pub struct FilterFn<F = fn(_: &Metadata<'_>) -> bool> { /* private fields */ }
Expand description
A filter implemented by a closure or function pointer that
determines whether a given span or event is enabled, based on its
Metadata
.
This type can be used for both per-layer filtering (using its
Filter
implementation) and global filtering (using its
Layer
implementation).
See the documentation on filtering with layers for details.
Implementations§
Source§impl<F> FilterFn<F>
impl<F> FilterFn<F>
Sourcepub fn new(enabled: F) -> Self
pub fn new(enabled: F) -> Self
Constructs a FilterFn
from a function or closure that returns true
if a span or event should be enabled, based on its Metadata
.
If determining whether a span or event should be enabled also requires
information about the current span context, use DynFilterFn
instead.
See the documentation on per-layer filtering for details on using
Filter
s.
§Examples
use tracing_subscriber::{
layer::{Layer, SubscriberExt},
filter::FilterFn,
util::SubscriberInitExt,
};
let my_filter = FilterFn::new(|metadata| {
// Only enable spans or events with the target "interesting_things"
metadata.target() == "interesting_things"
});
let my_layer = tracing_subscriber::fmt::layer();
tracing_subscriber::registry()
.with(my_layer.with_filter(my_filter))
.init();
// This event will not be enabled.
tracing::warn!("something important but uninteresting happened!");
// This event will be enabled.
tracing::debug!(target: "interesting_things", "an interesting minor detail...");
Sourcepub fn with_max_level_hint(self, max_level_hint: impl Into<LevelFilter>) -> Self
pub fn with_max_level_hint(self, max_level_hint: impl Into<LevelFilter>) -> Self
Sets the highest verbosity Level
the filter function will enable.
The value passed to this method will be returned by this FilterFn
’s
Filter::max_level_hint
method.
If the provided function will not enable all levels, it is recommended to call this method to configure it with the most verbose level it will enable.
§Examples
use tracing_subscriber::{
layer::{Layer, SubscriberExt},
filter::{filter_fn, LevelFilter},
util::SubscriberInitExt,
};
use tracing_core::Level;
let my_filter = filter_fn(|metadata| {
// Only enable spans or events with targets starting with `my_crate`
// and levels at or below `INFO`.
metadata.level() <= &Level::INFO && metadata.target().starts_with("my_crate")
})
// Since the filter closure will only enable the `INFO` level and
// below, set the max level hint
.with_max_level_hint(LevelFilter::INFO);
let my_layer = tracing_subscriber::fmt::layer();
tracing_subscriber::registry()
.with(my_layer.with_filter(my_filter))
.init();
Trait Implementations§
Source§impl<S, F> Filter<S> for FilterFn<F>
impl<S, F> Filter<S> for FilterFn<F>
Source§fn enabled(&self, metadata: &Metadata<'_>, _: &Context<'_, S>) -> bool
fn enabled(&self, metadata: &Metadata<'_>, _: &Context<'_, S>) -> bool
true
if this layer is interested in a span or event with the
given Metadata
in the current Context
, similarly to
Subscriber::enabled
. Read moreSource§fn callsite_enabled(&self, metadata: &'static Metadata<'static>) -> Interest
fn callsite_enabled(&self, metadata: &'static Metadata<'static>) -> Interest
Source§fn max_level_hint(&self) -> Option<LevelFilter>
fn max_level_hint(&self) -> Option<LevelFilter>
Source§fn event_enabled(&self, event: &Event<'_>, cx: &Context<'_, S>) -> bool
fn event_enabled(&self, event: &Event<'_>, cx: &Context<'_, S>) -> bool
Layer]'s [
on_event], to determine if
on_event` should be called. Read moreSource§fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>)
fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>)
Source§fn on_enter(&self, id: &Id, ctx: Context<'_, S>)
fn on_enter(&self, id: &Id, ctx: Context<'_, S>)
Source§impl<S, F> Layer<S> for FilterFn<F>
impl<S, F> Layer<S> for FilterFn<F>
Source§fn enabled(&self, metadata: &Metadata<'_>, _: Context<'_, S>) -> bool
fn enabled(&self, metadata: &Metadata<'_>, _: Context<'_, S>) -> bool
true
if this layer is interested in a span or event with the
given metadata
in the current Context
, similarly to
Subscriber::enabled
. Read moreSource§fn register_callsite(&self, metadata: &'static Metadata<'static>) -> Interest
fn register_callsite(&self, metadata: &'static Metadata<'static>) -> Interest
Subscriber::register_callsite
. Read moreSource§fn on_register_dispatch(&self, subscriber: &Dispatch)
fn on_register_dispatch(&self, subscriber: &Dispatch)
Subscriber
. Read moreSource§fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>)
fn on_new_span(&self, attrs: &Attributes<'_>, id: &Id, ctx: Context<'_, S>)
Attributes
and Id
.Source§fn on_record(&self, _span: &Id, _values: &Record<'_>, _ctx: Context<'_, S>)
fn on_record(&self, _span: &Id, _values: &Record<'_>, _ctx: Context<'_, S>)
Id
recorded the given
values
.Source§fn on_follows_from(&self, _span: &Id, _follows: &Id, _ctx: Context<'_, S>)
fn on_follows_from(&self, _span: &Id, _follows: &Id, _ctx: Context<'_, S>)
span
recorded that it
follows from the span with the ID follows
.Source§fn on_event(&self, _event: &Event<'_>, _ctx: Context<'_, S>)
fn on_event(&self, _event: &Event<'_>, _ctx: Context<'_, S>)
Source§fn on_enter(&self, _id: &Id, _ctx: Context<'_, S>)
fn on_enter(&self, _id: &Id, _ctx: Context<'_, S>)
Source§fn on_exit(&self, _id: &Id, _ctx: Context<'_, S>)
fn on_exit(&self, _id: &Id, _ctx: Context<'_, S>)
Source§fn on_close(&self, _id: Id, _ctx: Context<'_, S>)
fn on_close(&self, _id: Id, _ctx: Context<'_, S>)
Source§fn on_id_change(&self, _old: &Id, _new: &Id, _ctx: Context<'_, S>)
fn on_id_change(&self, _old: &Id, _new: &Id, _ctx: Context<'_, S>)
Source§fn and_then<L>(self, layer: L) -> Layered<L, Self, S>
fn and_then<L>(self, layer: L) -> Layered<L, Self, S>
Layer
, returning a Layered
struct implementing Layer
. Read moreSource§fn with_subscriber(self, inner: S) -> Layered<Self, S>where
Self: Sized,
fn with_subscriber(self, inner: S) -> Layered<Self, S>where
Self: Sized,
Layer
with the given Subscriber
, returning a
Layered
struct that implements Subscriber
. Read more