Merge pull request #938 from teloxide/⚠️polling-in-flight⚠️

Improve graceful shutdown
This commit is contained in:
Tima Kinsart 2023-09-29 19:02:05 +00:00 committed by GitHub
commit d21ca11a54
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6 changed files with 115 additions and 84 deletions

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@ -10,6 +10,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
- Add `MessageToCopyNotFound` error to `teloxide::errors::ApiError` ([PR 917](https://github.com/teloxide/teloxide/pull/917))
### Fixed
- Use `UserId` instead of `i64` for `user_id` in `html::user_mention` and `markdown::user_mention` ([PR 896](https://github.com/teloxide/teloxide/pull/896))
- Greatly improved the speed of graceful shutdown (`^C`) ([PR 938](https://github.com/teloxide/teloxide/pull/938))
### Removed
- `UpdateListener::timeout_hint` and related APIs ([PR 938](https://github.com/teloxide/teloxide/pull/938))
## 0.12.2 - 2023-02-15

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@ -7,12 +7,10 @@ use crate::{
requests::{Request, Requester},
types::{Update, UpdateKind},
update_listeners::{self, UpdateListener},
utils::shutdown_token::shutdown_check_timeout_for,
};
use dptree::di::{DependencyMap, DependencySupplier};
use futures::{future::BoxFuture, stream::FuturesUnordered, StreamExt};
use tokio::time::timeout;
use tokio_stream::wrappers::ReceiverStream;
use std::{
@ -312,7 +310,6 @@ where
log::debug!("hinting allowed updates: {:?}", allowed_updates);
update_listener.hint_allowed_updates(&mut allowed_updates.into_iter());
let shutdown_check_timeout = shutdown_check_timeout_for(&update_listener);
let mut stop_token = Some(update_listener.stop_token());
self.state.start_dispatching();
@ -324,19 +321,16 @@ where
loop {
self.remove_inactive_workers_if_needed().await;
// False positive
#[allow(clippy::collapsible_match)]
if let Ok(upd) = timeout(shutdown_check_timeout, stream.next()).await {
match upd {
tokio::select! {
upd = stream.next() => match upd {
None => break,
Some(upd) => self.process_update(upd, &update_listener_error_handler).await,
}
}
if self.state.is_shutting_down() {
if let Some(token) = stop_token.take() {
log::debug!("Start shutting down dispatching...");
token.stop();
},
() = self.state.wait_for_changes() => if self.state.is_shutting_down() {
if let Some(token) = stop_token.take() {
log::debug!("Start shutting down dispatching...");
token.stop();
}
}
}
}

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@ -32,8 +32,6 @@ pub mod webhooks;
use futures::Stream;
use std::time::Duration;
use crate::{
stop::StopToken,
types::{AllowedUpdate, Update},
@ -94,19 +92,6 @@ pub trait UpdateListener:
fn hint_allowed_updates(&mut self, hint: &mut dyn Iterator<Item = AllowedUpdate>) {
let _ = hint;
}
/// The timeout duration hint.
///
/// This hints how often dispatcher should check for a shutdown. E.g., for
/// [`polling()`] this returns the [`timeout`].
///
/// [`timeout`]: crate::payloads::GetUpdates::timeout
///
/// If you are implementing this trait and not sure what to return from this
/// function, just leave it with the default implementation.
fn timeout_hint(&self) -> Option<Duration> {
None
}
}
/// [`UpdateListener`]'s supertrait/extension.

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@ -1,6 +1,7 @@
use std::{
convert::TryInto,
future::Future,
mem,
pin::Pin,
task::{
self,
@ -97,8 +98,16 @@ where
pub fn build(self) -> Polling<R> {
let Self { bot, timeout, limit, allowed_updates, drop_pending_updates } = self;
let (token, flag) = mk_stop_token();
let polling =
Polling { bot, timeout, limit, allowed_updates, drop_pending_updates, flag, token };
let polling = Polling {
bot,
timeout,
limit,
allowed_updates,
drop_pending_updates,
flag: Some(flag),
token,
stop_token_cloned: false,
};
assert_update_listener(polling)
}
@ -240,17 +249,21 @@ pub struct Polling<B: Requester> {
limit: Option<u8>,
allowed_updates: Option<Vec<AllowedUpdate>>,
drop_pending_updates: bool,
flag: StopFlag,
flag: Option<StopFlag>,
token: StopToken,
stop_token_cloned: bool,
}
impl<R> Polling<R>
where
R: Requester + Send + 'static,
<R as Requester>::GetUpdates: Send,
R: Requester,
{
/// Returns a builder for polling update listener.
pub fn builder(bot: R) -> PollingBuilder<R> {
pub fn builder(bot: R) -> PollingBuilder<R>
where
R: Send + 'static,
<R as Requester>::GetUpdates: Send,
{
PollingBuilder {
bot,
timeout: None,
@ -259,6 +272,19 @@ where
drop_pending_updates: false,
}
}
/// Returns true if re-initialization happened *and*
/// the previous token was cloned.
fn reinit_stop_flag_if_needed(&mut self) -> bool {
if self.flag.is_some() {
return false;
}
let (token, flag) = mk_stop_token();
self.token = token;
self.flag = Some(flag);
mem::replace(&mut self.stop_token_cloned, false)
}
}
#[pin_project::pin_project]
@ -287,12 +313,18 @@ pub struct PollingStream<'a, B: Requester> {
/// In-flight `get_updates()` call.
#[pin]
in_flight: Option<<B::GetUpdates as Request>::Send>,
/// The flag that notifies polling to stop polling.
#[pin]
flag: StopFlag,
}
impl<B: Requester + Send + 'static> UpdateListener for Polling<B> {
type Err = B::Err;
fn stop_token(&mut self) -> StopToken {
self.reinit_stop_flag_if_needed();
self.stop_token_cloned = true;
self.token.clone()
}
@ -301,10 +333,6 @@ impl<B: Requester + Send + 'static> UpdateListener for Polling<B> {
// before
self.allowed_updates = Some(hint.collect());
}
fn timeout_hint(&self) -> Option<Duration> {
self.timeout
}
}
impl<'a, B: Requester + Send + 'a> AsUpdateStream<'a> for Polling<B> {
@ -315,6 +343,21 @@ impl<'a, B: Requester + Send + 'a> AsUpdateStream<'a> for Polling<B> {
let timeout = self.timeout.map(|t| t.as_secs().try_into().expect("timeout is too big"));
let allowed_updates = self.allowed_updates.clone();
let drop_pending_updates = self.drop_pending_updates;
let token_used_and_updated = self.reinit_stop_flag_if_needed();
// FIXME: document that `as_stream` is a destructive operation, actually,
// and you need to call `stop_token` *again* after it
if token_used_and_updated {
panic!(
"detected calling `as_stream` a second time after calling `stop_token`. \
`as_stream` updates the stop token, thus you need to call it again after calling \
`as_stream`"
)
}
// Unwrap: just called reinit
let flag = self.flag.take().unwrap();
PollingStream {
polling: self,
drop_pending_updates,
@ -325,6 +368,7 @@ impl<'a, B: Requester + Send + 'a> AsUpdateStream<'a> for Polling<B> {
stopping: false,
buffer: Vec::new().into_iter(),
in_flight: None,
flag,
}
}
}
@ -333,15 +377,33 @@ impl<B: Requester> Stream for PollingStream<'_, B> {
type Item = Result<Update, B::Err>;
fn poll_next(mut self: Pin<&mut Self>, cx: &mut task::Context<'_>) -> Poll<Option<Self::Item>> {
log::trace!("polling polling stream");
let mut this = self.as_mut().project();
if *this.force_stop {
return Ready(None);
}
// If there are any buffered updates, return one
if let Some(upd) = this.buffer.next() {
return Ready(Some(Ok(upd)));
}
// Check if we should stop and if so — drop in flight request,
// we don't care about updates that happened *after* we started stopping
//
// N.B.: it's important to use `poll` and not `is_stopped` here,
// so that *this stream* is polled when the flag is set to stop
if !*this.stopping && matches!(this.flag.poll(cx), Poll::Ready(())) {
*this.stopping = true;
log::trace!("dropping in-flight request");
this.in_flight.set(None);
}
// Poll in-flight future until completion
if let Some(in_flight) = this.in_flight.as_mut().as_pin_mut() {
else if let Some(in_flight) = this.in_flight.as_mut().as_pin_mut() {
let res = ready!(in_flight.poll(cx));
log::trace!("in-flight request completed");
this.in_flight.set(None);
match res {
@ -366,12 +428,6 @@ impl<B: Requester> Stream for PollingStream<'_, B> {
}
}
// If there are any buffered updates, return one
if let Some(upd) = this.buffer.next() {
return Ready(Some(Ok(upd)));
}
*this.stopping = this.polling.flag.is_stopped();
let (offset, limit, timeout) = match (this.stopping, this.drop_pending_updates) {
// Normal `get_updates()` call
(false, false) => (*this.offset, this.polling.limit, *this.timeout),
@ -380,7 +436,10 @@ impl<B: Requester> Stream for PollingStream<'_, B> {
//
// When stopping we set `timeout = 0` and `limit = 1` so that `get_updates()`
// set last seen update (offset) and return immediately
(true, _) => (*this.offset, Some(1), Some(0)),
(true, _) => {
log::trace!("graceful shutdown `get_updates` call");
(*this.offset, Some(1), Some(0))
}
// Drop pending updates
(_, true) => (-1, Some(1), Some(0)),
};
@ -398,8 +457,10 @@ impl<B: Requester> Stream for PollingStream<'_, B> {
.send();
this.in_flight.set(Some(req));
// Recurse to poll `self.in_flight`
self.poll_next(cx)
// Immediately wake up to poll `self.in_flight`
// (without this this stream becomes a zombie)
cx.waker().wake_by_ref();
Poll::Pending
}
}

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@ -1,5 +1,3 @@
use std::time::Duration;
use futures::Stream;
use crate::{
@ -17,7 +15,7 @@ use crate::{
///
/// [`polling`]: crate::update_listeners::polling()
#[non_exhaustive]
pub struct StatefulListener<St, Assf, Sf, Hauf, Thf> {
pub struct StatefulListener<St, Assf, Sf, Hauf> {
/// The state of the listener.
pub state: St,
@ -36,38 +34,30 @@ pub struct StatefulListener<St, Assf, Sf, Hauf, Thf> {
/// Must implement `FnMut(&mut St, &mut dyn Iterator<Item =
/// AllowedUpdate>)`.
pub hint_allowed_updates: Option<Hauf>,
/// The function used as [`UpdateListener::timeout_hint`].
///
/// Must implement `Fn(&St) -> Option<Duration>`.
pub timeout_hint: Option<Thf>,
}
type Haufn<State> = for<'a, 'b> fn(&'a mut State, &'b mut dyn Iterator<Item = AllowedUpdate>);
type Thfn<State> = for<'a> fn(&'a State) -> Option<Duration>;
impl<St, Assf, Sf> StatefulListener<St, Assf, Sf, Haufn<St>, Thfn<St>> {
impl<St, Assf, Sf> StatefulListener<St, Assf, Sf, Haufn<St>> {
/// Creates a new stateful listener from its components.
pub fn new(state: St, stream: Assf, stop_token: Sf) -> Self {
Self::new_with_hints(state, stream, stop_token, None, None)
Self::new_with_hints(state, stream, stop_token, None)
}
}
impl<St, Assf, Sf, Hauf, Thf> StatefulListener<St, Assf, Sf, Hauf, Thf> {
impl<St, Assf, Sf, Hauf> StatefulListener<St, Assf, Sf, Hauf> {
/// Creates a new stateful listener from its components.
pub fn new_with_hints(
state: St,
stream: Assf,
stop_token: Sf,
hint_allowed_updates: Option<Hauf>,
timeout_hint: Option<Thf>,
) -> Self {
Self { state, stream, stop_token, hint_allowed_updates, timeout_hint }
Self { state, stream, stop_token, hint_allowed_updates }
}
}
impl<'a, St, Assf, Sf, Hauf, Thf, Strm, E> AsUpdateStream<'a>
for StatefulListener<St, Assf, Hauf, Sf, Thf>
impl<'a, St, Assf, Sf, Hauf, Strm, E> AsUpdateStream<'a> for StatefulListener<St, Assf, Hauf, Sf>
where
(St, Strm): 'a,
Strm: Send,
@ -82,12 +72,11 @@ where
}
}
impl<St, Assf, Sf, Hauf, Thf, E> UpdateListener for StatefulListener<St, Assf, Sf, Hauf, Thf>
impl<St, Assf, Sf, Hauf, E> UpdateListener for StatefulListener<St, Assf, Sf, Hauf>
where
Self: for<'a> AsUpdateStream<'a, StreamErr = E>,
Sf: FnMut(&mut St) -> StopToken,
Hauf: FnMut(&mut St, &mut dyn Iterator<Item = AllowedUpdate>),
Thf: Fn(&St) -> Option<Duration>,
{
type Err = E;
@ -100,8 +89,4 @@ where
f(&mut self.state, hint);
}
}
fn timeout_hint(&self) -> Option<Duration> {
self.timeout_hint.as_ref().and_then(|f| f(&self.state))
}
}

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@ -5,18 +5,16 @@ use std::{
atomic::{AtomicU8, Ordering},
Arc,
},
time::Duration,
};
use tokio::sync::Notify;
use crate::update_listeners::UpdateListener;
/// A token which used to shutdown [`Dispatcher`].
///
/// [`Dispatcher`]: crate::dispatching::Dispatcher
#[derive(Clone)]
pub struct ShutdownToken {
// FIXME: use a single arc
dispatcher_state: Arc<DispatcherState>,
shutdown_notify_back: Arc<Notify>,
}
@ -49,11 +47,16 @@ impl ShutdownToken {
Self {
dispatcher_state: Arc::new(DispatcherState {
inner: AtomicU8::new(ShutdownState::Idle as _),
notify: <_>::default(),
}),
shutdown_notify_back: <_>::default(),
}
}
pub(crate) async fn wait_for_changes(&self) {
self.dispatcher_state.notify.notified().await;
}
pub(crate) fn start_dispatching(&self) {
if let Err(actual) =
self.dispatcher_state.compare_exchange(ShutdownState::Idle, ShutdownState::Running)
@ -93,27 +96,20 @@ impl fmt::Display for IdleShutdownError {
impl std::error::Error for IdleShutdownError {}
pub(crate) fn shutdown_check_timeout_for(update_listener: &impl UpdateListener) -> Duration {
const MIN_SHUTDOWN_CHECK_TIMEOUT: Duration = Duration::from_secs(1);
const DZERO: Duration = Duration::ZERO;
let shutdown_check_timeout = update_listener.timeout_hint().unwrap_or(DZERO);
shutdown_check_timeout.saturating_add(MIN_SHUTDOWN_CHECK_TIMEOUT)
}
struct DispatcherState {
inner: AtomicU8,
notify: Notify,
}
impl DispatcherState {
// Ordering::Relaxed: only one atomic variable, nothing to synchronize.
fn load(&self) -> ShutdownState {
ShutdownState::from_u8(self.inner.load(Ordering::Relaxed))
}
fn store(&self, new: ShutdownState) {
self.inner.store(new as _, Ordering::Relaxed)
self.inner.store(new as _, Ordering::Relaxed);
self.notify.notify_waiters();
}
fn compare_exchange(
@ -125,6 +121,11 @@ impl DispatcherState {
.compare_exchange(current as _, new as _, Ordering::Relaxed, Ordering::Relaxed)
.map(ShutdownState::from_u8)
.map_err(ShutdownState::from_u8)
// FIXME: `Result::inspect` when :(
.map(|st| {
self.notify.notify_waiters();
st
})
}
}