field)*} + ) + ); + (?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + { ?$($k).+, $($field)*} + ) + ); + (%$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + { %$($k).+, $($field)*} + ) + ); + (?$($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + { ?$($k).+ } + ) + ); + (%$($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + { %$($k).+ } + ) + ); + ($($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + { $($k).+ } + ) + ); + ($($arg:tt)+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::DEBUG, + {}, + $($arg)+ + ) + ); +} + +/// Constructs an event at the info level. +/// +/// This functions similarly to the [`event!`] macro. See [the top-level +/// documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [`event!`]: crate::event! +/// [lib]: crate#using-the-macros +/// +/// # Examples +/// +/// ```rust +/// use tracing::info; +/// # // this is so the test will still work in no-std mode +/// # #[derive(Debug)] +/// # pub struct Ipv4Addr; +/// # impl Ipv4Addr { fn new(o1: u8, o2: u8, o3: u8, o4: u8) -> Self { Self } } +/// # fn main() { +/// # struct Connection { port: u32, speed: f32 } +/// use tracing::field; +/// +/// let addr = Ipv4Addr::new(127, 0, 0, 1); +/// let conn = Connection { port: 40, speed: 3.20 }; +/// +/// info!(conn.port, "connected to {:?}", addr); +/// info!( +/// target: "connection_events", +/// ip = ?addr, +/// conn.port, +/// ?conn.speed, +/// ); +/// # } +/// ``` +#[macro_export] +macro_rules! info { + (target: $target:expr, parent: $parent:expr, { $($field:tt)* }, $($arg:tt)* ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::INFO, { $($field)* }, $($arg)*) + ); + (target: $target:expr, parent: $parent:expr, $($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::INFO, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, ?$($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::INFO, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, %$($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::INFO, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::INFO, {}, $($arg)+) + ); + (parent: $parent:expr, { $($field:tt)+ }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::INFO, + { $($field)+ }, + $($arg)+ + ) + ); + (parent: $parent:expr, $($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::INFO, + { $($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, ?$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::INFO, + { ?$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, %$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::INFO, + { %$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, $($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::INFO, + { $($k).+, $($field)*} + ) + ); + (parent: $parent:expr, ?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::INFO, + { ?$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, %$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::INFO, + { %$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, $($arg:tt)+) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::INFO, + {}, + $($arg)+ + ) + ); + (target: $target:expr, { $($field:tt)* }, $($arg:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::INFO, { $($field)* }, $($arg)*) + ); + (target: $target:expr, $($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::INFO, { $($k).+ $($field)* }) + ); + (target: $target:expr, ?$($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::INFO, { ?$($k).+ $($field)* }) + ); + (target: $target:expr, %$($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::INFO, { $($k).+ $($field)* }) + ); + (target: $target:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, $crate::Level::INFO, {}, $($arg)+) + ); + ({ $($field:tt)+ }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + { $($field)+ }, + $($arg)+ + ) + ); + ($($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + { $($k).+ = $($field)*} + ) + ); + (?$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + { ?$($k).+ = $($field)*} + ) + ); + (%$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + { %$($k).+ = $($field)*} + ) + ); + ($($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + { $($k).+, $($field)*} + ) + ); + (?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + { ?$($k).+, $($field)*} + ) + ); + (%$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + { %$($k).+, $($field)*} + ) + ); + (?$($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + { ?$($k).+ } + ) + ); + (%$($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + { %$($k).+ } + ) + ); + ($($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + { $($k).+ } + ) + ); + ($($arg:tt)+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::INFO, + {}, + $($arg)+ + ) + ); +} + +/// Constructs an event at the warn level. +/// +/// This functions similarly to the [`event!`] macro. See [the top-level +/// documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [`event!`]: crate::event! +/// [lib]: crate#using-the-macros +/// +/// # Examples +/// +/// ```rust +/// use tracing::warn; +/// # fn main() { +/// +/// let warn_description = "Invalid Input"; +/// let input = &[0x27, 0x45]; +/// +/// warn!(?input, warning = warn_description); +/// warn!( +/// target: "input_events", +/// warning = warn_description, +/// "Received warning for input: {:?}", input, +/// ); +/// # } +/// ``` +#[macro_export] +macro_rules! warn { + (target: $target:expr, parent: $parent:expr, { $($field:tt)* }, $($arg:tt)* ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::WARN, { $($field)* }, $($arg)*) + ); + (target: $target:expr, parent: $parent:expr, $($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::WARN, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, ?$($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::WARN, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, %$($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::WARN, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::WARN, {}, $($arg)+) + ); + (parent: $parent:expr, { $($field:tt)+ }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::WARN, + { $($field)+ }, + $($arg)+ + ) + ); + (parent: $parent:expr, $($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::WARN, + { $($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, ?$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::WARN, + { ?$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, %$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::WARN, + { %$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, $($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::WARN, + { $($k).+, $($field)*} + ) + ); + (parent: $parent:expr, ?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::WARN, + { ?$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, %$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::WARN, + { %$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, $($arg:tt)+) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::WARN, + {}, + $($arg)+ + ) + ); + (target: $target:expr, { $($field:tt)* }, $($arg:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::WARN, { $($field)* }, $($arg)*) + ); + (target: $target:expr, $($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::WARN, { $($k).+ $($field)* }) + ); + (target: $target:expr, ?$($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::WARN, { ?$($k).+ $($field)* }) + ); + (target: $target:expr, %$($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::WARN, { %$($k).+ $($field)* }) + ); + (target: $target:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, $crate::Level::WARN, {}, $($arg)+) + ); + ({ $($field:tt)+ }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + { $($field)+ }, + $($arg)+ + ) + ); + ($($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + { $($k).+ = $($field)*} + ) + ); + (?$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + { ?$($k).+ = $($field)*} + ) + ); + (%$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + { %$($k).+ = $($field)*} + ) + ); + ($($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + { $($k).+, $($field)*} + ) + ); + (?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + { ?$($k).+, $($field)*} + ) + ); + (%$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + { %$($k).+, $($field)*} + ) + ); + (?$($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + { ?$($k).+ } + ) + ); + (%$($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + { %$($k).+ } + ) + ); + ($($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + { $($k).+ } + ) + ); + ($($arg:tt)+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::WARN, + {}, + $($arg)+ + ) + ); +} + +/// Constructs an event at the error level. +/// +/// This functions similarly to the [`event!`] macro. See [the top-level +/// documentation][lib] for details on the syntax accepted by +/// this macro. +/// +/// [`event!`]: crate::event! +/// [lib]: crate#using-the-macros +/// +/// # Examples +/// +/// ```rust +/// use tracing::error; +/// # fn main() { +/// +/// let (err_info, port) = ("No connection", 22); +/// +/// error!(port, error = %err_info); +/// error!(target: "app_events", "App Error: {}", err_info); +/// error!({ info = err_info }, "error on port: {}", port); +/// # } +/// ``` +#[macro_export] +macro_rules! error { + (target: $target:expr, parent: $parent:expr, { $($field:tt)* }, $($arg:tt)* ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::ERROR, { $($field)* }, $($arg)*) + ); + (target: $target:expr, parent: $parent:expr, $($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::ERROR, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, ?$($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::ERROR, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, %$($k:ident).+ $($field:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::ERROR, { $($k).+ $($field)+ }) + ); + (target: $target:expr, parent: $parent:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, parent: $parent, $crate::Level::ERROR, {}, $($arg)+) + ); + (parent: $parent:expr, { $($field:tt)+ }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::ERROR, + { $($field)+ }, + $($arg)+ + ) + ); + (parent: $parent:expr, $($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::ERROR, + { $($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, ?$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::ERROR, + { ?$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, %$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::ERROR, + { %$($k).+ = $($field)*} + ) + ); + (parent: $parent:expr, $($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::ERROR, + { $($k).+, $($field)*} + ) + ); + (parent: $parent:expr, ?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::ERROR, + { ?$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, %$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::ERROR, + { %$($k).+, $($field)*} + ) + ); + (parent: $parent:expr, $($arg:tt)+) => ( + $crate::event!( + target: module_path!(), + parent: $parent, + $crate::Level::ERROR, + {}, + $($arg)+ + ) + ); + (target: $target:expr, { $($field:tt)* }, $($arg:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::ERROR, { $($field)* }, $($arg)*) + ); + (target: $target:expr, $($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::ERROR, { $($k).+ $($field)* }) + ); + (target: $target:expr, ?$($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::ERROR, { ?$($k).+ $($field)* }) + ); + (target: $target:expr, %$($k:ident).+ $($field:tt)* ) => ( + $crate::event!(target: $target, $crate::Level::ERROR, { %$($k).+ $($field)* }) + ); + (target: $target:expr, $($arg:tt)+ ) => ( + $crate::event!(target: $target, $crate::Level::ERROR, {}, $($arg)+) + ); + ({ $($field:tt)+ }, $($arg:tt)+ ) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + { $($field)+ }, + $($arg)+ + ) + ); + ($($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + { $($k).+ = $($field)*} + ) + ); + (?$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + { ?$($k).+ = $($field)*} + ) + ); + (%$($k:ident).+ = $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + { %$($k).+ = $($field)*} + ) + ); + ($($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + { $($k).+, $($field)*} + ) + ); + (?$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + { ?$($k).+, $($field)*} + ) + ); + (%$($k:ident).+, $($field:tt)*) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + { %$($k).+, $($field)*} + ) + ); + (?$($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + { ?$($k).+ } + ) + ); + (%$($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + { %$($k).+ } + ) + ); + ($($k:ident).+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + { $($k).+ } + ) + ); + ($($arg:tt)+) => ( + $crate::event!( + target: module_path!(), + $crate::Level::ERROR, + {}, + $($arg)+ + ) + ); +} + +/// Constructs a new static callsite for a span or event. +#[doc(hidden)] +#[macro_export] +macro_rules! callsite { + (name: $name:expr, kind: $kind:expr, fields: $($fields:tt)*) => {{ + $crate::callsite! { + name: $name, + kind: $kind, + target: module_path!(), + level: $crate::Level::TRACE, + fields: $($fields)* + } + }}; + ( + name: $name:expr, + kind: $kind:expr, + level: $lvl:expr, + fields: $($fields:tt)* + ) => {{ + $crate::callsite! { + name: $name, + kind: $kind, + target: module_path!(), + level: $lvl, + fields: $($fields)* + } + }}; + ( + name: $name:expr, + kind: $kind:expr, + target: $target:expr, + level: $lvl:expr, + fields: $($fields:tt)* + ) => {{ + static META: $crate::Metadata<'static> = { + $crate::metadata! { + name: $name, + target: $target, + level: $lvl, + fields: $crate::fieldset!( $($fields)* ), + callsite: &CALLSITE, + kind: $kind, + } + }; + static CALLSITE: $crate::callsite::DefaultCallsite = $crate::callsite::DefaultCallsite::new(&META); + CALLSITE.register(); + &CALLSITE + }}; +} + +/// Constructs a new static callsite for a span or event. +#[doc(hidden)] +#[macro_export] +macro_rules! callsite2 { + (name: $name:expr, kind: $kind:expr, fields: $($fields:tt)*) => {{ + $crate::callsite2! { + name: $name, + kind: $kind, + target: module_path!(), + level: $crate::Level::TRACE, + fields: $($fields)* + } + }}; + ( + name: $name:expr, + kind: $kind:expr, + level: $lvl:expr, + fields: $($fields:tt)* + ) => {{ + $crate::callsite2! { + name: $name, + kind: $kind, + target: module_path!(), + level: $lvl, + fields: $($fields)* + } + }}; + ( + name: $name:expr, + kind: $kind:expr, + target: $target:expr, + level: $lvl:expr, + fields: $($fields:tt)* + ) => {{ + static META: $crate::Metadata<'static> = { + $crate::metadata! { + name: $name, + target: $target, + level: $lvl, + fields: $crate::fieldset!( $($fields)* ), + callsite: &CALLSITE, + kind: $kind, + } + }; + $crate::callsite::DefaultCallsite::new(&META) + }}; +} + +#[macro_export] +// TODO: determine if this ought to be public API?` +#[doc(hidden)] +macro_rules! level_enabled { + ($lvl:expr) => { + $lvl <= $crate::level_filters::STATIC_MAX_LEVEL + && $lvl <= $crate::level_filters::LevelFilter::current() + }; +} + +#[doc(hidden)] +#[macro_export] +macro_rules! valueset { + + // === base case === + (@ { $(,)* $($val:expr),* $(,)* }, $next:expr $(,)*) => { + &[ $($val),* ] + }; + + // === recursive case (more tts) === + + // TODO(#1138): determine a new syntax for uninitialized span fields, and + // re-enable this. + // (@{ $(,)* $($out:expr),* }, $next:expr, $($k:ident).+ = _, $($rest:tt)*) => { + // $crate::valueset!(@ { $($out),*, (&$next, None) }, $next, $($rest)*) + // }; + (@ { $(,)* $($out:expr),* }, $next:expr, $($k:ident).+ = ?$val:expr, $($rest:tt)*) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&debug(&$val) as &Value)) }, + $next, + $($rest)* + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $($k:ident).+ = %$val:expr, $($rest:tt)*) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&display(&$val) as &Value)) }, + $next, + $($rest)* + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $($k:ident).+ = $val:expr, $($rest:tt)*) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&$val as &Value)) }, + $next, + $($rest)* + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $($k:ident).+, $($rest:tt)*) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&$($k).+ as &Value)) }, + $next, + $($rest)* + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, ?$($k:ident).+, $($rest:tt)*) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&debug(&$($k).+) as &Value)) }, + $next, + $($rest)* + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, %$($k:ident).+, $($rest:tt)*) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&display(&$($k).+) as &Value)) }, + $next, + $($rest)* + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $($k:ident).+ = ?$val:expr) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&debug(&$val) as &Value)) }, + $next, + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $($k:ident).+ = %$val:expr) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&display(&$val) as &Value)) }, + $next, + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $($k:ident).+ = $val:expr) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&$val as &Value)) }, + $next, + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $($k:ident).+) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&$($k).+ as &Value)) }, + $next, + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, ?$($k:ident).+) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&debug(&$($k).+) as &Value)) }, + $next, + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, %$($k:ident).+) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&display(&$($k).+) as &Value)) }, + $next, + ) + }; + + // Handle literal names + (@ { $(,)* $($out:expr),* }, $next:expr, $k:literal = ?$val:expr, $($rest:tt)*) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&debug(&$val) as &Value)) }, + $next, + $($rest)* + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $k:literal = %$val:expr, $($rest:tt)*) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&display(&$val) as &Value)) }, + $next, + $($rest)* + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $k:literal = $val:expr, $($rest:tt)*) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&$val as &Value)) }, + $next, + $($rest)* + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $k:literal = ?$val:expr) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&debug(&$val) as &Value)) }, + $next, + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $k:literal = %$val:expr) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&display(&$val) as &Value)) }, + $next, + ) + }; + (@ { $(,)* $($out:expr),* }, $next:expr, $k:literal = $val:expr) => { + $crate::valueset!( + @ { $($out),*, (&$next, Some(&$val as &Value)) }, + $next, + ) + }; + + // Remainder is unparseable, but exists --- must be format args! + (@ { $(,)* $($out:expr),* }, $next:expr, $($rest:tt)+) => { + $crate::valueset!(@ { (&$next, Some(&format_args!($($rest)+) as &Value)), $($out),* }, $next, ) + }; + + // === entry === + ($fields:expr, $($kvs:tt)+) => { + { + #[allow(unused_imports)] + use $crate::field::{debug, display, Value}; + let mut iter = $fields.iter(); + $fields.value_set($crate::valueset!( + @ { }, + iter.next().expect("FieldSet corrupted (this is a bug)"), + $($kvs)+ + )) + } + }; + ($fields:expr,) => { + { + $fields.value_set(&[]) + } + }; +} + +#[doc(hidden)] +#[macro_export] +macro_rules! fieldset { + // == base case == + (@ { $(,)* $($out:expr),* $(,)* } $(,)*) => { + &[ $($out),* ] + }; + + // == recursive cases (more tts) == + (@ { $(,)* $($out:expr),* } $($k:ident).+ = ?$val:expr, $($rest:tt)*) => { + $crate::fieldset!(@ { $($out),*, $crate::__tracing_stringify!($($k).+) } $($rest)*) + }; + (@ { $(,)* $($out:expr),* } $($k:ident).+ = %$val:expr, $($rest:tt)*) => { + $crate::fieldset!(@ { $($out),*, $crate::__tracing_stringify!($($k).+) } $($rest)*) + }; + (@ { $(,)* $($out:expr),* } $($k:ident).+ = $val:expr, $($rest:tt)*) => { + $crate::fieldset!(@ { $($out),*, $crate::__tracing_stringify!($($k).+) } $($rest)*) + }; + // TODO(#1138): determine a new syntax for uninitialized span fields, and + // re-enable this. + // (@ { $($out:expr),* } $($k:ident).+ = _, $($rest:tt)*) => { + // $crate::fieldset!(@ { $($out),*, $crate::__tracing_stringify!($($k).+) } $($rest)*) + // }; + (@ { $(,)* $($out:expr),* } ?$($k:ident).+, $($rest:tt)*) => { + $crate::fieldset!(@ { $($out),*, $crate::__tracing_stringify!($($k).+) } $($rest)*) + }; + (@ { $(,)* $($out:expr),* } %$($k:ident).+, $($rest:tt)*) => { + $crate::fieldset!(@ { $($out),*, $crate::__tracing_stringify!($($k).+) } $($rest)*) + }; + (@ { $(,)* $($out:expr),* } $($k:ident).+, $($rest:tt)*) => { + $crate::fieldset!(@ { $($out),*, $crate::__tracing_stringify!($($k).+) } $($rest)*) + }; + + // Handle literal names + (@ { $(,)* $($out:expr),* } $k:literal = ?$val:expr, $($rest:tt)*) => { + $crate::fieldset!(@ { $($out),*, $k } $($rest)*) + }; + (@ { $(,)* $($out:expr),* } $k:literal = %$val:expr, $($rest:tt)*) => { + $crate::fieldset!(@ { $($out),*, $k } $($rest)*) + }; + (@ { $(,)* $($out:expr),* } $k:literal = $val:expr, $($rest:tt)*) => { + $crate::fieldset!(@ { $($out),*, $k } $($rest)*) + }; + + // Remainder is unparseable, but exists --- must be format args! + (@ { $(,)* $($out:expr),* } $($rest:tt)+) => { + $crate::fieldset!(@ { "message", $($out),*, }) + }; + + // == entry == + ($($args:tt)*) => { + $crate::fieldset!(@ { } $($args)*,) + }; + +} + +#[cfg(feature = "log")] +#[doc(hidden)] +#[macro_export] +macro_rules! level_to_log { + ($level:expr) => { + match $level { + $crate::Level::ERROR => $crate::log::Level::Error, + $crate::Level::WARN => $crate::log::Level::Warn, + $crate::Level::INFO => $crate::log::Level::Info, + $crate::Level::DEBUG => $crate::log::Level::Debug, + _ => $crate::log::Level::Trace, + } + }; +} + +#[doc(hidden)] +#[macro_export] +macro_rules! __tracing_stringify { + ($s:expr) => { + stringify!($s) + }; +} + +#[cfg(not(feature = "log"))] +#[doc(hidden)] +#[macro_export] +macro_rules! __tracing_log { + ($level:expr, $callsite:expr, $value_set:expr) => {}; +} + +#[cfg(feature = "log")] +#[doc(hidden)] +#[macro_export] +macro_rules! __tracing_log { + ($level:expr, $callsite:expr, $value_set:expr) => { + $crate::if_log_enabled! { $level, { + use $crate::log; + let level = $crate::level_to_log!($level); + if level <= log::max_level() { + let meta = $callsite.metadata(); + let log_meta = log::Metadata::builder() + .level(level) + .target(meta.target()) + .build(); + let logger = log::logger(); + if logger.enabled(&log_meta) { + $crate::__macro_support::__tracing_log(meta, logger, log_meta, $value_set) + } + } + }} + }; +} + +#[cfg(not(feature = "log"))] +#[doc(hidden)] +#[macro_export] +macro_rules! if_log_enabled { + ($lvl:expr, $e:expr;) => { + $crate::if_log_enabled! { $lvl, $e } + }; + ($lvl:expr, $if_log:block) => { + $crate::if_log_enabled! { $lvl, $if_log else {} } + }; + ($lvl:expr, $if_log:block else $else_block:block) => { + $else_block + }; +} + +#[cfg(all(feature = "log", not(feature = "log-always")))] +#[doc(hidden)] +#[macro_export] +macro_rules! if_log_enabled { + ($lvl:expr, $e:expr;) => { + $crate::if_log_enabled! { $lvl, $e } + }; + ($lvl:expr, $if_log:block) => { + $crate::if_log_enabled! { $lvl, $if_log else {} } + }; + ($lvl:expr, $if_log:block else $else_block:block) => { + if $crate::level_to_log!($lvl) <= $crate::log::STATIC_MAX_LEVEL { + if !$crate::dispatcher::has_been_set() { + $if_log + } else { + $else_block + } + } else { + $else_block + } + }; +} + +#[cfg(all(feature = "log", feature = "log-always"))] +#[doc(hidden)] +#[macro_export] +macro_rules! if_log_enabled { + ($lvl:expr, $e:expr;) => { + $crate::if_log_enabled! { $lvl, $e } + }; + ($lvl:expr, $if_log:block) => { + $crate::if_log_enabled! { $lvl, $if_log else {} } + }; + ($lvl:expr, $if_log:block else $else_block:block) => { + if $crate::level_to_log!($lvl) <= $crate::log::STATIC_MAX_LEVEL { + #[allow(unused_braces)] + $if_log + } else { + $else_block + } + }; +} diff --git a/vendor/tracing/src/span.rs b/vendor/tracing/src/span.rs new file mode 100644 index 000000000..21358eb27 --- /dev/null +++ b/vendor/tracing/src/span.rs @@ -0,0 +1,1617 @@ +//! Spans represent periods of time in which a program was executing in a +//! particular context. +//! +//! A span consists of [fields], user-defined key-value pairs of arbitrary data +//! that describe the context the span represents, and a set of fixed attributes +//! that describe all `tracing` spans and events. Attributes describing spans +//! include: +//! +//! - An [`Id`] assigned by the subscriber that uniquely identifies it in relation +//! to other spans. +//! - The span's [parent] in the trace tree. +//! - [Metadata] that describes static characteristics of all spans +//! originating from that callsite, such as its name, source code location, +//! [verbosity level], and the names of its fields. +//! +//! # Creating Spans +//! +//! Spans are created using the [`span!`] macro. This macro is invoked with the +//! following arguments, in order: +//! +//! - The [`target`] and/or [`parent`][parent] attributes, if the user wishes to +//! override their default values. +//! - The span's [verbosity level] +//! - A string literal providing the span's name. +//! - Finally, between zero and 32 arbitrary key/value fields. +//! +//! [`target`]: super::Metadata::target +//! +//! For example: +//! ```rust +//! use tracing::{span, Level}; +//! +//! /// Construct a new span at the `INFO` level named "my_span", with a single +//! /// field named answer , with the value `42`. +//! let my_span = span!(Level::INFO, "my_span", answer = 42); +//! ``` +//! +//! The documentation for the [`span!`] macro provides additional examples of +//! the various options that exist when creating spans. +//! +//! The [`trace_span!`], [`debug_span!`], [`info_span!`], [`warn_span!`], and +//! [`error_span!`] exist as shorthand for constructing spans at various +//! verbosity levels. +//! +//! ## Recording Span Creation +//! +//! The [`Attributes`] type contains data associated with a span, and is +//! provided to the [`Subscriber`] when a new span is created. It contains +//! the span's metadata, the ID of [the span's parent][parent] if one was +//! explicitly set, and any fields whose values were recorded when the span was +//! constructed. The subscriber, which is responsible for recording `tracing` +//! data, can then store or record these values. +//! +//! # The Span Lifecycle +//! +//! ## Entering a Span +//! +//! A thread of execution is said to _enter_ a span when it begins executing, +//! and _exit_ the span when it switches to another context. Spans may be +//! entered through the [`enter`], [`entered`], and [`in_scope`] methods. +//! +//! The [`enter`] method enters a span, returning a [guard] that exits the span +//! when dropped +//! ``` +//! # use tracing::{span, Level}; +//! let my_var: u64 = 5; +//! let my_span = span!(Level::TRACE, "my_span", my_var); +//! +//! // `my_span` exists but has not been entered. +//! +//! // Enter `my_span`... +//! let _enter = my_span.enter(); +//! +//! // Perform some work inside of the context of `my_span`... +//! // Dropping the `_enter` guard will exit the span. +//!``` +//! +//! <div class="example-wrap" style="display:inline-block"><pre class="compile_fail" style="white-space:normal;font:inherit;"> +//! <strong>Warning</strong>: In asynchronous code that uses async/await syntax, +//! <code>Span::enter</code> may produce incorrect traces if the returned drop +//! guard is held across an await point. See +//! <a href="struct.Span.html#in-asynchronous-code">the method documentation</a> +//! for details. +//! </pre></div> +//! +//! The [`entered`] method is analogous to [`enter`], but moves the span into +//! the returned guard, rather than borrowing it. This allows creating and +//! entering a span in a single expression: +//! +//! ``` +//! # use tracing::{span, Level}; +//! // Create a span and enter it, returning a guard: +//! let span = span!(Level::INFO, "my_span").entered(); +//! +//! // We are now inside the span! Like `enter()`, the guard returned by +//! // `entered()` will exit the span when it is dropped... +//! +//! // ...but, it can also be exited explicitly, returning the `Span` +//! // struct: +//! let span = span.exit(); +//! ``` +//! +//! Finally, [`in_scope`] takes a closure or function pointer and executes it +//! inside the span: +//! +//! ``` +//! # use tracing::{span, Level}; +//! let my_var: u64 = 5; +//! let my_span = span!(Level::TRACE, "my_span", my_var = &my_var); +//! +//! my_span.in_scope(|| { +//! // perform some work in the context of `my_span`... +//! }); +//! +//! // Perform some work outside of the context of `my_span`... +//! +//! my_span.in_scope(|| { +//! // Perform some more work in the context of `my_span`. +//! }); +//! ``` +//! +//! <pre class="ignore" style="white-space:normal;font:inherit;"> +//! <strong>Note</strong>: Since entering a span takes <code>&self</code>, and +//! <code>Span</code>s are <code>Clone</code>, <code>Send</code>, and +//! <code>Sync</code>, it is entirely valid for multiple threads to enter the +//! same span concurrently. +//! </pre> +//! +//! ## Span Relationships +//! +//! Spans form a tree structure — unless it is a root span, all spans have a +//! _parent_, and may have one or more _children_. When a new span is created, +//! the current span becomes the new span's parent. The total execution time of +//! a span consists of the time spent in that span and in the entire subtree +//! represented by its children. Thus, a parent span always lasts for at least +//! as long as the longest-executing span in its subtree. +//! +//! ``` +//! # use tracing::{Level, span}; +//! // this span is considered the "root" of a new trace tree: +//! span!(Level::INFO, "root").in_scope(|| { +//! // since we are now inside "root", this span is considered a child +//! // of "root": +//! span!(Level::DEBUG, "outer_child").in_scope(|| { +//! // this span is a child of "outer_child", which is in turn a +//! // child of "root": +//! span!(Level::TRACE, "inner_child").in_scope(|| { +//! // and so on... +//! }); +//! }); +//! // another span created here would also be a child of "root". +//! }); +//!``` +//! +//! In addition, the parent of a span may be explicitly specified in +//! the `span!` macro. For example: +//! +//! ```rust +//! # use tracing::{Level, span}; +//! // Create, but do not enter, a span called "foo". +//! let foo = span!(Level::INFO, "foo"); +//! +//! // Create and enter a span called "bar". +//! let bar = span!(Level::INFO, "bar"); +//! let _enter = bar.enter(); +//! +//! // Although we have currently entered "bar", "baz"'s parent span +//! // will be "foo". +//! let baz = span!(parent: &foo, Level::INFO, "baz"); +//! ``` +//! +//! A child span should typically be considered _part_ of its parent. For +//! example, if a subscriber is recording the length of time spent in various +//! spans, it should generally include the time spent in a span's children as +//! part of that span's duration. +//! +//! In addition to having zero or one parent, a span may also _follow from_ any +//! number of other spans. This indicates a causal relationship between the span +//! and the spans that it follows from, but a follower is *not* typically +//! considered part of the duration of the span it follows. Unlike the parent, a +//! span may record that it follows from another span after it is created, using +//! the [`follows_from`] method. +//! +//! As an example, consider a listener task in a server. As the listener accepts +//! incoming connections, it spawns new tasks that handle those connections. We +//! might want to have a span representing the listener, and instrument each +//! spawned handler task with its own span. We would want our instrumentation to +//! record that the handler tasks were spawned as a result of the listener task. +//! However, we might not consider the handler tasks to be _part_ of the time +//! spent in the listener task, so we would not consider those spans children of +//! the listener span. Instead, we would record that the handler tasks follow +//! from the listener, recording the causal relationship but treating the spans +//! as separate durations. +//! +//! ## Closing Spans +//! +//! Execution may enter and exit a span multiple times before that span is +//! _closed_. Consider, for example, a future which has an associated +//! span and enters that span every time it is polled: +//! ```rust +//! # use std::future::Future; +//! # use std::task::{Context, Poll}; +//! # use std::pin::Pin; +//! struct MyFuture { +//! // data +//! span: tracing::Span, +//! } +//! +//! impl Future for MyFuture { +//! type Output = (); +//! +//! fn poll(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Self::Output> { +//! let _enter = self.span.enter(); +//! // Do actual future work... +//! # Poll::Ready(()) +//! } +//! } +//! ``` +//! +//! If this future was spawned on an executor, it might yield one or more times +//! before `poll` returns [`Poll::Ready`]. If the future were to yield, then +//! the executor would move on to poll the next future, which may _also_ enter +//! an associated span or series of spans. Therefore, it is valid for a span to +//! be entered repeatedly before it completes. Only the time when that span or +//! one of its children was the current span is considered to be time spent in +//! that span. A span which is not executing and has not yet been closed is said +//! to be _idle_. +//! +//! Because spans may be entered and exited multiple times before they close, +//! [`Subscriber`]s have separate trait methods which are called to notify them +//! of span exits and when span handles are dropped. When execution exits a +//! span, [`exit`] will always be called with that span's ID to notify the +//! subscriber that the span has been exited. When span handles are dropped, the +//! [`drop_span`] method is called with that span's ID. The subscriber may use +//! this to determine whether or not the span will be entered again. +//! +//! If there is only a single handle with the capacity to exit a span, dropping +//! that handle "closes" the span, since the capacity to enter it no longer +//! exists. For example: +//! ``` +//! # use tracing::{Level, span}; +//! { +//! span!(Level::TRACE, "my_span").in_scope(|| { +//! // perform some work in the context of `my_span`... +//! }); // --> Subscriber::exit(my_span) +//! +//! // The handle to `my_span` only lives inside of this block; when it is +//! // dropped, the subscriber will be informed via `drop_span`. +//! +//! } // --> Subscriber::drop_span(my_span) +//! ``` +//! +//! However, if multiple handles exist, the span can still be re-entered even if +//! one or more is dropped. For determining when _all_ handles to a span have +//! been dropped, `Subscriber`s have a [`clone_span`] method, which is called +//! every time a span handle is cloned. Combined with `drop_span`, this may be +//! used to track the number of handles to a given span — if `drop_span` has +//! been called one more time than the number of calls to `clone_span` for a +//! given ID, then no more handles to the span with that ID exist. The +//! subscriber may then treat it as closed. +//! +//! # When to use spans +//! +//! As a rule of thumb, spans should be used to represent discrete units of work +//! (e.g., a given request's lifetime in a server) or periods of time spent in a +//! given context (e.g., time spent interacting with an instance of an external +//! system, such as a database). +//! +//! Which scopes in a program correspond to new spans depend somewhat on user +//! intent. For example, consider the case of a loop in a program. Should we +//! construct one span and perform the entire loop inside of that span, like: +//! +//! ```rust +//! # use tracing::{Level, span}; +//! # let n = 1; +//! let span = span!(Level::TRACE, "my_loop"); +//! let _enter = span.enter(); +//! for i in 0..n { +//! # let _ = i; +//! // ... +//! } +//! ``` +//! Or, should we create a new span for each iteration of the loop, as in: +//! ```rust +//! # use tracing::{Level, span}; +//! # let n = 1u64; +//! for i in 0..n { +//! let span = span!(Level::TRACE, "my_loop", iteration = i); +//! let _enter = span.enter(); +//! // ... +//! } +//! ``` +//! +//! Depending on the circumstances, we might want to do either, or both. For +//! example, if we want to know how long was spent in the loop overall, we would +//! create a single span around the entire loop; whereas if we wanted to know how +//! much time was spent in each individual iteration, we would enter a new span +//! on every iteration. +//! +//! [fields]: super::field +//! [Metadata]: super::Metadata +//! [verbosity level]: super::Level +//! [`Poll::Ready`]: std::task::Poll::Ready +//! [`span!`]: super::span! +//! [`trace_span!`]: super::trace_span! +//! [`debug_span!`]: super::debug_span! +//! [`info_span!`]: super::info_span! +//! [`warn_span!`]: super::warn_span! +//! [`error_span!`]: super::error_span! +//! [`clone_span`]: super::subscriber::Subscriber::clone_span() +//! [`drop_span`]: super::subscriber::Subscriber::drop_span() +//! [`exit`]: super::subscriber::Subscriber::exit +//! [`Subscriber`]: super::subscriber::Subscriber +//! [`enter`]: Span::enter() +//! [`entered`]: Span::entered() +//! [`in_scope`]: Span::in_scope() +//! [`follows_from`]: Span::follows_from() +//! [guard]: Entered +//! [parent]: #span-relationships +pub use tracing_core::span::{Attributes, Id, Record}; + +use crate::stdlib::{ + cmp, fmt, + hash::{Hash, Hasher}, + marker::PhantomData, + mem, + ops::Deref, +}; +use crate::{ + dispatcher::{self, Dispatch}, + field, Metadata, +}; + +/// Trait implemented by types which have a span `Id`. +pub trait AsId: crate::sealed::Sealed { + /// Returns the `Id` of the span that `self` corresponds to, or `None` if + /// this corresponds to a disabled span. + fn as_id(&self) -> Option<&Id>; +} + +/// A handle representing a span, with the capability to enter the span if it +/// exists. +/// +/// If the span was rejected by the current `Subscriber`'s filter, entering the +/// span will silently do nothing. Thus, the handle can be used in the same +/// manner regardless of whether or not the trace is currently being collected. +#[derive(Clone)] +pub struct Span { + /// A handle used to enter the span when it is not executing. + /// + /// If this is `None`, then the span has either closed or was never enabled. + inner: Option<Inner>, + /// Metadata describing the span. + /// + /// This might be `Some` even if `inner` is `None`, in the case that the + /// span is disabled but the metadata is needed for `log` support. + meta: Option<&'static Metadata<'static>>, +} + +/// A handle representing the capacity to enter a span which is known to exist. +/// +/// Unlike `Span`, this type is only constructed for spans which _have_ been +/// enabled by the current filter. This type is primarily used for implementing +/// span handles; users should typically not need to interact with it directly. +#[derive(Debug)] +pub(crate) struct Inner { + /// The span's ID, as provided by `subscriber`. + id: Id, + + /// The subscriber that will receive events relating to this span. + /// + /// This should be the same subscriber that provided this span with its + /// `id`. + subscriber: Dispatch, +} + +/// A guard representing a span which has been entered and is currently +/// executing. +/// +/// When the guard is dropped, the span will be exited. +/// +/// This is returned by the [`Span::enter`] function. +/// +/// [`Span::enter`]: super::Span::enter +#[derive(Debug)] +#[must_use = "once a span has been entered, it should be exited"] +pub struct Entered<'a> { + span: &'a Span, +} + +/// An owned version of [`Entered`], a guard representing a span which has been +/// entered and is currently executing. +/// +/// When the guard is dropped, the span will be exited. +/// +/// This is returned by the [`Span::entered`] function. +/// +/// [`Span::entered`]: super::Span::entered() +#[derive(Debug)] +#[must_use = "once a span has been entered, it should be exited"] +pub struct EnteredSpan { + span: Span, + + /// ```compile_fail + /// use tracing::span::*; + /// trait AssertSend: Send {} + /// + /// impl AssertSend for EnteredSpan {} + /// ``` + _not_send: PhantomNotSend, +} + +/// `log` target for all span lifecycle (creation/enter/exit/close) records. +#[cfg(feature = "log")] +const LIFECYCLE_LOG_TARGET: &str = "tracing::span"; +/// `log` target for span activity (enter/exit) records. +#[cfg(feature = "log")] +const ACTIVITY_LOG_TARGET: &str = "tracing::span::active"; + +// ===== impl Span ===== + +impl Span { + /// Constructs a new `Span` with the given [metadata] and set of + /// [field values]. + /// + /// The new span will be constructed by the currently-active [`Subscriber`], + /// with the current span as its parent (if one exists). + /// + /// After the span is constructed, [field values] and/or [`follows_from`] + /// annotations may be added to it. + /// + /// [metadata]: super::Metadata + /// [`Subscriber`]: super::subscriber::Subscriber + /// [field values]: super::field::ValueSet + /// [`follows_from`]: super::Span::follows_from + pub fn new(meta: &'static Metadata<'static>, values: &field::ValueSet<'_>) -> Span { + dispatcher::get_default(|dispatch| Self::new_with(meta, values, dispatch)) + } + + #[inline] + #[doc(hidden)] + pub fn new_with( + meta: &'static Metadata<'static>, + values: &field::ValueSet<'_>, + dispatch: &Dispatch, + ) -> Span { + let new_span = Attributes::new(meta, values); + Self::make_with(meta, new_span, dispatch) + } + + /// Constructs a new `Span` as the root of its own trace tree, with the + /// given [metadata] and set of [field values]. + /// + /// After the span is constructed, [field values] and/or [`follows_from`] + /// annotations may be added to it. + /// + /// [metadata]: super::Metadata + /// [field values]: super::field::ValueSet + /// [`follows_from`]: super::Span::follows_from + pub fn new_root(meta: &'static Metadata<'static>, values: &field::ValueSet<'_>) -> Span { + dispatcher::get_default(|dispatch| Self::new_root_with(meta, values, dispatch)) + } + + #[inline] + #[doc(hidden)] + pub fn new_root_with( + meta: &'static Metadata<'static>, + values: &field::ValueSet<'_>, + dispatch: &Dispatch, + ) -> Span { + let new_span = Attributes::new_root(meta, values); + Self::make_with(meta, new_span, dispatch) + } + + /// Constructs a new `Span` as child of the given parent span, with the + /// given [metadata] and set of [field values]. + /// + /// After the span is constructed, [field values] and/or [`follows_from`] + /// annotations may be added to it. + /// + /// [metadata]: super::Metadata + /// [field values]: super::field::ValueSet + /// [`follows_from`]: super::Span::follows_from + pub fn child_of( + parent: impl Into<Option<Id>>, + meta: &'static Metadata<'static>, + values: &field::ValueSet<'_>, + ) -> Span { + let mut parent = parent.into(); + dispatcher::get_default(move |dispatch| { + Self::child_of_with(Option::take(&mut parent), meta, values, dispatch) + }) + } + + #[inline] + #[doc(hidden)] + pub fn child_of_with( + parent: impl Into<Option<Id>>, + meta: &'static Metadata<'static>, + values: &field::ValueSet<'_>, + dispatch: &Dispatch, + ) -> Span { + let new_span = match parent.into() { + Some(parent) => Attributes::child_of(parent, meta, values), + None => Attributes::new_root(meta, values), + }; + Self::make_with(meta, new_span, dispatch) + } + + /// Constructs a new disabled span with the given `Metadata`. + /// + /// This should be used when a span is constructed from a known callsite, + /// but the subscriber indicates that it is disabled. + /// + /// Entering, exiting, and recording values on this span will not notify the + /// `Subscriber` but _may_ record log messages if the `log` feature flag is + /// enabled. + #[inline(always)] + pub fn new_disabled(meta: &'static Metadata<'static>) -> Span { + Self { + inner: None, + meta: Some(meta), + } + } + + /// Constructs a new span that is *completely disabled*. + /// + /// This can be used rather than `Option<Span>` to represent cases where a + /// span is not present. + /// + /// Entering, exiting, and recording values on this span will do nothing. + #[inline(always)] + pub const fn none() -> Span { + Self { + inner: None, + meta: None, + } + } + + /// Returns a handle to the span [considered by the `Subscriber`] to be the + /// current span. + /// + /// If the subscriber indicates that it does not track the current span, or + /// that the thread from which this function is called is not currently + /// inside a span, the returned span will be disabled. + /// + /// [considered by the `Subscriber`]: + /// super::subscriber::Subscriber::current_span + pub fn current() -> Span { + dispatcher::get_default(|dispatch| { + if let Some((id, meta)) = dispatch.current_span().into_inner() { + let id = dispatch.clone_span(&id); + Self { + inner: Some(Inner::new(id, dispatch)), + meta: Some(meta), + } + } else { + Self::none() + } + }) + } + + fn make_with( + meta: &'static Metadata<'static>, + new_span: Attributes<'_>, + dispatch: &Dispatch, + ) -> Span { + let attrs = &new_span; + let id = dispatch.new_span(attrs); + let inner = Some(Inner::new(id, dispatch)); + + let span = Self { + inner, + meta: Some(meta), + }; + + if_log_enabled! { *meta.level(), { + let target = if attrs.is_empty() { + LIFECYCLE_LOG_TARGET + } else { + meta.target() + }; + let values = attrs.values(); + span.log( + target, + level_to_log!(*meta.level()), + format_args!("++ {};{}", meta.name(), crate::log::LogValueSet { values, is_first: false }), + ); + }} + + span + } + + /// Enters this span, returning a guard that will exit the span when dropped. + /// + /// If this span is enabled by the current subscriber, then this function will + /// call [`Subscriber::enter`] with the span's [`Id`], and dropping the guard + /// will call [`Subscriber::exit`]. If the span is disabled, this does + /// nothing. + /// + /// # In Asynchronous Code + /// + /// **Warning**: in asynchronous code that uses [async/await syntax][syntax], + /// `Span::enter` should be used very carefully or avoided entirely. Holding + /// the drop guard returned by `Span::enter` across `.await` points will + /// result in incorrect traces. For example, + /// + /// ``` + /// # use tracing::info_span; + /// # async fn some_other_async_function() {} + /// async fn my_async_function() { + /// let span = info_span!("my_async_function"); + /// + /// // WARNING: This span will remain entered until this + /// // guard is dropped... + /// let _enter = span.enter(); + /// // ...but the `await` keyword may yield, causing the + /// // runtime to switch to another task, while remaining in + /// // this span! + /// some_other_async_function().await + /// + /// // ... + /// } + /// ``` + /// + /// The drop guard returned by `Span::enter` exits the span when it is + /// dropped. When an async function or async block yields at an `.await` + /// point, the current scope is _exited_, but values in that scope are + /// **not** dropped (because the async block will eventually resume + /// execution from that await point). This means that _another_ task will + /// begin executing while _remaining_ in the entered span. This results in + /// an incorrect trace. + /// + /// Instead of using `Span::enter` in asynchronous code, prefer the + /// following: + /// + /// * To enter a span for a synchronous section of code within an async + /// block or function, prefer [`Span::in_scope`]. Since `in_scope` takes a + /// synchronous closure and exits the span when the closure returns, the + /// span will always be exited before the next await point. For example: + /// ``` + /// # use tracing::info_span; + /// # async fn some_other_async_function(_: ()) {} + /// async fn my_async_function() { + /// let span = info_span!("my_async_function"); + /// + /// let some_value = span.in_scope(|| { + /// // run some synchronous code inside the span... + /// }); + /// + /// // This is okay! The span has already been exited before we reach + /// // the await point. + /// some_other_async_function(some_value).await; + /// + /// // ... + /// } + /// ``` + /// * For instrumenting asynchronous code, `tracing` provides the + /// [`Future::instrument` combinator][instrument] for + /// attaching a span to a future (async function or block). This will + /// enter the span _every_ time the future is polled, and exit it whenever + /// the future yields. + /// + /// `Instrument` can be used with an async block inside an async function: + /// ```ignore + /// # use tracing::info_span; + /// use tracing::Instrument; + /// + /// # async fn some_other_async_function() {} + /// async fn my_async_function() { + /// let span = info_span!("my_async_function"); + /// async move { + /// // This is correct! If we yield here, the span will be exited, + /// // and re-entered when we resume. + /// some_other_async_function().await; + /// + /// //more asynchronous code inside the span... + /// + /// } + /// // instrument the async block with the span... + /// .instrument(span) + /// // ...and await it. + /// .await + /// } + /// ``` + /// + /// It can also be used to instrument calls to async functions at the + /// callsite: + /// ```ignore + /// # use tracing::debug_span; + /// use tracing::Instrument; + /// + /// # async fn some_other_async_function() {} + /// async fn my_async_function() { + /// let some_value = some_other_async_function() + /// .instrument(debug_span!("some_other_async_function")) + /// .await; + /// + /// // ... + /// } + /// ``` + /// + /// * The [`#[instrument]` attribute macro][attr] can automatically generate + /// correct code when used on an async function: + /// + /// ```ignore + /// # async fn some_other_async_function() {} + /// #[tracing::instrument(level = "info")] + /// async fn my_async_function() { + /// + /// // This is correct! If we yield here, the span will be exited, + /// // and re-entered when we resume. + /// some_other_async_function().await; + /// + /// // ... + /// + /// } + /// ``` + /// + /// [syntax]: https://rust-lang.github.io/async-book/01_getting_started/04_async_await_primer.html + /// [`Span::in_scope`]: Span::in_scope() + /// [instrument]: crate::Instrument + /// [attr]: macro@crate::instrument + /// + /// # Examples + /// + /// ``` + /// # use tracing::{span, Level}; + /// let span = span!(Level::INFO, "my_span"); + /// let guard = span.enter(); + /// + /// // code here is within the span + /// + /// drop(guard); + /// + /// // code here is no longer within the span + /// + /// ``` + /// + /// Guards need not be explicitly dropped: + /// + /// ``` + /// # use tracing::trace_span; + /// fn my_function() -> String { + /// // enter a span for the duration of this function. + /// let span = trace_span!("my_function"); + /// let _enter = span.enter(); + /// + /// // anything happening in functions we call is still inside the span... + /// my_other_function(); + /// + /// // returning from the function drops the guard, exiting the span. + /// return "Hello world".to_owned(); + /// } + /// + /// fn my_other_function() { + /// // ... + /// } + /// ``` + /// + /// Sub-scopes may be created to limit the duration for which the span is + /// entered: + /// + /// ``` + /// # use tracing::{info, info_span}; + /// let span = info_span!("my_great_span"); + /// + /// { + /// let _enter = span.enter(); + /// + /// // this event occurs inside the span. + /// info!("i'm in the span!"); + /// + /// // exiting the scope drops the guard, exiting the span. + /// } + /// + /// // this event is not inside the span. + /// info!("i'm outside the span!") + /// ``` + /// + /// [`Subscriber::enter`]: super::subscriber::Subscriber::enter() + /// [`Subscriber::exit`]: super::subscriber::Subscriber::exit() + /// [`Id`]: super::Id + #[inline(always)] + pub fn enter(&self) -> Entered<'_> { + self.do_enter(); + Entered { span: self } + } + + /// Enters this span, consuming it and returning a [guard][`EnteredSpan`] + /// that will exit the span when dropped. + /// + /// <pre class="compile_fail" style="white-space:normal;font:inherit;"> + /// <strong>Warning</strong>: In asynchronous code that uses async/await syntax, + /// <code>Span::entered</code> may produce incorrect traces if the returned drop + /// guard is held across an await point. See <a href="#in-asynchronous-code">the + /// <code>Span::enter</code> documentation</a> for details. + /// </pre> + /// + /// + /// If this span is enabled by the current subscriber, then this function will + /// call [`Subscriber::enter`] with the span's [`Id`], and dropping the guard + /// will call [`Subscriber::exit`]. If the span is disabled, this does + /// nothing. + /// + /// This is similar to the [`Span::enter`] method, except that it moves the + /// span by value into the returned guard, rather than borrowing it. + /// Therefore, this method can be used to create and enter a span in a + /// single expression, without requiring a `let`-binding. For example: + /// + /// ``` + /// # use tracing::info_span; + /// let _span = info_span!("something_interesting").entered(); + /// ``` + /// rather than: + /// ``` + /// # use tracing::info_span; + /// let span = info_span!("something_interesting"); + /// let _e = span.enter(); + /// ``` + /// + /// Furthermore, `entered` may be used when the span must be stored in some + /// other struct or be passed to a function while remaining entered. + /// + /// <pre class="ignore" style="white-space:normal;font:inherit;"> + /// <strong>Note</strong>: The returned <a href="../struct.EnteredSpan.html"> + /// <code>EnteredSpan</a></code> guard does not implement <code>Send</code>. + /// Dropping the guard will exit <em>this</em> span, and if the guard is sent + /// to another thread and dropped there, that thread may never have entered + /// this span. Thus, <code>EnteredSpan</code>s should not be sent between threads. + /// </pre> + /// + /// [syntax]: https://rust-lang.github.io/async-book/01_getting_started/04_async_await_primer.html + /// + /// # Examples + /// + /// The returned guard can be [explicitly exited][EnteredSpan::exit], + /// returning the un-entered span: + /// + /// ``` + /// # use tracing::{Level, span}; + /// let span = span!(Level::INFO, "doing_something").entered(); + /// + /// // code here is within the span + /// + /// // explicitly exit the span, returning it + /// let span = span.exit(); + /// + /// // code here is no longer within the span + /// + /// // enter the span again + /// let span = span.entered(); + /// + /// // now we are inside the span once again + /// ``` + /// + /// Guards need not be explicitly dropped: + /// + /// ``` + /// # use tracing::trace_span; + /// fn my_function() -> String { + /// // enter a span for the duration of this function. + /// let span = trace_span!("my_function").entered(); + /// + /// // anything happening in functions we call is still inside the span... + /// my_other_function(); + /// + /// // returning from the function drops the guard, exiting the span. + /// return "Hello world".to_owned(); + /// } + /// + /// fn my_other_function() { + /// // ... + /// } + /// ``` + /// + /// Since the [`EnteredSpan`] guard can dereference to the [`Span`] itself, + /// the span may still be accessed while entered. For example: + /// + /// ```rust + /// # use tracing::info_span; + /// use tracing::field; + /// + /// // create the span with an empty field, and enter it. + /// let span = info_span!("my_span", some_field = field::Empty).entered(); + /// + /// // we can still record a value for the field while the span is entered. + /// span.record("some_field", &"hello world!"); + /// ``` + /// + + /// [`Subscriber::enter`]: super::subscriber::Subscriber::enter() + /// [`Subscriber::exit`]: super::subscriber::Subscriber::exit() + /// [`Id`]: super::Id + #[inline(always)] + pub fn entered(self) -> EnteredSpan { + self.do_enter(); + EnteredSpan { + span: self, + _not_send: PhantomNotSend, + } + } + + /// Returns this span, if it was [enabled] by the current [`Subscriber`], or + /// the [current span] (whose lexical distance may be further than expected), + /// if this span [is disabled]. + /// + /// This method can be useful when propagating spans to spawned threads or + /// [async tasks]. Consider the following: + /// + /// ``` + /// let _parent_span = tracing::info_span!("parent").entered(); + /// + /// // ... + /// + /// let child_span = tracing::debug_span!("child"); + /// + /// std::thread::spawn(move || { + /// let _entered = child_span.entered(); + /// + /// tracing::info!("spawned a thread!"); + /// + /// // ... + /// }); + /// ``` + /// + /// If the current [`Subscriber`] enables the [`DEBUG`] level, then both + /// the "parent" and "child" spans will be enabled. Thus, when the "spawaned + /// a thread!" event occurs, it will be inside of the "child" span. Because + /// "parent" is the parent of "child", the event will _also_ be inside of + /// "parent". + /// + /// However, if the [`Subscriber`] only enables the [`INFO`] level, the "child" + /// span will be disabled. When the thread is spawned, the + /// `child_span.entered()` call will do nothing, since "child" is not + /// enabled. In this case, the "spawned a thread!" event occurs outside of + /// *any* span, since the "child" span was responsible for propagating its + /// parent to the spawned thread. + /// + /// If this is not the desired behavior, `Span::or_current` can be used to + /// ensure that the "parent" span is propagated in both cases, either as a + /// parent of "child" _or_ directly. For example: + /// + /// ``` + /// let _parent_span = tracing::info_span!("parent").entered(); + /// + /// // ... + /// + /// // If DEBUG is enabled, then "child" will be enabled, and `or_current` + /// // returns "child". Otherwise, if DEBUG is not enabled, "child" will be + /// // disabled, and `or_current` returns "parent". + /// let child_span = tracing::debug_span!("child").or_current(); + /// + /// std::thread::spawn(move || { + /// let _entered = child_span.entered(); + /// + /// tracing::info!("spawned a thread!"); + /// + /// // ... + /// }); + /// ``` + /// + /// When spawning [asynchronous tasks][async tasks], `Span::or_current` can + /// be used similarly, in combination with [`instrument`]: + /// + /// ``` + /// use tracing::Instrument; + /// # // lol + /// # mod tokio { + /// # pub(super) fn spawn(_: impl std::future::Future) {} + /// # } + /// + /// let _parent_span = tracing::info_span!("parent").entered(); + /// + /// // ... + /// + /// let child_span = tracing::debug_span!("child"); + /// + /// tokio::spawn( + /// async { + /// tracing::info!("spawned a task!"); + /// + /// // ... + /// + /// }.instrument(child_span.or_current()) + /// ); + /// ``` + /// + /// In general, `or_current` should be preferred over nesting an + /// [`instrument`] call inside of an [`in_current_span`] call, as using + /// `or_current` will be more efficient. + /// + /// ``` + /// use tracing::Instrument; + /// # // lol + /// # mod tokio { + /// # pub(super) fn spawn(_: impl std::future::Future) {} + /// # } + /// async fn my_async_fn() { + /// // ... + /// } + /// + /// let _parent_span = tracing::info_span!("parent").entered(); + /// + /// // Do this: + /// tokio::spawn( + /// my_async_fn().instrument(tracing::debug_span!("child").or_current()) + /// ); + /// + /// // ...rather than this: + /// tokio::spawn( + /// my_async_fn() + /// .instrument(tracing::debug_span!("child")) + /// .in_current_span() + /// ); + /// ``` + /// + /// [enabled]: crate::Subscriber::enabled + /// [`Subscriber`]: crate::Subscriber + /// [current span]: Span::current + /// [is disabled]: Span::is_disabled + /// [`INFO`]: crate::Level::INFO + /// [`DEBUG`]: crate::Level::DEBUG + /// [async tasks]: std::task + /// [`instrument`]: crate::instrument::Instrument::instrument + /// [`in_current_span`]: crate::instrument::Instrument::in_current_span + pub fn or_current(self) -> Self { + if self.is_disabled() { + return Self::current(); + } + self + } + + #[inline(always)] + fn do_enter(&self) { + if let Some(inner) = self.inner.as_ref() { + inner.subscriber.enter(&inner.id); + } + + if_log_enabled! { crate::Level::TRACE, { + if let Some(_meta) = self.meta { + self.log(ACTIVITY_LOG_TARGET, log::Level::Trace, format_args!("-> {};", _meta.name())); + } + }} + } + + // Called from [`Entered`] and [`EnteredSpan`] drops. + // + // Running this behaviour on drop rather than with an explicit function + // call means that spans may still be exited when unwinding. + #[inline(always)] + fn do_exit(&self) { + if let Some(inner) = self.inner.as_ref() { + inner.subscriber.exit(&inner.id); + } + + if_log_enabled! { crate::Level::TRACE, { + if let Some(_meta) = self.meta { + self.log(ACTIVITY_LOG_TARGET, log::Level::Trace, format_args!("<- {};", _meta.name())); + } + }} + } + + /// Executes the given function in the context of this span. + /// + /// If this span is enabled, then this function enters the span, invokes `f` + /// and then exits the span. If the span is disabled, `f` will still be + /// invoked, but in the context of the currently-executing span (if there is + /// one). + /// + /// Returns the result of evaluating `f`. + /// + /// # Examples + /// + /// ``` + /// # use tracing::{trace, span, Level}; + /// let my_span = span!(Level::TRACE, "my_span"); + /// + /// my_span.in_scope(|| { + /// // this event occurs within the span. + /// trace!("i'm in the span!"); + /// }); + /// + /// // this event occurs outside the span. + /// trace!("i'm not in the span!"); + /// ``` + /// + /// Calling a function and returning the result: + /// ``` + /// # use tracing::{info_span, Level}; + /// fn hello_world() -> String { + /// "Hello world!".to_owned() + /// } + /// + /// let span = info_span!("hello_world"); + /// // the span will be entered for the duration of the call to + /// // `hello_world`. + /// let a_string = span.in_scope(hello_world); + /// + pub fn in_scope<F: FnOnce() -> T, T>(&self, f: F) -> T { + let _enter = self.enter(); + f() + } + + /// Returns a [`Field`][super::field::Field] for the field with the + /// given `name`, if one exists, + pub fn field<Q: ?Sized>(&self, field: &Q) -> Option<field::Field> + where + Q: field::AsField, + { + self.metadata().and_then(|meta| field.as_field(meta)) + } + + /// Returns true if this `Span` has a field for the given + /// [`Field`][super::field::Field] or field name. + #[inline] + pub fn has_field<Q: ?Sized>(&self, field: &Q) -> bool + where + Q: field::AsField, + { + self.field(field).is_some() + } + + /// Records that the field described by `field` has the value `value`. + /// + /// This may be used with [`field::Empty`] to declare fields whose values + /// are not known when the span is created, and record them later: + /// ``` + /// use tracing::{trace_span, field}; + /// + /// // Create a span with two fields: `greeting`, with the value "hello world", and + /// // `parting`, without a value. + /// let span = trace_span!("my_span", greeting = "hello world", parting = field::Empty); + /// + /// // ... + /// + /// // Now, record a value for parting as well. + /// // (note that the field name is passed as a string slice) + /// span.record("parting", &"goodbye world!"); + /// ``` + /// However, it may also be used to record a _new_ value for a field whose + /// value was already recorded: + /// ``` + /// use tracing::info_span; + /// # fn do_something() -> Result<(), ()> { Err(()) } + /// + /// // Initially, let's assume that our attempt to do something is going okay... + /// let span = info_span!("doing_something", is_okay = true); + /// let _e = span.enter(); + /// + /// match do_something() { + /// Ok(something) => { + /// // ... + /// } + /// Err(_) => { + /// // Things are no longer okay! + /// span.record("is_okay", &false); + /// } + /// } + /// ``` + /// + /// <pre class="ignore" style="white-space:normal;font:inherit;"> + /// <strong>Note</strong>: The fields associated with a span are part + /// of its <a href="../struct.Metadata.html"><code>Metadata</code></a>. + /// The <a href="../struct.Metadata.html"><code>Metadata</code></a> + /// describing a particular span is constructed statically when the span + /// is created and cannot be extended later to add new fields. Therefore, + /// you cannot record a value for a field that was not specified when the + /// span was created: + /// </pre> + /// + /// ``` + /// use tracing::{trace_span, field}; + /// + /// // Create a span with two fields: `greeting`, with the value "hello world", and + /// // `parting`, without a value. + /// let span = trace_span!("my_span", greeting = "hello world", parting = field::Empty); + /// + /// // ... + /// + /// // Now, you try to record a value for a new field, `new_field`, which was not + /// // declared as `Empty` or populated when you created `span`. + /// // You won't get any error, but the assignment will have no effect! + /// span.record("new_field", &"interesting_value_you_really_need"); + /// + /// // Instead, all fields that may be recorded after span creation should be declared up front, + /// // using field::Empty when a value is not known, as we did for `parting`. + /// // This `record` call will indeed replace field::Empty with "you will be remembered". + /// span.record("parting", &"you will be remembered"); + /// ``` + /// + /// [`field::Empty`]: super::field::Empty + /// [`Metadata`]: super::Metadata + pub fn record<Q: ?Sized, V>(&self, field: &Q, value: &V) -> &Self + where + Q: field::AsField, + V: field::Value, + { + if let Some(meta) = self.meta { + if let Some(field) = field.as_field(meta) { + self.record_all( + &meta + .fields() + .value_set(&[(&field, Some(value as &dyn field::Value))]), + ); + } + } + + self + } + + /// Records all the fields in the provided `ValueSet`. + pub fn record_all(&self, values: &field::ValueSet<'_>) -> &Self { + let record = Record::new(values); + if let Some(ref inner) = self.inner { + inner.record(&record); + } + + if let Some(_meta) = self.meta { + if_log_enabled! { *_meta.level(), { + let target = if record.is_empty() { + LIFECYCLE_LOG_TARGET + } else { + _meta.target() + }; + self.log( + target, + level_to_log!(*_meta.level()), + format_args!("{};{}", _meta.name(), crate::log::LogValueSet { values, is_first: false }), + ); + }} + } + + self + } + + /// Returns `true` if this span was disabled by the subscriber and does not + /// exist. + /// + /// See also [`is_none`]. + /// + /// [`is_none`]: Span::is_none() + #[inline] + pub fn is_disabled(&self) -> bool { + self.inner.is_none() + } + + /// Returns `true` if this span was constructed by [`Span::none`] and is + /// empty. + /// + /// If `is_none` returns `true` for a given span, then [`is_disabled`] will + /// also return `true`. However, when a span is disabled by the subscriber + /// rather than constructed by `Span::none`, this method will return + /// `false`, while `is_disabled` will return `true`. + /// + /// [`Span::none`]: Span::none() + /// [`is_disabled`]: Span::is_disabled() + #[inline] + pub fn is_none(&self) -> bool { + self.is_disabled() && self.meta.is_none() + } + + /// Indicates that the span with the given ID has an indirect causal + /// relationship with this span. + /// + /// This relationship differs somewhat from the parent-child relationship: a + /// span may have any number of prior spans, rather than a single one; and + /// spans are not considered to be executing _inside_ of the spans they + /// follow from. This means that a span may close even if subsequent spans + /// that follow from it are still open, and time spent inside of a + /// subsequent span should not be included in the time its precedents were + /// executing. This is used to model causal relationships such as when a + /// single future spawns several related background tasks, et cetera. + /// + /// If this span is disabled, or the resulting follows-from relationship + /// would be invalid, this function will do nothing. + /// + /// # Examples + /// + /// Setting a `follows_from` relationship with a `Span`: + /// ``` + /// # use tracing::{span, Id, Level, Span}; + /// let span1 = span!(Level::INFO, "span_1"); + /// let span2 = span!(Level::DEBUG, "span_2"); + /// span2.follows_from(span1); + /// ``` + /// + /// Setting a `follows_from` relationship with the current span: + /// ``` + /// # use tracing::{span, Id, Level, Span}; + /// let span = span!(Level::INFO, "hello!"); + /// span.follows_from(Span::current()); + /// ``` + /// + /// Setting a `follows_from` relationship with a `Span` reference: + /// ``` + /// # use tracing::{span, Id, Level, Span}; + /// let span = span!(Level::INFO, "hello!"); + /// let curr = Span::current(); + /// span.follows_from(&curr); + /// ``` + /// + /// Setting a `follows_from` relationship with an `Id`: + /// ``` + /// # use tracing::{span, Id, Level, Span}; + /// let span = span!(Level::INFO, "hello!"); + /// let id = span.id(); + /// span.follows_from(id); + /// ``` + pub fn follows_from(&self, from: impl Into<Option<Id>>) -> &Self { + if let Some(ref inner) = self.inner { + if let Some(from) = from.into() { + inner.follows_from(&from); + } + } + self + } + + /// Returns this span's `Id`, if it is enabled. + pub fn id(&self) -> Option<Id> { + self.inner.as_ref().map(Inner::id) + } + + /// Returns this span's `Metadata`, if it is enabled. + pub fn metadata(&self) -> Option<&'static Metadata<'static>> { + self.meta + } + + #[cfg(feature = "log")] + #[inline] + fn log(&self, target: &str, level: log::Level, message: fmt::Arguments<'_>) { + if let Some(meta) = self.meta { + if level_to_log!(*meta.level()) <= log::max_level() { + let logger = log::logger(); + let log_meta = log::Metadata::builder().level(level).target(target).build(); + if logger.enabled(&log_meta) { + if let Some(ref inner) = self.inner { + logger.log( + &log::Record::builder() + .metadata(log_meta) + .module_path(meta.module_path()) + .file(meta.file()) + .line(meta.line()) + .args(format_args!("{} span={}", message, inner.id.into_u64())) + .build(), + ); + } else { + logger.log( + &log::Record::builder() + .metadata(log_meta) + .module_path(meta.module_path()) + .file(meta.file()) + .line(meta.line()) + .args(message) + .build(), + ); + } + } + } + } + } + + /// Invokes a function with a reference to this span's ID and subscriber. + /// + /// if this span is enabled, the provided function is called, and the result is returned. + /// If the span is disabled, the function is not called, and this method returns `None` + /// instead. + pub fn with_subscriber<T>(&self, f: impl FnOnce((&Id, &Dispatch)) -> T) -> Option<T> { + self.inner + .as_ref() + .map(|inner| f((&inner.id, &inner.subscriber))) + } +} + +impl cmp::PartialEq for Span { + fn eq(&self, other: &Self) -> bool { + match (&self.meta, &other.meta) { + (Some(this), Some(that)) => { + this.callsite() == that.callsite() && self.inner == other.inner + } + _ => false, + } + } +} + +impl Hash for Span { + fn hash<H: Hasher>(&self, hasher: &mut H) { + self.inner.hash(hasher); + } +} + +impl fmt::Debug for Span { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + let mut span = f.debug_struct("Span"); + if let Some(meta) = self.meta { + span.field("name", &meta.name()) + .field("level", &meta.level()) + .field("target", &meta.target()); + + if let Some(ref inner) = self.inner { + span.field("id", &inner.id()); + } else { + span.field("disabled", &true); + } + + if let Some(ref path) = meta.module_path() { + span.field("module_path", &path); + } + + if let Some(ref line) = meta.line() { + span.field("line", &line); + } + + if let Some(ref file) = meta.file() { + span.field("file", &file); + } + } else { + span.field("none", &true); + } + + span.finish() + } +} + +impl<'a> From<&'a Span> for Option<&'a Id> { + fn from(span: &'a Span) -> Self { + span.inner.as_ref().map(|inner| &inner.id) + } +} + +impl<'a> From<&'a Span> for Option<Id> { + fn from(span: &'a Span) -> Self { + span.inner.as_ref().map(Inner::id) + } +} + +impl From<Span> for Option<Id> { + fn from(span: Span) -> Self { + span.inner.as_ref().map(Inner::id) + } +} + +impl<'a> From<&'a EnteredSpan> for Option<&'a Id> { + fn from(span: &'a EnteredSpan) -> Self { + span.inner.as_ref().map(|inner| &inner.id) + } +} + +impl<'a> From<&'a EnteredSpan> for Option<Id> { + fn from(span: &'a EnteredSpan) -> Self { + span.inner.as_ref().map(Inner::id) + } +} + +impl Drop for Span { + #[inline(always)] + fn drop(&mut self) { + if let Some(Inner { + ref id, + ref subscriber, + }) = self.inner + { + subscriber.try_close(id.clone()); + } + + if_log_enabled! { crate::Level::TRACE, { + if let Some(meta) = self.meta { + self.log( + LIFECYCLE_LOG_TARGET, + log::Level::Trace, + format_args!("-- {};", meta.name()), + ); + } + }} + } +} + +// ===== impl Inner ===== + +impl Inner { + /// Indicates that the span with the given ID has an indirect causal + /// relationship with this span. + /// + /// This relationship differs somewhat from the parent-child relationship: a + /// span may have any number of prior spans, rather than a single one; and + /// spans are not considered to be executing _inside_ of the spans they + /// follow from. This means that a span may close even if subsequent spans + /// that follow from it are still open, and time spent inside of a + /// subsequent span should not be included in the time its precedents were + /// executing. This is used to model causal relationships such as when a + /// single future spawns several related background tasks, et cetera. + /// + /// If this span is disabled, this function will do nothing. Otherwise, it + /// returns `Ok(())` if the other span was added as a precedent of this + /// span, or an error if this was not possible. + fn follows_from(&self, from: &Id) { + self.subscriber.record_follows_from(&self.id, from) + } + + /// Returns the span's ID. + fn id(&self) -> Id { + self.id.clone() + } + + fn record(&self, values: &Record<'_>) { + self.subscriber.record(&self.id, values) + } + + fn new(id: Id, subscriber: &Dispatch) -> Self { + Inner { + id, + subscriber: subscriber.clone(), + } + } +} + +impl cmp::PartialEq for Inner { + fn eq(&self, other: &Self) -> bool { + self.id == other.id + } +} + +impl Hash for Inner { + fn hash<H: Hasher>(&self, state: &mut H) { + self.id.hash(state); + } +} + +impl Clone for Inner { + fn clone(&self) -> Self { + Inner { + id: self.subscriber.clone_span(&self.id), + subscriber: self.subscriber.clone(), + } + } +} + +// ===== impl Entered ===== + +impl EnteredSpan { + /// Returns this span's `Id`, if it is enabled. + pub fn id(&self) -> Option<Id> { + self.inner.as_ref().map(Inner::id) + } + + /// Exits this span, returning the underlying [`Span`]. + #[inline] + pub fn exit(mut self) -> Span { + // One does not simply move out of a struct with `Drop`. + let span = mem::replace(&mut self.span, Span::none()); + span.do_exit(); + span + } +} + +impl Deref for EnteredSpan { + type Target = Span; + + #[inline] + fn deref(&self) -> &Span { + &self.span + } +} + +impl<'a> Drop for Entered<'a> { + #[inline(always)] + fn drop(&mut self) { + self.span.do_exit() + } +} + +impl Drop for EnteredSpan { + #[inline(always)] + fn drop(&mut self) { + self.span.do_exit() + } +} + +/// Technically, `EnteredSpan` _can_ implement both `Send` *and* +/// `Sync` safely. It doesn't, because it has a `PhantomNotSend` field, +/// specifically added in order to make it `!Send`. +/// +/// Sending an `EnteredSpan` guard between threads cannot cause memory unsafety. +/// However, it *would* result in incorrect behavior, so we add a +/// `PhantomNotSend` to prevent it from being sent between threads. This is +/// because it must be *dropped* on the same thread that it was created; +/// otherwise, the span will never be exited on the thread where it was entered, +/// and it will attempt to exit the span on a thread that may never have entered +/// it. However, we still want them to be `Sync` so that a struct holding an +/// `Entered` guard can be `Sync`. +/// +/// Thus, this is totally safe. +#[derive(Debug)] +struct PhantomNotSend { + ghost: PhantomData<*mut ()>, +} + +#[allow(non_upper_case_globals)] +const PhantomNotSend: PhantomNotSend = PhantomNotSend { ghost: PhantomData }; + +/// # Safety +/// +/// Trivially safe, as `PhantomNotSend` doesn't have any API. +unsafe impl Sync for PhantomNotSend {} + +#[cfg(test)] +mod test { + use super::*; + + trait AssertSend: Send {} + impl AssertSend for Span {} + + trait AssertSync: Sync {} + impl AssertSync for Span {} + impl AssertSync for Entered<'_> {} + impl AssertSync for EnteredSpan {} +} diff --git a/vendor/tracing/src/stdlib.rs b/vendor/tracing/src/stdlib.rs new file mode 100644 index 000000000..12b54084d --- /dev/null +++ b/vendor/tracing/src/stdlib.rs @@ -0,0 +1,55 @@ +//! Re-exports either the Rust `std` library or `core` and `alloc` when `std` is +//! disabled. +//! +//! `crate::stdlib::...` should be used rather than `std::` when adding code that +//! will be available with the standard library disabled. +//! +//! Note that this module is called `stdlib` rather than `std`, as Rust 1.34.0 +//! does not permit redefining the name `stdlib` (although this works on the +//! latest stable Rust). +#[cfg(feature = "std")] +pub(crate) use std::*; + +#[cfg(not(feature = "std"))] +pub(crate) use self::no_std::*; + +#[cfg(not(feature = "std"))] +mod no_std { + // We pre-emptively export everything from libcore/liballoc, (even modules + // we aren't using currently) to make adding new code easier. Therefore, + // some of these imports will be unused. + #![allow(unused_imports)] + + pub(crate) use core::{ + any, array, ascii, cell, char, clone, cmp, convert, default, f32, f64, ffi, future, hash, + hint, i128, i16, i8, isize, iter, marker, mem, num, ops, option, pin, ptr, result, task, + time, u128, u16, u32, u8, usize, + }; + + pub(crate) use alloc::{boxed, collections, rc, string, vec}; + + pub(crate) mod borrow { + pub(crate) use alloc::borrow::*; + pub(crate) use core::borrow::*; + } + + pub(crate) mod fmt { + pub(crate) use alloc::fmt::*; + pub(crate) use core::fmt::*; + } + + pub(crate) mod slice { + pub(crate) use alloc::slice::*; + pub(crate) use core::slice::*; + } + + pub(crate) mod str { + pub(crate) use alloc::str::*; + pub(crate) use core::str::*; + } + + pub(crate) mod sync { + pub(crate) use alloc::sync::*; + pub(crate) use core::sync::*; + } +} diff --git a/vendor/tracing/src/subscriber.rs b/vendor/tracing/src/subscriber.rs new file mode 100644 index 000000000..343dc5914 --- /dev/null +++ b/vendor/tracing/src/subscriber.rs @@ -0,0 +1,68 @@ +//! Collects and records trace data. +pub use tracing_core::subscriber::*; + +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +pub use tracing_core::dispatcher::DefaultGuard; + +/// Sets this subscriber as the default for the duration of a closure. +/// +/// The default subscriber is used when creating a new [`Span`] or +/// [`Event`], _if no span is currently executing_. If a span is currently +/// executing, new spans or events are dispatched to the subscriber that +/// tagged that span, instead. +/// +/// [`Span`]: super::span::Span +/// [`Subscriber`]: super::subscriber::Subscriber +/// [`Event`]: super::event::Event +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +pub fn with_default<T, S>(subscriber: S, f: impl FnOnce() -> T) -> T +where + S: Subscriber + Send + Sync + 'static, +{ + crate::dispatcher::with_default(&crate::Dispatch::new(subscriber), f) +} + +/// Sets this subscriber as the global default for the duration of the entire program. +/// Will be used as a fallback if no thread-local subscriber has been set in a thread (using `with_default`.) +/// +/// Can only be set once; subsequent attempts to set the global default will fail. +/// Returns whether the initialization was successful. +/// +/// Note: Libraries should *NOT* call `set_global_default()`! That will cause conflicts when +/// executables try to set them later. +/// +/// [span]: super::span +/// [`Subscriber`]: super::subscriber::Subscriber +/// [`Event`]: super::event::Event +pub fn set_global_default<S>(subscriber: S) -> Result<(), SetGlobalDefaultError> +where + S: Subscriber + Send + Sync + 'static, +{ + crate::dispatcher::set_global_default(crate::Dispatch::new(subscriber)) +} + +/// Sets the subscriber as the default for the duration of the lifetime of the +/// returned [`DefaultGuard`] +/// +/// The default subscriber is used when creating a new [`Span`] or +/// [`Event`], _if no span is currently executing_. If a span is currently +/// executing, new spans or events are dispatched to the subscriber that +/// tagged that span, instead. +/// +/// [`Span`]: super::span::Span +/// [`Subscriber`]: super::subscriber::Subscriber +/// [`Event`]: super::event::Event +/// [`DefaultGuard`]: super::dispatcher::DefaultGuard +#[cfg(feature = "std")] +#[cfg_attr(docsrs, doc(cfg(feature = "std")))] +#[must_use = "Dropping the guard unregisters the subscriber."] +pub fn set_default<S>(subscriber: S) -> DefaultGuard +where + S: Subscriber + Send + Sync + 'static, +{ + crate::dispatcher::set_default(&crate::Dispatch::new(subscriber)) +} + +pub use tracing_core::dispatcher::SetGlobalDefaultError; |