Trait WithCollector

pub trait WithCollector: Sized {
    // Provided methods
    fn with_collector<C>(self, collector: C) -> WithDispatch<Self> 
       where C: Into<Dispatch> { ... }
    fn with_current_collector(self) -> WithDispatch<Self>  { ... }
}

Available on crate feature std only.

Extension trait allowing futures to be instrumented with a tracing collector.

Provided Methods

fn with_collector<C>(self, collector: C) -> WithDispatch<Self>

where C: Into<Dispatch>,

Attaches the provided collector to this type, returning a WithDispatch wrapper.

The attached collector will be set as the default when the returned Future is polled.

Examples

use tracing::instrument::WithCollector;

// Set the default collector
let _default = tracing::collect::set_default(MyCollector::new());

tracing::info!("this event will be recorded by the default collector");

// Create a different collector and attach it to a future.
let other_collector = MyCollector::new();
let future = async {
    tracing::info!("this event will be recorded by the other collector");
    // ...
};

future
    // Attach the other collector to the future before awaiting it
    .with_collector(other_collector)
    .await;

// Once the future has completed, we return to the default collector.
tracing::info!("this event will be recorded by the default collector");

fn with_current_collector(self) -> WithDispatch<Self>

Attaches the current default collector to this type, returning a WithDispatch wrapper.

The attached collector will be set as the default when the returned Future is polled.

This can be used to propagate the current dispatcher context when spawning a new future that may run on a different thread.

Examples

use tracing::instrument::WithCollector;

// Using `set_default` (rather than `set_global_default`) sets the
// default collector for *this* thread only.
let _default = tracing::collect::set_default(MyCollector::new());

let future = async {
    // ...
};

// If a multi-threaded async runtime is in use, this spawned task may
// run on a different thread, in a different default collector's context.
tokio::spawn(future);

// However, calling `with_current_collector` on the future before
// spawning it, ensures that the current thread's default collector is
// propagated to the spawned task, regardless of where it executes:
tokio::spawn(future.with_current_collector());

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<T: Sized> WithCollector for T