Files
nanoreth/crates/tasks/src/lib.rs
Léo Vincent 0096739dbb doc: add reth logo to docs (#3317)
Co-authored-by: Oliver Nordbjerg <hi@notbjerg.me>
2023-06-26 15:41:11 +00:00

516 lines
16 KiB
Rust

#![cfg_attr(docsrs, feature(doc_cfg))]
#![doc(
html_logo_url = "https://raw.githubusercontent.com/paradigmxyz/reth/main/assets/reth-docs.png",
html_favicon_url = "https://avatars0.githubusercontent.com/u/97369466?s=256",
issue_tracker_base_url = "https://github.com/paradigmxzy/reth/issues/"
)]
#![warn(missing_docs, unreachable_pub)]
#![deny(unused_must_use, rust_2018_idioms)]
#![doc(test(
no_crate_inject,
attr(deny(warnings, rust_2018_idioms), allow(dead_code, unused_variables))
))]
//! reth task management
use crate::{
metrics::TaskExecutorMetrics,
shutdown::{signal, Shutdown, Signal},
};
use dyn_clone::DynClone;
use futures_util::{
future::{select, BoxFuture},
pin_mut, Future, FutureExt, TryFutureExt,
};
use std::{
any::Any,
fmt::{Display, Formatter},
pin::Pin,
task::{ready, Context, Poll},
};
use tokio::{
runtime::Handle,
sync::mpsc::{unbounded_channel, UnboundedReceiver, UnboundedSender},
task::JoinHandle,
};
use tracing::error;
use tracing_futures::Instrument;
pub mod metrics;
pub mod shutdown;
/// A type that can spawn tasks.
///
/// The main purpose of this type is to abstract over [TaskExecutor] so it's more convenient to
/// provide default impls for testing.
///
///
/// # Examples
///
/// Use the [TokioTaskExecutor] that spawns with [tokio::task::spawn]
///
/// ```
/// # async fn t() {
/// use reth_tasks::{TaskSpawner, TokioTaskExecutor};
/// let executor = TokioTaskExecutor::default();
///
/// let task = executor.spawn(Box::pin(async {
/// // -- snip --
/// }));
/// task.await.unwrap();
/// # }
/// ```
///
/// Use the [TaskExecutor] that spawns task directly onto the tokio runtime via the [Handle].
///
/// ```
/// # use reth_tasks::TaskManager;
/// fn t() {
/// use reth_tasks::TaskSpawner;
/// let rt = tokio::runtime::Runtime::new().unwrap();
/// let manager = TaskManager::new(rt.handle().clone());
/// let executor = manager.executor();
/// let task = TaskSpawner::spawn(&executor, Box::pin(async {
/// // -- snip --
/// }));
/// rt.block_on(task).unwrap();
/// # }
/// ```
///
/// The [TaskSpawner] trait is [DynClone] so `Box<dyn TaskSpawner>` are also `Clone`.
pub trait TaskSpawner: Send + Sync + Unpin + std::fmt::Debug + DynClone {
/// Spawns the task onto the runtime.
/// See also [`Handle::spawn`].
fn spawn(&self, fut: BoxFuture<'static, ()>) -> JoinHandle<()>;
/// This spawns a critical task onto the runtime.
fn spawn_critical(&self, name: &'static str, fut: BoxFuture<'static, ()>) -> JoinHandle<()>;
/// Spawns a blocking task onto the runtime.
fn spawn_blocking(&self, fut: BoxFuture<'static, ()>) -> JoinHandle<()>;
/// This spawns a critical blocking task onto the runtime.
fn spawn_critical_blocking(
&self,
name: &'static str,
fut: BoxFuture<'static, ()>,
) -> JoinHandle<()>;
}
dyn_clone::clone_trait_object!(TaskSpawner);
/// An [TaskSpawner] that uses [tokio::task::spawn] to execute tasks
#[derive(Debug, Clone, Default)]
#[non_exhaustive]
pub struct TokioTaskExecutor;
impl TaskSpawner for TokioTaskExecutor {
fn spawn(&self, fut: BoxFuture<'static, ()>) -> JoinHandle<()> {
tokio::task::spawn(fut)
}
fn spawn_critical(&self, _name: &'static str, fut: BoxFuture<'static, ()>) -> JoinHandle<()> {
tokio::task::spawn(fut)
}
fn spawn_blocking(&self, fut: BoxFuture<'static, ()>) -> JoinHandle<()> {
tokio::task::spawn_blocking(move || tokio::runtime::Handle::current().block_on(fut))
}
fn spawn_critical_blocking(
&self,
_name: &'static str,
fut: BoxFuture<'static, ()>,
) -> JoinHandle<()> {
tokio::task::spawn_blocking(move || tokio::runtime::Handle::current().block_on(fut))
}
}
/// Many reth components require to spawn tasks for long-running jobs. For example `discovery`
/// spawns tasks to handle egress and ingress of udp traffic or `network` that spawns session tasks
/// that handle the traffic to and from a peer.
///
/// To unify how tasks are created, the [`TaskManager`] provides access to the configured Tokio
/// runtime. A [`TaskManager`] stores the [`tokio::runtime::Handle`] it is associated with. In this
/// way it is possible to configure on which runtime a task is executed.
///
/// The main purpose of this type is to be able to monitor if a critical task panicked, for
/// diagnostic purposes, since tokio task essentially fail silently. Therefore, this type is a
/// Stream that yields the name of panicked task, See [`TaskExecutor::spawn_critical`]. In order to
/// execute Tasks use the [`TaskExecutor`] type [`TaskManager::executor`].
pub struct TaskManager {
/// Handle to the tokio runtime this task manager is associated with.
///
/// See [`Handle`] docs.
handle: Handle,
/// Sender half for sending panic signals to this type
panicked_tasks_tx: UnboundedSender<PanickedTaskError>,
/// Listens for panicked tasks
panicked_tasks_rx: UnboundedReceiver<PanickedTaskError>,
/// The [Signal] to fire when all tasks should be shutdown.
///
/// This is fired on drop.
_signal: Signal,
/// Receiver of the shutdown signal.
on_shutdown: Shutdown,
}
// === impl TaskManager ===
impl TaskManager {
/// Create a new instance connected to the given handle's tokio runtime.
pub fn new(handle: Handle) -> Self {
let (panicked_tasks_tx, panicked_tasks_rx) = unbounded_channel();
let (_signal, on_shutdown) = signal();
Self { handle, panicked_tasks_tx, panicked_tasks_rx, _signal, on_shutdown }
}
/// Returns a new [`TaskExecutor`] that can spawn new tasks onto the tokio runtime this type is
/// connected to.
pub fn executor(&self) -> TaskExecutor {
TaskExecutor {
handle: self.handle.clone(),
on_shutdown: self.on_shutdown.clone(),
panicked_tasks_tx: self.panicked_tasks_tx.clone(),
metrics: Default::default(),
}
}
}
/// An endless future that resolves if a critical task panicked.
///
/// See [`TaskExecutor::spawn_critical`]
impl Future for TaskManager {
type Output = PanickedTaskError;
fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
let err = ready!(self.get_mut().panicked_tasks_rx.poll_recv(cx));
Poll::Ready(err.expect("stream can not end"))
}
}
/// Error with the name of the task that panicked and an error downcasted to string, if possible.
#[derive(Debug, thiserror::Error)]
pub struct PanickedTaskError {
task_name: &'static str,
error: Option<String>,
}
impl Display for PanickedTaskError {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
let task_name = self.task_name;
if let Some(error) = &self.error {
write!(f, "Critical task `{task_name}` panicked: `{error}`")
} else {
write!(f, "Critical task `{task_name}` panicked")
}
}
}
impl PanickedTaskError {
fn new(task_name: &'static str, error: Box<dyn Any>) -> Self {
let error = match error.downcast::<String>() {
Ok(value) => Some(*value),
Err(error) => match error.downcast::<&str>() {
Ok(value) => Some(value.to_string()),
Err(_) => None,
},
};
Self { task_name, error }
}
}
/// A type that can spawn new tokio tasks
#[derive(Debug, Clone)]
pub struct TaskExecutor {
/// Handle to the tokio runtime this task manager is associated with.
///
/// See [`Handle`] docs.
handle: Handle,
/// Receiver of the shutdown signal.
on_shutdown: Shutdown,
/// Sender half for sending panic signals to this type
panicked_tasks_tx: UnboundedSender<PanickedTaskError>,
// Task Executor Metrics
metrics: TaskExecutorMetrics,
}
// === impl TaskExecutor ===
impl TaskExecutor {
/// Returns the [Handle] to the tokio runtime.
pub fn handle(&self) -> &Handle {
&self.handle
}
/// Returns the receiver of the shutdown signal.
pub fn on_shutdown_signal(&self) -> &Shutdown {
&self.on_shutdown
}
/// Spawns a future on the tokio runtime depending on the [TaskKind]
fn spawn_on_rt<F>(&self, fut: F, task_kind: TaskKind) -> JoinHandle<()>
where
F: Future<Output = ()> + Send + 'static,
{
match task_kind {
TaskKind::Default => self.handle.spawn(fut),
TaskKind::Blocking => {
let handle = self.handle.clone();
self.handle.spawn_blocking(move || handle.block_on(fut))
}
}
}
/// Spawns a regular task depending on the given [TaskKind]
fn spawn_task_as<F>(&self, fut: F, task_kind: TaskKind) -> JoinHandle<()>
where
F: Future<Output = ()> + Send + 'static,
{
let on_shutdown = self.on_shutdown.clone();
let task = async move {
pin_mut!(fut);
let _ = select(on_shutdown, fut).await;
}
.in_current_span();
self.spawn_on_rt(task, task_kind)
}
/// Spawns the task onto the runtime.
/// The given future resolves as soon as the [Shutdown] signal is received.
///
/// See also [`Handle::spawn`].
pub fn spawn<F>(&self, fut: F) -> JoinHandle<()>
where
F: Future<Output = ()> + Send + 'static,
{
self.spawn_task_as(fut, TaskKind::Default)
}
/// Spawns a blocking task onto the runtime.
/// The given future resolves as soon as the [Shutdown] signal is received.
///
/// See also [`Handle::spawn_blocking`].
pub fn spawn_blocking<F>(&self, fut: F) -> JoinHandle<()>
where
F: Future<Output = ()> + Send + 'static,
{
self.spawn_task_as(fut, TaskKind::Blocking)
}
/// Spawns the task onto the runtime.
/// The given future resolves as soon as the [Shutdown] signal is received.
///
/// See also [`Handle::spawn`].
pub fn spawn_with_signal<F>(&self, f: impl FnOnce(Shutdown) -> F) -> JoinHandle<()>
where
F: Future<Output = ()> + Send + 'static,
{
let on_shutdown = self.on_shutdown.clone();
let fut = f(on_shutdown);
let task = fut.in_current_span();
self.handle.spawn(task)
}
/// Spawns a critical task depending on the given [TaskKind]
fn spawn_critical_as<F>(
&self,
name: &'static str,
fut: F,
task_kind: TaskKind,
) -> JoinHandle<()>
where
F: Future<Output = ()> + Send + 'static,
{
let panicked_tasks_tx = self.panicked_tasks_tx.clone();
let on_shutdown = self.on_shutdown.clone();
// wrap the task in catch unwind
let task = std::panic::AssertUnwindSafe(fut)
.catch_unwind()
.map_err(move |error| {
let task_error = PanickedTaskError::new(name, error);
error!("{task_error}");
let _ = panicked_tasks_tx.send(task_error);
})
.in_current_span();
let task = async move {
pin_mut!(task);
let _ = select(on_shutdown, task).await;
};
self.spawn_on_rt(task, task_kind)
}
/// This spawns a critical blocking task onto the runtime.
/// The given future resolves as soon as the [Shutdown] signal is received.
///
/// If this task panics, the [`TaskManager`] is notified.
pub fn spawn_critical_blocking<F>(&self, name: &'static str, fut: F) -> JoinHandle<()>
where
F: Future<Output = ()> + Send + 'static,
{
self.spawn_critical_as(name, fut, TaskKind::Blocking)
}
/// This spawns a critical task onto the runtime.
/// The given future resolves as soon as the [Shutdown] signal is received.
///
/// If this task panics, the [`TaskManager`] is notified.
pub fn spawn_critical<F>(&self, name: &'static str, fut: F) -> JoinHandle<()>
where
F: Future<Output = ()> + Send + 'static,
{
self.spawn_critical_as(name, fut, TaskKind::Default)
}
/// This spawns a critical task onto the runtime.
///
/// If this task panics, the [`TaskManager`] is notified.
pub fn spawn_critical_with_signal<F>(
&self,
name: &'static str,
f: impl FnOnce(Shutdown) -> F,
) -> JoinHandle<()>
where
F: Future<Output = ()> + Send + 'static,
{
let panicked_tasks_tx = self.panicked_tasks_tx.clone();
let on_shutdown = self.on_shutdown.clone();
let fut = f(on_shutdown);
// wrap the task in catch unwind
let task = std::panic::AssertUnwindSafe(fut)
.catch_unwind()
.map_err(move |error| {
let task_error = PanickedTaskError::new(name, error);
error!("{task_error}");
let _ = panicked_tasks_tx.send(task_error);
})
.map(|_| ())
.in_current_span();
self.handle.spawn(task)
}
}
impl TaskSpawner for TaskExecutor {
fn spawn(&self, fut: BoxFuture<'static, ()>) -> JoinHandle<()> {
self.metrics.inc_regular_task();
self.spawn(fut)
}
fn spawn_critical(&self, name: &'static str, fut: BoxFuture<'static, ()>) -> JoinHandle<()> {
self.metrics.inc_critical_tasks();
TaskExecutor::spawn_critical(self, name, fut)
}
fn spawn_blocking(&self, fut: BoxFuture<'static, ()>) -> JoinHandle<()> {
self.spawn_blocking(fut)
}
fn spawn_critical_blocking(
&self,
name: &'static str,
fut: BoxFuture<'static, ()>,
) -> JoinHandle<()> {
TaskExecutor::spawn_critical_blocking(self, name, fut)
}
}
/// Determines how a task is spawned
enum TaskKind {
/// Spawn the task to the default executor [Handle::spawn]
Default,
/// Spawn the task to the blocking executor [Handle::spawn_blocking]
Blocking,
}
#[cfg(test)]
mod tests {
use super::*;
use std::time::Duration;
#[test]
fn test_cloneable() {
#[derive(Clone)]
struct ExecutorWrapper {
_e: Box<dyn TaskSpawner>,
}
let executor: Box<dyn TaskSpawner> = Box::<TokioTaskExecutor>::default();
let _e = dyn_clone::clone_box(&*executor);
let e = ExecutorWrapper { _e };
let _e2 = e;
}
#[test]
fn test_critical() {
let runtime = tokio::runtime::Runtime::new().unwrap();
let handle = runtime.handle().clone();
let manager = TaskManager::new(handle);
let executor = manager.executor();
executor.spawn_critical(
"this is a critical task",
Box::pin(async { panic!("intentionally panic") }),
);
runtime.block_on(async move {
let err = manager.await;
assert_eq!(err.task_name, "this is a critical task");
assert_eq!(err.error, Some("intentionally panic".to_string()));
})
}
// Tests that spawned tasks are terminated if the `TaskManager` drops
#[test]
fn test_manager_shutdown_critical() {
let runtime = tokio::runtime::Runtime::new().unwrap();
let handle = runtime.handle().clone();
let manager = TaskManager::new(handle.clone());
let executor = manager.executor();
let (signal, shutdown) = signal();
executor.spawn_critical(
"this is a critical task",
Box::pin(async move {
tokio::time::sleep(Duration::from_millis(200)).await;
drop(signal);
}),
);
drop(manager);
handle.block_on(shutdown);
}
// Tests that spawned tasks are terminated if the `TaskManager` drops
#[test]
fn test_manager_shutdown() {
let runtime = tokio::runtime::Runtime::new().unwrap();
let handle = runtime.handle().clone();
let manager = TaskManager::new(handle.clone());
let executor = manager.executor();
let (signal, shutdown) = signal();
executor.spawn(Box::pin(async move {
tokio::time::sleep(Duration::from_millis(200)).await;
drop(signal);
}));
drop(manager);
handle.block_on(shutdown);
}
}