agent: disconnect rpc get_oom_event when destroy_sandbox.

Otherwise it would block the shutdown of ttrpc.

Fixes: #1524

Signed-off-by: Tim Zhang <tim@hyper.sh>

src/agent/src/rpc.rs

@@ -1040,6 +1040,10 @@ impl protocols::agent_ttrpc::AgentService for AgentService {
         // destroy all containers, clean up, notify agent to exit
         // etc.
         sandbox.destroy().await.unwrap();
+        // Close get_oom_event connection,
+        // otherwise it will block the shutdown of ttrpc.
+        sandbox.event_tx.take();
+
         sandbox.sender.take().unwrap().send(1).unwrap();
 
         Ok(Empty::new())
@@ -1188,15 +1192,16 @@ impl protocols::agent_ttrpc::AgentService for AgentService {
         drop(s);
         drop(sandbox);
 
-        match event_rx.recv().await {
-            None => Err(ttrpc_error(ttrpc::Code::INTERNAL, "")),
-            Some(container_id) => {
+        if let Some(container_id) = event_rx.recv().await {
             info!(sl!(), "get_oom_event return {}", &container_id);
+
             let mut resp = OOMEvent::new();
             resp.container_id = container_id;
-                Ok(resp)
-            }
+
+            return Ok(resp);
         }
+
+        Err(ttrpc_error(ttrpc::Code::INTERNAL, ""))
     }
 }
 

src/agent/src/sandbox.rs

@@ -47,7 +47,7 @@ pub struct Sandbox {
     pub rtnl: Handle,
     pub hooks: Option<Hooks>,
     pub event_rx: Arc<Mutex<Receiver<String>>>,
-    pub event_tx: Sender<String>,
+    pub event_tx: Option<Sender<String>>,
 }
 
 impl Sandbox {
@@ -76,7 +76,7 @@ impl Sandbox {
             rtnl: Handle::new()?,
             hooks: None,
             event_rx,
-            event_tx: tx,
+            event_tx: Some(tx),
         })
     }
 
@@ -311,9 +311,18 @@ impl Sandbox {
     }
 
     pub async fn run_oom_event_monitor(&self, mut rx: Receiver<String>, container_id: String) {
-        let tx = self.event_tx.clone();
         let logger = self.logger.clone();
 
+        if self.event_tx.is_none() {
+            error!(
+                logger,
+                "sandbox.event_tx not found in run_oom_event_monitor"
+            );
+            return;
+        }
+
+        let tx = self.event_tx.as_ref().unwrap().clone();
+
         tokio::spawn(async move {
             loop {
                 let event = rx.recv().await;