These are the slides from my talk at the CodeMash 2017 conferenece: http://www.codemash.org/session/creating-a-responsive-application-using-reactive-extensions/ Code examples are located here: https://github.com/tamirdresher/FromZeroToTheActorModel

1. 1
Tamir Dresher (@tamir_dresher)
Senior Software Architect
J
From Zero to the Actor Model
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2. 2
• Author of Rx.NET in Action (manning publications)
• Software architect, consultant and instructor
• Software Engineering Lecturer @ Ruppin Academic Center
@tamir_dresher
tamirdr@codevalue.net
http://www.TamirDresher.com.
About Me

3. Software Architecture is like Pasta
3By @benorama

4. Agenda
1. Actor Model
2. Semiconductors
3. Metrology Target Designer (MTD) by KLA-Tencor
4. Rearchitecting to Actor Model with Akka.NET
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5. The Actor Model (Hewitt et al. 1973)
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Alice
Mailbox
Bob
Sally
Mailbox
Mailbox
“the Actor model retained
more of what I thought
were the good features of
the object idea.”
Alan Kay
Object Orientation pioneer
and Smalltalk co-designer
Alice
Parent
Bob
Parent
Sally
Parent

6. The future platform (Juval Löwy)
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7. Actors in Akka.NET
public class CoordinatorActor : ReceiveActor
{
public CoordinatorActor()
{
Receive<StartSimulation>(start =>
{
//Initiate a new simulation
});
}
}
public class StartSimulation
{
public Guid ProjectId { get; set; }
}
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8. Demo
Echo Actor
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9. Location Transparency (kind of…)
Actors live inside an ActorSystem
Each Actor has a unique address
Local: akka://ActorSystem-A/user/A2
Remote: akka.tcp://ActorSystem-C@Machine-B:5678/user/C1
Machine A Machine B
ActorSystem A
A1
A2
ActorSystem B
B1
B2
ActorSystem C
C1
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10. Actor Model  Messaging  Decoupling
Message passing yields decoupling
Interesting messaging patterns are now available
Alice
Sally
Bob
Forwarding
Alice
Sally
Bob
Multiple Responses
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11. MTD Case Study
Metrology Target Design
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12. KLA-Tencor Corporation is a
leading supplier of process control
and yield management solutions
for the semiconductor and related
microelectronics industries
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13. How chip is born
UV Radiation
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14. Meaning of Overlay
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15. Metrology Target Design (MTD)
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16. MTD Original Architecture
Technology B Services
Technology A ServicesUI Clients
Stack
composer
Material
manager
Simulation
setup
DOE
generator
Geometry
Materials
Simulation
Results
HTTP requests
Notification hubSubscribe 
Notify
Notify
Distribution
Service
Cluster
Outgoing queue
per simulation
Incoming queue
per simulation
Simulation Coordinator
Technology A
Simulator
Technology B
Simulator
otify
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17. MTD Challenges
Long simulations
PauseResumeStop lifecycle
Simulation failures
Extendibility
New Technologies
Configurable simulation tasks
Scalability
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18. Actor Based Architecture - Hierarchy
/user
Simulation
Coordinator
Simulation
Queue
Simulation
Notifier
Technology A
Coordinator
Technology A
Simulation
Sub
Simulation 1
Sub
Simulation 2
Sub
Simulation 3
Technology B
Coordinator
Technology B
Simulation
Sub
Simulation 1
Sub
Simulation 2
Sub
Simulation 3
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19. Actor Based Architecture – Messages Flow
WebApi
Controller
Simulation
Coordinator
1.Start Simulation
Queue
2.AddNew
Simulation
Notifier
4. SimulationStatusChanged
3.SimulationStatusChanged
5.SimulationStatusChanged
[Technology]
Coordinator
[Technology]
Simualtion
(id=xxxx)
11.MarkStarted
12. SimulationStatusChanged
SignalR
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20. Statefulness and Behavior switching
Stateful is no longer a dirty word (kind of…)
The less calls you have for the persistence store the better the
performance will be
Durability is a must (state-awareness)
State goes hand-in-hand with supported behavior
Actors have the power to switch their behaviors at any point in time.
the actor becomes busy or the actor becomes connected.
Which messages to Receive, Deny, Postpone (Stashing)
State machine
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21. <configuration>
<configSections>
<section name="akka" type="Akka.Configuration.Hocon.AkkaConfigurationSection, Akka"/>
</configSections>
<akka>
<hocon>
<![CDATA[
akka {
actor {
provider = "Akka.Remote.RemoteActorRefProvider, Akka.Remote"
}
remote {
helios.tcp {
port = 8098
hostname = localhost
}
}
[[>
</hocon>
</akka>
</configuration>
Remoting and Location Transparancy
ActorSelection selection =
sys.ActorSelection("akka.tcp://ActorSystem-C@Machine-B:5678/user/C1");
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22. Routers
http://getakka.net/docs/working-with-actors/Routers
ConsistentHashing
akka.actor.deployment {
/workers {
router = round-robin-group
routees.paths = ["/user/workers/w1", "/user/workers/w2", "/user/workers/w3"]
}
}
Broadcast RoundRobin
var props = Props.Create<Worker>().WithRouter(FromConfig.Instance);
IActroRef actor = system.ActorOf(props, "workers");
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23. Routing to Remote Actors
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<hocon>
<![CDATA[
akka {
actor {
provider = "Akka.Remote.RemoteActorRefProvider, Akka.Remote"
deployment {
/Technologies {
router = broadcast-group
routees.paths = ["akka.tcp://TechnologyA@localhost:8091/user/coordinator"]
}
}
}
:
:
}
]]>
</hocon> IActroRef technologies =
_system.ActorOf(Props.Empty.WithRouter(FromConfig.Instance), "Technologies");

24. Final thoughts
Testing – easier sometimes, harder sometimes
Dependency injection – injecting ActorRefsActorSelections is not intuitive
Runtime contract vs. compile-time contract
Your messages are the contract
Messages versioning should be considered up-front
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25. Summary
1. Actor Model
2. Semi conductor
3. Metrology Target Designer (MTD) by KLA-Tencor
4. Rearchitecting to Actor Model with Akka.NET
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26. https://www.manning.com/books/
rx-dot-net-in-action
www.manning.com/books/
reactive-applications-with-akka-net
Discount code: ctwcodemash17
Thank You
Tamir Dresher (@tamir_dresher)
http://getakka.net/
https://github.com/akkadotnet/akka.net
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