Actors入門

先決條件

• .Net Core SDK 3.0

• Dapr CLI

• Dapr DotNet SDK

概述

本文檔描述如何在客戶端應用程序上創建Actor（MyActor）并調用其方法.

MyActor --- MyActor.Interfaces|+- MyActorService|+- MyActorClient

• 接口項目（\MyActor\MyActor.Interfaces）。此項目包含參與者的接口定義。Actor接口可以在任何名稱的項目中定義。接口定義了actor實現和調用actor的客戶機共享的actor契約。因為客戶機項目可能依賴于它，所以通常在與actor實現分離的程序集中定義它是有意義的.

• actor服務項目（\MyActor\MyActor service）。這個項目實現了ASP.Net核心web服務，該服務將承載參與者。它包含actor MyActor.cs的實現。actor實現是從基類型actor派生并實現MyActor.interfaces項目中定義的接口的類。actor類還必須實現一個構造函數，該構造函數接受ActorService實例和ActorId，并將它們傳遞給基本actor類.

• actor客戶端項目（\MyActor\MyActor client）此項目包含actor客戶端的實現，該客戶端調用actor接口中定義的MyActor方法.

第1步 -?創建Actor接口

Actor接口定義Actor實現和調用Actor的客戶機共享的Actor契約.

Actor接口定義如下:

• Actor接口必須繼承?Dapr.Actors.IActor?接口

• Actor方法的返回類型必須是Task或Task<object>

• Actor方法最多可以有一個參數

創建項目和添加依賴

# Create Actor Interfaces dotnet new classlib -o MyActor.Interfacescd MyActor.Interfaces# Add Dapr.Actors nuget package dotnet add package Dapr.Actors

升級項目到 .NET Core 3.0

更新csproj文件中的netcore到 .NET Core 3.0

<Project Sdk="Microsoft.NET.Sdk"><PropertyGroup><TargetFramework>netcoreapp3.0</TargetFramework></PropertyGroup><ItemGroup><PackageReference Include="Dapr.Actors" Version="0.1.0-preview01" /></ItemGroup> </Project>

實現 IMyActor?接口

定義 IMyActor?接口和 MyData?數據對象.

using Dapr.Actors; using System.Threading.Tasks;namespace MyActor.Interfaces {public interface IMyActor : IActor{Task<string> SetDataAsync(MyData data);Task<MyData> GetDataAsync();Task RegisterReminder();Task UnregisterReminder();Task RegisterTimer();Task UnregisterTimer();}public class MyData{public string PropertyA { get; set; }public string PropertyB { get; set; }public override string ToString(){var propAValue = this.PropertyA == null ? "null" : this.PropertyA;var propBValue = this.PropertyB == null ? "null" : this.PropertyB;return $"PropertyA: {propAValue}, PropertyB: {propBValue}";}} }

第2步 -?創建Actor服務

Dapr使用ASP.NET web服務托管Actor服務.?本節將實現?IMyActor?接口以及注冊Actor到Dapr運行時.

創建項目及添加依賴

# Create ASP.Net Web service to host Dapr actor dotnet new webapi -o MyActorServicecd MyActorService# Add Dapr.Actors nuget package dotnet add package Dapr.Actors# Add Dapr.Actors.AspNetCore nuget package dotnet add package Dapr.Actors.AspNetCore# Add Actor Interface reference dotnet add reference ../MyActor.Interfaces/MyActor.Interfaces.csproj

添加Actor實現

實現IMyActor接口并從Dapr.Actors.Actor類派生。下面的示例還演示了如何使用Actor提醒。對于Actor來說，使用提醒，它必須來源于IRemindable。如果不打算使用提醒功能，可以跳過實現下面代碼中顯示的IRemindable和提醒特定方法.

using Dapr.Actors; using Dapr.Actors.Runtime; using MyActor.Interfaces; using System; using System.Threading.Tasks;namespace MyActorService {internal class MyActor : Actor, IMyActor, IRemindable{/// <summary>/// Initializes a new instance of MyActor/// </summary>/// <param name="actorService">The Dapr.Actors.Runtime.ActorService that will host this actor instance.</param>/// <param name="actorId">The Dapr.Actors.ActorId for this actor instance.</param>public MyActor(ActorService actorService, ActorId actorId): base(actorService, actorId){}/// <summary>/// This method is called whenever an actor is activated./// An actor is activated the first time any of its methods are invoked./// </summary>protected override Task OnActivateAsync(){// Provides opportunity to perform some optional setup.Console.WriteLine($"Activating actor id: {this.Id}");return Task.CompletedTask;}/// <summary>/// This method is called whenever an actor is deactivated after a period of inactivity./// </summary>protected override Task OnDeactivateAsync(){// Provides Opporunity to perform optional cleanup.Console.WriteLine($"Deactivating actor id: {this.Id}");return Task.CompletedTask;}/// <summary>/// Set MyData into actor's private state store/// </summary>/// <param name="data">the user-defined MyData which will be stored into state store as "my_data" state</param>public async Task<string> SetDataAsync(MyData data){// Data is saved to configured state store implicitly after each method execution by Actor's runtime.// Data can also be saved explicitly by calling this.StateManager.SaveStateAsync();// State to be saved must be DataContract serialziable.await this.StateManager.SetStateAsync<MyData>("my_data", // state namedata); // data saved for the named state "my_data"return "Success";}/// <summary>/// Get MyData from actor's private state store/// </summary>/// <return>the user-defined MyData which is stored into state store as "my_data" state</return>public Task<MyData> GetDataAsync(){// Gets state from the state store.return this.StateManager.GetStateAsync<MyData>("my_data");}/// <summary>/// Register MyReminder reminder with the actor/// </summary>public async Task RegisterReminder(){await this.RegisterReminderAsync("MyReminder", // The name of the remindernull, // User state passed to IRemindable.ReceiveReminderAsync()TimeSpan.FromSeconds(5), // Time to delay before invoking the reminder for the first timeTimeSpan.FromSeconds(5)); // Time interval between reminder invocations after the first invocation}/// <summary>/// Unregister MyReminder reminder with the actor/// </summary>public Task UnregisterReminder(){Console.WriteLine("Unregistering MyReminder...");return this.UnregisterReminderAsync("MyReminder");}// <summary>// Implement IRemindeable.ReceiveReminderAsync() which is call back invoked when an actor reminder is triggered.// </summary>public Task ReceiveReminderAsync(string reminderName, byte[] state, TimeSpan dueTime, TimeSpan period){Console.WriteLine("ReceiveReminderAsync is called!");return Task.CompletedTask;}/// <summary>/// Register MyTimer timer with the actor/// </summary>public Task RegisterTimer(){return this.RegisterTimerAsync("MyTimer", // The name of the timerthis.OnTimerCallBack, // Timer callbacknull, // User state passed to OnTimerCallback()TimeSpan.FromSeconds(5), // Time to delay before the async callback is first invokedTimeSpan.FromSeconds(5)); // Time interval between invocations of the async callback}/// <summary>/// Unregister MyTimer timer with the actor/// </summary>public Task UnregisterTimer(){Console.WriteLine("Unregistering MyTimer...");return this.UnregisterTimerAsync("MyTimer");}/// <summary>/// Timer callback once timer is expired/// </summary>private Task OnTimerCallBack(object data){Console.WriteLine("OnTimerCallBack is called!");return Task.CompletedTask;}} }

使用顯式actor類型名

默認情況下，客戶端看到的actor的“類型”是從actor實現類的名稱派生的。如果需要，可以通過將actor attribute屬性附加到actor實現類來指定顯式類型名.

[Actor(TypeName = "MyCustomActorTypeName")] internal class MyActor : Actor, IMyActor {// ... }

注冊 Actor?到 Dapr?運行時

將?MyActor?注冊到 actor?runtime并設置本地主機端口(https://localhost:3000) , Dapr runtime可以通過該端口調用actor.

private const int AppChannelHttpPort = 3000;public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>WebHost.CreateDefaultBuilder(args).UseStartup<Startup>().UseActors(actorRuntime =>{// Register MyActor actor typeactorRuntime.RegisterActor<MyActor>();}).UseUrls($"http://localhost:{AppChannelHttpPort}/");

更新Startup.cs

public class Startup{...public void ConfigureServices(IServiceCollection services){services.AddRouting();}public void Configure(IApplicationBuilder app, IWebHostEnvironment env){if (env.IsDevelopment()){app.UseDeveloperExceptionPage();}else{app.UseHsts();}}}

第3步 -?添加客戶端

創建一個簡單的控制臺應用程序來調用actor服務。Dapr SDK提供Actor代理客戶端來調用Actor接口中定義的Actor方法.

創建項目并添加依賴

# Create Actor's Client dotnet new console -o MyActorClientcd MyActorClient# Add Dapr.Actors nuget package dotnet add package Dapr.Actors# Add Actor Interface reference dotnet add reference ../MyActor.Interfaces/MyActor.Interfaces.csproj

使用Actor遠程服務調用Actor方法

我們建議使用本地代理到actor實例，因為ActorProxy.Create<IMyActor>（actorID，actorType）返回強類型actor實例來設置遠程過程調用.

namespace MyActorClient {using Dapr.Actors;using Dapr.Actors.Client;using MyActor.Interfaces;using System;using System.Threading.Tasks;...static async Task InvokeActorMethodWithRemotingAsync(){var actorType = "MyActor"; // Registered Actor Type in Actor Servicevar actorID = new ActorId("1");// Create the local proxy by using the same interface that the service implements// By using this proxy, you can call strongly typed methods on the interface using Remoting.var proxy = ActorProxy.Create<IMyActor>(actorID, actorType);var response = await proxy.SetDataAsync(new MyData(){PropertyA = "ValueA",PropertyB = "ValueB",});Console.WriteLine(response);var savedData = await proxy.GetDataAsync();Console.WriteLine(savedData);}... }

非遠程方式調用 Actor?方法

如果Actor方法最多接受一個參數，則可以調用Actor方法而無需遠程處理（直接通過http或使用ActorProxy中提供的helper方法）。Actor運行時將從客戶端反序列化傳入的請求體，并將其用作方法參數來調用Actor方法。當進行非遠程處理調用時，Actor方法參數和返回類型被序列化，反序列化為JSON.

ActorProxy.Create(actorID, actorType)?返回?ActorProxy?實例并允許使用原始http客戶端調用IMyActor中定義的方法.

namespace MyActorClient {using Dapr.Actors;using Dapr.Actors.Client;using MyActor.Interfaces;using System;using System.Threading.Tasks;...static async Task InvokeActorMethodWithoutRemotingAsync(){var actorType = "MyActor";var actorID = new ActorId("1");// Create Actor Proxy instance to invoke the methods defined in the interfacevar proxy = ActorProxy.Create(actorID, actorType);// Need to specify the method name and response type explicitlyvar response = await proxy.InvokeAsync<string>("SetMyDataAsync", new MyData(){PropertyA = "ValueA",PropertyB = "ValueB",});Console.WriteLine(response);var savedData = await proxy.InvokeAsync<MyData>("GetMyDataAsync");Console.WriteLine(savedData);}... }

運行Actor

為了驗證及調試 actor?服務及客戶端,?我們首先需要通過Dapr CLI運行actor服務.

Run Dapr Runtime via Dapr cli

$ dapr run --app-id myapp --app-port 3000 dotnet MyActorService.dll

在通過Dapr運行時執行MyActorService之后，確保在端口3000上發現應用程序并成功建立actor連接.

INFO[0000] starting Dapr Runtime -- version -- commitINFO[0000] log level set to: infoINFO[0000] standalone mode configuredINFO[0000] dapr id: myappINFO[0000] loaded component statestore (state.redis)INFO[0000] application protocol: http. waiting on port 3000INFO[0000] application discovered on port 3000INFO[0000] application configuration loaded2019/08/27 14:42:06 redis: connecting to localhost:63792019/08/27 14:42:06 redis: connected to localhost:6379 (localAddr: [::1]:53155, remAddr: [::1]:6379)INFO[0000] actor runtime started. actor idle timeout: 1h0m0s. actor scan interval: 30sINFO[0000] actors: starting connection attempt to placement service at localhost:50005INFO[0000] http server is running on port 3500INFO[0000] gRPC server is running on port 50001INFO[0000] dapr initialized. Status: Running. Init Elapsed 19.699438msINFO[0000] actors: established connection to placement service at localhost:50005INFO[0000] actors: placement order received: lockINFO[0000] actors: placement order received: updateINFO[0000] actors: placement tables updatedINFO[0000] actors: placement order received: unlock...

運行 MyActorClient

如果MyActorClient成功調用托管在MyActorService中的actor，它將在控制臺輸出.

如果指定不同的Dapr運行時http端口（默認端口：3500），則需要在運行客戶端之前設置Dapr_http_port環境變量.

Success PropertyA: ValueA, PropertyB: ValueB

?

原文參考翻譯：https://github.com/dapr/dotnet-sdk/blob/master/docs/get-started-dapr-actor.md

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