From d47ff04c0323b08f05eeaa3ab49de0d10d424bc3 Mon Sep 17 00:00:00 2001
From: Patrik Nordwall <patrik.nordwall@gmail.com>
Date: Fri, 29 Jun 2012 08:56:58 +0200
Subject: [PATCH] Moved GossipDifferentViewProbability to config, see #2253

---
 akka-cluster/src/main/resources/reference.conf               | 5 +++++
 akka-cluster/src/main/scala/akka/cluster/Cluster.scala       | 4 +---
 .../src/main/scala/akka/cluster/ClusterSettings.scala        | 1 +
 .../src/test/scala/akka/cluster/ClusterConfigSpec.scala      | 1 +
 4 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/akka-cluster/src/main/resources/reference.conf b/akka-cluster/src/main/resources/reference.conf
index a06e9273cb..b60b91ec43 100644
--- a/akka-cluster/src/main/resources/reference.conf
+++ b/akka-cluster/src/main/resources/reference.conf
@@ -52,6 +52,11 @@ akka {
     # of the cluster within this deadline.
     join-timeout = 60s
 
+    # Gossip to random node with newer or older state information, if any with some
+    # this probability. Otherwise Gossip to any random live node.
+    # Probability value is between 0.0 and 1.0. 0.0 means never, 1.0 means always.
+    gossip-different-view-probability = 0.8
+
     failure-detector {
 
       # defines the failure detector threshold
diff --git a/akka-cluster/src/main/scala/akka/cluster/Cluster.scala b/akka-cluster/src/main/scala/akka/cluster/Cluster.scala
index 0d87a4b89c..40d67d7161 100644
--- a/akka-cluster/src/main/scala/akka/cluster/Cluster.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/Cluster.scala
@@ -1066,8 +1066,6 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
     }
   }
 
-  private def gossipToDifferentViewProbability: Double = 0.8
-
   /**
    * INTERNAL API.
    *
@@ -1099,7 +1097,7 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
         } yield address
       }
       val gossipedToAlive =
-        if (nodesWithdifferentView.nonEmpty && ThreadLocalRandom.current.nextDouble() < gossipToDifferentViewProbability)
+        if (nodesWithdifferentView.nonEmpty && ThreadLocalRandom.current.nextDouble() < GossipDifferentViewProbability)
           gossipToRandomNodeOf(nodesWithdifferentView.toIndexedSeq)
         else
           gossipToRandomNodeOf(localMemberAddresses)
diff --git a/akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala b/akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala
index 08a9b5160d..6e4cbc4e60 100644
--- a/akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala
@@ -36,6 +36,7 @@ class ClusterSettings(val config: Config, val systemName: String) {
   final val AutoJoin: Boolean = getBoolean("akka.cluster.auto-join")
   final val AutoDown: Boolean = getBoolean("akka.cluster.auto-down")
   final val JoinTimeout: Duration = Duration(getMilliseconds("akka.cluster.join-timeout"), MILLISECONDS)
+  final val GossipDifferentViewProbability: Double = getDouble("akka.cluster.gossip-different-view-probability")
   final val SchedulerTickDuration: Duration = Duration(getMilliseconds("akka.cluster.scheduler.tick-duration"), MILLISECONDS)
   final val SchedulerTicksPerWheel: Int = getInt("akka.cluster.scheduler.ticks-per-wheel")
 }
diff --git a/akka-cluster/src/test/scala/akka/cluster/ClusterConfigSpec.scala b/akka-cluster/src/test/scala/akka/cluster/ClusterConfigSpec.scala
index 92e219a540..07671c6164 100644
--- a/akka-cluster/src/test/scala/akka/cluster/ClusterConfigSpec.scala
+++ b/akka-cluster/src/test/scala/akka/cluster/ClusterConfigSpec.scala
@@ -32,6 +32,7 @@ class ClusterConfigSpec extends AkkaSpec {
       NrOfGossipDaemons must be(4)
       AutoJoin must be(true)
       AutoDown must be(true)
+      GossipDifferentViewProbability must be(0.8 plusOrMinus 0.0001)
       SchedulerTickDuration must be(33 millis)
       SchedulerTicksPerWheel must be(512)
     }