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Crate tracing_core

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tracing_core0.1.32

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  • Re-exports
  • Modules
  • Macros
  • Structs
  • Traits

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  • tracing_core
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Crate tracing_core

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Expand description

Core primitives for tracing.

tracing is a framework for instrumenting Rust programs to collect structured, event-based diagnostic information. This crate defines the core primitives of tracing.

This crate provides:

  • span::Id identifies a span within the execution of a program.

  • Event represents a single event within a trace.

  • Subscriber, the trait implemented to collect trace data.

  • Metadata and Callsite provide information describing spans and Events.

  • Field, FieldSet, Value, and ValueSet represent the structured data attached to a span.

  • Dispatch allows spans and events to be dispatched to Subscribers.

In addition, it defines the global callsite registry and per-thread current dispatcher which other components of the tracing system rely on.

Compiler support: requires rustc 1.56+

Usage

Application authors will typically not use this crate directly. Instead, they will use the tracing crate, which provides a much more fully-featured API. However, this crate’s API will change very infrequently, so it may be used when dependencies must be very stable.

Subscriber implementations may depend on tracing-core rather than tracing, as the additional APIs provided by tracing are primarily useful for instrumenting libraries and applications, and are generally not necessary for Subscriber implementations.

The tokio-rs/tracing repository contains less stable crates designed to be used with the tracing ecosystem. It includes a collection of Subscriber implementations, as well as utility and adapter crates.

Crate Feature Flags

The following crate feature flags are available:

  • std: Depend on the Rust standard library (enabled by default).

    no_std users may disable this feature with default-features = false:

    [dependencies]
    tracing-core = { version = "0.1.22", default-features = false }
    

    Note:tracing-core’s no_std support requires liballoc.

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:

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:

[build]
rustflags = ["--cfg", "tracing_unstable"]

Supported Rust Versions

Tracing is built against the latest stable release. The minimum supported version is 1.56. 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 1.69, the minimum supported version will not be increased past 1.66, 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.

Re-exports

  • pub use self::metadata::Kind;
  • pub use self::subscriber::Interest;

Modules

  • callsite
    Callsites represent the source locations from which spans or events originate.
  • dispatcher
    Dispatches trace events to Subscribers.
  • event
    Events represent single points in time during the execution of a program.
  • field
    Span and Event key-value data.
  • metadata
    Metadata describing trace data.
  • span
    Spans represent periods of time in the execution of a program.
  • subscriber
    Collectors collect and record trace data.

Macros

  • identify_callsite
    Statically constructs an Identifier for the provided Callsite.
  • metadata
    Statically constructs new span metadata.

Structs

  • Dispatch
    Dispatch trace data to a Subscriber.
  • Event
    Events represent single points in time where something occurred during the execution of a program.
  • Field
    An opaque key allowing O(1) access to a field in a Span’s key-value data.
  • Level
    Describes the level of verbosity of a span or event.
  • LevelFilter
    A filter comparable to a verbosity Level.
  • Metadata
    Metadata describing a span or event.
  • Once
    A synchronization primitive which can be used to run a one-time global initialization. Useful for one-time initialization for FFI or related functionality. This type can only be constructed with Once::new().

Traits

  • Callsite
    Trait implemented by callsites.
  • Subscriber
    Trait representing the functions required to collect trace data.

Results

struct
tracing_core::Dispatch
Dispatch trace data to a Subscriber.
struct
tracing_core::dispatcher::Dispatch
Dispatch trace data to a Subscriber.
method
tracing_core::event::Event::dispatch
Constructs a new Event with the specified metadata and set …
module
tracing_core::dispatcher
Dispatches trace events to Subscribers.
struct
tracing_core::dispatcher::WeakDispatch
WeakDispatch is a version of Dispatch that holds a …
method
tracing_core::Subscriber::on_register_dispatch
Invoked when this subscriber becomes a Dispatch.
method
tracing_core::subscriber::Subscriber::on_register_dispatch
Invoked when this subscriber becomes a Dispatch.
method
tracing_core::dispatcher::Dispatch::is
Returns true if this Dispatch forwards to a Subscriber of …
method
tracing_core::Dispatch::fmt
method
tracing_core::dispatcher::Dispatch::exit
Records that a span has been exited.
method
tracing_core::Dispatch::clone
method
tracing_core::dispatcher::Dispatch::enter
Records that a span has been can_enter.
method
tracing_core::dispatcher::Dispatch::event
Records that an Event has occurred.
method
tracing_core::dispatcher::Dispatch::record
Record a set of values on a span.
method
tracing_core::dispatcher::Dispatch::enabled
Returns true if a span with the specified metadata would be
method
tracing_core::dispatcher::Dispatch::new_span
Record the construction of a new span, returning a new ID …
method
tracing_core::dispatcher::Dispatch::downgrade
Creates a WeakDispatch from this Dispatch.
method
tracing_core::dispatcher::Dispatch::try_close
Notifies the subscriber that a span ID has been dropped, …
method
tracing_core::dispatcher::Dispatch::clone_span
Notifies the subscriber that a span ID has been cloned.
function
tracing_core::dispatcher::get_default
Executes a closure with a reference to this thread’s …
function
tracing_core::dispatcher::set_default
Sets the dispatch as the default dispatch for the duration …
method
tracing_core::dispatcher::Dispatch::current_span
Returns a type representing this subscriber’s view of …
method
tracing_core::dispatcher::Dispatch::downcast_ref
Returns some reference to the Subscriber this Dispatch …
function
tracing_core::dispatcher::with_default
Sets this dispatch as the default for the duration of a …
method
tracing_core::dispatcher::Dispatch::register_callsite
Registers a new callsite with this subscriber, returning …
function
tracing_core::dispatcher::set_global_default
Sets this dispatch as the global default for the duration …
method
tracing_core::dispatcher::Dispatch::record_follows_from
Adds an indication that span follows from the span with …
method
tracing_core::Subscriber::on_register_dispatch
Invoked when this subscriber becomes a Dispatch.
method
tracing_core::subscriber::Subscriber::on_register_dispatch
Invoked when this subscriber becomes a Dispatch.
method
tracing_core::dispatcher::Dispatch::drop_span
Notifies the subscriber that a span ID has been dropped.
method
tracing_core::dispatcher::Dispatch::new
Returns a Dispatch that forwards to the given Subscriber.
method
tracing_core::Dispatch::from
method
tracing_core::dispatcher::Dispatch::none
Returns a new Dispatch that discards events and spans.
method
tracing_core::Dispatch::clone
method
tracing_core::Dispatch::default
Returns the current default dispatcher
method
tracing_core::dispatcher::WeakDispatch::upgrade
Attempts to upgrade this WeakDispatch to a Dispatch.