pub struct BoxMakeWriter { /* private fields */ }
Available on crate features
fmt
and std
only.Expand description
A writer that erases the specific io::Write
and MakeWriter
types being used.
This is useful in cases where the concrete type of the writer cannot be known until runtime.
§Examples
A function that returns a Subscriber
that will write to either stdout or stderr:
fn dynamic_writer(use_stderr: bool) -> impl Subscriber {
let writer = if use_stderr {
BoxMakeWriter::new(std::io::stderr)
} else {
BoxMakeWriter::new(std::io::stdout)
};
tracing_subscriber::fmt().with_writer(writer).finish()
}
Implementations§
Source§impl BoxMakeWriter
impl BoxMakeWriter
Sourcepub fn new<M>(make_writer: M) -> Self
pub fn new<M>(make_writer: M) -> Self
Constructs a BoxMakeWriter
wrapping a type implementing MakeWriter
.
Trait Implementations§
Source§impl Debug for BoxMakeWriter
impl Debug for BoxMakeWriter
Source§impl<'a> MakeWriter<'a> for BoxMakeWriter
impl<'a> MakeWriter<'a> for BoxMakeWriter
Auto Trait Implementations§
impl Freeze for BoxMakeWriter
impl !RefUnwindSafe for BoxMakeWriter
impl Send for BoxMakeWriter
impl Sync for BoxMakeWriter
impl Unpin for BoxMakeWriter
impl !UnwindSafe for BoxMakeWriter
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
Source§impl<'a, M> MakeWriterExt<'a> for Mwhere
M: MakeWriter<'a>,
impl<'a, M> MakeWriterExt<'a> for Mwhere
M: MakeWriter<'a>,
Source§fn with_max_level(self, level: Level) -> WithMaxLevel<Self>where
Self: Sized,
fn with_max_level(self, level: Level) -> WithMaxLevel<Self>where
Self: Sized,
Available on crate features
fmt
and std
only.Wraps
self
and returns a MakeWriter
that will only write output
for events at or below the provided verbosity Level
. For instance,
Level::TRACE
is considered to be _more verbosethan
Level::INFO`. Read moreSource§fn with_min_level(self, level: Level) -> WithMinLevel<Self>where
Self: Sized,
fn with_min_level(self, level: Level) -> WithMinLevel<Self>where
Self: Sized,
Available on crate features
fmt
and std
only.Wraps
self
and returns a MakeWriter
that will only write output
for events at or above the provided verbosity Level
. Read moreSource§fn with_filter<F>(self, filter: F) -> WithFilter<Self, F>
fn with_filter<F>(self, filter: F) -> WithFilter<Self, F>
Available on crate features
fmt
and std
only.Wraps
self
with a predicate that takes a span or event’s Metadata
and returns a bool
. The returned MakeWriter
’s
MakeWriter::make_writer_for
method will check the predicate to
determine if a writer should be produced for a given span or event. Read moreSource§fn and<B>(self, other: B) -> Tee<Self, B> ⓘ
fn and<B>(self, other: B) -> Tee<Self, B> ⓘ
Available on crate features
fmt
and std
only.Combines
self
with another type implementing MakeWriter
, returning
a new MakeWriter
that produces writers that write to both
outputs. Read moreSource§fn or_else<W, B>(self, other: B) -> OrElse<Self, B>where
Self: MakeWriter<'a, Writer = OptionalWriter<W>> + Sized,
B: MakeWriter<'a> + Sized,
W: Write,
fn or_else<W, B>(self, other: B) -> OrElse<Self, B>where
Self: MakeWriter<'a, Writer = OptionalWriter<W>> + Sized,
B: MakeWriter<'a> + Sized,
W: Write,
Available on crate features
fmt
and std
only.Combines
self
with another type implementing MakeWriter
, returning
a new MakeWriter
that calls other
’s make_writer
if self
’s
make_writer
returns OptionalWriter::none
. Read moreLayout§
Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...)
attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.
Size: 32 bytes