[1.6.4/Scala] Testkit starts up Akka cluster for StandaloneLagomClientFactory when not requested

Lagom Version (1.2.x / 1.3.x / etc)

1.6.4

API (Scala / Java / Neither / Both)

Scala

Operating System (Ubuntu 15.10 / MacOS 10.10 / Windows 10)

Mac OS 10.15.7

JDK (Oracle 1.8.0_112, OpenJDK 1.8.x, Azul Zing)

java version “1.8.0_172” Java™ SE Runtime Environment (build 1.8.0_172-b11) Java HotSpot™ 64-Bit Server VM (build 25.172-b11, mixed mode)

Library Dependencies

"com.lightbend.lagom" %% "lagom-scaladsl-testkit" % "1.6.4"

Expected Behavior

When creating a client with StandaloneLagomClientFactory, unless explicitly requested an Akka cluster is not bootstrapped.

Actual Behavior

When the client starts up, an Akka cluster is bootstrapped:

[INFO ][2021-03-31 17:32:54,771][akka.remote.artery.tcp.ArteryTcpTransport][application-akka.actor.default-dispatcher-5][akkaAddress=akka://application@192.168.1.15:25520, sourceThread=pool-7-thread-4-ScalaTest-running-ExampleValidLagomOpenApiCompatibilitySpec, akkaSource=ArteryTcpTransport(akka://application), sourceActorSystem=application, akkaTimestamp=22:32:54.771UTC] Remoting started with transport [Artery tcp]; listening on address [akka://application@192.168.1.15:25520] with UID [-6744528107701742272] [---]
[INFO ][2021-03-31 17:32:54,796][akka.cluster.Cluster][application-akka.actor.default-dispatcher-5][akkaAddress=akka://application@192.168.1.15:25520, sourceThread=pool-7-thread-4-ScalaTest-running-ExampleValidLagomOpenApiCompatibilitySpec, akkaSource=Cluster(akka://application), sourceActorSystem=application, akkaTimestamp=22:32:54.796UTC] Cluster Node [akka://application@192.168.1.15:25520] - Starting up, Akka version [2.6.8] ... [---]
[INFO ][2021-03-31 17:32:54,903][akka.cluster.Cluster][application-akka.actor.default-dispatcher-5][akkaAddress=akka://application@192.168.1.15:25520, sourceThread=pool-7-thread-4-ScalaTest-running-ExampleValidLagomOpenApiCompatibilitySpec, akkaSource=Cluster(akka://application), sourceActorSystem=application, akkaTimestamp=22:32:54.903UTC] Cluster Node [akka://application@192.168.1.15:25520] - Registered cluster JMX MBean [akka:type=Cluster] [---]
[INFO ][2021-03-31 17:32:54,903][akka.cluster.Cluster][application-akka.actor.default-dispatcher-5][akkaAddress=akka://application@192.168.1.15:25520, sourceThread=pool-7-thread-4-ScalaTest-running-ExampleValidLagomOpenApiCompatibilitySpec, akkaSource=Cluster(akka://application), sourceActorSystem=application, akkaTimestamp=22:32:54.903UTC] Cluster Node [akka://application@192.168.1.15:25520] - Started up successfully [---]
[INFO ][2021-03-31 17:32:54,931][akka.cluster.Cluster][application-akka.actor.default-dispatcher-5][akkaAddress=akka://application@192.168.1.15:25520, sourceThread=application-akka.actor.internal-dispatcher-3, akkaSource=Cluster(akka://application), sourceActorSystem=application, akkaTimestamp=22:32:54.930UTC] Cluster Node [akka://application@192.168.1.15:25520] - No downing-provider-class configured, manual cluster downing required, see https://doc.akka.io/docs/akka/current/typed/cluster.html#downing [---]
[INFO ][2021-03-31 17:32:54,931][akka.cluster.Cluster][application-akka.actor.default-dispatcher-5][akkaAddress=akka://application@192.168.1.15:25520, sourceThread=application-akka.actor.internal-dispatcher-3, akkaSource=Cluster(akka://application), sourceActorSystem=application, akkaTimestamp=22:32:54.931UTC] Cluster Node [akka://application@192.168.1.15:25520] - No seed-nodes configured, manual cluster join required, see https://doc.akka.io/docs/akka/current/typed/cluster.html#joining [---]

Reproducible Test Case

import com.lightbend.lagom.scaladsl.client.{StandaloneLagomClientFactory, StaticServiceLocatorComponents}
import org.scalatest.matchers.should.Matchers
import org.scalatest.wordspec.AnyWordSpec
import org.scalatest.BeforeAndAfterAll
import play.api.libs.ws.ahc.AhcWSComponents

import java.net.URI

class Lagom3211Tests extends AnyWordSpec with Matchers with BeforeAndAfterAll {
  private val clientFactory = new StandaloneLagomClientFactory("client")
    with AhcWSComponents
    with StaticServiceLocatorComponents {
    override def staticServiceUri: URI = new URI("http://lagomframework.com")
  }

  override protected def afterAll(): Unit = clientFactory.stop()

  "client" should {
    "use 'local' provider" in {
      val provider = clientFactory.actorSystem.settings.config.getString("akka.actor.provider")
      provider shouldBe "local"
    }
  }
}

[octonato]

I think the core problem here is that I wanted to use the testkit without using Akka Cluster and there doesn’t seem to be an easy way to do that, at least without excluding Akka Cluster dependencies when including the testkit

I don’t think this is the case. You can have the cluster dependencies in the classpath and the testkit will make sure that its actor system will be configured to use the local provider.

What is happening here is that there is another unmanaged actor system that is being start by the StandaloneLagomClientFactory.

This is not something that I think we should ‘fix’ because the StandaloneLagomClientFactory wasn’t designed to be used in a Lagom application.

[octonato]

@solarmosaic-kflorence, this is not what I observed.

Please check this minimal hello-world I published here: https://github.com/octonato/minimal-lagom-without-cluster

Check the tests. It isn’t using cluster and the loaded config shows it is a local provider.

Please, verify if your loader is not loading any component that is requiring cluster. If the cluster component is included, it will bootstrap the cluster.