How is handle_error used with state in axum?

help
1

I am trying to build on the example server in axum by adding a handle_error builder along with State: axum::error_handling - Rust

pub async fn init() -> Result<(), tokio::io::Error> {
    let state = ServerState { client: 1 };
    let app = Router::new()
        .route(
            "/",
            get(stuff)
        )
        .with_state(state)
        .handle_error(handle_error);

    // run our app with hyper, listening globally on port 3000
    let listener = tokio::net::TcpListener::bind("0.0.0.0:2772").await?;
    axum::serve(listener, app.into()).await
}

async fn handle_error(err: BoxError) -> Result<(StatusCode, String), Infallible>  {
    Ok::<_, Infallible>((
        StatusCode::INTERNAL_SERVER_ERROR,
        format!("Unhandled internal error: {}", err),
    ))
}

But for some reason this handle_error builder isn't documented for when you have state as well.

How can I make sense of this compilation error to get errors handled with state?:

error[E0283]: type annotations needed
  --> src/route.rs:22:10
   |
22 |         .handle_error(handle_error);
   |          ^^^^^^^^^^^^
   |
   = note: multiple `impl`s satisfying `Router<_>: Service<_>` found in the `axum` crate:
           - impl Service<IncomingStream<'_>> for Router;
           - impl<B> Service<axum::http::Request<B>> for Router
             where <B as HttpBody>::Data == axum::body::Bytes, B: HttpBody, B: Send, B: 'static, <B as HttpBody>::Error: Into<Box<(dyn StdError + Send + Sync + 'static)>>;
note: required by a bound in `axum::ServiceExt::handle_error`
  --> /usr/local/cargo/registry/src/index.crates.io-6f17d22bba15001f/axum-0.7.9/src/service_ext.rs:8:26
   |
8  | pub trait ServiceExt<R>: Service<R> + Sized {
   |                          ^^^^^^^^^^ required by this bound in `ServiceExt::handle_error`
...
42 |     fn handle_error<F, T>(self, f: F) -> HandleError<Self, F, T> {
   |        ------------ required by a bound in this associated function
help: try using a fully qualified path to specify the expected types
   |
16 ~     let app = <Router<S2> as axum::ServiceExt<R>>::handle_error::<_, T>(Router::new()
17 |         .route(
...
20 |         )
21 ~         .with_state(state), handle_error);

I need state as my routes must interact with other services tracking and caching data. I need error handler because those other services throw errors that must all be converted to axum errors.

2

maybe I found it? If you have state must you handle errors from a layer?:

But I thought middleware extensions weren't preferred over with_state? Can anyone break this down for me what this layer means instead of the handle_error builder?

3

There's no handle_error method in Router. I think you might have an old version of Axum.

The current documentation for error handling in Axum uses a tower layer to convert errors into responses.

4

I am using 0.7.9 and I think it's here in the latest version of axum:

5

I see. It's in MethodRouter, not in Router. For the record, it's easier to navigate a library using docs.rs: MethodRouter in axum::routing::method_routing - Rust.