Module request_id

Available on crate feature request-id only.

Set and propagate request ids.

Example

use http::{Request, Response, header::HeaderName};
use http_body_util::Full;
use bytes::Bytes;
use tower_async::{Service, ServiceExt, ServiceBuilder};
use tower_async_http::request_id::{
    SetRequestIdLayer, PropagateRequestIdLayer, MakeRequestId, RequestId,
};
use std::sync::{Arc, atomic::{AtomicU64, Ordering}};

// A `MakeRequestId` that increments an atomic counter
#[derive(Clone, Default)]
struct MyMakeRequestId {
    counter: Arc<AtomicU64>,
}

impl MakeRequestId for MyMakeRequestId {
    fn make_request_id<B>(&self, request: &Request<B>) -> Option<RequestId> {
        let request_id = self.counter
            .fetch_add(1, Ordering::SeqCst)
            .to_string()
            .parse()
            .unwrap();

        Some(RequestId::new(request_id))
    }
}

let x_request_id = HeaderName::from_static("x-request-id");

let mut svc = ServiceBuilder::new()
    // set `x-request-id` header on all requests
    .layer(SetRequestIdLayer::new(
        x_request_id.clone(),
        MyMakeRequestId::default(),
    ))
    // propagate `x-request-id` headers from request to response
    .layer(PropagateRequestIdLayer::new(x_request_id))
    .service(handler);

let request = Request::new(Full::default());
let response = svc.call(request).await?;

assert_eq!(response.headers()["x-request-id"], "0");

Additional convenience methods are available on ServiceBuilderExt:

use tower_async_http::ServiceBuilderExt;

let mut svc = ServiceBuilder::new()
    .set_x_request_id(MyMakeRequestId::default())
    .propagate_x_request_id()
    .service(handler);

let request = Request::new(Body::default());
let response = svc.call(request).await?;

assert_eq!(response.headers()["x-request-id"], "0");

See SetRequestId and PropagateRequestId for more details.

Doesn’t override existing headers

SetRequestId and PropagateRequestId wont override request ids if its already present on requests or responses. Among other things, this allows other middleware to conditionally set request ids and use the middleware in this module as a fallback.

Structs

MakeRequestUuid

A MakeRequestId that generates UUIDs.

PropagateRequestId

Propagate request ids from requests to responses.

PropagateRequestIdLayer

Propagate request ids from requests to responses.

RequestId

An identifier for a request.

SetRequestId

Set request id headers and extensions on requests.

SetRequestIdLayer

Set request id headers and extensions on requests.

Traits

MakeRequestId

Trait for producing RequestIds.