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//! Set and propagate request ids.
//!
//! # Example
//!
//! ```
//! 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}};
//!
//! # #[tokio::main]
//! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
//! # let handler = tower::service_fn(|request: Request<Body>| async move {
//! # Ok::<_, std::convert::Infallible>(Response::new(request.into_body()))
//! # });
//! #
//! // 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");
//!
//! 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(Body::empty());
//! let response = svc.ready().await?.call(request).await?;
//!
//! assert_eq!(response.headers()["x-request-id"], "0");
//! #
//! # Ok(())
//! # }
//! ```
//!
//! Additional convenience methods are available on [`ServiceBuilderExt`]:
//!
//! ```
//! use tower_http::ServiceBuilderExt;
//! # 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}};
//! # #[tokio::main]
//! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
//! # let handler = tower::service_fn(|request: Request<Body>| async move {
//! # Ok::<_, std::convert::Infallible>(Response::new(request.into_body()))
//! # });
//! # #[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 mut svc = ServiceBuilder::new()
//! .set_x_request_id(MyMakeRequestId::default())
//! .propagate_x_request_id()
//! .service(handler);
//!
//! let request = Request::new(Body::empty());
//! let response = svc.ready().await?.call(request).await?;
//!
//! assert_eq!(response.headers()["x-request-id"], "0");
//! #
//! # Ok(())
//! # }
//! ```
//!
//! See [`SetRequestId`] and [`PropagateRequestId`] for more details.
//!
//! # Using `Trace`
//!
//! To have request ids show up correctly in logs produced by [`Trace`] you must apply the layers
//! in this order:
//!
//! ```
//! use tower_http::{
//! ServiceBuilderExt,
//! trace::{TraceLayer, DefaultMakeSpan, DefaultOnResponse},
//! };
//! # 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}};
//! # #[tokio::main]
//! # async fn main() -> Result<(), Box<dyn std::error::Error>> {
//! # let handler = tower::service_fn(|request: Request<Body>| async move {
//! # Ok::<_, std::convert::Infallible>(Response::new(request.into_body()))
//! # });
//! # #[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 svc = ServiceBuilder::new()
//! // make sure to set request ids before the request reaches `TraceLayer`
//! .set_x_request_id(MyMakeRequestId::default())
//! // log requests and responses
//! .layer(
//! TraceLayer::new_for_http()
//! .make_span_with(DefaultMakeSpan::new().include_headers(true))
//! .on_response(DefaultOnResponse::new().include_headers(true))
//! )
//! // propagate the header to the response before the response reaches `TraceLayer`
//! .propagate_x_request_id()
//! .service(handler);
//! #
//! # Ok(())
//! # }
//! ```
//!
//! # 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.
//!
//! [`ServiceBuilderExt`]: crate::ServiceBuilderExt
//! [`Uuid`]: https://crates.io/crates/uuid
//! [`Trace`]: crate::trace::Trace
use http::{
header::{HeaderName, HeaderValue},
Request, Response,
};
use pin_project_lite::pin_project;
use std::task::{Context, Poll};
use std::{future::Future, pin::Pin};
use tower_layer::Layer;
use tower_service::Service;
use uuid::Uuid;
pub(crate) const X_REQUEST_ID: &str = "x-request-id";
/// Trait for producing [`RequestId`]s.
///
/// Used by [`SetRequestId`].
pub trait MakeRequestId {
/// Try and produce a [`RequestId`] from the request.
fn make_request_id<B>(&mut self, request: &Request<B>) -> Option<RequestId>;
}
/// An identifier for a request.
#[derive(Debug, Clone)]
pub struct RequestId(HeaderValue);
impl RequestId {
/// Create a new `RequestId` from a [`HeaderValue`].
pub fn new(header_value: HeaderValue) -> Self {
Self(header_value)
}
/// Gets a reference to the underlying [`HeaderValue`].
pub fn header_value(&self) -> &HeaderValue {
&self.0
}
/// Consumes `self`, returning the underlying [`HeaderValue`].
pub fn into_header_value(self) -> HeaderValue {
self.0
}
}
impl From<HeaderValue> for RequestId {
fn from(value: HeaderValue) -> Self {
Self::new(value)
}
}
/// Set request id headers and extensions on requests.
///
/// This layer applies the [`SetRequestId`] middleware.
///
/// See the [module docs](self) and [`SetRequestId`] for more details.
#[derive(Debug, Clone)]
pub struct SetRequestIdLayer<M> {
header_name: HeaderName,
make_request_id: M,
}
impl<M> SetRequestIdLayer<M> {
/// Create a new `SetRequestIdLayer`.
pub fn new(header_name: HeaderName, make_request_id: M) -> Self
where
M: MakeRequestId,
{
SetRequestIdLayer {
header_name,
make_request_id,
}
}
/// Create a new `SetRequestIdLayer` that uses `x-request-id` as the header name.
pub fn x_request_id(make_request_id: M) -> Self
where
M: MakeRequestId,
{
SetRequestIdLayer::new(HeaderName::from_static(X_REQUEST_ID), make_request_id)
}
}
impl<S, M> Layer<S> for SetRequestIdLayer<M>
where
M: Clone + MakeRequestId,
{
type Service = SetRequestId<S, M>;
fn layer(&self, inner: S) -> Self::Service {
SetRequestId::new(
inner,
self.header_name.clone(),
self.make_request_id.clone(),
)
}
}
/// Set request id headers and extensions on requests.
///
/// See the [module docs](self) for an example.
///
/// If [`MakeRequestId::make_request_id`] returns `Some(_)` and the request doesn't already have a
/// header with the same name, then the header will be inserted.
///
/// Additionally [`RequestId`] will be inserted into [`Request::extensions`] so other
/// services can access it.
#[derive(Debug, Clone)]
pub struct SetRequestId<S, M> {
inner: S,
header_name: HeaderName,
make_request_id: M,
}
impl<S, M> SetRequestId<S, M> {
/// Create a new `SetRequestId`.
pub fn new(inner: S, header_name: HeaderName, make_request_id: M) -> Self
where
M: MakeRequestId,
{
Self {
inner,
header_name,
make_request_id,
}
}
/// Create a new `SetRequestId` that uses `x-request-id` as the header name.
pub fn x_request_id(inner: S, make_request_id: M) -> Self
where
M: MakeRequestId,
{
Self::new(
inner,
HeaderName::from_static(X_REQUEST_ID),
make_request_id,
)
}
define_inner_service_accessors!();
/// Returns a new [`Layer`] that wraps services with a `SetRequestId` middleware.
pub fn layer(header_name: HeaderName, make_request_id: M) -> SetRequestIdLayer<M>
where
M: MakeRequestId,
{
SetRequestIdLayer::new(header_name, make_request_id)
}
}
impl<S, M, ReqBody, ResBody> Service<Request<ReqBody>> for SetRequestId<S, M>
where
S: Service<Request<ReqBody>, Response = Response<ResBody>>,
M: MakeRequestId,
{
type Response = S::Response;
type Error = S::Error;
type Future = S::Future;
#[inline]
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.inner.poll_ready(cx)
}
fn call(&mut self, mut req: Request<ReqBody>) -> Self::Future {
if let Some(request_id) = req.headers().get(&self.header_name) {
if req.extensions().get::<RequestId>().is_none() {
let request_id = request_id.clone();
req.extensions_mut().insert(RequestId::new(request_id));
}
} else if let Some(request_id) = self.make_request_id.make_request_id(&req) {
req.extensions_mut().insert(request_id.clone());
req.headers_mut()
.insert(self.header_name.clone(), request_id.0);
}
self.inner.call(req)
}
}
/// Propagate request ids from requests to responses.
///
/// This layer applies the [`PropagateRequestId`] middleware.
///
/// See the [module docs](self) and [`PropagateRequestId`] for more details.
#[derive(Debug, Clone)]
pub struct PropagateRequestIdLayer {
header_name: HeaderName,
}
impl PropagateRequestIdLayer {
/// Create a new `PropagateRequestIdLayer`.
pub fn new(header_name: HeaderName) -> Self {
PropagateRequestIdLayer { header_name }
}
/// Create a new `PropagateRequestIdLayer` that uses `x-request-id` as the header name.
pub fn x_request_id() -> Self {
Self::new(HeaderName::from_static(X_REQUEST_ID))
}
}
impl<S> Layer<S> for PropagateRequestIdLayer {
type Service = PropagateRequestId<S>;
fn layer(&self, inner: S) -> Self::Service {
PropagateRequestId::new(inner, self.header_name.clone())
}
}
/// Propagate request ids from requests to responses.
///
/// See the [module docs](self) for an example.
///
/// If the request contains a matching header that header will be applied to responses. If a
/// [`RequestId`] extension is also present it will be propagated as well.
#[derive(Debug, Clone)]
pub struct PropagateRequestId<S> {
inner: S,
header_name: HeaderName,
}
impl<S> PropagateRequestId<S> {
/// Create a new `PropagateRequestId`.
pub fn new(inner: S, header_name: HeaderName) -> Self {
Self { inner, header_name }
}
/// Create a new `PropagateRequestId` that uses `x-request-id` as the header name.
pub fn x_request_id(inner: S) -> Self {
Self::new(inner, HeaderName::from_static(X_REQUEST_ID))
}
define_inner_service_accessors!();
/// Returns a new [`Layer`] that wraps services with a `PropagateRequestId` middleware.
pub fn layer(header_name: HeaderName) -> PropagateRequestIdLayer {
PropagateRequestIdLayer::new(header_name)
}
}
impl<S, ReqBody, ResBody> Service<Request<ReqBody>> for PropagateRequestId<S>
where
S: Service<Request<ReqBody>, Response = Response<ResBody>>,
{
type Response = S::Response;
type Error = S::Error;
type Future = PropagateRequestIdResponseFuture<S::Future>;
fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
self.inner.poll_ready(cx)
}
fn call(&mut self, req: Request<ReqBody>) -> Self::Future {
let request_id = req
.headers()
.get(&self.header_name)
.cloned()
.map(RequestId::new);
PropagateRequestIdResponseFuture {
inner: self.inner.call(req),
header_name: self.header_name.clone(),
request_id,
}
}
}
pin_project! {
/// Response future for [`PropagateRequestId`].
pub struct PropagateRequestIdResponseFuture<F> {
#[pin]
inner: F,
header_name: HeaderName,
request_id: Option<RequestId>,
}
}
impl<F, B, E> Future for PropagateRequestIdResponseFuture<F>
where
F: Future<Output = Result<Response<B>, E>>,
{
type Output = Result<Response<B>, E>;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let this = self.project();
let mut response = futures_core::ready!(this.inner.poll(cx))?;
if let Some(current_id) = response.headers().get(&*this.header_name) {
if response.extensions().get::<RequestId>().is_none() {
let current_id = current_id.clone();
response.extensions_mut().insert(RequestId::new(current_id));
}
} else if let Some(request_id) = this.request_id.take() {
response
.headers_mut()
.insert(this.header_name.clone(), request_id.0.clone());
response.extensions_mut().insert(request_id);
}
Poll::Ready(Ok(response))
}
}
/// A [`MakeRequestId`] that generates `UUID`s.
#[derive(Clone, Copy, Default)]
pub struct MakeRequestUuid;
impl MakeRequestId for MakeRequestUuid {
fn make_request_id<B>(&mut self, _request: &Request<B>) -> Option<RequestId> {
let request_id = Uuid::new_v4().to_string().parse().unwrap();
Some(RequestId::new(request_id))
}
}
#[cfg(test)]
mod tests {
use crate::ServiceBuilderExt as _;
use hyper::{Body, Response};
use std::{
convert::Infallible,
sync::{
atomic::{AtomicU64, Ordering},
Arc,
},
};
use tower::{ServiceBuilder, ServiceExt};
#[allow(unused_imports)]
use super::*;
#[tokio::test]
async fn basic() {
let svc = ServiceBuilder::new()
.set_x_request_id(Counter::default())
.propagate_x_request_id()
.service_fn(handler);
// header on response
let req = Request::builder().body(Body::empty()).unwrap();
let res = svc.clone().oneshot(req).await.unwrap();
assert_eq!(res.headers()["x-request-id"], "0");
let req = Request::builder().body(Body::empty()).unwrap();
let res = svc.clone().oneshot(req).await.unwrap();
assert_eq!(res.headers()["x-request-id"], "1");
// doesn't override if header is already there
let req = Request::builder()
.header("x-request-id", "foo")
.body(Body::empty())
.unwrap();
let res = svc.clone().oneshot(req).await.unwrap();
assert_eq!(res.headers()["x-request-id"], "foo");
// extension propagated
let req = Request::builder().body(Body::empty()).unwrap();
let res = svc.clone().oneshot(req).await.unwrap();
assert_eq!(res.extensions().get::<RequestId>().unwrap().0, "2");
}
#[tokio::test]
async fn other_middleware_setting_request_id() {
let svc = ServiceBuilder::new()
.override_request_header(
HeaderName::from_static("x-request-id"),
HeaderValue::from_str("foo").unwrap(),
)
.set_x_request_id(Counter::default())
.map_request(|request: Request<_>| {
// `set_x_request_id` should set the extension if its missing
assert_eq!(request.extensions().get::<RequestId>().unwrap().0, "foo");
request
})
.propagate_x_request_id()
.service_fn(handler);
let req = Request::builder()
.header(
"x-request-id",
"this-will-be-overriden-by-override_request_header-middleware",
)
.body(Body::empty())
.unwrap();
let res = svc.clone().oneshot(req).await.unwrap();
assert_eq!(res.headers()["x-request-id"], "foo");
assert_eq!(res.extensions().get::<RequestId>().unwrap().0, "foo");
}
#[tokio::test]
async fn other_middleware_setting_request_id_on_response() {
let svc = ServiceBuilder::new()
.set_x_request_id(Counter::default())
.propagate_x_request_id()
.override_response_header(
HeaderName::from_static("x-request-id"),
HeaderValue::from_str("foo").unwrap(),
)
.service_fn(handler);
let req = Request::builder()
.header("x-request-id", "foo")
.body(Body::empty())
.unwrap();
let res = svc.clone().oneshot(req).await.unwrap();
assert_eq!(res.headers()["x-request-id"], "foo");
assert_eq!(res.extensions().get::<RequestId>().unwrap().0, "foo");
}
#[derive(Clone, Default)]
struct Counter(Arc<AtomicU64>);
impl MakeRequestId for Counter {
fn make_request_id<B>(&mut self, _request: &Request<B>) -> Option<RequestId> {
let id =
HeaderValue::from_str(&self.0.fetch_add(1, Ordering::SeqCst).to_string()).unwrap();
Some(RequestId::new(id))
}
}
async fn handler(_: Request<Body>) -> Result<Response<Body>, Infallible> {
Ok(Response::new(Body::empty()))
}
#[tokio::test]
async fn uuid() {
let svc = ServiceBuilder::new()
.set_x_request_id(MakeRequestUuid)
.propagate_x_request_id()
.service_fn(handler);
// header on response
let req = Request::builder().body(Body::empty()).unwrap();
let mut res = svc.clone().oneshot(req).await.unwrap();
let id = res.headers_mut().remove("x-request-id").unwrap();
id.to_str().unwrap().parse::<Uuid>().unwrap();
}
}