feat(kafka): Trigger graceful shutdown on actor failure

Author: john-z-yang

src/consumer/kafka.rs

@@ -32,7 +32,7 @@ use tokio::{
         mpsc::{self, unbounded_channel, UnboundedReceiver, UnboundedSender},
         oneshot,
     },
-    task::{self, JoinSet},
+    task::{self, JoinError, JoinSet},
     time::{self, sleep, MissedTickBehavior},
 };
 use tokio_stream::wrappers::UnboundedReceiverStream;
@@ -75,7 +75,7 @@ pub fn handle_os_signals(event_sender: UnboundedSender<(Event, SyncSender<()>)>)
     let guard = elegant_departure::get_shutdown_guard();
     tokio::spawn(async move {
         let _ = guard.wait().await;
-        info!("Cancellation token received, shutting down consumer");
+        info!("Cancellation token received, shutting down consumer...");
         let (rendezvous_sender, _) = sync_channel(0);
         let _ = event_sender.send((Event::Shutdown, rendezvous_sender));
     });
@@ -189,6 +189,10 @@ impl ActorHandles {
             }
         }
     }
+
+    async fn join_next(&mut self) -> Option<Result<Result<(), Error>, JoinError>> {
+        self.join_set.join_next().await
+    }
 }
 
 #[macro_export]
@@ -333,54 +337,65 @@ pub async fn handle_events(
     let mut state = ConsumerState::Ready;
 
     while let ConsumerState::Ready { .. } | ConsumerState::Consuming { .. } = state {
-        let Some((event, _rendezvous_guard)) = events_stream.next().await else {
-            unreachable!("Unexpected end to event stream")
-        };
-        info!("Received event: {:?}", event);
-        state = match (state, event) {
-            (ConsumerState::Ready, Event::Assign(tpl)) => {
-                ConsumerState::Consuming(spawn_actors(consumer.clone(), &tpl), tpl)
-            }
-            (ConsumerState::Ready, Event::Revoke(_)) => {
-                unreachable!("Got partition revocation before the consumer has started")
-            }
-            (ConsumerState::Ready, Event::Shutdown) => ConsumerState::Stopped,
-            (ConsumerState::Consuming(actor_handles, mut tpl), Event::Assign(mut assigned_tpl)) => {
-                assert!(
-                    tpl.is_disjoint(&assigned_tpl),
-                    "Newly assigned TPL should be disjoint from TPL we're consuming from"
-                );
-                tpl.append(&mut assigned_tpl);
-                debug!(
-                    "{} additional topic partitions added after assignment",
-                    assigned_tpl.len()
-                );
-                actor_handles.shutdown(CALLBACK_DURATION).await;
-                ConsumerState::Consuming(spawn_actors(consumer.clone(), &tpl), tpl)
+        select! {
+            res = match state {
+                ConsumerState::Consuming(ref mut handles, _) => Either::Left(handles.join_next()),
+                _ => Either::Right(future::pending::<_>())
+            } => {
+                error!("Actor exited unexpectedly with {:?}, shutting down...", res);
+                drop(elegant_departure::shutdown());
             }
-            (ConsumerState::Consuming(actor_handles, mut tpl), Event::Revoke(revoked_tpl)) => {
-                assert!(
-                    tpl.is_subset(&revoked_tpl),
-                    "Revoked TPL should be a subset of TPL we're consuming from"
-                );
-                tpl.retain(|e| !revoked_tpl.contains(e));
-                debug!("{} topic partitions remaining after revocation", tpl.len());
-                actor_handles.shutdown(CALLBACK_DURATION).await;
-                if tpl.is_empty() {
-                    ConsumerState::Ready
-                } else {
-                    ConsumerState::Consuming(spawn_actors(consumer.clone(), &tpl), tpl)
+            event = events_stream.next() => {
+                let Some((event, _rendezvous_guard)) = event else {
+                    unreachable!("Unexpected end to event stream");
+                };
+                info!("Received event: {:?}", event);
+                state = match (state, event) {
+                    (ConsumerState::Ready, Event::Assign(tpl)) => {
+                        ConsumerState::Consuming(spawn_actors(consumer.clone(), &tpl), tpl)
+                    }
+                    (ConsumerState::Ready, Event::Revoke(_)) => {
+                        unreachable!("Got partition revocation before the consumer has started")
+                    }
+                    (ConsumerState::Ready, Event::Shutdown) => ConsumerState::Stopped,
+                    (ConsumerState::Consuming(handles, mut tpl), Event::Assign(mut assigned)) => {
+                        assert!(
+                            tpl.is_disjoint(&assigned),
+                            "Newly assigned TPL should be disjoint from TPL we're consuming from"
+                        );
+                        tpl.append(&mut assigned);
+                        debug!(
+                            "{} additional topic partitions added after assignment",
+                            assigned.len()
+                        );
+                        handles.shutdown(CALLBACK_DURATION).await;
+                        ConsumerState::Consuming(spawn_actors(consumer.clone(), &tpl), tpl)
+                    }
+                    (ConsumerState::Consuming(handles, mut tpl), Event::Revoke(revoked)) => {
+                        assert!(
+                            tpl.is_subset(&revoked),
+                            "Revoked TPL should be a subset of TPL we're consuming from"
+                        );
+                        tpl.retain(|e| !revoked.contains(e));
+                        debug!("{} topic partitions remaining after revocation", tpl.len());
+                        handles.shutdown(CALLBACK_DURATION).await;
+                        if tpl.is_empty() {
+                            ConsumerState::Ready
+                        } else {
+                            ConsumerState::Consuming(spawn_actors(consumer.clone(), &tpl), tpl)
+                        }
+                    }
+                    (ConsumerState::Consuming(handles, _), Event::Shutdown) => {
+                        handles.shutdown(CALLBACK_DURATION).await;
+                        debug!("Signaling shutdown to client...");
+                        shutdown_client.take();
+                        ConsumerState::Stopped
+                    }
+                    (ConsumerState::Stopped, _) => {
+                        unreachable!("Got event after consumer has stopped")
+                    }
                 }
             }
-            (ConsumerState::Consuming(actor_handles, _), Event::Shutdown) => {
-                actor_handles.shutdown(CALLBACK_DURATION).await;
-                debug!("Signaling shutdown to client...");
-                shutdown_client.take();
-                ConsumerState::Stopped
-            }
-            (ConsumerState::Stopped, _) => {
-                unreachable!("Got event after consumer has stopped")
-            }
         }
     }
     debug!("Shutdown complete");