javaone: a tour of (advanced) akka features in 60 minutes [con1706]

A Tour of (Advanced) Akka Features in 60 Minutes [CON1706]Johan Janssen, Info Support@johanjanssen42

Content

▪ Why Akka?▪ Local actor▪ Remote actor▪ Scheduling▪ Cluster▪ Routing▪ Cluster singleton

▪ Sharding▪ Persistence▪ Akka HTTP▪ Finite State Machines▪ Conclusion▪ Questions

Why Akka?

▪ Concurrent▪ Scalable▪ Fault tolerant

▪ More natural programming experience when connecting to other systems

▪ Easy to use?

Disclai

Local actor

Actor on JVM 1

Local actor

Coordinator Actor

Hello conferenc

Local actor

Coordinator Actor

println("Hello conference")

class Worker extends Actor { def receive = { case x => println(x) }}

val system = ActorSystem("ExampleActorSystem")

val workerActorRef = system.actorOf(Props[Worker])workerActorRef ! "Hello conference"

Remote actor

Actor on JVM 1

Actor on JVM 2

val workerActorRef = system.actorOf(Props[Worker])workerActorRef ! "Hello conference"

val workerActorRef = context.actorSelection("akka.tcp://

ExampleActorSystem@127.0.0.1:9005/user/workerActor")

workerActorRef ! "Hello conference"

akka { actor { provider =

"akka.remote.RemoteActorRefProvider" } remote { enabled-transports =

["akka.remote.netty.tcp"] netty.tcp { hostname = "127.0.0.1" port = 9002

Remote actor

Coordinator actor

Worker actor

StartMessage

Hello conferenc

Remote actor

Coordinator actor

Worker actor

WorkerMessage

Greetings from the coordinator:

Hello Conference

Remote actor

Coordinator actor

Worker actor

WorkerResponseMessage

Item processed successfully

Scheduling

Scheduled once after 1 second

Scheduled every 5 seconds

system.scheduler.scheduleOnce(1 seconds, scheduleReceiveActor, Tick)

system.scheduler.schedule(0 seconds, 5 seconds, scheduleReceiveActor, Tock)

Scheduling

▪ Does not work for fixed point in time like 17:00– Use Quartz

Cluster

ActorSystem on JVM

Seed nodes

▪ Contact points for automatically joining a cluster

akka { cluster { seed-nodes = [ "akka.tcp://ClusterNode@127.0.0.1:2551", "akka.tcp://ClusterNode@127.0.0.1:2552" ] }}

Cluster Worker Node

Port 2551

Association failed with [akka.tcp://ClusterSystem@127.0.0.1:2552

Cluster Worker Node

Port 2551

Worker Node

Port 2552

Member Up with IP: 127.0.0.1 and port: 2551Member Up with IP: 127.0.0.1 and port: 2552

Cluster Worker Node

Port 2551

Worker Node

Port 2552

Member Up with IP: 127.0.0.1 and port: 2550

CoordinatorNode

Port 2550

Cluster Worker Node

Port 2551

Worker Node

Port 2552

CoordinatorNode

Port 2550

RegisterWorker

Cluster Worker Node

Port 2551

Worker Node

Port 2552

CoordinatorNode

Port 2550

Worker registered with IP: 127.0.0.1 and port: 2551Worker registered with IP: 127.0.0.1 and port: 2552

Routing

Actor on JVM 1

Actor on JVM 3

Actor on JVM 4

Actor on JVM 2

Loadbalancer

akka { actor { provider = "akka.cluster.ClusterActorRefProvider"

deployment { /coordinator/router { router = round-robin-pool nr-of-instances = 10 routees.paths = ["/user/emptystringactor"] cluster { enabled = on allow-local-routees = off } } } }}

Routing

CoordinatorActor

on JVM 1

EmptyString Actor on JVM 3

EmptyString Actor on JVM 2""

Routing

CoordinatorActor

on JVM 1

HashMap[hostname, counter]

Routing

CoordinatorActor

on JVM 1

Routing

CoordinatorActor

on JVM 1

Cluster singleton

▪ Only one instance of the actor in the cluster▪ (Re)created on the oldest node▪ Can be used for instance for scheduling/caching

Cluster singleton

Actor on JVM 1

Other actors on

Singleton actor and

other actors on

Cluster singleton

Coordinator

Cluster singleton

Coordinator

Cluster singleton

Coordinator

Cluster singleton

Coordinator

Cluster singleton

Coordinator

EmptyString Actor on JVM 2Crash

Cluster singleton

Coordinator

Cluster singleton

Coordinator

Cluster singleton

Coordinator

Cluster singleton

Coordinator

Sharding

▪ Dividing a set of actors over a cluster▪ Actors will be divided into groups called shards▪ It will divide based on a logical identifier

Sharding

Actor on JVM 1

oddShard on

evenShard on

JVM 20, 2, 4, 6, 8

1, 3, 5, 7, 9

Persistence

▪ Store actor information▪ Recover after crash▪ Possibility to take snapshots

Example without persistence

Java Cobol

CobolJava

ActorCrash

Restart

Persistence

PersistentActor

Command

Journal

PersistenceJournal

CobolEvent

PersistentActor

PersistenceJournal

PersistentActor CobolEvent

Persistence

Journal

CobolEvent

PersistentActor

Persistence

Journal

CobolEvent

PersistentActor

JavaEven

Persistence

CobolJava

Journal

CobolEvent

PersistentActorCrash

Restart JavaEven

PersistenceJournal

CobolEvent

PersistentActor

JavaEven

Persistence

CobolJava

Journal

CobolEvent

PersistentActor

JavaEven

Persistence

CobolJavaScala

Journal

CobolEvent

PersistentActor

JavaEven

Snapshots

JournalPersistentActorSnapshot

State until

Event C++

C++Cobol

Snapshots

store State until

Event C++ C++

Snapshots

storeState until

Event C++ C++

Snapshots

storeState until

Event C++ Java

C++Cobol

Snapshots

storeState until

Event C++

Restart

C++Cobol

Snapshots

storeState until

Event C++ C++

Snapshots

CobolC++

storeState until

Event C++ C++

Snapshots

CobolC++Java

storeState until

Event C++ C++

Snapshots

CobolC++JavaScala

storeState until

Event C++ C++

Akka HTTP

Actor on JVM 1

Actor on JVM 2

Finite State Machine

▪ State▪ Event

Finite State Machines (FSM)

InprogressProject

CrappyProject

NewProject

Progress, iterationProgress, iteration

Progress, iteration

NoProgressProgress, 2

InprogressProject

CrappyProject

NewProject

Work harderIteration: 0

InprogressProject

CrappyProject

NewProject

Good job!

Iteration: 0

InprogressProject

CrappyProject

NewProject

Wrong direction

Iteration: 0

InprogressProject

CrappyProject

NewProject

Use Akka

Iteration: 0

InprogressProject

CrappyProject

NewProject

Good job!

Iteration: 1

InprogressProject

CrappyProject

NewProject

Wrong direction

Iteration: 1

InprogressProject

CrappyProject

NewProject

Use Akka

Iteration: 1

InprogressProject

CrappyProject

NewProject Get another job!

Iteration: 2

Conclusion

▪ Akka can be used with Scala or Java▪ There is even a .NET version of Akka▪ Akka is really powerful▪ Akka is quite easy to use▪ Some features are still experimental

Questions

Johan Janssen @johanjanssen42GitHub: https://github.com/johanjanssen/Akka-examples

javaone: a tour of (advanced) akka features in 60 minutes [con1706]

Technology

linkedin javaone

javaone 2007 - kjartan aanestad (objectware)1 javaone 2007

javaone 2003, san francisco 10.-13.6.2003 java.sun/javaone

sachi akka

javaone 2014

akka business unit germany - akka-technologies.com · akka...

real world akka actor recipes javaone 2013

javaone ts4693 v2

a tour of (advanced) akka features in 40 minutes

akka frukostseminarium

akka documentation · 2019-03-28 · akka documentation,...

akka 101 - durtchrt.github.io · akka actor actorref,...

datafx - javaone 2013

spring me javaone

akka: Введение

javaone summary

akka 2.2.0

akka stream

nuxeo javaone 2007

2007 javaone conference