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Change Service::call to take &self #3040
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My experience is that most services need to be
Therefore to share state across clones you generally need |
I will write up more once I have explored what the async fn in traits feature provides us. But from my experience tonic has used |
This may have been brought up elsewhere, but actix-web's |
This is one of my practices |
@seanmonstar you can assign this to me |
change Service::call to take &self instead of &mut self. Because of this change, the trait bound in the service::util::service_fn and the trait bound in the impl for the ServiceFn struct were changed from FnMut to Fn. This change was decided on for the following reasons: - It prepares the way for async fn, since then the future only borrows &self, and thus a Service can concurrently handle multiple outstanding requests at once. - It's clearer that Services can likely be cloned - To share state across clones you generally need Arc<Mutex<_>> that means you're not really using the &mut self and could do with a &self This commit closses issue: hyperium#3040 BREAKING CHANGE: The Service::call function no longer takes a mutable reference to self. The FnMut trait bound on the service::util::service_fn function and the trait bound on the impl for the ServiceFn struct were changed from FnMut to Fn
change Service::call to take &self instead of &mut self. Because of this change, the trait bound in the service::util::service_fn and the trait bound in the impl for the ServiceFn struct were changed from FnMut to Fn. This change was decided on for the following reasons: - It prepares the way for async fn, since then the future only borrows &self, and thus a Service can concurrently handle multiple outstanding requests at once. - It's clearer that Services can likely be cloned - To share state across clones you generally need Arc<Mutex<_>> that means you're not really using the &mut self and could do with a &self This commit closses issue: hyperium#3040 BREAKING CHANGE: The Service::call function no longer takes a mutable reference to self. The FnMut trait bound on the service::util::service_fn function and the trait bound on the impl for the ServiceFn struct were changed from FnMut to Fn
Includes a lightly-modified version of hyper-util's `TokioIo` utility. Hyper changes: v1.0.0-rc.4 (2023-07-10) Bug Fixes http1: http1 server graceful shutdown fix (#3261) ([f4b51300](hyperium/hyper@f4b5130)) send error on Incoming body when connection errors (#3256) ([52f19259](hyperium/hyper@52f1925), closes hyperium/hyper#3253) properly end chunked bodies when it was known to be empty (#3254) ([fec64cf0](hyperium/hyper@fec64cf), closes hyperium/hyper#3252) Features client: Make clients able to use non-Send executor (#3184) ([d977f209](hyperium/hyper@d977f20), closes hyperium/hyper#3017) rt: replace IO traits with hyper::rt ones (#3230) ([f9f65b7a](hyperium/hyper@f9f65b7), closes hyperium/hyper#3110) add downcast on Sleep trait (#3125) ([d92d3917](hyperium/hyper@d92d391), closes hyperium/hyper#3027) service: change Service::call to take &self (#3223) ([d894439e](hyperium/hyper@d894439), closes hyperium/hyper#3040) Breaking Changes Any IO transport type provided must not implement hyper::rt::{Read, Write} instead of tokio::io traits. You can grab a helper type from hyper-util to wrap Tokio types, or implement the traits yourself, if it's a custom type. ([f9f65b7a](hyperium/hyper@f9f65b7)) client::conn::http2 types now use another generic for an Executor. Code that names Connection needs to include the additional generic parameter. ([d977f209](hyperium/hyper@d977f20)) The Service::call function no longer takes a mutable reference to self. The FnMut trait bound on the service::util::service_fn function and the trait bound on the impl for the ServiceFn struct were changed from FnMut to Fn.
change Service::call to take &self instead of &mut self. Because of this change, the trait bound in the service::util::service_fn and the trait bound in the impl for the ServiceFn struct were changed from FnMut to Fn. This change was decided on for the following reasons: - It prepares the way for async fn, since then the future only borrows &self, and thus a Service can concurrently handle multiple outstanding requests at once. - It's clearer that Services can likely be cloned - To share state across clones you generally need Arc<Mutex<_>> that means you're not really using the &mut self and could do with a &self Closes hyperium#3040 BREAKING CHANGE: The Service::call function no longer takes a mutable reference to self. The FnMut trait bound on the service::util::service_fn function and the trait bound on the impl for the ServiceFn struct were changed from FnMut to Fn.
change Service::call to take &self instead of &mut self. Because of this change, the trait bound in the service::util::service_fn and the trait bound in the impl for the ServiceFn struct were changed from FnMut to Fn. This change was decided on for the following reasons: - It prepares the way for async fn, since then the future only borrows &self, and thus a Service can concurrently handle multiple outstanding requests at once. - It's clearer that Services can likely be cloned - To share state across clones you generally need Arc<Mutex<_>> that means you're not really using the &mut self and could do with a &self Closes hyperium#3040 BREAKING CHANGE: The Service::call function no longer takes a mutable reference to self. The FnMut trait bound on the service::util::service_fn function and the trait bound on the impl for the ServiceFn struct were changed from FnMut to Fn. Signed-off-by: Sven Pfennig <s.pfennig@reply.de>
``` /!\ this is a work in progress and will /!\ /!\ be force pushed until ready for review /!\ ``` ## 👀 overview fixes #3627. this reorganizes the logic in pd's startup code related to automatically managed https functionality. ## 🎨 background & motivation this PR, besides cleaning up the `rustls-acme`-related auto-https logic, is also interested in *creating a state-of-affairs that will dovetail into pr #3522*. in particular, this expression to start the GRPC serve given a bound listener... ```rust tokio::task::Builder::new() .name("grpc_server") .spawn(grpc_server.serve_with_incoming(tls_incoming)) .expect("failed to spawn grpc server") ``` ...should be adjusted so as to accept an `axum::Router`. other tertiary requirements: - when no `grpc_auto_https` flag has been configured, serve without using an ACME resolver - ALPN permit http/1.1 for grpc-web backwards compatibility. ### ⚖️ `rustls-acme` and `tokio-rustls-acme` quoth the #3627 description, citing an earlier comment: > In the ~year since this code was written, there may be better options. > `tokio-rustls-acme` seems promising \- <#3522 (comment)> for reference, the repositories for each live here, and here: - <https://github.com/FlorianUekermann/rustls-acme> - <https://github.com/n0-computer/tokio-rustls-acme> after some comparison, i have come to the opinion that `rustls-acme` will still be adequate for our purposes. the latter is a fork of the former, but active development appears to have continued in the former, and i did not see any particular "_must-have_" features for us in the latter. ## 🚰 dropping down to `axum` (this part is lengthy...) as stated above, we want to switch to an `axum::Router`. this means that we won't be able to use the `AcmeConfig::incoming` function. the `rustls-acme` library provides some "low-level" examples we can check out: - <https://github.com/FlorianUekermann/rustls-acme/blob/main/examples/low_level_tokio.rs> - <https://github.com/FlorianUekermann/rustls-acme/blob/main/examples/low_level_axum.rs> `low_level_axum` sounds promising, given that #3522 itself drops down from tonic into axum. a catch is that the "axum" example is referring to `axum-server`, a library that wraps `axum`, rather than `axum` itself. more on that momentarily. we also use `tonic` 0.10.2 in pd, and elsewhere in the penumbra monorepo. tonic isn't using hyper 1.x yet. this was being worked on in hyperium/tonic#1583, continued on in hyperium/tonic#1595, and tracked in hyperium/tonic#1579. that work also depends upon hyperium/hyper#3461. this is complicated by the fact that `axum-server` 0.6.0 depends on `hyper` 1.1.0. this is particularly relevant because of hyperium/hyper#3040. so, we must be mindful that there is now a `tower::Service` and a `hyper::Service`. `hyper-util` provides facilities to convert between the two, and other helper glue. additionally, see the "_upgrading"_ migration guide for more information on the differences between pre- and post-1.0 interfaces in `hyper`. - https://hyper.rs/guides/1/upgrading/ - <https://docs.rs/hyper-util/latest/hyper_util/service/struct.TowerToHyperService.html> at a high level we need to take our `tonic::Router`, and turn that into a `MakeService`, some object that can be used to _generate_ `Service` instances to process a request. this is additionally complicated by the fact that `axum-server` defines its _own_ `MakeService` trait. that trait is sealed, blanket implemented, and is a bound included in `axum_server::server::Server::serve`. ```rust // axum_server::serve impl Server { pub async fn serve<M>(self, mut make_service: M) -> io::Result<()> where M: MakeService<SocketAddr, Request<Incoming>>, // ... { todo!() } } ``` the `SocketAddr` parameter above is of importance. `axum::Router::into_make_service` gives us `IntoMakeService<Router>` - <https://docs.rs/axum/latest/axum/routing/struct.IntoMakeService.html> ```rust impl<S, T> Service<T> for IntoMakeService<S> where S: Clone, { type Response = S; type Error = Infallible; type Future = IntoMakeServiceFuture<S>; ``` ...which means that we are faced with this error: ``` error[E0277]: the trait bound `Router: tower_service::Service<http::request::Request<hyper::body::incoming::Incoming>>` is not satisfied --> crates/bin/pd/src/auto_https.rs:62:20 | 62 | .serve(make_svc) | ----- ^^^^^^^^ the trait `tower_service::Service<http::request::Request<hyper::body::incoming::Incoming>>` is not implemented for `Router` | | | required by a bound introduced by this call | = help: the trait `tower_service::Service<axum::http::Request<axum::body::Body>>` is implemented for `Router` = help: for that trait implementation, expected `axum::http::Request<axum::body::Body>`, found `http::request::Request<hyper::body::incoming::Incoming>` = note: required for `IntoMakeService<Router>` to implement `axum_server::service::MakeService<std::net::SocketAddr, http::request::Request<hyper::body::incoming::Incoming>>` ``` `axum::Router::into_make_service` does not play well with `axum_server::Server`. ...and if we specify the new `hyper::body::incoming::Incoming` as the body type for the axum router, ``` error[E0599]: the method `into_make_service` exists for struct `Router<(), Incoming>`, but its trait bounds were not satisfied --> crates/bin/pd/src/auto_https.rs:57:31 | 57 | let make_svc = router.into_make_service(); | ^^^^^^^^^^^^^^^^^ method cannot be called on `Router<(), Incoming>` due to unsatisfied trait bounds | ::: /home/katie/.cargo/registry/src/index.crates.io-6f17d22bba15001f/hyper-1.1.0/src/body/incoming.rs:47:1 | 47 | pub struct Incoming { | ------------------- doesn't satisfy `hyper::body::Incoming: HttpBody` | = note: the following trait bounds were not satisfied: `hyper::body::Incoming: HttpBody` ``` `HttpBody` was the pre-1.0 trait, that is now `Body` post-1.0. in short, there are some incongruencies at play as different libraries catch up to the new breaking changes in `hyper`. ## 🤨 ...so now what? TODO(kate): write up course of action for tomorrow. --- 🟥 NB: i worry about breakage due to untested load-bearing behavior during a migration like this. see "tertiary requirements", above. consider this a PR to be suspect of when deploying a new testnet. Refs: #3627 Refs: #3646 Refs: #3522
Now that hyper defines its own
Service
trait (#2853), there's a key part we should clarify before hitting 1.0 Final: Should it take&self
or&mut self
? Whichever the decision, the why should be documented (not necessarily in the API docs, but in code comments or in thedocs/
folder).The usual arguments are here:
&self
async fn
, since then the future only borrows&self
, and thus aService
can concurrently handle multiple outstanding requests at once.Service
s can likely be cloned.&mut self
Service
has state (usually per-connection), it's cheaper to mutate it on each connection. Not being&mut
would require internal synchronization.I'm happy to open it up to discussion here. I'd recommend that comments are arguments be well-formed and reasoned, and try to provide something new, so that we keep the signal high. Chat is a fine place to bounce an idea around, and then come back and write it up so we can keep the history (decision history is extremely valuable).
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