Add SetRequestId and PropagateRequestId middleware

[davidpdrsn]

Fixes #135

Example usage:

use http::{Request, Response, header::HeaderName};
use tower::{Service, ServiceExt, ServiceBuilder};
use tower_http::request_id::{
    SetRequestIdLayer, PropagateRequestIdLayer, MakeRequestId, RequestId,
};
use hyper::Body;
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>(&mut 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");

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);

Or slightly shorter using ServiceBuilderExt:

use tower_http::ServiceBuilderExt;

ServiceBuilder::new()
    .set_x_request_id(MyMakeRequestId::default())
    .propagate_x_request_id()
    .service(handler);

These are two different middleware since they need to be applied around any logging you might have. The docs have an example.

[davidpdrsn]

@DoumanAsh what do you think about this?

[DoumanAsh]

That looks pretty good and generic too for most use cases
I left some comments based on my own middleware

[Nehliin]

Really like this feature! Will be super nice when its merged, I only had a couple of small comments

[Nehliin]

🎉

[MarcusGrass]

LGTM, convenient implementation