1 files changed, 125 insertions, 0 deletions
diff --git a/karyons_p2p/src/net/connector.rs b/karyons_p2p/src/net/connector.rs
new file mode 100644
index 0000000..72dc0d8
--- /dev/null
+++ b/karyons_p2p/src/net/connector.rs
@@ -0,0 +1,125 @@
+use std::{future::Future, sync::Arc};
+
+use log::{trace, warn};
+
+use karyons_core::{
+    async_utils::{Backoff, TaskGroup, TaskResult},
+    Executor,
+};
+use karyons_net::{dial, Conn, Endpoint, NetError};
+
+use crate::{
+    monitor::{ConnEvent, Monitor},
+    Result,
+};
+
+use super::slots::ConnectionSlots;
+
+/// Responsible for creating outbound connections with other peers.
+pub struct Connector {
+    /// Managing spawned tasks.
+    task_group: TaskGroup,
+
+    /// 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>,
+    ) -> Arc<Self> {
+        Arc::new(Self {
+            task_group: TaskGroup::new(),
+            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<'a, Fut>(
+        self: &Arc<Self>,
+        ex: Executor<'a>,
+        endpoint: &Endpoint,
+        callback: impl FnOnce(Conn) -> Fut + Send + 'a,
+    ) -> Result<()>
+    where
+        Fut: Future<Output = Result<()>> + Send + 'a,
+    {
+        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(ex.clone(), callback(conn), on_disconnect);
+
+        Ok(())
+    }
+}