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use std::error::Error as StdError;
use pin_project_lite::pin_project;
use tokio::io::{AsyncRead, AsyncWrite};
use tracing::debug;
use super::accept::Accept;
use super::conn::UpgradeableConnection;
use super::server::{Server, Watcher};
use crate::body::{Body, HttpBody};
use crate::common::drain::{self, Draining, Signal, Watch, Watching};
use crate::common::exec::{ConnStreamExec, NewSvcExec};
use crate::common::{task, Future, Pin, Poll, Unpin};
use crate::service::{HttpService, MakeServiceRef};
pin_project! {
#[allow(missing_debug_implementations)]
pub struct Graceful<I, S, F, E> {
#[pin]
state: State<I, S, F, E>,
}
}
pin_project! {
#[project = StateProj]
pub(super) enum State<I, S, F, E> {
Running {
drain: Option<(Signal, Watch)>,
#[pin]
server: Server<I, S, E>,
#[pin]
signal: F,
},
Draining { draining: Draining },
}
}
impl<I, S, F, E> Graceful<I, S, F, E> {
pub(super) fn new(server: Server<I, S, E>, signal: F) -> Self {
let drain = Some(drain::channel());
Graceful {
state: State::Running {
drain,
server,
signal,
},
}
}
}
impl<I, IO, IE, S, B, F, E> Future for Graceful<I, S, F, E>
where
I: Accept<Conn = IO, Error = IE>,
IE: Into<Box<dyn StdError + Send + Sync>>,
IO: AsyncRead + AsyncWrite + Unpin + Send + 'static,
S: MakeServiceRef<IO, Body, ResBody = B>,
S::Error: Into<Box<dyn StdError + Send + Sync>>,
B: HttpBody + 'static,
B::Error: Into<Box<dyn StdError + Send + Sync>>,
F: Future<Output = ()>,
E: ConnStreamExec<<S::Service as HttpService<Body>>::Future, B>,
E: NewSvcExec<IO, S::Future, S::Service, E, GracefulWatcher>,
{
type Output = crate::Result<()>;
fn poll(self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Self::Output> {
let mut me = self.project();
loop {
let next = {
match me.state.as_mut().project() {
StateProj::Running {
drain,
server,
signal,
} => match signal.poll(cx) {
Poll::Ready(()) => {
debug!("signal received, starting graceful shutdown");
let sig = drain.take().expect("drain channel").0;
State::Draining {
draining: sig.drain(),
}
}
Poll::Pending => {
let watch = drain.as_ref().expect("drain channel").1.clone();
return server.poll_watch(cx, &GracefulWatcher(watch));
}
},
StateProj::Draining { ref mut draining } => {
return Pin::new(draining).poll(cx).map(Ok);
}
}
};
me.state.set(next);
}
}
}
#[allow(missing_debug_implementations)]
#[derive(Clone)]
pub struct GracefulWatcher(Watch);
impl<I, S, E> Watcher<I, S, E> for GracefulWatcher
where
I: AsyncRead + AsyncWrite + Unpin + Send + 'static,
S: HttpService<Body>,
E: ConnStreamExec<S::Future, S::ResBody>,
S::ResBody: 'static,
<S::ResBody as HttpBody>::Error: Into<Box<dyn StdError + Send + Sync>>,
{
type Future =
Watching<UpgradeableConnection<I, S, E>, fn(Pin<&mut UpgradeableConnection<I, S, E>>)>;
fn watch(&self, conn: UpgradeableConnection<I, S, E>) -> Self::Future {
self.0.clone().watch(conn, on_drain)
}
}
fn on_drain<I, S, E>(conn: Pin<&mut UpgradeableConnection<I, S, E>>)
where
S: HttpService<Body>,
S::Error: Into<Box<dyn StdError + Send + Sync>>,
I: AsyncRead + AsyncWrite + Unpin,
S::ResBody: HttpBody + 'static,
<S::ResBody as HttpBody>::Error: Into<Box<dyn StdError + Send + Sync>>,
E: ConnStreamExec<S::Future, S::ResBody>,
{
conn.graceful_shutdown()
}