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|
use std::{future::Future, sync::Arc};
use log::{trace, warn};
use karyons_core::{
async_utils::{Backoff, TaskGroup, TaskResult},
GlobalExecutor,
};
use karyons_net::{dial, Conn, Endpoint, NetError};
use crate::{
monitor::{ConnEvent, Monitor},
slots::ConnectionSlots,
Result,
};
/// Responsible for creating outbound connections with other peers.
pub struct Connector {
/// Managing spawned tasks.
task_group: TaskGroup<'static>,
/// Manages available outbound slots.
connection_slots: Arc<ConnectionSlots>,
/// The maximum number of retries allowed before successfully
/// establishing a connection.
max_retries: usize,
/// Responsible for network and system monitoring.
monitor: Arc<Monitor>,
}
impl Connector {
/// Creates a new Connector
pub fn new(
max_retries: usize,
connection_slots: Arc<ConnectionSlots>,
monitor: Arc<Monitor>,
ex: GlobalExecutor,
) -> Arc<Self> {
Arc::new(Self {
task_group: TaskGroup::new(ex),
monitor,
connection_slots,
max_retries,
})
}
/// Shuts down the connector
pub async fn shutdown(&self) {
self.task_group.cancel().await;
}
/// Establish a connection to the specified `endpoint`. If the connection
/// attempt fails, it performs a backoff and retries until the maximum allowed
/// number of retries is exceeded. On a successful connection, it returns a
/// `Conn` instance.
///
/// This method will block until it finds an available slot.
pub async fn connect(&self, endpoint: &Endpoint) -> Result<Conn> {
self.connection_slots.wait_for_slot().await;
self.connection_slots.add();
let mut retry = 0;
let backoff = Backoff::new(500, 2000);
while retry < self.max_retries {
let conn_result = dial(endpoint).await;
if let Ok(conn) = conn_result {
self.monitor
.notify(&ConnEvent::Connected(endpoint.clone()).into())
.await;
return Ok(conn);
}
self.monitor
.notify(&ConnEvent::ConnectRetried(endpoint.clone()).into())
.await;
backoff.sleep().await;
warn!("try to reconnect {endpoint}");
retry += 1;
}
self.monitor
.notify(&ConnEvent::ConnectFailed(endpoint.clone()).into())
.await;
self.connection_slots.remove().await;
Err(NetError::Timeout.into())
}
/// Establish a connection to the given `endpoint`. For each new connection,
/// it invokes the provided `callback`, and pass the connection to the callback.
pub async fn connect_with_cback<Fut>(
self: &Arc<Self>,
endpoint: &Endpoint,
callback: impl FnOnce(Conn) -> Fut + Send + 'static,
) -> Result<()>
where
Fut: Future<Output = Result<()>> + Send + 'static,
{
let conn = self.connect(endpoint).await?;
let selfc = self.clone();
let endpoint = endpoint.clone();
let on_disconnect = |res| async move {
if let TaskResult::Completed(Err(err)) = res {
trace!("Outbound connection dropped: {err}");
}
selfc
.monitor
.notify(&ConnEvent::Disconnected(endpoint.clone()).into())
.await;
selfc.connection_slots.remove().await;
};
self.task_group.spawn(callback(conn), on_disconnect);
Ok(())
}
}
|
