+act #3949 add LoggingReceive.withLabel

def someState = LoggingReceive.withLabel("some state") {
  case msg => ...
}

akka-actor/src/main/scala/akka/event/LoggingReceive.scala

@@ -26,27 +26,37 @@ object LoggingReceive {
    * This method does NOT modify the given Receive unless
    * `akka.actor.debug.receive` is set in configuration.
    */
-  def apply(r: Receive)(implicit context: ActorContext): Receive = r match {
-    case _: LoggingReceive ⇒ r
-    case _                 ⇒ if (context.system.settings.AddLoggingReceive) new LoggingReceive(None, r) else r
-  }
+  def apply(r: Receive)(implicit context: ActorContext): Receive = withLabel(null)(r)
 
   /**
    * Java API: compatible with lambda expressions
    * This is an EXPERIMENTAL feature and is subject to change until it has received more real world testing.
    */
   def create(r: Receive, context: ActorContext): Receive = apply(r)(context)
+
+  /**
+   * Create a decorated logger which will append `" in state " + label` to each message it logs.
+   */
+  def withLabel(label: String)(r: Receive)(implicit context: ActorContext): Receive = r match {
+    case _: LoggingReceive ⇒ r
+    case _                 ⇒ if (context.system.settings.AddLoggingReceive) new LoggingReceive(None, r, Option(label)) else r
+  }
 }
 
 /**
  * This decorator adds invocation logging to a Receive function.
  * @param source the log source, if not defined the actor of the context will be used
  */
-class LoggingReceive(source: Option[AnyRef], r: Receive)(implicit context: ActorContext) extends Receive {
+class LoggingReceive(source: Option[AnyRef], r: Receive, label: Option[String])(implicit context: ActorContext) extends Receive {
+  def this(source: Option[AnyRef], r: Receive)(implicit context: ActorContext) = this(source, r, None)
   def isDefinedAt(o: Any): Boolean = {
     val handled = r.isDefinedAt(o)
     val (str, clazz) = LogSource.fromAnyRef(source getOrElse context.asInstanceOf[ActorCell].actor)
-    context.system.eventStream.publish(Debug(str, clazz, "received " + (if (handled) "handled" else "unhandled") + " message " + o))
+    context.system.eventStream.publish(Debug(str, clazz, "received " + (if (handled) "handled" else "unhandled") + " message " + o
+      + (label match {
+        case Some(l) ⇒ " in state " + l
+        case _       ⇒ ""
+      })))
     handled
   }
   def apply(o: Any): Unit = r(o)

akka-docs/rst/scala/code/docs/testkit/TestkitDocSpec.scala

@@ -76,6 +76,9 @@ object TestkitDocSpec {
     def receive = LoggingReceive {
       case msg => // Do something ...
     }
+    def otherState: Receive = LoggingReceive.withLabel("other") {
+      case msg => // Do something else ...
+    }
     //#logging-receive
   }
 }