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|
use std::{future::Future, sync::Arc};
use log::{error, info, trace};
use karyons_core::{
async_utils::{TaskGroup, TaskResult},
Executor,
};
use karyons_net::{listen, Conn, Endpoint, Listener as NetListener};
use crate::{
monitor::{ConnEvent, Monitor},
Result,
};
use super::slots::ConnectionSlots;
/// Responsible for creating inbound connections with other peers.
pub struct Listener {
/// Managing spawned tasks.
task_group: TaskGroup,
/// Manages available inbound slots.
connection_slots: Arc<ConnectionSlots>,
/// Responsible for network and system monitoring.
monitor: Arc<Monitor>,
}
impl Listener {
/// Creates a new Listener
pub fn new(connection_slots: Arc<ConnectionSlots>, monitor: Arc<Monitor>) -> Arc<Self> {
Arc::new(Self {
connection_slots,
task_group: TaskGroup::new(),
monitor,
})
}
/// Starts a listener on the given `endpoint`. For each incoming connection
/// that is accepted, it invokes the provided `callback`, and pass the
/// connection to the callback.
///
/// Returns the resloved listening endpoint.
pub async fn start<'a, Fut>(
self: &Arc<Self>,
ex: Executor<'a>,
endpoint: Endpoint,
// https://github.com/rust-lang/rfcs/pull/2132
callback: impl FnOnce(Conn) -> Fut + Clone + Send + 'a,
) -> Result<Endpoint>
where
Fut: Future<Output = Result<()>> + Send + 'a,
{
let listener = match listen(&endpoint).await {
Ok(listener) => {
self.monitor
.notify(&ConnEvent::Listening(endpoint.clone()).into())
.await;
listener
}
Err(err) => {
error!("Failed to listen on {endpoint}: {err}");
self.monitor
.notify(&ConnEvent::ListenFailed(endpoint).into())
.await;
return Err(err.into());
}
};
let resolved_endpoint = listener.local_endpoint()?;
info!("Start listening on {endpoint}");
let selfc = self.clone();
self.task_group.spawn(
ex.clone(),
selfc.listen_loop(ex.clone(), listener, callback),
|res| async move {
if let TaskResult::Completed(Err(err)) = res {
error!("Listen loop stopped: {endpoint} {err}");
}
},
);
Ok(resolved_endpoint)
}
/// Shuts down the listener
pub async fn shutdown(&self) {
self.task_group.cancel().await;
}
async fn listen_loop<'a, Fut>(
self: Arc<Self>,
ex: Executor<'a>,
listener: Box<dyn NetListener>,
callback: impl FnOnce(Conn) -> Fut + Clone + Send + 'a,
) -> Result<()>
where
Fut: Future<Output = Result<()>> + Send + 'a,
{
loop {
// Wait for an available inbound slot.
self.connection_slots.wait_for_slot().await;
let result = listener.accept().await;
let conn = match result {
Ok(c) => {
self.monitor
.notify(&ConnEvent::Accepted(c.peer_endpoint()?).into())
.await;
c
}
Err(err) => {
error!("Failed to accept a new connection: {err}");
self.monitor.notify(&ConnEvent::AcceptFailed.into()).await;
return Err(err.into());
}
};
self.connection_slots.add();
let selfc = self.clone();
let endpoint = conn.peer_endpoint()?;
let on_disconnect = |res| async move {
if let TaskResult::Completed(Err(err)) = res {
trace!("Inbound connection dropped: {err}");
}
selfc
.monitor
.notify(&ConnEvent::Disconnected(endpoint).into())
.await;
selfc.connection_slots.remove().await;
};
let callback = callback.clone();
self.task_group
.spawn(ex.clone(), callback(conn), on_disconnect);
}
}
}
|
