Core primitives for application-level tracing.
[tracing] is a framework for instrumenting Rust programs to collect
structured, event-based diagnostic information. This crate defines the core
primitives of tracing.
The 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 spans and events.
[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.
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 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:
toml
[dependencies]
tracing-core = { version = "0.1.14", default-features = false }
Compiler support: requires rustc 1.39+
Note:tracing-core's no_std support requires liballoc.
This project is licensed under the MIT license.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Tokio by you, shall be licensed as MIT, without any additional terms or conditions.
