Autofac - 解決多線程環境中的依賴關系

Question

public class MultithreadTester
{

    public void Run()
    {
        var builder = new ContainerBuilder();
        builder.RegisterType<ManualWork>().As<IWork>();
        builder.RegisterType<ColabManualWork>().As<IColabWork>();
        builder.RegisterType<RelaxAfterManualWork>().As<IRelax>();

        var container = builder.Build();

        //#1 - Simple single thread
        using (var scope = container.BeginLifetimeScope())
        {
            var work = scope.Resolve<IWork>();
            work.DoWork();
        }

        //#2 - Resolving dependecies in worker threads in scopes of these threads without passing lifetime scopes are container into implementation
        using (var scope = container.BeginLifetimeScope())
        {
            var work = scope.Resolve<IColabWork>();
            work.DoWork();
        }

        //#3 - Resolving dependecies in worker threads when original scope is already gone (simulates fast request on same service which spawns threads for request processing)
        IColabWork workForSample3;
        using (var scope = container.BeginLifetimeScope())
        {
            workForSample3 = scope.Resolve<IColabWork>();
        }
        workForSample3.DoWork();

        Console.ReadKey();

    }

    public interface IRelax
    {
        void DoRelax();
    }

    public class RelaxAfterManualWork : IRelax
    {
        public void DoRelax()
        {
            Console.WriteLine("Relaxing after hard work...");
            Thread.Sleep(1000);
            Console.WriteLine("Relax is done...");
        }
    }


    public interface IWork
    {
        void DoWork();
    }

    public class ManualWork : IWork
    {
        private readonly IRelax _relaxActivity;

        public ManualWork(IRelax relaxActivity)
        {
            _relaxActivity = relaxActivity;
        }

        public void DoWork()
        {
            Console.WriteLine("Ufff, this is so hard...");
            Thread.Sleep(5000);
            Console.WriteLine("Work is done...");
            _relaxActivity.DoRelax();
        }
    }

    public interface IColabWork
    {
        void DoWork();
    }

    public class ColabManualWork : IColabWork
    {
        public void DoWork()
        {
            Console.WriteLine("We must discuss how to share the workload...");
            Thread.Sleep(1500);

            Action action = () => 
            {
                //IT WOULD BE FINE TO HAVE RESOLVED DEPENDENCIES PER THREAD AND IN THREAD OWN LIFETIMESCOPE

                Console.WriteLine("Ufff, this is so hard but working with my buddies helps...");
                Thread.Sleep(2500);
                Console.WriteLine("Work is done...");
                var relaxActivity = new RelaxAfterManualWork();
                relaxActivity.DoRelax();
            };

            var thread1 = new Thread(() => { action(); });
            var thread2 = new Thread(() => { action(); });
            thread1.Start();
            thread2.Start();

            thread1.Join();
            thread2.Join();
        }
    }


}

在標記為＃1的示例中，我正在解析IWork並執行一些操作。 對於單線程環境，我了解DI中發生了什么，我應該如何使用DI，lifetimescope以及如何解決依賴關系。

但是我在多線程環境中很難理解DI。 我試圖證明我的一些問題是樣品＃2，＃3。 在這些示例中，我會以某種方式解決LifetimeScope中的依賴關系，這些依賴關系將在ColabManualWork中為每個線程創建。 當然我不希望從Autofac的任何類引用來防止耦合。

我甚至創建了一個簡單的工廠，適合從當前的一個創建嵌套的LifetimeScopes：

public interface IIsolatedLifetimeScopeFactory<TA>
{
    void Create(Action<TA> action);
}

public class IsolatedLifetimeScopeFactory<TA> : IIsolatedLifetimeScopeFactory<TA>
{
    private readonly ILifetimeScope _scope;

    public IsolatedLifetimeScopeFactory(ILifetimeScope scope)
    {
        _scope = scope;
    }

    public void Create(Action<TA> action)
    {
        using (var subScope = _scope.BeginLifetimeScope())
        {
            var a = subScope.Resolve<TA>();
            action(a);
        }
    }
}

但我不太喜歡這個解決方案。 有三個大問題 - 1）所有邏輯必須是lambda函數（或等效方法）; 2）將來，如果再次處理父作用域，Autoflac可以重新實現處理子作用域的功能（此功能已在此處使用了幾個月）; 3）正如樣本＃3中所示，我可以在ColabManualWork中的任何功能開始之前配置父LifetimeScope，因此我的工廠將使用已經處置過的LifetimeScope。

有人可以幫我解決如何有效解決工作線程中的解決問題嗎？ 我在多線程應用程序中閱讀了與SimpleInjector相關的一些名為Work with dependency injection的內容，但我並沒有完全理解它，而且與Autofac不相關。 在那篇文章中編寫了一個多線程應用程序，每個線程都應該得到自己的對象圖。 這意味着您通常應該在線程執行開始時調用container.GetInstance（）一次以獲取用於處理該線程的根對象

如何解決工作線程中的依賴關系而不與Autofac和線程相關的lifetimescope耦合？

Answer 1

要為每個線程提供自己的生命周期范圍，只需將IsolatedLifetimeScopeFactory注冊為SingleInstance 。 這將解決您的顧慮2）和3）

[TestMethod]
public void MyTestMethod()
{
    var cb = new ContainerBuilder();
    cb.RegisterGeneric(typeof(IsolatedLifetimeScopeFactory<>))
        .SingleInstance();
    var container = cb.Build();

    using (var scope1 = container.BeginLifetimeScope("scope1"))
    using (var scope2 = scope1.BeginLifetimeScope("scope2"))
    {
        var factory = scope2.Resolve<IsolatedLifetimeScopeFactory<object>>();
        var tag = factory._scope.Tag; // made _scope public for testing purposes
        Assert.AreNotEqual("scope1", tag);
        Assert.AreNotEqual("scope2", tag);

        // This particular string "root" is probably not guaranteed behavior, but
        // being in the root scope is guaranteed for SingleInstance registrations.
        Assert.AreEqual("root", tag);
    }
}

您的關注1）可以通過使用不同的抽象來解決。 例如，您可以將其添加到IsolatedLifetimeScopeFactory

public Autofac.Features.OwnedInstances.Owned<TA> Create()
{
    return _scope.Resolve<Autofac.Features.OwnedInstances.Owned<TA>>();
}

如果你真的想要，你可以隱藏抽象背后的Owned ，雖然我會說這太過分了。