patriknw’s gists

patriknw / ActorSelectionSample.scala

Created July 8, 2013 06:51

ActorSelection spotlight

	val selection = context.actorSelection(
	"akka.tcp://[email protected]:2552/user/world")
	selection ! "hello"

patriknw / LoggingMailbox.scala

Last active January 5, 2023 08:12

Logs the mailbox size when exceeding the configured limit. Implemented in Scala and Java. Copy one of them to your project and define the configuration. This code is licensed under the Apache 2 license.

	/**
	* Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
	*/
	package akka.contrib.mailbox

	import scala.concurrent.duration._
	import java.util.concurrent.atomic.AtomicInteger
	import java.util.concurrent.atomic.AtomicLong
	import com.typesafe.config.Config
	import akka.actor.{ ActorContext, ActorRef, ActorSystem, ExtendedActorSystem }

patriknw / application.conf

Created July 5, 2013 08:10

Spotlight min members of role

	akka.cluster.role {
	frontend.min-nr-of-members = 1
	backend.min-nr-of-members = 2
	}

patriknw / Client.scala

Created July 5, 2013 07:03

ClusterClient spotlight

	// on the client
	val initialContacts = Set(
	system.actorSelection("akka.tcp://Other@host1:2552/user/receptionist"),
	system.actorSelection("akka.tcp://Other@host2:2552/user/receptionist"))
	val c = system.actorOf(ClusterClient.props(initialContacts))

	c ! ClusterClient.Send("/user/serviceA", "hello", localAffinity = true)

patriknw / Publisher.scala

Created July 5, 2013 06:33

Pub/Sub Spotlight

	class Publisher extends Actor {
	import DistributedPubSubMediator.Publish
	// activate the extension
	val mediator = DistributedPubSubExtension(context.system).mediator

	def receive = {
	case in: String ⇒
	val out = in.toUpperCase
	mediator ! Publish("content", out)
	}

patriknw / RegisterOnMemberUp.scala

Created July 4, 2013 08:13

Spotlight registerOnMemberUp

	Cluster(system) registerOnMemberUp {
	system.actorOf(Props(classOf[FactorialFrontend], upToN, true),
	name = "factorialFrontend")
	}

patriknw / MetricsMailbox.scala

Created June 15, 2013 03:39

Sample of mailbox extension that counts messages in queue

	package akka.contrib.mailbox

	import java.util.concurrent.ConcurrentHashMap
	import java.util.concurrent.atomic.AtomicInteger
	import com.typesafe.config.Config
	import akka.actor.{ ActorContext, ActorRef, ActorSystem, ExtendedActorSystem, Extension, ExtensionId, ExtensionIdProvider }
	import akka.dispatch.{ Envelope, MailboxType, MessageQueue, UnboundedMailbox, UnboundedQueueBasedMessageQueue }

	object MetricsMailboxExtension extends ExtensionId[MetricsMailboxExtension] with ExtensionIdProvider {
	def lookup = this

patriknw / MemberAge.scala

Last active December 18, 2015 11:39

Code for 2.2 spotlight: Cluster Member Age

	// sort by age, oldest first
	val ageOrdering = Ordering.fromLessThan[Member] { (a, b) =>
	a.isOlderThan(b)
	}
	var membersByAge: SortedSet[Member] = SortedSet.empty(ageOrdering)

	def receive = {
	case state: CurrentClusterState =>
	membersByAge = SortedSet.empty(ageOrdering) ++ state.members
	}

patriknw / Backend.scala

Created June 10, 2013 18:23

Code for 2.2. Spotlight: Cluster Node Roles

	class TransformationBackend extends Actor {
	val cluster = Cluster(context.system)

	override def preStart(): Unit =
	cluster.subscribe(self, classOf[MemberUp])
	override def postStop(): Unit =
	cluster.unsubscribe(self)

	def receive = {
	case state: CurrentClusterState ⇒

patriknw / ClusterRegistrySpec.scala

Last active May 28, 2019 10:58

Example of how to implement a simple cluster wide actor registry.

	/**
	* Copyright (C) 2009-2013 Typesafe Inc. <http://www.typesafe.com>
	*/

	package akka.contrib.pattern

	import language.postfixOps
	import scala.concurrent.duration._
	import com.typesafe.config.ConfigFactory
	import akka.actor.Actor

Patrik Nordwall patriknw