Struct tracing_subscriber::registry::SpanRef
source · [−]pub struct SpanRef<'a, R: LookupSpan<'a>> { /* private fields */ }
Expand description
Implementations
Returns a static reference to the span’s metadata.
Returns a SpanRef
describing this span’s parent, or None
if this
span is the root of its trace tree.
Returns an iterator over all parents of this span, starting with this span, ordered from leaf to root.
The iterator will first return the span, then the span’s immediate parent, followed by that span’s parent, and so on, until it reaches a root span.
use tracing::{span, Subscriber};
use tracing_subscriber::{
layer::{Context, Layer},
prelude::*,
registry::LookupSpan,
};
struct PrintingLayer;
impl<S> Layer<S> for PrintingLayer
where
S: Subscriber + for<'lookup> LookupSpan<'lookup>,
{
fn on_enter(&self, id: &span::Id, ctx: Context<S>) {
let span = ctx.span(id).unwrap();
let scope = span.scope().map(|span| span.name()).collect::<Vec<_>>();
println!("Entering span: {:?}", scope);
}
}
tracing::subscriber::with_default(tracing_subscriber::registry().with(PrintingLayer), || {
let _root = tracing::info_span!("root").entered();
// Prints: Entering span: ["root"]
let _child = tracing::info_span!("child").entered();
// Prints: Entering span: ["child", "root"]
let _leaf = tracing::info_span!("leaf").entered();
// Prints: Entering span: ["leaf", "child", "root"]
});
If the opposite order (from the root to this span) is desired, calling Scope::from_root
on
the returned iterator reverses the order.
impl<S> Layer<S> for PrintingLayer
where
S: Subscriber + for<'lookup> LookupSpan<'lookup>,
{
fn on_enter(&self, id: &span::Id, ctx: Context<S>) {
let span = ctx.span(id).unwrap();
let scope = span.scope().from_root().map(|span| span.name()).collect::<Vec<_>>();
println!("Entering span: {:?}", scope);
}
}
tracing::subscriber::with_default(tracing_subscriber::registry().with(PrintingLayer), || {
let _root = tracing::info_span!("root").entered();
// Prints: Entering span: ["root"]
let _child = tracing::info_span!("child").entered();
// Prints: Entering span: ["root", "child"]
let _leaf = tracing::info_span!("leaf").entered();
// Prints: Entering span: ["root", "child", "leaf"]
});
This is supported on crate feature std
only.
std
only.Returns a reference to this span’s Extensions
.
The extensions may be used by Layer
s to store additional data
describing the span.
This is supported on crate feature std
only.
std
only.Returns a mutable reference to this span’s Extensions
.
The extensions may be used by Layer
s to store additional data
describing the span.
Trait Implementations
Auto Trait Implementations
impl<'a, R> RefUnwindSafe for SpanRef<'a, R> where
R: RefUnwindSafe,
<R as LookupSpan<'a>>::Data: RefUnwindSafe,
impl<'a, R> Unpin for SpanRef<'a, R> where
<R as LookupSpan<'a>>::Data: Unpin,
impl<'a, R> UnwindSafe for SpanRef<'a, R> where
R: RefUnwindSafe,
<R as LookupSpan<'a>>::Data: UnwindSafe,
Blanket Implementations
Mutably borrows from an owned value. Read more
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more