From a01eea8f25907d3758d746b511f424ccf9a91add Mon Sep 17 00:00:00 2001
From: Arnout Engelen <arnouten@bzzt.net>
Date: Mon, 24 Jul 2017 15:16:32 +0200
Subject: [PATCH] Add some logging to track down #20180

---
 .../akka/remote/RemoteReDeploymentSpec.scala  | 20 ++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/akka-remote-tests/src/multi-jvm/scala/akka/remote/RemoteReDeploymentSpec.scala b/akka-remote-tests/src/multi-jvm/scala/akka/remote/RemoteReDeploymentSpec.scala
index 67c7a64d15..c6ff21ec3b 100644
--- a/akka-remote-tests/src/multi-jvm/scala/akka/remote/RemoteReDeploymentSpec.scala
+++ b/akka-remote-tests/src/multi-jvm/scala/akka/remote/RemoteReDeploymentSpec.scala
@@ -35,6 +35,7 @@ class RemoteReDeploymentConfig(artery: Boolean) extends MultiNodeConfig {
          acceptable-heartbeat-pause=2.5s
        }
        akka.remote.artery.enabled = $artery
+       akka.loglevel = INFO
        """)).withFallback(RemotingMultiNodeSpec.commonConfig))
 
   testTransport(on = true)
@@ -79,16 +80,18 @@ abstract class RemoteReDeploymentSlowMultiJvmSpec(artery: Boolean) extends Remot
 }
 
 object RemoteReDeploymentMultiJvmSpec {
-  class Parent extends Actor {
+  class Parent extends Actor with ActorLogging {
     val monitor = context.actorSelection("/user/echo")
+    log.info(s"Started Parent on path ${self.path}")
     def receive = {
       case (p: Props, n: String) ⇒ context.actorOf(p, n)
       case msg                   ⇒ monitor ! msg
     }
   }
 
-  class Hello extends Actor {
+  class Hello extends Actor with ActorLogging {
     val monitor = context.actorSelection("/user/echo")
+    log.info(s"Started Hello on path ${self.path} with parent ${context.parent.path}")
     context.parent ! "HelloParent"
     override def preStart(): Unit = monitor ! "PreStart"
     override def postStop(): Unit = monitor ! "PostStop"
@@ -119,26 +122,32 @@ abstract class RemoteReDeploymentMultiJvmSpec(multiNodeConfig: RemoteReDeploymen
   "A remote deployment target system" must {
 
     "terminate the child when its parent system is replaced by a new one" in {
-
+      // Any message sent to `echo` will be passed on to `testActor`
       val echo = system.actorOf(echoProps(testActor), "echo")
       enterBarrier("echo-started")
 
       runOn(second) {
+        // Create a 'Parent' actor on the 'second' node
+        // have it create a 'Hello' child (which will be on the 'first' node due to the deployment config):
         system.actorOf(Props[Parent], "parent") ! ((Props[Hello], "hello"))
+        // The 'Hello' child will send "HelloParent" to the 'Parent', which will pass it to the 'echo' monitor:
         expectMsg(15.seconds, "HelloParent")
       }
 
       runOn(first) {
+        // Check the 'Hello' actor was started on the first node
         expectMsg(15.seconds, "PreStart")
       }
 
       enterBarrier("first-deployed")
 
+      // Disconnect the second system from the first, and shut it down
       runOn(first) {
         testConductor.blackhole(second, first, Both).await
         testConductor.shutdown(second, abort = true).await
         if (expectQuarantine)
           within(sleepAfterKill) {
+            // The quarantine of node 2, where the Parent lives, should cause the Hello child to be stopped:
             expectMsg("PostStop")
             expectNoMsg()
           }
@@ -148,6 +157,7 @@ abstract class RemoteReDeploymentMultiJvmSpec(multiNodeConfig: RemoteReDeploymen
 
       var sys: ActorSystem = null
 
+      // Start the second system again
       runOn(second) {
         Await.ready(system.whenTerminated, 30.seconds)
         expectNoMsg(sleepAfterKill)
@@ -156,6 +166,7 @@ abstract class RemoteReDeploymentMultiJvmSpec(multiNodeConfig: RemoteReDeploymen
 
       enterBarrier("cable-cut")
 
+      // add new echo, parent, and (if needed) Hello actors:
       runOn(second) {
         val p = TestProbe()(sys)
         sys.actorOf(echoProps(p.ref), "echo")
@@ -165,6 +176,7 @@ abstract class RemoteReDeploymentMultiJvmSpec(multiNodeConfig: RemoteReDeploymen
 
       enterBarrier("re-deployed")
 
+      // Check the Hello actor is (re)started on node 1:
       runOn(first) {
         within(15.seconds) {
           if (expectQuarantine) expectMsg("PreStart")
@@ -174,8 +186,10 @@ abstract class RemoteReDeploymentMultiJvmSpec(multiNodeConfig: RemoteReDeploymen
 
       enterBarrier("the-end")
 
+      // After this we expect no further messages
       expectNoMsg(1.second)
 
+      // Until we clean up after ourselves
       enterBarrier("stopping")
 
       runOn(second) {