Learn Orleans 02 - Hello World

基础概念

Orleans的核心概念见上图。

--https://www.cnblogs.com/sheng-jie/p/11223848.html

--https://github.com/sheng-jie/Samples.AllInOne/tree/dev/Orleans

Grain就是Actor，是执行的最小单位。Silo是Orleans的运行时，用于托管Grains。一组Silo能够形成分布式集群，并能够进行容错处理。

--https://dotnet.github.io/orleans/Documentation/index.html

Grain = 身份 + 行为 + 状态(可选)

Grain的生命周期由运行时管理，状态变化如下图：

Hello World

https://dotnet.github.io/orleans/Documentation/tutorials_and_samples/tutorial_1.html

Orleans Hello World由四个项目组成：

1. grain interfaces
2. grain classes
3. Silo Host
4. Console Client

首先创建项目结构

dotnet new console -n Silo
dotnet new console -n Client
dotnet new classlib -n GrainInterfaces
dotnet new classlib -n Grains
dotnet new sln -n OrleansHelloWorld
dotnet sln add Silo Client GrainInterfaces Grains

设置这四个项目的依赖关系如上图所示。

随后添加所需的nuget包

#silo
dotnet add package Microsoft.Orleans.Server
dotnet add package Microsoft.Extensions.Logging.Console
#client
dotnet add package Microsoft.Orleans.Client 
dotnet add package Microsoft.Extensions.Logging.Console
#GrainInterfaces
dotnet add package Microsoft.Orleans.Core.Abstractions 
dotnet add package Microsoft.Orleans.CodeGenerator.MSBuild
#Grains
dotnet add package Microsoft.Orleans.Core.Abstractions
dotnet add package Microsoft.Orleans.CodeGenerator.MSBuild
dotnet add package Microsoft.Extensions.Logging.Abstractions

GrainInterface - IHello.cs

using System.Threading.Tasks;

namespace OrleansBasics
{
    public interface IHello : Orleans.IGrainWithIntegerKey
    {
        Task<string> SayHello(string greeting);
    }
}

Grain - HelloGrain.cs

using Microsoft.Extensions.Logging;
using System.Threading.Tasks;

namespace OrleansBasics
{
    public class HelloGrain : Orleans.Grain, IHello
    {
        private readonly ILogger logger;

        public HelloGrain(ILogger<HelloGrain> logger)
        {
            this.logger = logger;
        }

        Task<string> IHello.SayHello(string greeting)
        {
            logger.LogInformation($"\n SayHello message received: greeting = '{greeting}'");
            return Task.FromResult($"\n Client said: '{greeting}', so HelloGrain says: Hello!");
        }
    }
}

Silo – Program.cs

using System;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using Orleans;
using Orleans.Configuration;
using Orleans.Hosting;

namespace OrleansBasics
{
    public class Program
    {
        public static int Main(string[] args)
        {
            return RunMainAsync().Result;
        }

        private static async Task<int> RunMainAsync()
        {
            try
            {
                var host = await StartSilo();
                Console.WriteLine("\n\n Press Enter to terminate...\n\n");
                Console.ReadLine();

                await host.StopAsync();

                return 0;
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
                return 1;
            }
        }

        private static async Task<ISiloHost> StartSilo()
        {
            // define the cluster configuration
            var builder = new SiloHostBuilder()
                .UseLocalhostClustering()
                .Configure<ClusterOptions>(options =>
                {
                    options.ClusterId = "dev";
                    options.ServiceId = "OrleansBasics";
                })
                .ConfigureApplicationParts(parts => parts.AddApplicationPart(typeof(HelloGrain).Assembly).WithReferences())
                .ConfigureLogging(logging => logging.AddConsole());

            var host = builder.Build();
            await host.StartAsync();
            return host;
        }
    }
}

Client – Program.cs

using Microsoft.Extensions.Logging;
using Orleans;
using Orleans.Configuration;
using System;
using System.Threading.Tasks;

namespace OrleansBasics
{
    public class Program
    {
        static int Main(string[] args)
        {
            return RunMainAsync().Result;
        }

        private static async Task<int> RunMainAsync()
        {
            try
            {
                using (var client = await ConnectClient())
                {
                    await DoClientWork(client);
                    Console.ReadKey();
                }

                return 0;
            }
            catch (Exception e)
            {
                Console.WriteLine($"\nException while trying to run client: {e.Message}");
                Console.WriteLine("Make sure the silo the client is trying to connect to is running.");
                Console.WriteLine("\nPress any key to exit.");
                Console.ReadKey();
                return 1;
            }
        }

        private static async Task<IClusterClient> ConnectClient()
        {
            IClusterClient client;
            client = new ClientBuilder()
                .UseLocalhostClustering()
                .Configure<ClusterOptions>(options =>
                {
                    options.ClusterId = "dev";
                    options.ServiceId = "OrleansBasics";
                })
                .ConfigureLogging(logging => logging.AddConsole())
                .Build();

            await client.Connect();
            Console.WriteLine("Client successfully connected to silo host \n");
            return client;
        }

        private static async Task DoClientWork(IClusterClient client)
        {
            // example of calling grains from the initialized client
            var friend = client.GetGrain<IHello>(0);
            var response = await friend.SayHello("Good morning, HelloGrain!");
            Console.WriteLine("\n\n{0}\n\n", response);
        }
    }
}

Run起来：

先启动Silo再启动Client，结果如下：

总结

这个例子其实就是简单的RPC调用，通过引用相同的接口组件，Client能够直接访问Server，它更贴近面向对象的编程风格。下一篇我们来讲解Actor的无锁特性。