Struct tracing_appender::non_blocking::WorkerGuard

#[must_use]pub struct WorkerGuard { /* fields omitted */ }

A guard that flushes spans/events associated to a NonBlocking on a drop

Writing to a NonBlocking writer will not immediately write a span or event to the underlying output. Instead, the span or event will be written by a dedicated logging thread at some later point. To increase throughput, the non-blocking writer will flush to the underlying output on a periodic basis rather than every time a span or event is written. This means that if the program terminates abruptly (such as through an uncaught panic or a std::process::exit), some spans or events may not be written.

Since spans/events and events recorded near a crash are often necessary for diagnosing the failure, WorkerGuard provides a mechanism to ensure that all buffered logs are flushed to their output. WorkerGuard should be assigned in the main function or whatever the entrypoint of the program is. This will ensure that the guard will be dropped during an unwinding or when main exits successfully.

Examples

fn main () {
    let (non_blocking, _guard) = tracing_appender::non_blocking(std::io::stdout());
    let subscriber = tracing_subscriber::fmt().with_writer(non_blocking);
    tracing::subscriber::with_default(subscriber.finish(), || {
        // Emit some tracing events within context of the non_blocking `_guard` and tracing subscriber
        tracing::event!(tracing::Level::INFO, "Hello");
    });
    // Exiting the context of `main` will drop the `_guard` and any remaining logs should get flushed
}

Trait Implementations

impl Debug for WorkerGuard

pub fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for WorkerGuard

pub fn drop(&mut self)

Executes the destructor for this type.