Struct tracing_subscriber::layer::Context [−][src]
pub struct Context<'a, S> { /* fields omitted */ }
Expand description
Represents information about the current context provided to Layer
s by the
wrapped Subscriber
.
To access stored data keyed by a span ID, implementors of the Layer
trait should ensure that the Subscriber
type parameter is also bound by the
LookupSpan
:
use tracing::Subscriber; use tracing_subscriber::{Layer, registry::LookupSpan}; pub struct MyLayer; impl<S> Layer<S> for MyLayer where S: Subscriber + for<'a> LookupSpan<'a>, { // ... }
Implementations
Returns the wrapped subscriber’s view of the current span.
Returns whether the wrapped subscriber would enable the current span.
Records the provided event
with the wrapped subscriber.
Notes
- The subscriber is free to expect that the event’s callsite has been
registered, and may panic or fail to observe the event if this is
not the case. The
tracing
crate’s macros ensure that all events are registered, but if the event is constructed through other means, the user is responsible for ensuring thatregister_callsite
has been called prior to calling this method. - This does not call
enabled
on the inner subscriber. If the caller wishes to apply the wrapped subscriber’s filter before choosing whether to record the event, it may first callContext::enabled
to check whether the event would be enabled. This allowsLayer
s to elide constructing the event if it would not be recorded.
pub fn metadata(&self, id: &Id) -> Option<&'static Metadata<'static>> where
S: for<'lookup> LookupSpan<'lookup>,
[src]This is supported on crate feature registry
only.
pub fn metadata(&self, id: &Id) -> Option<&'static Metadata<'static>> where
S: for<'lookup> LookupSpan<'lookup>,
[src]registry
only.Returns metadata for the span with the given id
, if it exists.
If this returns None
, then no span exists for that ID (either it has
closed or the ID is invalid).
pub fn span(&self, id: &Id) -> Option<SpanRef<'_, S>> where
S: for<'lookup> LookupSpan<'lookup>,
[src]This is supported on crate feature registry
only.
pub fn span(&self, id: &Id) -> Option<SpanRef<'_, S>> where
S: for<'lookup> LookupSpan<'lookup>,
[src]registry
only.Returns stored data for the span with the given id
, if it exists.
If this returns None
, then no span exists for that ID (either it has
closed or the ID is invalid).
Note: This requires the wrapped subscriber to implement theLookupSpan
trait. See the documentation onContext
's declaration for details.
This is supported on crate feature registry
only.
registry
only.Returns true
if an active span exists for the given Id
.
Note: This requires the wrapped subscriber to implement theLookupSpan
trait. See the documentation onContext
's declaration for details.
pub fn lookup_current(&self) -> Option<SpanRef<'_, S>> where
S: for<'lookup> LookupSpan<'lookup>,
[src]This is supported on crate feature registry
only.
pub fn lookup_current(&self) -> Option<SpanRef<'_, S>> where
S: for<'lookup> LookupSpan<'lookup>,
[src]registry
only.Returns stored data for the span that the wrapped subscriber considers to be the current.
If this returns None
, then we are not currently within a span.
Note: This requires the wrapped subscriber to implement theLookupSpan
trait. See the documentation onContext
's declaration for details.
This is supported on crate feature registry
only.
registry
only.Returns an iterator over the stored data for all the spans in the current context, starting the root of the trace tree and ending with the current span.
If this iterator is empty, then there are no spans in the current context.
Note: This requires the wrapped subscriber to implement theLookupSpan
trait. See the documentation onContext
's declaration for details.
Trait Implementations
Auto Trait Implementations
impl<'a, S> RefUnwindSafe for Context<'a, S> where
S: RefUnwindSafe,
impl<'a, S> UnwindSafe for Context<'a, S> where
S: RefUnwindSafe,
Blanket Implementations
Mutably borrows from an owned value. Read more
Instruments this type with the provided Span
, returning an
Instrumented
wrapper. Read more