Module tracing 

Available on crate feature tracing only.

Runtime components for use with tracing.

This module provides Executor implementations that configure instrumentation of spawned futures. These Executors can propagate tracing Spans to futures spawned onto the async runtime. See the crate-level documentation of tracing for more information about spans.

Choosing an Executor.

Hyper spawns Futures onto an Executor, to avoid tightly coupling APIs to any particular async runtime. This includes background tasks that might help service I/O for the lifetime of a connection, for example.

Some Subscriber implementations have different semantics regarding the lifecycle of Spans. Integrations with OpenTelemetry collectors, for example, might not emit the events within the context of a span until it is closed. Conversely, subscribers that print traces to the terminal may not have to contend with these details when instrumenting long-lived tasks that run in the background.

This module provides different executors to help pass tracing context in the manner appropriate for your application. For most typical applications, CurrentSpanExecutor<E> should suffice.

Examples

Run spawned tasks within a provided span.

use hyper_util::rt::{TokioExecutor, WithSpanExecutor};

let span = tracing::info_span!("example");
let executor = WithSpanExecutor::new(TokioExecutor::new(), span);

Run spawned tasks within the current span when Executor::execute() is called.

use hyper_util::rt::{TokioExecutor, CurrentSpanExecutor};

let executor = CurrentSpanExecutor::new(TokioExecutor::new());

Run spawned tasks within distinct spans that are marked as following from the active span when Executor::execute() is called.

use hyper_util::rt::{MkSpanExecutor, TokioExecutor};
use tracing::{info_span, Span};

let mk = || {
    let span = info_span!("example");
    span.follows_from(Span::current());
    span
};
let executor = MkSpanExecutor::new(TokioExecutor::new(), mk);

Structs

CurrentSpanExecutor

An executor that propagates the current tracing span to its futures.

MkSpanExecutor

An executor that uses a callback to propagate tracing span to its futures.

WithSpanExecutor

An executor that propagates a provided tracing span to its futures.