Struct TraceCapture 

pub struct TraceCapture(/* private fields */);

Available on crate feature test-utils only.

Records every span and event it sees. Clones share one record, so a test keeps a clone and installs another with TraceCapture::subscriber.

Field values are JSON: strings and Debug/Display renderings are strings, integers are numbers and booleans are booleans.

Implementations

impl TraceCapture

pub fn subscriber(&self) -> impl Subscriber + Send + Sync + 'static

A registry with this capture as its only layer.

pub fn spans(&self) -> Vec<CapturedSpan>

Every span seen so far, in creation order.

pub fn events(&self) -> Vec<CapturedEvent>

Every event seen so far, in order.

pub fn last_span(&self) -> Option<CapturedSpan>

The last span opened so far.

pub fn values_of(&self, field: &str) -> Vec<Value>

Every value field took on any span, at creation or later, span by span in creation order.

pub fn warnings(&self) -> Vec<String>

The events at WARN, in order, each as its message followed by name=value for every other field.

pub fn clear(&self)

Forgets every span and event seen so far.

Trait Implementations

impl Clone for TraceCapture

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for TraceCapture

fn default() -> Self

Returns the “default value” for a type.

impl<S> Layer<S> for TraceCapture

where S: Subscriber + for<'a> LookupSpan<'a>,

fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>)

Notifies this layer that a new span was constructed with the given Attributes and Id.

fn on_record(&self, id: &Id, values: &Record<'_>, _: Context<'_, S>)

Notifies this layer that a span with the given Id recorded the given values.

fn on_follows_from(&self, id: &Id, follows: &Id, _: Context<'_, S>)

Notifies this layer that a span with the ID span recorded that it follows from the span with the ID follows.

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

Notifies this layer that an event has occurred.

fn on_register_dispatch(&self, subscriber: &Dispatch)

Performs late initialization when installing this layer as a Subscriber.

fn on_layer(&mut self, subscriber: &mut S)

Performs late initialization when attaching a Layer to a Subscriber.

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

Registers a new callsite with this layer, returning whether or not the layer is interested in being notified about the callsite, similarly to Subscriber::register_callsite.

fn enabled(&self, metadata: &Metadata<'_>, ctx: Context<'_, S>) -> bool

Returns true if this layer is interested in a span or event with the given metadata in the current Context, similarly to Subscriber::enabled.

fn event_enabled(&self, _event: &Event<'_>, _ctx: Context<'_, S>) -> bool

Called before on_event, to determine if on_event should be called.

fn on_enter(&self, _id: &Id, _ctx: Context<'_, S>)

Notifies this layer that a span with the given ID was entered.

fn on_exit(&self, _id: &Id, _ctx: Context<'_, S>)

Notifies this layer that the span with the given ID was exited.

fn on_close(&self, _id: Id, _ctx: Context<'_, S>)

Notifies this layer that the span with the given ID has been closed.

fn on_id_change(&self, _old: &Id, _new: &Id, _ctx: Context<'_, S>)

Notifies this layer that a span ID has been cloned, and that the subscriber returned a different ID.

fn and_then<L>(self, layer: L) -> Layered<L, Self, S>

where L: Layer<S>, Self: Sized,

Composes this layer around the given Layer, returning a Layered struct implementing Layer.

fn with_subscriber(self, inner: S) -> Layered<Self, S>

where Self: Sized,

Composes this Layer with the given Subscriber, returning a Layered struct that implements Subscriber.

fn with_filter<F>(self, filter: F) -> Filtered<Self, F, S>

where Self: Sized, F: Filter<S>,

Available on crate features registry and std only.

Combines self with a Filter, returning a Filtered layer.

fn boxed(self) -> Box<dyn Layer<S> + Sync + Send>

where Self: Sized + Layer<S> + Send + Sync + 'static, S: Subscriber,

Available on crate features alloc or std only.

Erases the type of this Layer, returning a Boxed dyn Layer trait object.