Usage of Reliable Actors in Azure Service FabricBy Alexander LayshaLead .NET Developer at ScienceSoft

Hmm... Actor Model? What is that?

"An actor is a computational entity that, in response to a message it receives, can do the following:• Send a finite number of

messages to other actors• Create a finite number of new

actors• Designate the behavior to be

used for the next message it receives"

Let's take a look at example!

Actor Model Characteristics•Communication via direct asynchronous messaging•State machines•Share nothing• Lock-free concurrency• Parallelism•Actors come in systems• Location transparency•Supervision

Azure Service Fabric Overview

Sigh... Reliable Actors = Actor Model?

"Azure Fabric Actors is an implementation of the actor model that borrows some ideas from Erlang and distributed objects systems, adds a layer of actor indirection, and exposes them in an integrated, programming model that leverages the Azure Service Fabric platform."

Reliable Actor Characteristics•Actors are just objects• Single-threaded execution• Turn-based access•Automatic GC•Automatic lifetime management• Transparent activation• Explicit asynchrony• Location transparency & Automatic Failover

[timer, reminder, proxy, client events, SF explorer,

VM processes, lifetime, concurrency]

What Reliable Actor types exist?•Stateless - state can be lost due to failovers•Stateful - state preserved across GC and failoversPrimary-Secondary replicationAuto/On Demand saveReadonly methodsBuilt-in providers:

- volatile state provider- durable state provider

Can we scale Reliable Actors?At the partition level• Ranged partitioning• Actor Id maps to Partition Id• No partition control

At the service name level

[stateful actors, readonly methods, partitioning]

Reliable Actors Communication•Request-Response pattern[Default Pattern]

• Fire-and-Forget pattern[Return Task.CompletedTask (.NET 4.6) + Timer + Internal stateful Queue]

• Pub-Sub pattern[Community Package: https://www.nuget.org/packages/ServiceFabric.PubSubActors]

Want to contact me?https://www.linkedin.com/in/layshaalexander

https://www.facebook.com/alexander.laysha

@layshaalexander

layshaalex@gmail.com