Enhance leader's replication response handling

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 [Unreleased]: https://github.com/lerna-stack/akka-entity-replication/compare/v2.1.0...master
 
+### Changed
+- Enhance leader's replication response handling [PR#160](https://github.com/lerna-stack/akka-entity-replication/pull/160)
+
 ### Fixed
 - RaftActor might delete committed entries [#152](https://github.com/lerna-stack/akka-entity-replication/issues/152)  
   ⚠️ This fix adds a new persistent event type. It doesn't allow downgrading after being updated.

src/main/scala/lerna/akka/entityreplication/raft/Leader.scala

@@ -237,14 +237,27 @@ private[raft] trait Leader { this: RaftActor =>
 
   }
 
-  private[this] def receiveReplicationResponse(event: ReplicationResponse): Unit =
-    event match {
+  private[this] def receiveReplicationResponse(replicationResponse: ReplicationResponse): Unit =
+    replicationResponse match {
 
       case ReplicationSucceeded(NoOp, _, _) =>
       // ignore: no-op replication when become leader
 
-      case ReplicationSucceeded(unknownEvent, _, _) =>
-        if (log.isWarningEnabled) log.warning("unknown event: {}", unknownEvent)
+      case ReplicationSucceeded(unknownEvent, logEntryIndex, instanceId) =>
+        if (log.isWarningEnabled) {
+          log.warning(
+            "[Leader] received the unexpected ReplicationSucceeded message: event type=[{}], index=[{}], instanceId=[{}]",
+            unknownEvent.getClass.getName,
+            logEntryIndex,
+            instanceId.map(_.underlying),
+          )
+        }
+
+      case ReplicationFailed =>
+        if (log.isWarningEnabled) {
+          log.warning("[Leader] received the unexpected ReplicationFailed message")
+        }
+
     }
 
   private[this] def startEntityPassivationProcess(entityPath: ActorPath, stopMessage: Any): Unit = {

src/main/scala/lerna/akka/entityreplication/raft/RaftProtocol.scala

@@ -95,13 +95,11 @@ private[entityreplication] object RaftProtocol {
   final case class Replica(logEntry: LogEntry)                                            extends EntityCommand
   final case class TakeSnapshot(metadata: EntitySnapshotMetadata, replyTo: ActorRef)      extends EntityCommand
   final case object RecoveryTimeout                                                       extends EntityCommand
-  final case object ReplicationFailed                                                     extends EntityCommand
-
-  sealed trait ReplicationResponse
 
+  sealed trait ReplicationResponse extends EntityCommand
   final case class ReplicationSucceeded(event: Any, logEntryIndex: LogEntryIndex, instanceId: Option[EntityInstanceId])
       extends ReplicationResponse
-      with EntityCommand
+  final case object ReplicationFailed extends ReplicationResponse
 
   final case class EntityRecoveryTimeoutException(entityPath: ActorPath) extends RuntimeException
 }

src/test/scala/lerna/akka/entityreplication/raft/RaftActorLeaderSpec.scala

@@ -1410,6 +1410,32 @@ class RaftActorLeaderSpec
         }
     }
 
+    "log a warning if it receives a ReplicationSucceeded message containing an event other than NoOp" in {
+      val leader     = createRaftActor()
+      val leaderData = createLeaderData(Term(1))
+      setState(leader, Leader, leaderData)
+
+      LoggingTestKit
+        .warn(
+          "[Leader] received the unexpected ReplicationSucceeded message: event type=[java.lang.String], index=[3], instanceId=[Some(1)]",
+        ).expect {
+          leader ! ReplicationSucceeded("event-1", LogEntryIndex(3), Option(EntityInstanceId(1)))
+        }
+    }
+
+    "log a warning if it receives a ReplicationFailed message" in {
+      val leader     = createRaftActor()
+      val leaderData = createLeaderData(Term(1))
+      setState(leader, Leader, leaderData)
+
+      LoggingTestKit
+        .warn(
+          "[Leader] received the unexpected ReplicationFailed message",
+        ).expect {
+          leader ! ReplicationFailed
+        }
+    }
+
   }
 
   private[this] def createLeaderData(