Function trace_future

datafusion/common-runtime/src/trace_utils.rs:130–152

Optionally instruments a future with custom tracing. If a tracer has been injected via `set_tracer`, the future's output is boxed (erasing its type), passed to the tracer, and then downcast back to the expected type. If no tracer is set, the original future is returned. # Type Parameters `T` - The concrete output type of the future. `F` - The future type. # Parameters `future` - The future to p

(future: F)

/// # Parameters
/// * `future` - The future to potentially instrument.
pub fn trace_future<T, F>(future: F) -> BoxFuture<'static, T>
where
    F: Future<Output = T> + Send + 'static,
    T: Send + 'static,
{
    // Erase the future’s output type first:
    let erased_future = async move {
        let result = future.await;
        Box::new(result) as Box<dyn Any + Send>
    }
    .boxed();

    // Forward through the global tracer:
    get_tracer()
        .trace_future(erased_future)
        // Downcast from `Box<dyn Any + Send>` back to `T`:
        .map(|any_box| {
            *any_box
                .downcast::<T>()
                .expect("Tracer must preserve the future’s output type!")
        })
        .boxed()
}

/// Optionally instruments a blocking closure with custom tracing.
///