Crate axum_otel 

OpenTelemetry tracing for axum based on tower-http.

This crate provides a middleware for Axum web framework that automatically instruments HTTP requests and responses, and adds OpenTelemetry tracing to the request and response spans.

Features

• Automatic request and response tracing
• OpenTelemetry integration
• Request ID tracking
• Customizable span attributes
• Error tracking

Usage

use axum::{
    routing::get,
    Router,
};
use axum_otel::{AxumOtelOnFailure, AxumOtelOnResponse, AxumOtelSpanCreator, Level};
use tower_http::trace::TraceLayer;

async fn handler() -> &'static str {
    "Hello, world!"
}

// Build our application with a route
let app: Router<()> = Router::new()
    .route("/", get(handler))
    .layer(
        TraceLayer::new_for_http()
            .make_span_with(AxumOtelSpanCreator::new().level(Level::INFO))
            .on_response(AxumOtelOnResponse::new().level(Level::INFO))
            .on_failure(AxumOtelOnFailure::new()),
    );

Components

• AxumOtelSpanCreator - Creates spans for each request with relevant HTTP information
• AxumOtelOnResponse - Records response status and latency
• AxumOtelOnFailure - Handles error cases and updates span status

HTTP span attributes

Field names follow the OpenTelemetry HTTP traces semantic conventions where applicable. If you upgrade from older releases, update queries and dashboards:

Previous attribute	Replacement
http.host	server.address
http.user_agent	user_agent.original
http.client_ip	client.address

http.response.status_code is recorded as an integer when the response is sent (AxumOtelOnResponse).

See the examples directory for complete examples.

Structs

AxumOtelOnFailure

An implementor of OnFailure which records the failure status code.

AxumOtelOnResponse

An implementor of OnResponse which records the response status code and latency.

AxumOtelSpanCreator

An implementor of MakeSpan which creates tracing spans populated with information about the request received by an axum web server.

Level

Describes the level of verbosity of a span or event.