fix docs

README.md

@@ -11,8 +11,8 @@ to allow for client middleware chains.
 This crate provides functionality for building and running middleware but no middleware
 implementations. This repository also contains a couple of useful concrete middleware crates:
 
-* [`reqwest-retry`](https://crates.io/crates/reqwest-retry): retry failed requests.
+- [`reqwest-retry`](https://crates.io/crates/reqwest-retry): retry failed requests.
-* [`reqwest-tracing`](https://crates.io/crates/reqwest-tracing):
+- [`reqwest-tracing`](https://crates.io/crates/reqwest-tracing):
   [`tracing`](https://crates.io/crates/tracing) integration, optional opentelemetry support.
 
 ## Overview
@@ -29,10 +29,12 @@ reqwest-middleware = "0.1.6"
 reqwest-retry = "0.1.5"
 reqwest-tracing = "0.2.3"
 tokio = { version = "1.12.0", features = ["macros", "rt-multi-thread"] }
+tower = "0.4"
 ```
 
 ```rust
-use reqwest_middleware::{ClientBuilder, ClientWithMiddleware};
+use reqwest::Response;
+use reqwest_middleware::{ClientBuilder, ClientWithMiddleware, Error, MiddlewareRequest, RequestInitialiser, ReqwestService};
 use reqwest_retry::{RetryTransientMiddleware, policies::ExponentialBackoff};
 use reqwest_tracing::TracingMiddleware;
 
@@ -49,7 +51,12 @@ async fn main() {
     run(client).await;
 }
 
-async fn run(client: ClientWithMiddleware) {
+async fn run<M, I>(client: ClientWithMiddleware<M, I>)
+where
+    M: tower::Layer<ReqwestService>,
+    M::Service: tower::Service<MiddlewareRequest, Response = Response, Error = Error>,
+    I: RequestInitialiser,
+{
     client
         .get("https://truelayer.com")
         .header("foo", "bar")

reqwest-middleware/Cargo.toml

@@ -19,6 +19,7 @@ serde = "1"
 task-local-extensions = "0.1.1"
 thiserror = "1"
 tower = { version = "0.4", features = ["util"] }
+futures = "0.3"
 
 [dev-dependencies]
 reqwest = "0.11"

reqwest-middleware/src/client.rs

@@ -1,80 +1,62 @@
+use futures::future::BoxFuture;
+use futures::FutureExt;
 use reqwest::header::{HeaderMap, HeaderName, HeaderValue};
 use reqwest::multipart::Form;
 use reqwest::{Body, Client, IntoUrl, Method, Request, Response};
 use serde::Serialize;
 use std::convert::TryFrom;
 use std::fmt::{self, Display};
+use std::task::{Context, Poll};
 use std::time::Duration;
 use task_local_extensions::Extensions;
 use tower::layer::util::{Identity, Stack};
 use tower::{Layer, Service, ServiceBuilder, ServiceExt};
 
-use crate::error::Result;
+use crate::{Error, MiddlewareRequest, RequestInitialiser, RequestStack};
-use crate::{Error, MiddlewareRequest, RequestInitialiser};
 
 /// A `ClientBuilder` is used to build a [`ClientWithMiddleware`].
 ///
 /// [`ClientWithMiddleware`]: crate::ClientWithMiddleware
-pub struct ClientBuilder<M> {
+pub struct ClientBuilder<M, I> {
     client: Client,
     middleware_stack: ServiceBuilder<M>,
-    initialiser_stack: (),
+    initialiser_stack: I,
 }
 
-impl ClientBuilder<Identity> {
+impl ClientBuilder<Identity, Identity> {
     pub fn new(client: Client) -> Self {
         ClientBuilder {
             client,
             middleware_stack: ServiceBuilder::new(),
-            initialiser_stack: (),
+            initialiser_stack: Identity::new(),
         }
     }
 }
 
-impl<L> ClientBuilder<L> {
+impl<M, I> ClientBuilder<M, I> {
     /// Convenience method to attach middleware.
-    ///
+    pub fn with<T>(self, layer: T) -> ClientBuilder<Stack<T, M>, I> {
-    /// If you need to keep a reference to the middleware after attaching, use [`with_arc`].
-    ///
-    /// [`with_arc`]: Self::with_arc
-    pub fn layer<T>(self, layer: T) -> ClientBuilder<Stack<T, L>> {
         ClientBuilder {
             client: self.client,
             middleware_stack: self.middleware_stack.layer(layer),
-            initialiser_stack: (),
+            initialiser_stack: self.initialiser_stack,
         }
     }
 
-    // /// Add middleware to the chain. [`with`] is more ergonomic if you don't need the `Arc`.
+    /// Convenience method to attach a request initialiser.
-    // ///
+    pub fn with_init<T>(self, initialiser: T) -> ClientBuilder<M, RequestStack<T, I>> {
-    // /// [`with`]: Self::with
+        ClientBuilder {
-    // pub fn with_arc(mut self, middleware: Arc<dyn Middleware>) -> Self {
+            client: self.client,
-    //     self.middleware_stack.push(middleware);
+            middleware_stack: self.middleware_stack,
-    //     self
+            initialiser_stack: RequestStack {
-    // }
+                inner: initialiser,
-
+                outer: self.initialiser_stack,
-    // /// Convenience method to attach a request initialiser.
+            },
-    // ///
+        }
-    // /// If you need to keep a reference to the initialiser after attaching, use [`with_arc_init`].
+    }
-    // ///
-    // /// [`with_arc_init`]: Self::with_arc_init
-    // pub fn with_init<I>(self, initialiser: I) -> Self
-    // where
-    //     I: RequestInitialiser,
-    // {
-    //     self.with_arc_init(Arc::new(initialiser))
-    // }
-
-    // /// Add a request initialiser to the chain. [`with_init`] is more ergonomic if you don't need the `Arc`.
-    // ///
-    // /// [`with_init`]: Self::with_init
-    // pub fn with_arc_init(mut self, initialiser: Arc<dyn RequestInitialiser>) -> Self {
-    //     self.initialiser_stack.push(initialiser);
-    //     self
-    // }
 
     /// Returns a `ClientWithMiddleware` using this builder configuration.
-    pub fn build(self) -> ClientWithMiddleware<L, ()> {
+    pub fn build(self) -> ClientWithMiddleware<M, I> {
         ClientWithMiddleware {
             inner: self.client,
             middleware_stack: self.middleware_stack,
@@ -92,21 +74,7 @@ pub struct ClientWithMiddleware<M, I> {
     initialiser_stack: I,
 }
 
-// impl<M: Layer<ReqService>> ClientWithMiddleware<M, ()>
+impl<M: Layer<ReqwestService>, I: RequestInitialiser> ClientWithMiddleware<M, I>
-// where
-//     M::Service: Service<MiddlewareRequest, Response = Response, Error = Error>,
-// {
-//     /// See [`ClientBuilder`] for a more ergonomic way to build `ClientWithMiddleware` instances.
-//     pub fn new(client: Client, middleware_stack: M) -> Self {
-//         ClientWithMiddleware {
-//             inner: client,
-//             middleware_stack,
-//             initialiser_stack: (),
-//         }
-//     }
-// }
-
-impl<M: Layer<ReqService>, I: RequestInitialiser> ClientWithMiddleware<M, I>
 where
     M::Service: Service<MiddlewareRequest, Response = Response, Error = Error>,
 {
@@ -181,28 +149,26 @@ pub struct RequestBuilder<'client, M, I> {
     extensions: Extensions,
 }
 
-pub type BoxFuture<'a, T> = std::pin::Pin<Box<dyn std::future::Future<Output = T> + Send + 'a>>;
-
 #[derive(Clone)]
-pub struct ReqService(Client);
+pub struct ReqwestService(Client);
 
-impl Service<MiddlewareRequest> for ReqService {
+impl Service<MiddlewareRequest> for ReqwestService {
     type Response = Response;
     type Error = Error;
-    type Future = BoxFuture<'static, Result<Response>>;
+    type Future = BoxFuture<'static, Result<Response, Error>>;
 
-    fn poll_ready(&mut self, _: &mut std::task::Context<'_>) -> std::task::Poll<Result<()>> {
+    fn poll_ready(&mut self, _: &mut Context<'_>) -> Poll<Result<(), Error>> {
-        std::task::Poll::Ready(Ok(()))
+        Poll::Ready(Ok(()))
     }
 
     fn call(&mut self, req: MiddlewareRequest) -> Self::Future {
         let req = req.request;
         let client = self.0.clone();
-        Box::pin(async move { client.execute(req).await.map_err(Error::from) })
+        async move { client.execute(req).await.map_err(Error::from) }.boxed()
     }
 }
 
-impl<M: Layer<ReqService>, I: RequestInitialiser> RequestBuilder<'_, M, I>
+impl<M: Layer<ReqwestService>, I: RequestInitialiser> RequestBuilder<'_, M, I>
 where
     M::Service: Service<MiddlewareRequest, Response = Response, Error = Error>,
 {
@@ -304,7 +270,7 @@ where
         &mut self.extensions
     }
 
-    pub async fn send(self) -> Result<Response> {
+    pub async fn send(self) -> Result<Response, Error> {
         let Self {
             inner,
             client,
@@ -313,7 +279,7 @@ where
         let req = inner.build()?;
         client
             .middleware_stack
-            .service(ReqService(client.inner.clone()))
+            .service(ReqwestService(client.inner.clone()))
             .oneshot(MiddlewareRequest {
                 request: req,
                 extensions,

reqwest-middleware/src/error.rs

@@ -1,7 +1,5 @@
 use thiserror::Error;
 
-pub type Result<T> = std::result::Result<T, Error>;
-
 #[derive(Error, Debug)]
 pub enum Error {
     /// There was an error running some middleware

reqwest-middleware/src/lib.rs

@@ -7,9 +7,9 @@
 //!
 //! ```
 //! use reqwest::{Client, Request, Response};
-//! use reqwest_middleware::{ClientBuilder, Middleware, Next, Result};
+//! use reqwest_middleware::{ClientBuilder, Error, Extension, MiddlewareRequest};
 //! use task_local_extensions::Extensions;
-//! use futures::FutureExt;
+//! use futures::future::{BoxFuture, FutureExt};
 //! use std::task::{Context, Poll};
 //!
 //! struct LoggingLayer;
@@ -23,10 +23,14 @@
 //!     }
 //! }
 //!
-//! impl<S: tower::Service<MiddlewareRequest>> tower::Service<MiddlewareRequest> for LoggingService<S> {
+//! impl<S> tower::Service<MiddlewareRequest> for LoggingService<S>
-//!     type Response = S::Response;
+//! where
-//!     type Error = S::Error;
+//!     S: tower::Service<MiddlewareRequest, Response = Response, Error = Error>,
-//!     type Future = futures::BoxFuture<'static, Result<S::Response, S::Error>>;
+//!     S::Future: Send + 'static,
+//! {
+//!     type Response = Response;
+//!     type Error = Error;
+//!     type Future = BoxFuture<'static, Result<Response, Error>>;
 //!
 //!     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
 //!         self.0.poll_ready(cx)
@@ -46,7 +50,7 @@
 //! async fn run() {
 //!     let reqwest_client = Client::builder().build().unwrap();
 //!     let client = ClientBuilder::new(reqwest_client)
-//!         .layer(LoggingLayer)
+//!         .with(LoggingLayer)
 //!         .build();
 //!     let resp = client.get("https://truelayer.com").send().await.unwrap();
 //!     println!("TrueLayer page HTML: {}", resp.text().await.unwrap());
@@ -69,9 +73,9 @@ mod client;
 mod error;
 mod req_init;
 
-pub use client::{ClientBuilder, ClientWithMiddleware, ReqService, RequestBuilder};
+pub use client::{ClientBuilder, ClientWithMiddleware, RequestBuilder, ReqwestService};
-pub use error::{Error, Result};
+pub use error::Error;
-pub use req_init::{Extension, RequestInitialiser};
+pub use req_init::{Extension, RequestInitialiser, RequestStack};
 
 pub struct MiddlewareRequest {
     pub request: reqwest::Request,

reqwest-middleware/src/req_init.rs

@@ -1,5 +1,6 @@
 use reqwest::RequestBuilder;
 use task_local_extensions::Extensions;
+use tower::layer::util::Identity;
 
 /// When attached to a [`ClientWithMiddleware`] (generally using [`with_init`]), it is run
 /// whenever the client starts building a request, in the order it was attached.
@@ -7,12 +8,14 @@ use task_local_extensions::Extensions;
 /// # Example
 ///
 /// ```
-/// use reqwest_middleware::{RequestInitialiser, MiddlewareRequest};
+/// use reqwest::RequestBuilder;
+/// use reqwest_middleware::RequestInitialiser;
+/// use task_local_extensions::Extensions;
 ///
 /// struct AuthInit;
 ///
 /// impl RequestInitialiser for AuthInit {
-///     fn init(&self, req: MiddlewareRequest) -> MiddlewareRequest {
+///     fn init(&self, req: RequestBuilder, ext: &mut Extensions) -> RequestBuilder {
 ///         req.bearer_auth("my_auth_token")
 ///     }
 /// }
@@ -24,51 +27,82 @@ pub trait RequestInitialiser: 'static + Send + Sync {
     fn init(&self, req: RequestBuilder, ext: &mut Extensions) -> RequestBuilder;
 }
 
-impl RequestInitialiser for () {
+impl RequestInitialiser for Identity {
     fn init(&self, req: RequestBuilder, _: &mut Extensions) -> RequestBuilder {
         req
     }
 }
 
-// impl<F> RequestInitialiser for F
+/// Two [`RequestInitialiser`]s chained together.
-// where
+#[derive(Clone)]
-//     F: Send + Sync + 'static + Fn(MiddlewareRequest) -> MiddlewareRequest,
+pub struct RequestStack<Inner, Outer> {
-// {
+    pub(crate) inner: Inner,
-//     fn init(&self, req: RequestBuilder, ext: &mut Extensions) -> RequestBuilder {
+    pub(crate) outer: Outer,
-//         (self)(req)
+}
-//     }
+
-// }
+impl<I, O> RequestInitialiser for RequestStack<I, O>
+where
+    I: RequestInitialiser,
+    O: RequestInitialiser,
+{
+    fn init(&self, req: RequestBuilder, ext: &mut Extensions) -> RequestBuilder {
+        let req = self.inner.init(req, ext);
+        self.outer.init(req, ext)
+    }
+}
 
 /// A middleware that inserts the value into the [`Extensions`](task_local_extensions::Extensions) during the call.
 ///
 /// This is a good way to inject extensions to middleware deeper in the stack
 ///
 /// ```
-/// use reqwest::{Client, Request, Response};
+/// use reqwest::{Client, RequestBuilder, Response};
-/// use reqwest_middleware::{ClientBuilder, Middleware, Next, Result, Extension};
+/// use reqwest_middleware::{ClientBuilder, Error, Extension, MiddlewareRequest};
 /// use task_local_extensions::Extensions;
+/// use futures::future::{BoxFuture, FutureExt};
+/// use std::task::{Context, Poll};
 ///
 /// #[derive(Clone)]
 /// struct LogName(&'static str);
-/// struct LoggingMiddleware;
 ///
-/// #[async_trait::async_trait]
+/// struct LoggingLayer;
-/// impl Middleware for LoggingMiddleware {
+/// struct LoggingService<S>(S);
-///     async fn handle(
+///
-///         &self,
+/// impl<S> tower::Layer<S> for LoggingLayer {
-///         req: Request,
+///     type Service = LoggingService<S>;
-///         extensions: &mut Extensions,
+///
-///         next: Next<'_>,
+///     fn layer(&self, inner: S) -> Self::Service {
-///     ) -> Result<Response> {
+///         LoggingService(inner)
+///     }
+/// }
+///
+/// impl<S> tower::Service<MiddlewareRequest> for LoggingService<S>
+/// where
+///     S: tower::Service<MiddlewareRequest, Response = Response, Error = Error>,
+///     S::Future: Send + 'static,
+/// {
+///     type Response = Response;
+///     type Error = Error;
+///     type Future = BoxFuture<'static, Result<Response, Error>>;
+///
+///     fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+///         self.0.poll_ready(cx)
+///     }
+///     
+///     fn call(&mut self, req: MiddlewareRequest) -> Self::Future {
 ///         // get the log name or default to "unknown"
-///         let name = extensions
+///         let name = req
+///             .extensions
 ///             .get()
 ///             .map(|&LogName(name)| name)
 ///             .unwrap_or("unknown");
-///         println!("[{name}] Request started {req:?}");
+///         println!("[{name}] Request started {:?}", &req.request);
-///         let res = next.run(req, extensions).await;
+///         let fut = self.0.call(req);
+///         async move {
+///             let res = fut.await;
 ///             println!("[{name}] Result: {res:?}");
 ///             res
+///         }.boxed()
 ///     }
 /// }
 ///
@@ -76,7 +110,7 @@ impl RequestInitialiser for () {
 ///     let reqwest_client = Client::builder().build().unwrap();
 ///     let client = ClientBuilder::new(reqwest_client)
 ///         .with_init(Extension(LogName("my-client")))
-///         .with(LoggingMiddleware)
+///         .with(LoggingLayer)
 ///         .build();
 ///     let resp = client.get("https://truelayer.com").send().await.unwrap();
 ///     println!("TrueLayer page HTML: {}", resp.text().await.unwrap());

reqwest-retry/src/lib.rs

@@ -13,7 +13,7 @@
 //!     // Retry up to 3 times with increasing intervals between attempts.
 //!     let retry_policy = ExponentialBackoff::builder().build_with_max_retries(3);
 //!     let client = ClientBuilder::new(reqwest::Client::new())
-//!         .layer(RetryTransientMiddleware::new_with_policy(retry_policy))
+//!         .with(RetryTransientMiddleware::new_with_policy(retry_policy))
 //!         .build();
 //!
 //!     client

reqwest-retry/src/middleware.rs

@@ -36,7 +36,7 @@ use tower::{Layer, Service};
 ///     };
 ///
 ///     let retry_transient_middleware = RetryTransientMiddleware::new_with_policy(retry_policy);
-///     let client = ClientBuilder::new(Client::new()).layer(retry_transient_middleware).build();
+///     let client = ClientBuilder::new(Client::new()).with(retry_transient_middleware).build();
 ///```
 ///
 /// # Note

reqwest-retry/tests/all/retry.rs

@@ -48,7 +48,7 @@ macro_rules! assert_retry_succeeds_inner {
 
             let reqwest_client = Client::builder().build().unwrap();
             let client = ClientBuilder::new(reqwest_client)
-                .layer(RetryTransientMiddleware::new_with_policy(
+                .with(RetryTransientMiddleware::new_with_policy(
                     ExponentialBackoff {
                         max_n_retries: retry_amount,
                         max_retry_interval: std::time::Duration::from_millis(30),
@@ -184,7 +184,7 @@ async fn assert_retry_on_request_timeout() {
 
     let reqwest_client = Client::builder().build().unwrap();
     let client = ClientBuilder::new(reqwest_client)
-        .layer(RetryTransientMiddleware::new_with_policy(
+        .with(RetryTransientMiddleware::new_with_policy(
             ExponentialBackoff {
                 max_n_retries: 3,
                 max_retry_interval: std::time::Duration::from_millis(100),
@@ -239,7 +239,7 @@ async fn assert_retry_on_incomplete_message() {
 
     let reqwest_client = Client::builder().build().unwrap();
     let client = ClientBuilder::new(reqwest_client)
-        .layer(RetryTransientMiddleware::new_with_policy(
+        .with(RetryTransientMiddleware::new_with_policy(
             ExponentialBackoff {
                 max_n_retries: 3,
                 max_retry_interval: std::time::Duration::from_millis(100),

reqwest-tracing/src/lib.rs

@@ -4,11 +4,11 @@
 //!
 //! The simplest possible usage:
 //! ```no_run
-//! # use reqwest_middleware::Result;
+//! # use reqwest_middleware::Error;
 //! use reqwest_middleware::{ClientBuilder};
 //! use reqwest_tracing::TracingMiddleware;
 //!
-//! # async fn example() -> Result<()> {
+//! # async fn example() -> Result<(), Error> {
 //! let reqwest_client = reqwest::Client::builder().build().unwrap();
 //! let client = ClientBuilder::new(reqwest_client)
 //!    // Insert the tracing middleware
@@ -22,12 +22,12 @@
 //!
 //! To customise the span names use [`OtelName`].
 //! ```no_run
-//! # use reqwest_middleware::Result;
+//! # use reqwest_middleware::Error;
 //! use reqwest_middleware::{ClientBuilder, Extension};
 //! use reqwest_tracing::{
 //!     TracingMiddleware, OtelName
 //! };
-//! # async fn example() -> Result<()> {
+//! # async fn example() -> Result<(), Error> {
 //! let reqwest_client = reqwest::Client::builder().build().unwrap();
 //! let client = ClientBuilder::new(reqwest_client)
 //!    // Inserts the extension before the request is started
@@ -52,7 +52,7 @@
 //!
 //! Note that Opentelemetry tracks start and stop already, there is no need to have a custom builder like this.
 //! ```rust
-//! use reqwest_middleware::Result;
+//! use reqwest_middleware::Error;
 //! use task_local_extensions::Extensions;
 //! use reqwest::{Request, Response};
 //! use reqwest_middleware::ClientBuilder;
@@ -70,7 +70,7 @@
 //!         reqwest_otel_span!(name="example-request", req, time_elapsed = tracing::field::Empty)
 //!     }
 //!
-//!     fn on_request_end(span: &Span, outcome: &Result<Response>, extension: &mut Extensions) {
+//!     fn on_request_end(span: &Span, outcome: &Result<Response, Error>, extension: &mut Extensions) {
 //!         let time_elapsed = extension.get::<Instant>().unwrap().elapsed().as_millis() as i64;
 //!         default_on_request_end(span, outcome);
 //!         span.record("time_elapsed", &time_elapsed);
@@ -103,18 +103,3 @@ pub use reqwest_otel_span_builder::{
 
 #[doc(hidden)]
 pub mod reqwest_otel_span_macro;
-
-#[cfg(test)]
-mod tests {
-    use crate::{TracingMiddleware, DefaultSpanBackend};
-    use reqwest_middleware::ClientBuilder;
-
-    #[tokio::test]
-    async fn compiles() {
-        let client = ClientBuilder::new(reqwest::Client::new())
-            .layer(TracingMiddleware::<DefaultSpanBackend>::new())
-            .build();
-        let resp = client.get("http://example.com").send().await.unwrap();
-        dbg!(resp);
-    }
-}

reqwest-tracing/src/middleware.rs

@@ -1,4 +1,7 @@
-use std::{future::Future, task::ready};
+use std::{
+    future::Future,
+    task::{ready, Context, Poll},
+};
 
 use pin_project_lite::pin_project;
 use reqwest::Response;
@@ -65,10 +68,7 @@ where
     type Error = Error;
     type Future = TracingMiddlewareFuture<ReqwestOtelSpan, Svc::Future>;
 
-    fn poll_ready(
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        &mut self,
-        cx: &mut std::task::Context<'_>,
-    ) -> std::task::Poll<Result<(), Self::Error>> {
         self.service.poll_ready(cx)
     }
 
@@ -117,16 +117,13 @@ impl<S: ReqwestOtelSpanBackend, F: Future<Output = Result<Response, Error>>> Fut
 {
     type Output = F::Output;
 
-    fn poll(
+    fn poll(self: std::pin::Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
-        self: std::pin::Pin<&mut Self>,
-        cx: &mut std::task::Context<'_>,
-    ) -> std::task::Poll<Self::Output> {
         let this = self.project();
         let outcome = {
             let _guard = this.span.enter();
             ready!(this.future.poll(cx))
         };
         S::on_request_end(this.span, &outcome);
-        std::task::Poll::Ready(outcome)
+        Poll::Ready(outcome)
     }
 }

reqwest-tracing/src/reqwest_otel_span_builder.rs

@@ -2,7 +2,7 @@ use std::borrow::Cow;
 
 use reqwest::header::{HeaderMap, HeaderValue};
 use reqwest::{Request, Response, StatusCode as RequestStatusCode, Url};
-use reqwest_middleware::{Error, Result};
+use reqwest_middleware::Error;
 use task_local_extensions::Extensions;
 use tracing::Span;
 
@@ -44,12 +44,12 @@ pub trait ReqwestOtelSpanBackend {
     fn on_request_start(req: &Request, extension: &mut Extensions) -> Span;
 
     /// Runs after the request call has executed.
-    fn on_request_end(span: &Span, outcome: &Result<Response>);
+    fn on_request_end(span: &Span, outcome: &Result<Response, Error>);
 }
 
 /// Populates default success/failure fields for a given [`reqwest_otel_span!`] span.
 #[inline]
-pub fn default_on_request_end(span: &Span, outcome: &Result<Response>) {
+pub fn default_on_request_end(span: &Span, outcome: &Result<Response, Error>) {
     match outcome {
         Ok(res) => default_on_request_success(span, res),
         Err(err) => default_on_request_failure(span, err),
@@ -103,7 +103,7 @@ impl ReqwestOtelSpanBackend for DefaultSpanBackend {
         reqwest_otel_span!(name = name, req)
     }
 
-    fn on_request_end(span: &Span, outcome: &Result<Response>) {
+    fn on_request_end(span: &Span, outcome: &Result<Response, Error>) {
         default_on_request_end(span, outcome)
     }
 }
@@ -128,7 +128,7 @@ impl ReqwestOtelSpanBackend for SpanBackendWithUrl {
         reqwest_otel_span!(name = name, req, http.url = %remove_credentials(req.url()))
     }
 
-    fn on_request_end(span: &Span, outcome: &Result<Response>) {
+    fn on_request_end(span: &Span, outcome: &Result<Response, Error>) {
         default_on_request_end(span, outcome)
     }
 }
@@ -156,12 +156,12 @@ fn get_span_status(request_status: RequestStatusCode) -> Option<&'static str> {
 ///
 /// Usage:
 /// ```no_run
-/// # use reqwest_middleware::Result;
+/// # use reqwest_middleware::Error;
 /// use reqwest_middleware::{ClientBuilder, Extension};
 /// use reqwest_tracing::{
 ///     TracingMiddleware, OtelName
 /// };
-/// # async fn example() -> Result<()> {
+/// # async fn example() -> Result<(), Error> {
 /// let reqwest_client = reqwest::Client::builder().build().unwrap();
 /// let client = ClientBuilder::new(reqwest_client)
 ///     // Inserts the extension before the request is started

reqwest-tracing/src/reqwest_otel_span_macro.rs

@@ -30,7 +30,7 @@
 /// The second argument passed to [`reqwest_otel_span!`](crate::reqwest_otel_span) is a reference to an [`reqwest::Request`].
 ///
 /// ```rust
-/// use reqwest_middleware::Result;
+/// use reqwest_middleware::Error;
 /// use task_local_extensions::Extensions;
 /// use reqwest::{Request, Response};
 /// use reqwest_tracing::{
@@ -45,7 +45,7 @@
 ///         reqwest_otel_span!(name = "reqwest-http-request", req)
 ///     }
 ///
-///     fn on_request_end(span: &Span, outcome: &Result<Response>, _extension: &mut Extensions) {
+///     fn on_request_end(span: &Span, outcome: &Result<Response, Error>) {
 ///         default_on_request_end(span, outcome)
 ///     }
 /// }