71e8084de2
## Motivation Currently, `tracing-opentelemetry` v0.17.1 fails to compile with `default-features = false`. This is because there's a `let` binding for `normalized_metadata` with a `None` where the `Some` type can't be inferred. This managed to slip past CI and get released because we were never actually building the crate with its default features disabled, an oversight in our CI configuration. ## Solution This branch fixes the issue by adding an explicit type annotation to the `let` binding, so the `Option`'s type is known and the type error no longer occurs. I also removed a feature-flagged import that was not actually used. I also added `tracing-opentelemetry` to the `cargo hack` CI job. This way, we will now ensure that all its feature combinations are built on CI (including no features), which should prevent this kind of thing from occurring in the future. Without the fix, we can confirm that this job does fail: https://github.com/tokio-rs/tracing/runs/5279139893?check_suite_focus=true Fixes #1944
Tracing OpenTelemetry
Utilities for adding OpenTelemetry interoperability to tracing.
Overview
tracing is a framework for instrumenting Rust programs to collect
structured, event-based diagnostic information. This crate provides a layer
that connects spans from multiple systems into a trace and emits them to
OpenTelemetry-compatible distributed tracing systems for processing and
visualization.
The crate provides the following types:
OpenTelemetryLayeradds OpenTelemetry context to alltracingspans.OpenTelemetrySpanExtallows OpenTelemetry parent trace information to be injected and extracted from atracingspan.
Compiler support: requires rustc 1.49+
Examples
Basic Usage
use opentelemetry::exporter::trace::stdout;
use tracing::{error, span};
use tracing_subscriber::layer::SubscriberExt;
use tracing_subscriber::Registry;
fn main() {
// Install a new OpenTelemetry trace pipeline
let (tracer, _uninstall) = stdout::new_pipeline().install();
// Create a tracing layer with the configured tracer
let telemetry = tracing_opentelemetry::layer().with_tracer(tracer);
// Use the tracing subscriber `Registry`, or any other subscriber
// that impls `LookupSpan`
let subscriber = Registry::default().with(telemetry);
// Trace executed code
tracing::subscriber::with_default(subscriber, || {
// Spans will be sent to the configured OpenTelemetry exporter
let root = span!(tracing::Level::TRACE, "app_start", work_units = 2);
let _enter = root.enter();
error!("This event will be logged in the root span.");
});
}
Visualization example
# Run a supported collector like jaeger in the background
$ docker run -d -p6831:6831/udp -p6832:6832/udp -p16686:16686 jaegertracing/all-in-one:latest
# Run example to produce spans (from parent examples directory)
$ cargo run --example opentelemetry
# View spans (see the image below)
$ firefox http://localhost:16686/
Supported Rust Versions
Tracing Opentelemetry is built against the latest stable release. The minimum supported version is 1.46. The current Tracing version is not guaranteed to build on Rust versions earlier than the minimum supported version.
Tracing follows the same compiler support policies as the rest of the Tokio project. The current stable Rust compiler and the three most recent minor versions before it will always be supported. For example, if the current stable compiler version is 1.45, the minimum supported version will not be increased past 1.42, three minor versions prior. Increasing the minimum supported compiler version is not considered a semver breaking change as long as doing so complies with this policy.
License
This project is licensed under the MIT license.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in Tracing by you, shall be licensed as MIT, without any additional terms or conditions.