+con #3677 Limit delta in DistributedPubSubMediator

akka-contrib/src/main/resources/reference.conf

@@ -24,6 +24,11 @@ akka.contrib.cluster.pub-sub {
 
   # Removed entries are pruned after this duration
   removed-time-to-live = 120s
+  
+  # Maximum number of elements to transfer in one message when synchronizing the registries.
+  # Next chunk will be transferred in next round of gossip. 
+  max-delta-elements = 500
+  
 }
 # //#pub-sub-ext-config
 

akka-contrib/src/main/scala/akka/contrib/pattern/ClusterClient.scala

@@ -63,7 +63,12 @@ object ClusterClient {
   }
 
   @SerialVersionUID(1L)
-  case class Send(path: String, msg: Any, localAffinity: Boolean)
+  case class Send(path: String, msg: Any, localAffinity: Boolean) {
+    /**
+     * Convenience constructor with `localAffinity` false
+     */
+    def this(path: String, msg: Any) = this(path, msg, localAffinity = false)
+  }
   @SerialVersionUID(1L)
   case class SendToAll(path: String, msg: Any)
   @SerialVersionUID(1L)

akka-contrib/src/main/scala/akka/contrib/pattern/DistributedPubSubMediator.scala

@@ -42,8 +42,9 @@ object DistributedPubSubMediator {
     role: Option[String],
     routingLogic: RoutingLogic = RandomRoutingLogic(),
     gossipInterval: FiniteDuration = 1.second,
-    removedTimeToLive: FiniteDuration = 2.minutes): Props =
+    removedTimeToLive: FiniteDuration = 2.minutes,
-    Props(classOf[DistributedPubSubMediator], role, routingLogic, gossipInterval, removedTimeToLive)
+    maxDeltaElements: Int = 500): Props =
+    Props(classOf[DistributedPubSubMediator], role, routingLogic, gossipInterval, removedTimeToLive, maxDeltaElements)
 
   /**
    * Java API: Factory method for `DistributedPubSubMediator` [[akka.actor.Props]].
@@ -52,8 +53,9 @@ object DistributedPubSubMediator {
     role: String,
     routingLogic: RoutingLogic,
     gossipInterval: FiniteDuration,
-    removedTimeToLive: FiniteDuration): Props =
+    removedTimeToLive: FiniteDuration,
-    props(Internal.roleOption(role), routingLogic, gossipInterval, removedTimeToLive)
+    maxDeltaElements: Int): Props =
+    props(Internal.roleOption(role), routingLogic, gossipInterval, removedTimeToLive, maxDeltaElements)
 
   /**
    * Java API: Factory method for `DistributedPubSubMediator` [[akka.actor.Props]]
@@ -213,7 +215,8 @@ class DistributedPubSubMediator(
   role: Option[String],
   routingLogic: RoutingLogic,
   gossipInterval: FiniteDuration,
-  removedTimeToLive: FiniteDuration)
+  removedTimeToLive: FiniteDuration,
+  maxDeltaElements: Int)
   extends Actor with ActorLogging {
 
   import DistributedPubSubMediator._
@@ -404,13 +407,22 @@ class DistributedPubSubMediator(
   def collectDelta(otherVersions: Map[Address, Long]): immutable.Iterable[Bucket] = {
     // missing entries are represented by version 0
     val filledOtherVersions = myVersions.map { case (k, _) ⇒ k -> 0L } ++ otherVersions
+    var count = 0
     filledOtherVersions.collect {
-      case (owner, v) if registry(owner).version > v ⇒
+      case (owner, v) if registry(owner).version > v && count < maxDeltaElements ⇒
         val bucket = registry(owner)
         val deltaContent = bucket.content.filter {
           case (_, value) ⇒ value.version > v
         }
-        bucket.copy(content = deltaContent)
+        count += deltaContent.size
+        if (count <= maxDeltaElements)
+          bucket.copy(content = deltaContent)
+        else {
+          // exceeded the maxDeltaElements, pick the elements with lowest versions
+          val sortedContent = deltaContent.toVector.sortBy(_._2.version)
+          val chunk = sortedContent.take(maxDeltaElements - (count - sortedContent.size))
+          bucket.copy(content = chunk.toMap, version = chunk.last._2.version)
+        }
     }
   }
 
@@ -482,11 +494,13 @@ class DistributedPubSubExtension(system: ExtendedActorSystem) extends Extension
         case "round-robin"        ⇒ RoundRobinRoutingLogic()
         case "consistent-hashing" ⇒ ConsistentHashingRoutingLogic(system)
         case "broadcast"          ⇒ BroadcastRoutingLogic()
+        case other                ⇒ throw new IllegalArgumentException(s"Unknown 'routing-logic': [$other]")
       }
       val gossipInterval = Duration(config.getMilliseconds("gossip-interval"), MILLISECONDS)
       val removedTimeToLive = Duration(config.getMilliseconds("removed-time-to-live"), MILLISECONDS)
+      val maxDeltaElements = config.getInt("max-delta-elements")
       val name = config.getString("name")
-      system.actorOf(DistributedPubSubMediator.props(role, routingLogic, gossipInterval, removedTimeToLive),
+      system.actorOf(DistributedPubSubMediator.props(role, routingLogic, gossipInterval, removedTimeToLive, maxDeltaElements),
         name)
     }
   }

akka-contrib/src/multi-jvm/scala/akka/contrib/pattern/DistributedPubSubMediatorSpec.scala

@@ -18,6 +18,8 @@ import akka.remote.testkit.MultiNodeSpec
 import akka.remote.testkit.STMultiNodeSpec
 import akka.testkit._
 import akka.actor.ActorLogging
+import akka.contrib.pattern.DistributedPubSubMediator.Internal.Status
+import akka.contrib.pattern.DistributedPubSubMediator.Internal.Delta
 
 object DistributedPubSubMediatorSpec extends MultiNodeConfig {
   val first = role("first")
@@ -29,6 +31,8 @@ object DistributedPubSubMediatorSpec extends MultiNodeConfig {
     akka.actor.provider = "akka.cluster.ClusterActorRefProvider"
     akka.remote.log-remote-lifecycle-events = off
     akka.cluster.auto-down-unreachable-after = 0s
+    akka.contrib.cluster.pub-sub.max-delta-elements = 500
+    #akka.remote.log-frame-size-exceeding = 1024b
     """))
 
   object TestChatUser {
@@ -341,5 +345,47 @@ class DistributedPubSubMediatorSpec extends MultiNodeSpec(DistributedPubSubMedia
 
       enterBarrier("after-11")
     }
+
+    "transfer delta correctly" in {
+      val firstAddress = node(first).address
+          val secondAddress = node(second).address
+          val thirdAddress = node(third).address
+
+      runOn(first) {
+        mediator ! Status(versions = Map.empty)
+        val deltaBuckets = expectMsgType[Delta].buckets
+        deltaBuckets.size must be (3)
+        deltaBuckets.find(_.owner == firstAddress).get.content.size must be(7)
+        deltaBuckets.find(_.owner == secondAddress).get.content.size must be(6)
+        deltaBuckets.find(_.owner == thirdAddress).get.content.size must be(2)
+      }
+      enterBarrier("verified-initial-delta")
+
+      // this test is configured with max-delta-elements = 500
+      val many = 1010
+      runOn(first) {
+        for (i <- 0 until many)
+          mediator ! Put(createChatUser("u" + (1000 + i)))
+
+        mediator ! Status(versions = Map.empty)
+        val deltaBuckets1 = expectMsgType[Delta].buckets
+        deltaBuckets1.map(_.content.size).sum must be (500)
+
+        mediator ! Status(versions = deltaBuckets1.map(b => b.owner -> b.version).toMap)
+        val deltaBuckets2 = expectMsgType[Delta].buckets
+        deltaBuckets1.map(_.content.size).sum must be (500)
+
+        mediator ! Status(versions = deltaBuckets2.map(b => b.owner -> b.version).toMap)
+        val deltaBuckets3 = expectMsgType[Delta].buckets
+
+        deltaBuckets3.map(_.content.size).sum must be (7 + 6 + 2 + many - 500 - 500)
+      }
+
+
+      enterBarrier("verified-delta-with-many")
+      awaitCount(13 + many)
+
+      enterBarrier("after-12")
+    }
   }
 }