axum-tracing-opentelemetry

crates license crate version

Project Status: Active – The project has reached a stable, usable state and is being actively developed.

Middlewares and tools to integrate axum + tracing + opentelemetry.

For examples, you can look at:

```rust //... use axumtracingopentelemetry::opentelemetrytracinglayer;

fn inittracing() -> Result<(), Box> { use tracingsubscriber::filter::EnvFilter; use tracingsubscriber::fmt::format::FmtSpan; use tracingsubscriber::layer::SubscriberExt;

let subscriber = tracing_subscriber::registry();

// register opentelemetry tracer layer
let otel_layer = {
    use axum_tracing_opentelemetry::{
        init_propagator, //stdio,
        make_resource,
        otlp,
    };
    let otel_rsrc = make_resource(
        std::env::var("OTEL_SERVICE_NAME")
            .unwrap_or_else(|_| env!("CARGO_PKG_NAME").to_string()),
        env!("CARGO_PKG_VERSION"),
    );
    let otel_tracer = otlp::init_tracer(otel_rsrc, otlp::identity).expect("setup of Tracer");
    // let otel_tracer =
    //     stdio::init_tracer(otel_rsrc, stdio::identity, stdio::WriteNoWhere::default())
    //         .expect("setup of Tracer");

    // init propagator based on OTEL_PROPAGATORS value
    init_propagator()?;
    tracing_opentelemetry::layer().with_tracer(otel_tracer)
};
let subscriber = subscriber.with(otel_layer);

// filter what is output on log (fmt), but not what is send to trace (opentelemetry collector)
// std::env::set_var("RUST_LOG", "info,kube=trace");
std::env::set_var(
    "RUST_LOG",
    std::env::var("RUST_LOG")
        .or_else(|_| std::env::var("OTEL_LOG_LEVEL"))
        .unwrap_or_else(|_| "info".to_string()),
);
let subscriber = subscriber.with(EnvFilter::from_default_env());

if cfg!(debug_assertions) {
    let fmt_layer = tracing_subscriber::fmt::layer()
        .pretty()
        .with_line_number(true)
        .with_thread_names(true)
        .with_span_events(FmtSpan::NEW | FmtSpan::CLOSE)
        .with_timer(tracing_subscriber::fmt::time::uptime());
    let subscriber = subscriber.with(fmt_layer);
    tracing::subscriber::set_global_default(subscriber)?;
} else {
    let fmt_layer = tracing_subscriber::fmt::layer()
        .json()
        .with_span_events(FmtSpan::NEW | FmtSpan::CLOSE)
        .with_timer(tracing_subscriber::fmt::time::uptime());
    let subscriber = subscriber.with(fmt_layer);
    tracing::subscriber::set_global_default(subscriber)?;
};
Ok(())

}

[tokio::main]

async fn main() -> Result<(), Box> { inittracing()?; let app = app(); // run it let addr = &"0.0.0.0:3000".parse::()?; tracing::warn!("listening on {}", addr); axum::Server::bind(&addr) .serve(app.intomakeservice()) .withgracefulshutdown(shutdownsignal()) .await?; Ok(()) }

fn app() -> Router { // build our application with a route Router::new() .route("/", get(health)) // request processed inside span // opentelemetrytracinglayer setup TraceLayer, that is provided by tower-http so you have to add that as a dependency. .layer(opentelemetrytracinglayer()) .route("/health", get(health)) // request processed without span / trace }

async fn shutdownsignal() { //... opentelemetry::global::shutdowntracer_provider(); } ```

To retrieve the current trace_id (eg to add it into error message (as header or attributes))

rust let trace_id = axum_tracing_opentelemetry::find_current_trace_id(); json!({ "error" : "xxxxxx", "trace_id": trace_id})

To also inject the trace id into the response (could be useful for debugging) uses the layer response_with_trace_layer

rust // build our application with a route Router::new() ... // include trace context as header into the response .layer(response_with_trace_layer())

Configuration based on environment variable

To ease setup and compliancy with Opentelemetry SDK configuration, the configuration can be done with the following environment variables (see sample init_tracing() above):

In the context of kubernetes, the above environment variable can be injected by the Opentelemetry operator (via inject-sdk):

yaml apiVersion: apps/v1 kind: Deployment spec: template: metadata: annotations: # to inject environment variables only by opentelemetry-operator instrumentation.opentelemetry.io/inject-sdk: "opentelemetry-operator/instrumentation" instrumentation.opentelemetry.io/container-names: "app" containers: - name: app

Or if you don't setup inject-sdk, you can manually set the environment variable eg

yaml apiVersion: apps/v1 kind: Deployment spec: template: metadata: containers: - name: app env: - name: OTEL_SERVICE_NAME value: "app" - name: OTEL_EXPORTER_OTLP_PROTOCOL value: "grpc" # for otel collector in `deployment` mode, use the name of the service # - name: OTEL_EXPORTER_OTLP_ENDPOINT # value: "http://opentelemetry-collector.opentelemetry-collector:4317" # for otel collector in sidecar mode (imply to deploy a sidecar CR per namespace) - name: OTEL_EXPORTER_OTLP_ENDPOINT value: "http://localhost:4317" # for `daemonset` mode: need to use the local daemonset (value interpolated by k8s: `$(...)`) # - name: OTEL_EXPORTER_OTLP_ENDPOINT # value: "http://$(HOST_IP):4317" # - name: HOST_IP # valueFrom: # fieldRef: # fieldPath: status.hostIP

examples/otlp

In a terminal, run

``sh ❯ cd examples/otlp ❯ cargo run Compiling examples-otlp v0.1.0 (/home/david/src/github.com/davidB/axum-tracing-opentelemetry/examples/otlp) Finished dev [unoptimized + debuginfo] target(s) in 2.96s Runningtarget/debug/examples-otlp` 0.000170750s WARN examples_otlp: listening on 0.0.0.0:3003 at src/main.rs:70 on main

 0.000203401s  INFO examples_otlp: try to call `curl -i http://127.0.0.1:3003/` (with trace)
at src/main.rs:71 on main

 0.000213920s  INFO examples_otlp: try to call `curl -i http://127.0.0.1:3003/heatlh` (with NO trace)
at src/main.rs:72 on main

... ```

Into an other terminal, call the / (endpoint with opentelemetry_tracing_layer and response_with_trace_layer)

```sh ❯ curl -i http://127.0.0.1:3003/ HTTP/1.1 200 OK content-type: application/json content-length: 50 traceparent: 00-b2611246a58fd7ea623d2264c5a1e226-b2c9b811f2f424af-01 tracestate: date: Wed, 28 Dec 2022 17:04:59 GMT

{"mytraceid":"b2611246a58fd7ea623d2264c5a1e226"} ```

call the /health (endpoint with NO layer)

```sh ❯ curl -i http://127.0.0.1:3003/health HTTP/1.1 200 OK content-type: application/json content-length: 15 date: Wed, 28 Dec 2022 17:14:07 GMT

{"status":"UP"} ```

Compatibility

|axum|axum-tracing-opentelemetry| |----|--------------------------| |0.6 | latest - 0.6 | |0.5 | 0.1 - 0.5 |

History

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