//! 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(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(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(subscriber: S) -> DefaultGuard where S: Subscriber + Send + Sync + 'static, { crate::dispatcher::set_default(&crate::Dispatch::new(subscriber)) } pub use tracing_core::dispatcher::SetGlobalDefaultError;