This document discusses Akka.NET, a framework for building distributed, concurrent applications using the actor model. It explains that in the actor model, everything is an actor that can send and receive immutable messages asynchronously. Actors in Akka.NET are lightweight threads that handle messages concurrently without shared state. The document provides examples of how to define actors and send messages in Akka.NET. It argues that the actor model enables building highly concurrent, scalable and fault-tolerant applications more easily than traditional threading approaches.

1. Full-Stack, Message-Oriented
Programming With Akka.NET Actors
Andrew Skotzko
Co-founder, Petabridge
Contributor, Akka.NET
@askotzko

2. My Wish For You

3. Messaging

4. MESSAGE
ALL THE THINGS

5. Concurrency.
Why should we care?

6. 1973–2005

11. What the hell are you
talking about?

12. Concurrency
...time to embrace it.

13. Why is this hard?

14. Writing Multithreaded Code
→ Make classes/functions
→ Find places we can do multiple things at once
→ Queue work onto new thread / threadpool
→ Use synchronization mechanisms (protect shared
mem)
→ Finish work on one thread; consume on another

15. Shared State Programming Sucks
→ Synchronizing shared state = pit of doom
→ Coordinating work btw. threads
→ Debugging multi-threaded code...yay!
→ Third-party libraries
→ ...Writing great thread-safe code is hard.

16. Random?
1. .NET 4.0: TPL (2010)
2. .NET 4.5: async/await (2012)

17. There. must. be. a. better. way.

19. What is the actor model?

20. 1973

22. Everything is an actor.

23. Okay.. so what is an
actor?

24. 3 Core Abilities
1. Send messages
2. Create other actors
3. Change behavior

25. Messages

27. Sending a Message
myActorRef.Tell("this is my message");

28. Messages
→ Must be immutable
→ Processed serially

29. Create Other Actors

30. Akka.NET Actor Hierarchy

31. Change Behavior

33. Location Transparency

35. Actors Live at Unique Addresses

38. Which means...

41. Without
Rewriting Your Code

43. ReactiveManifesto.org

44. What is
Akka.NET?

47. This Is An Akka.NET Actor
public class FooActor : UntypedActor
{
public FooActor()
{
// message handling code goes here...
}
}

48. These Are Messages
// just POCOs
public class Hello {}
public class NewOrder {
public NewOrder (string name)
{
Username = name;
UserId = Guid.NewGuid ();
}
public Guid UserId { get; private set;}
public string Username {get; private set;}
}

51. Where can I use this?

52. → Analytics systems
→ Marketing automation
→ Multi-player games
→ Device / IoT tracking
→ Alerting & monitoring systems
→ Recommendation engines
→ Dynamic pricing
→ Scalable microservices
→ Reactive UI

53. Wait... How Can This Be
Massively Concurrent?

58. Message Buses & Actors

59. Akka.NET & NServiceBus

60. How Are They Different?

62. Default Durability

63. How Do They
Go Together?

64. Akka.NET is a great
consumer/producer
for NServiceBus

65. Shared Core Beliefs

66. async by
default

67. p2p mesh

68. Queued
Messages

69. Extensible

71. Messaging
Patterns

72. Pub-Sub

74. public class PubSubActor : ReceiveActor {
protected HashSet<IActorRef> Subscribers = new HashSet<IActorRef>();
public PubSubActor()
{
// add new subscriber
Receive<Subscribe>(subscribe => Subscribers.Add(subscribe.Subscriber));
// remove subscriber
Receive<Unsubscribe>(unsubscribe => Subscribers.Remove(unsubscribe.Subscriber));
// publish status to subscribers
Receive<JobStats>(stats =>
{
TotalStats = TotalStats.Merge(stats);
PublishStatus();
});
}
// push latest status into subscribers
private void PublishStatus()
{
foreach (var sub in Subscribers)
sub.Tell(RunningStatus);
}
}

75. What's Akka.NET Give
YOU?

76. Reactive Services
Speed!

77. Location Transparency

78. Intuitive code

79. Lower DB Contention

80. Efficient Use of Hardware

81. One Case Study
→ 85% reduction in code base
→ 60% reduction in hardware needed
→ "Code just lets us focus on the problem"

82. Benefits of Combination

83. Location transparency
+
Durability
+
Easy, thread-safe scale out

85. THANK YOU!
Email: andrew@petabridge.com
Twitterz:
@askotzko
@Petabridge