Log reason of lost worker on info level

Author: spirali

crates/tako/src/gateway.rs

@@ -1,4 +1,5 @@
 use serde::{Deserialize, Serialize, Serializer};
+use std::fmt::Display;
 
 use crate::internal::common::error::DsError;
 use crate::internal::messages::common::TaskFailInfo;
@@ -303,6 +304,18 @@ impl LostWorkerReason {
     }
 }
 
+impl Display for LostWorkerReason {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            LostWorkerReason::Stopped => "stopped",
+            LostWorkerReason::ConnectionLost => "connection lost",
+            LostWorkerReason::HeartbeatLost => "heartbeat lost",
+            LostWorkerReason::IdleTimeout => "idle timeout",
+            LostWorkerReason::TimeLimitReached => "time limit reached",
+        })
+    }
+}
+
 #[derive(Serialize, Deserialize, Debug)]
 pub struct LostWorkerMessage {
     pub worker_id: WorkerId,

crates/tako/src/internal/server/rpc.rs

@@ -230,9 +230,10 @@ async fn worker_rpc_loop(
     };
 
     log::info!(
-        "Worker {} connection closed (connection: {})",
+        "Worker {} ({}) connection closed: {}",
         worker_id,
-        connection.address
+        connection.address,
+        reason
     );
     let mut core = core_ref.get_mut();
     let mut comm = comm_ref.get_mut();