A BRIEF INTRO TO MICROSOFT ORLEANSURI GOLDSTEIN / @URIG / HTTP://URIG.IO/

Alt.Net Israel

MICROSOFT ORLEANS

A framework for building distributed applications

•Made by Microsoft Research• Free and Open Source (MIT License)• Production Ready (Halo 4, Azure Service Fabric)

TWO GOALS

• Simple Distributed Programming

• Scalable by Default

• The Actor Model of Programming

ACTOR PROGRAMMING MODEL

• An Actor is “Unit of Computation” that upon receiving a Message:• Can send Messages to other Actors.• Can Create new Actors.• Designates the behavior to be used

for the next Message it receives.

State + Logic

ACTORS

• Encapsulate State and Logic• Run Concurrently• Communicate AsynchronouslyVia Message Passing• Addressable (Addresses can go in Messages)

SOMEWHAT CONTRIVED EXAMPLE

Uri

WhatsAppGroup

Shay

Boris

“Hello”

Uri: “Hello”Uri: “Hello”

“Wanna hear a secret?”

ORLEANS: GRAIN = VIRTUAL ACTOR

• Grains are C# Classes• Derived from GrainBase• Implement an Interface (ex: IUser or IConversation)

• Messages Passing = Calling Interface Methods• Ex: SendMessageToMembers(string text)

• Can be Stateless or Stateful

GRAIN EXAMPLE

public class ConversationGrain : Grain, IConversation{ // State private string AdminId; private IEnumberable<IUserGrain> Members; // Receive messages public async Task SendMessageToAdmin(string message) { // Send a message var admin = GrainFactory.GetGrain<IUserGrain>(AdminId); await admin.GetMessage(message); } //...}

GRAIN LIFECYCLE

• Managed by Silos and Clusters• Grains always exist• Can be Active / Inactive• Garbage Collected• Single instance if Statefull• Many instances if Stateless Orleans Cluster

Silo Silo Silo

GRAIN COMMUNICATION

• Messages = Method Calls

• Method Calls are Queued

• Grains are Single Threaded

• Addresses are C# References

• Location is Transparent

var grain = GrainFactory .GetGrain<IUserGrain>("Uri");

await grain.SayHello("World");

GRAIN PERSISTENCE

Choose:• No State (Think functional!)• Transient State: In Memory • Persistent State:

• Azure Table Storage• Shared ATS• Roll your own

• Configurable per Grain• Implicitly Read upon

Activation• Explicitly Written by Grain

Logic• Storage Provider in charge

of Serialization

DEPLOYMENT

• Silos are self hosting• So Clusters run anywhere Windows can Ex: Azure Cloud Services (Worker Roles)• Server to Server over TCP• Entry point is GrainClient

• Message Passing (Method Call), or• Observer Pattren (Pub/Sub)

OrleansClient

OrleansCluster

Interfaces

SAMPLE ARCHITECTURE

Orleans Cluster(Azure Cloud Service)

Silo Silo SiloAzure Table

Storage

Shard

asp.net Web API

Shard

Shard

Request

Request

SAMPLE ARCHITECTURE

Orleans Cluster(Azure Cloud Service)

Silo Silo SiloAzure Table

Storage

Shard

asp.net Web API

Shard

Shard

Request

Request

THANK YOU

• Orleans websitehttp://dotnet.github.io/orleans• Orleans on GitHub

https://github.com/dotnet/orleans• 30 min intro from Carl

Hewitt who invented the Actor Modelhttp://tinyurl.com/CarlHewitt

•Ask me anything:Uri Goldsteintwitter.com/urighttp://urig.io/