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#![doc(html_root_url = "https://docs.rs/tower-reconnect/0.3.0-alpha.1")] #![deny(rust_2018_idioms)] #![allow(elided_lifetimes_in_paths)] pub mod future; use crate::future::ResponseFuture; use log::trace; use std::fmt; use std::{ future::Future, pin::Pin, task::{Context, Poll}, }; use tower_make::MakeService; use tower_service::Service; pub struct Reconnect<M, Target> where M: Service<Target>, { mk_service: M, state: State<M::Future, M::Response>, target: Target, } type Error = Box<dyn std::error::Error + Send + Sync>; #[derive(Debug)] enum State<F, S> { Idle, Connecting(F), Connected(S), } impl<M, Target> Reconnect<M, Target> where M: Service<Target>, { pub fn new<S, Request>(mk_service: M, target: Target) -> Self where M: Service<Target, Response = S>, S: Service<Request>, Error: From<M::Error> + From<S::Error>, Target: Clone, { Reconnect { mk_service, state: State::Idle, target, } } } impl<M, Target, S, Request> Service<Request> for Reconnect<M, Target> where M: Service<Target, Response = S>, S: Service<Request>, M::Future: Unpin, Error: From<M::Error> + From<S::Error>, Target: Clone, { type Response = S::Response; type Error = Error; type Future = ResponseFuture<S::Future>; fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> { let ret; let mut state; loop { match self.state { State::Idle => { trace!("poll_ready; idle"); match self.mk_service.poll_ready(cx) { Poll::Ready(r) => r?, Poll::Pending => { trace!("poll_ready; MakeService not ready"); return Poll::Pending; } } let fut = self.mk_service.make_service(self.target.clone()); self.state = State::Connecting(fut); continue; } State::Connecting(ref mut f) => { trace!("poll_ready; connecting"); match Pin::new(f).poll(cx) { Poll::Ready(Ok(service)) => { state = State::Connected(service); } Poll::Pending => { trace!("poll_ready; not ready"); return Poll::Pending; } Poll::Ready(Err(e)) => { trace!("poll_ready; error"); state = State::Idle; ret = Err(e.into()); break; } } } State::Connected(ref mut inner) => { trace!("poll_ready; connected"); match inner.poll_ready(cx) { Poll::Ready(Ok(())) => { trace!("poll_ready; ready"); return Poll::Ready(Ok(())); } Poll::Pending => { trace!("poll_ready; not ready"); return Poll::Pending; } Poll::Ready(Err(_)) => { trace!("poll_ready; error"); state = State::Idle; } } } } self.state = state; } self.state = state; Poll::Ready(ret) } fn call(&mut self, request: Request) -> Self::Future { let service = match self.state { State::Connected(ref mut service) => service, _ => panic!("service not ready; poll_ready must be called first"), }; let fut = service.call(request); ResponseFuture::new(fut) } } impl<M, Target> fmt::Debug for Reconnect<M, Target> where M: Service<Target> + fmt::Debug, M::Future: fmt::Debug, M::Response: fmt::Debug, Target: fmt::Debug, { fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { fmt.debug_struct("Reconnect") .field("mk_service", &self.mk_service) .field("state", &self.state) .field("target", &self.target) .finish() } }