Expand description
A non-blocking, off-thread writer.
This spawns a dedicated worker thread which is responsible for writing log
lines to the provided writer. When a line is written using the returned
NonBlocking
struct’s make_writer
method, it will be enqueued to be
written by the worker thread.
The queue has a fixed capacity, and if it becomes full, any logs written
to it will be dropped until capacity is once again available. This may
occur if logs are consistently produced faster than the worker thread can
output them. The queue capacity and behavior when full (i.e., whether to
drop logs or to exert backpressure to slow down senders) can be configured
using NonBlockingBuilder::default()
.
This function returns the default configuration. It is equivalent to:
tracing_appender::non_blocking(std::io::stdout())
This function returns a tuple of NonBlocking
and WorkerGuard
.
NonBlocking
implements MakeWriter
which integrates with tracing_subscriber
.
WorkerGuard
is a drop guard that is responsible for flushing any remaining logs when
the program terminates.
Note that the WorkerGuard
returned by non_blocking
must be assigned to a binding that
is not _
, as _
will result in the WorkerGuard
being dropped immediately.
Unintentional drops of WorkerGuard
remove the guarantee that logs will be flushed
during a program’s termination, in a panic or otherwise.
See WorkerGuard
for examples of using the guard.
§Examples
let (non_blocking, _guard) = tracing_appender::non_blocking(std::io::stdout());
let collector = tracing_subscriber::fmt().with_writer(non_blocking);
tracing::collect::with_default(collector.finish(), || {
tracing::event!(tracing::Level::INFO, "Hello");
});
Structs§
- Tracks the number of times a log line was dropped by the background thread.
- A non-blocking writer.
- A builder for
NonBlocking
. - A guard that flushes spans/events associated to a
NonBlocking
on a drop
Constants§
- The default maximum number of buffered log lines.