1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121

use std::error::Error as StdError;

use pin_project::pin_project;
use tokio::io::{AsyncRead, AsyncWrite};

use super::conn::{SpawnAll, UpgradeableConnection, Watcher};
use super::Accept;
use crate::body::{Body, HttpBody};
use crate::common::drain::{self, Draining, Signal, Watch, Watching};
use crate::common::exec::{H2Exec, NewSvcExec};
use crate::common::{task, Future, Pin, Poll, Unpin};
use crate::service::{HttpService, MakeServiceRef};

#[allow(missing_debug_implementations)]
#[pin_project]
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]
        spawn_all: SpawnAll<I, S, E>,
        #[pin]
        signal: F,
    },
    Draining(Draining),
}

impl<I, S, F, E> Graceful<I, S, F, E> {
    pub(super) fn new(spawn_all: SpawnAll<I, S, E>, signal: F) -> Self {
        let drain = Some(drain::channel());
        Graceful {
            state: State::Running {
                drain,
                spawn_all,
                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 + Send + Sync + 'static,
    B::Error: Into<Box<dyn StdError + Send + Sync>>,
    F: Future<Output = ()>,
    E: H2Exec<<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,
                        spawn_all,
                        signal,
                    } => match signal.poll(cx) {
                        Poll::Ready(()) => {
                            debug!("signal received, starting graceful shutdown");
                            let sig = drain.take().expect("drain channel").0;
                            State::Draining(sig.drain())
                        }
                        Poll::Pending => {
                            let watch = drain.as_ref().expect("drain channel").1.clone();
                            return spawn_all.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: H2Exec<S::Future, S::ResBody>,
    S::ResBody: Send + Sync + '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 + Send + 'static,
    <S::ResBody as HttpBody>::Error: Into<Box<dyn StdError + Send + Sync>>,
    E: H2Exec<S::Future, S::ResBody>,
{
    conn.graceful_shutdown()
}