Struct tracing_subscriber::Registry

pub struct Registry { /* private fields */ }

A shared, reusable store for spans.

A Registry is a Subscriber around which multiple Layers implementing various behaviors may be added. Unlike other types implementing Subscriber Registry does not actually record traces itself: instead, it collects and stores span data that is exposed to any Layers wrapping it through implementations of the LookupSpan trait. The Registry is responsible for storing span metadata, recording relationships between spans, and tracking which spans are active and whicb are closed. In addition, it provides a mechanism for Layers to store user-defined per-span data, called extensions, in the registry. This allows Layer-specific data to benefit from the Registry’s high-performance concurrent storage.

This registry is implemented using a lock-free sharded slab, and is highly optimized for concurrent access.

Trait Implementations

impl Debug for Registry

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Registry

fn default() -> Self

Returns the “default value” for a type.

impl<'a> LookupSpan<'a> for Registry

type Data = Data<'a>

The type of span data stored in this registry.

fn span_data(&'a self, id: &Id) -> Option<Self::Data>

Returns the SpanData for a given Id, if it exists.

fn span(&'a self, id: &Id) -> Option<SpanRef<'_, Self>> where
    Self: Sized, 

Returns a SpanRef for the span with the given Id, if it exists.

impl Subscriber for Registry

fn record(&self, _: &Id, _: &Record<'_>)

This is intentionally not implemented, as recording fields on a span is the responsibility of layers atop of this registry.

fn event(&self, _: &Event<'_>)

This is intentionally not implemented, as recording events is the responsibility of layers atop of this registry.

fn try_close(&self, id: Id) -> bool

Decrements the reference count of the span with the given id, and removes the span if it is zero.

The allocated span slot will be reused when a new span is created.

fn register_callsite(&self, _: &'static Metadata<'static>) -> Interest

Registers a new callsite with this subscriber, returning whether or not the subscriber is interested in being notified about the callsite.

fn enabled(&self, _: &Metadata<'_>) -> bool

Returns true if a span or event with the specified metadata would be recorded.

fn new_span(&self, attrs: &Attributes<'_>) -> Id

Visit the construction of a new span, returning a new span ID for the span being constructed.

fn record_follows_from(&self, _span: &Id, _follows: &Id)

Adds an indication that span follows from the span with the id follows.

fn enter(&self, id: &Id)

Records that a span has been entered.

fn exit(&self, id: &Id)

Records that a span has been exited.

fn clone_span(&self, id: &Id) -> Id

Notifies the subscriber that a span ID has been cloned.

fn current_span(&self) -> Current

Returns a type representing this subscriber’s view of the current span.

fn max_level_hint(&self) -> Option<LevelFilter>

Returns the highest verbosity level that this Subscriber will enable, or None, if the subscriber does not implement level-based filtering or chooses not to implement this method.

fn event_enabled(&self, event: &Event<'_>) -> bool

Determine if an Event should be recorded.

fn drop_span(&self, _id: Id)

👎 Deprecated since 0.1.2:

use Subscriber::try_close instead

This method is deprecated.

unsafe fn downcast_raw(&self, id: TypeId) -> Option<*const ()>

If self is the same type as the provided TypeId, returns an untyped *const pointer to that type. Otherwise, returns None.