Samples from "Actor-based Concurrency with F# and Akka.NET" http://bit.ly/FSharpAkkaNET

01_SayHello.fsx

#time "on"
#load "Bootstrap.fsx"

open System
open Akka.Actor
open Akka.Configuration
open Akka.FSharp
open Akka.TestKit

// #Using Actor
// Actors are one of Akka's concurrent models.
// An Actor is a like a thread instance with a mailbox. 
// It can be created with system.ActorOf: use receive to get a message, and <! to send a message.
// This example is an EchoServer which can receive messages then print them.

let system = ActorSystem.Create("FSharp")

type EchoServer =
    inherit Actor

    override x.OnReceive message =
        match message with
        | :? string as msg -> printfn "Hello %s" msg
        | _ ->  failwith "unknown message"

let echoServer = system.ActorOf(Props(typedefof<EchoServer>, Array.empty))

echoServer <! "F#!"

system.Shutdown()

02_SimplifySayHello.fsx

#time "on"
#load "Bootstrap.fsx"

open System
open Akka.Actor
open Akka.Configuration
open Akka.FSharp
open Akka.TestKit

// #Simplify Actor
// There is a simpler way to define an Actor

let system = ActorSystem.Create("FSharp")

let echoServer = 
    spawn system "EchoServer"
    <| fun mailbox ->
            actor {
                let! message = mailbox.Receive()
                match box message with
                | :? string as msg -> printfn "Hello %s" msg
                | _ ->  failwith "unknown message"
            } 

echoServer <! "F#!"

system.Shutdown()

03_ActorsAndThreads.fsx

#time "on"
#load "Bootstrap.fsx"

open System
open Akka.Actor
open Akka.Configuration
open Akka.FSharp
open Akka.TestKit

// #Actor Implementation
// An Actor is more lightweight than a thread. Millions of actors can be generated in Akka,
// the secret is that an Actor can reuse a thread.
//
// The mapping relationship between an Actor and a Thread is decided by a Dispatcher.
// 
// This example creates 10 Actors, and prints its thread name when invoked.
//
// You will find there is no fixed mapping relationship between Actors and Threads. 
// An Actor can use many threads. And a thread can be used by many Actors.

let system = ActorSystem.Create("FSharp")

type EchoServer(name) =
    inherit Actor()

    override x.OnReceive message =
        let tid = Threading.Thread.CurrentThread.ManagedThreadId
        match message with
        | :? string as msg -> printfn "Hello %s from %s at #%d thread" msg name tid
        | _ ->  failwith "unknown message"

let echoServers = 
    [1 .. 10]
    |> List.map(fun id ->   let properties = [| string(id) :> obj |]
                            system.ActorOf(Props(typedefof<EchoServer>, properties)))

let rand = Random(1234)

for id in [1 .. 10] do
    (rand.Next() % 10) |> List.nth echoServers <! sprintf "F# request %d!" id

system.Shutdown()

04_SynchronizedAsk.fsx

#time "on"
#load "Bootstrap.fsx"

open System
open Akka.Actor
open Akka.Configuration
open Akka.FSharp
open Akka.TestKit

// #Synchronized Return
// Actors are very suitable for long-running operations, like getting resources over a network.
//
// This example creates a Task with the ask function.
//
// In the actor we use 'sender <!' to return the value.
//
// #Asynchronous Return
// Asynchronous operations can provide better performance. 
// A Task in F# is very powerful, it can execute asynchronously.
// It can also set a in milliseconds to wait for the result of the computation 
// before raising a `TimeoutException`.

let versionUrl = @"https://raw.githubusercontent.com/akkadotnet/akka.net/dev/src/SharedAssemblyInfo.cs"

let system = ActorSystem.Create("FSharp")

let fromUrl (url:string) =
    use client = new System.Net.WebClient()
    let response = client.DownloadString(url)
    response

let echoServer = 
    spawn system "EchoServer"
    <| fun mailbox ->
        let rec loop() =
            actor {
                let! message = mailbox.Receive()
                let sender = mailbox.Sender()
                match box message with
                | :? string as url -> 
                    let response = fromUrl url
                    printfn "actor: done!"
                    sender <! response
                    return! loop()
                | _ ->  failwith "unknown message"
            } 
        loop()

for timeout in [10; 100; 250; 2500] do
    try
        let task = (echoServer <? versionUrl)

        let response = Async.RunSynchronously (task, timeout)
        let responseLength = string(response) |> String.length

        printfn "response: result has %d bytes" responseLength
    with :? TimeoutException ->
        printfn "ask: timeout!"

system.Shutdown()

05_RemoteActor.fsx

#time "on"
#load "Bootstrap.fsx"

open System
open Akka.Actor
open Akka.Configuration
open Akka.FSharp
open Akka.TestKit

// #Remote Actor
// Actor is not only a concurrency model, it can also be used for distributed computing.
// This example builds an EchoServer using an Actor.
// Then it creates a client to access the Akka URL.
// The usage is the same as with a normal Actor.

let configuration = 
    ConfigurationFactory.ParseString(
        @"akka {
            log-config-on-start : on
            stdout-loglevel : DEBUG
            loglevel : ERROR
            actor {
                provider = ""Akka.Remote.RemoteActorRefProvider, Akka.Remote""
                debug : {
                    receive : on
                    autoreceive : on
                    lifecycle : on
                    event-stream : on
                    unhandled : on
                }
            }

            remote {
                helios.tcp {
                    port = 8777
                    hostname = localhost
                }
            }
        }")

let system = ActorSystem.Create("RemoteFSharp", configuration)

let echoServer = 
    spawn system "EchoServer"
    <| fun mailbox ->
        let rec loop() =
            actor {
                let! message = mailbox.Receive()
                let sender = mailbox.Sender()
                match box message with
                | :? string -> 
                        printfn "super!"
                        sender <! sprintf "Hello %s remote" message
                        return! loop()
                | _ ->  failwith "unknown message"
            } 
        loop()

let echoClient = system.ActorSelection(
                            "akka.tcp://RemoteFSharp@localhost:8777/user/EchoServer")

let task = echoClient <? "F#!"

let response = Async.RunSynchronously (task, 1000)

printfn "Reply from remote %s" (string(response))

system.Shutdown()

06_EventStream.fsx

#time "on"
#load "Bootstrap.fsx"

open System
open Akka.Actor
open Akka.Configuration
open Akka.FSharp
open Akka.TestKit

// #Event Bus
// Originally conceived as a way to send messages to groups of actors, the EventBus has been generalized to Event Stream
// #Event Stream
// The event stream is the main event bus of each actor system: it is used for carrying log messages and Dead Letters and may be used by the user code for other purposes as well. It uses Subchannel Classification which enables registering to related sets of channels

let system = ActorSystem.Create("FSharp")

let echoServer = 
    spawn system "EchoServer"
    <| fun mailbox ->
        let rec loop() =
            actor {
                let! message = mailbox.Receive()
                match box message with
                | :? string -> 
                    printfn "Echo '%s'" message
                    return! loop()
                | _ ->  failwith "unknown message"
            } 
        loop()

let eventStream = system.EventStream

eventStream.Subscribe(echoServer, typedefof<string>)

eventStream.Publish("Anybody home?")
eventStream.Publish("Knock knock")

system.Shutdown()

07_TypedMessages.fsx

#time "on"
#load "Bootstrap.fsx"

open System
open Akka.Actor
open Akka.Configuration
open Akka.FSharp
open Akka.TestKit

// # Discriminated unions as messages
// Instead of passing primitive type, let's use discriminated union

type ActorMsg =
    | Hello of string
    | Hi

let system = ActorSystem.Create("FSharp")

let echoServer = 
    spawn system "EchoServer"
    <| fun mailbox ->
        let rec replyUa() =
            actor {
                let! message = mailbox.Receive()
                match message with
                | Hello name -> printfn "Привіт %s" name
                | Hi -> printfn "Привіт!"

                return! replySw()
            } 
        and replySw() =
            actor {
                let! message = mailbox.Receive()
                match message with
                | Hello name -> printfn "Hallå %s" name
                | Hi -> printfn "Hallå!"

                return! replyUa()
            } 

        replyUa()

echoServer <! Hello "Kyiv F# group!"
echoServer <! Hello "Akka.NET team!"

system.Shutdown()

Bootstrap.fsx

#time "on"

#I @"..\packages\Akka.0.7.0\lib\net45"
#I @"..\packages\Akka.FSharp.0.7.0\lib\net45"
#I @"..\packages\Akka.Remote.0.7.0\lib\net45"
#I @"..\packages\Akka.TestKit.0.7.0\lib\net45"
#I @"..\packages\FsPickler.0.9.11\lib\net45"
#I @"..\packages\FSPowerPack.Core.Community.3.0.0.0\Lib\Net40"
#I @"..\packages\FSPowerPack.Linq.Community.3.0.0.0\Lib\Net40"
#I @"..\packages\Newtonsoft.Json.6.0.1\lib\net45"
#I @"..\packages\Google.ProtocolBuffers.2.4.1.521\lib\net40"
#I @"..\packages\Helios.1.3.5.0\lib\net45"

#r "Akka.dll"
#r "Akka.FSharp.dll"
#r "Akka.Remote.dll"
#r "Akka.TestKit.dll"

commansd.sh

sudo mkdir -p /mnt/samples && sudo mount -r -t vboxsf samples /mnt/samples

cp /mnt/samples/Dockerfile . && cp -r /mnt/samples/bin .

docker build -t samples .

docker run -i samples

docker run -it samples bash

docker images

Dockerfile

FROM mono:latest

MAINTAINER Akim Boyko "akim dot boyko at gmail.com" version: 0.1

ENV AKKADIR /akka
RUN mkdir -p $AKKADIR

WORKDIR $AKKADIR
RUN mozroots --import --sync

ADD bin/Debug $AKKADIR 
CMD [ "mono",  "./Sample.exe" ]