feat(cbs): implemented some basic error handling

src/app/events/mod.rs

@@ -22,7 +22,7 @@
 mod handlers;
 pub mod listeners;
 
-use anyhow::{Context, Result};
+use anyhow::{Context, Error, Result};
 
 use crate::{
     app::{command_interface::Commands, App},
@@ -33,10 +33,29 @@ use crossterm::event::Event as CrosstermEvent;
 use handlers::{command, input};
 use uuid::Uuid;
 
+#[derive(Debug)]
+pub enum ErrorEvent {
+    CBSCrash(Uuid, Error),
+}
+
+impl ErrorEvent {
+    pub async fn handle<U: TrinitrixUi>(self, app: &mut App<U>) -> Result<EventStatus> {
+        match self {
+            Self::CBSCrash(cbs, err) => {
+                // TODO: Kill CBS process
+                // TODO: Kill CBS connection threads
+                cli_log::error!("The CBS handler for {cbs} crashed: {err}");
+                Ok(EventStatus::Ok)
+            }
+        }
+    }
+}
+
 #[derive(Debug)]
 pub enum Event {
     InputEvent(CrosstermEvent),
     CBSPacket(Uuid, triba_packet::Packet),
+    Error(ErrorEvent),
 
     // FIXME(@soispha): The `String` here is just wrong <2024-05-03>
     CommandEvent(Commands, Option<trixy::oneshot::Sender<String>>),
@@ -56,6 +75,8 @@ impl Event {
                 Ok(EventStatus::Ok)
             }
 
+            Event::Error(err) => err.handle(app).await,
+
             Event::LuaCommand(lua_code) => {
                 warn!(
                     "Got lua code to execute, but no exectuter is available:\n{}",

src/cbs/connection.rs

@@ -1,36 +1,35 @@
-use crate::app::events::Event as AppEvent;
+use crate::app::events::{ErrorEvent as AppErrorEvent, Event as AppEvent};
 
 use aes_gcm_siv::{Aes256GcmSiv, Nonce};
-use anyhow::{anyhow, Result};
+use anyhow::{anyhow, Context, Result};
 use interprocess::local_socket::tokio::{RecvHalf, SendHalf};
 use tokio::sync::mpsc;
 use tokio_util::sync::CancellationToken;
 use triba_packet::{IdPool, Packet, Request, Response};
 use uuid::Uuid;
 
-pub struct Connection {
-    req_tx: mpsc::UnboundedSender<Request>,
-    resp_tx: mpsc::UnboundedSender<(Response, u64)>,
-}
-
-impl Connection {
-    pub async fn send_request(&self, body: Request) -> Result<()> {
-        self.req_tx.send(body)?;
-        Ok(())
-    }
-
-    pub async fn send_response(&self, body: Response, receiver: u64) -> Result<()> {
-        self.resp_tx.send((body, receiver))?;
-        Ok(())
-    }
-}
-
 enum Event {
     ToCBSReq(Request),
     ToCBSResp(Response, u64),
     FromCBS(Packet),
 }
 
+pub struct Connection {
+    tx: mpsc::UnboundedSender<Event>,
+}
+
+impl Connection {
+    pub async fn send_request(&self, body: Request) -> Result<()> {
+        self.tx.send(Event::ToCBSReq(body))?;
+        Ok(())
+    }
+
+    pub async fn send_response(&self, body: Response, receiver: u64) -> Result<()> {
+        self.tx.send(Event::ToCBSResp(body, receiver))?;
+        Ok(())
+    }
+}
+
 pub struct UnstableConnection {
     kill_token: CancellationToken,
     id: Uuid,
@@ -109,37 +108,20 @@ impl UnstableConnection {
             let nonce = nonce.clone();
             let tx = tx.clone();
 
+            let id = self.id.clone();
+            let main_tx = self.main_tx.clone();
+
             tokio::spawn(async move {
-                loop {
-                    let packet = Packet::recv(&mut sock_rx, &cipher, &nonce).await.unwrap();
-                    tx.send(Event::FromCBS(packet)).unwrap();
+                match poll_from_socket(&mut sock_rx, &cipher, &nonce, tx).await {
+                    Err(e) => main_tx
+                        .send(AppEvent::Error(AppErrorEvent::CBSCrash(id, e)))
+                        .await
+                        .expect("Failed to propagate error back to main queue."),
+                    Ok(_) => (),
                 }
             });
         }
 
-        let (core_req_tx, mut core_req_rx) = mpsc::unbounded_channel();
-
-        // Poll requests from core
-        {
-            let tx = tx.clone();
-            tokio::spawn(async move {
-                loop {
-                    let body = core_req_rx.recv().await.unwrap();
-                    tx.send(Event::ToCBSReq(body)).unwrap();
-                }
-            });
-        }
-
-        let (core_resp_tx, mut core_resp_rx) = mpsc::unbounded_channel();
-
-        // Poll responses from core
-        tokio::spawn(async move {
-            loop {
-                let (body, req) = core_resp_rx.recv().await.unwrap();
-                tx.send(Event::ToCBSResp(body, req)).unwrap();
-            }
-        });
-
         // Handle and route all packets
         {
             let cipher = cipher.clone();
@@ -149,37 +131,76 @@ impl UnstableConnection {
             let id = self.id.clone();
 
             tokio::spawn(async move {
+                match route_packets(
+                    rx,
+                    kill_token,
+                    id_pool,
+                    &mut sock_tx,
+                    &cipher,
+                    &nonce,
+                    main_tx.clone(),
+                    id,
+                )
+                .await
+                {
+                    Err(e) => main_tx
+                        .send(AppEvent::Error(AppErrorEvent::CBSCrash(id, e)))
+                        .await
+                        .expect("Failed to propagate error back to main queue."),
+                    Ok(_) => (),
+                }
+            });
+        }
+
+        Ok(Connection { tx })
+    }
+}
+
+async fn poll_from_socket(
+    rx: &mut RecvHalf,
+    cipher: &Aes256GcmSiv,
+    nonce: &Nonce,
+    tx: mpsc::UnboundedSender<Event>,
+) -> Result<()> {
+    loop {
+        let packet = Packet::recv(rx, cipher, nonce).await?;
+        tx.send(Event::FromCBS(packet))?;
+    }
+}
+
+async fn route_packets(
+    mut rx: mpsc::UnboundedReceiver<Event>,
+    kill_token: CancellationToken,
+    mut id_pool: IdPool,
+    sock_tx: &mut SendHalf,
+    cipher: &Aes256GcmSiv,
+    nonce: &Nonce,
+    main_tx: mpsc::Sender<AppEvent>,
+    id: Uuid,
+) -> Result<()> {
     loop {
         let event = tokio::select! {
-                        event = rx.recv() => event.unwrap(),
+            event = rx.recv() => event.context("The cbs event queue was closed unexpectedly.")?,
             _ = kill_token.cancelled() => break,
         };
 
         match event {
             Event::ToCBSReq(req) => {
                 Packet::request(id_pool.acquire(), req)
-                                .send(&mut sock_tx, &cipher, &nonce)
-                                .await
-                                .unwrap();
+                    .send(sock_tx, cipher, nonce)
+                    .await?;
             }
             Event::ToCBSResp(resp, req) => {
                 Packet::response(id_pool.acquire(), req, resp)
-                                .send(&mut sock_tx, &cipher, &nonce)
-                                .await
-                                .unwrap();
+                    .send(sock_tx, cipher, nonce)
+                    .await?;
             }
-                        Event::FromCBS(packet) => main_tx
+            Event::FromCBS(packet) => {
+                main_tx
                     .send(AppEvent::CBSPacket(id.clone(), packet))
-                            .await
-                            .unwrap(),
+                    .await?
             }
         }
-            });
-        }
-
-        Ok(Connection {
-            req_tx: core_req_tx,
-            resp_tx: core_resp_tx,
-        })
     }
+    Ok(())
 }

src/cbs/dummy.rs

@@ -4,5 +4,7 @@ use uuid::Uuid;
 pub async fn cbs(sock_name: Name<'_>, id: Uuid) {
     let (session, rx) = triba::Session::new(id, sock_name).await.unwrap();
 
-    loop {}
+    loop {
+        tokio::task::yield_now().await;
+    }
 }