将 2 个 Autofac 容器合并为一个

Question

有没有办法可以将 2 个 autoface 容器合并为 1 个？ 我的意思是两个容器的所有注册都将包含在新容器中 或者，可以将其中一个升级为另一个

例如：

public IContainer Merge(IContainer container1, IContainer container2)
{
     return ???;
}

我尝试过迭代“container.ComponentRegistry.Registrations”并使用 containerBuilder 注册组件并升级第二个容器，但由于某种原因出现了一些冲突

    Autofac.Core.DependencyResolutionException : An exception was thrown while executing a resolve operation. See the InnerException for details. ---> The provided instance has already been used in an activation request. Did you combine a provided instance with non-root/single-instance lifetime/sharing? (See inner exception for details.)
  ----> System.InvalidOperationException : The provided instance has already been used in an activation request. Did you combine a provided instance with non-root/single-instance lifetime/sharing?
   at Autofac.Core.Resolving.ResolveOperation.Execute(IComponentRegistration registration, IEnumerable`1 parameters)
   at Autofac.Core.Lifetime.LifetimeScope.ResolveComponent(IComponentRegistration registration, IEnumerable`1 parameters)
   at Autofac.Core.Container.ResolveComponent(IComponentRegistration registration, IEnumerable`1 parameters)
   at Autofac.ResolutionExtensions.TryResolveService(IComponentContext context, Service service, IEnumerable`1 parameters, ref Object instance)
   at Autofac.ResolutionExtensions.ResolveService(IComponentContext context, Service service, IEnumerable`1 parameters)
   at Autofac.ResolutionExtensions.Resolve(IComponentContext context, Type serviceType, IEnumerable`1 parameters)
   at Autofac.ResolutionExtensions.Resolve(IComponentContext context, IEnumerable`1 parameters)
   at Autofac.ResolutionExtensions.Resolve(IComponentContext context)
   at Bootstrap.Bootstrapper.CreatePersistentTimerAsyncExecuter(IContainer container)
   at Bootstrap.Bootstrapper.Monitor(IContainer container)
   at Bootstrap.Bootstrapper.Boot(Assembly[] assemblies)
   at Soluto.Telemetry.Processing.Core.IntegrationTests.TelemetryProcessingBootstrapperTests.Boot_With2TelemetryHandlersInAssembly_ResolvesSubscriberWithItsHandlers() in TelemetryProcessingBootstrapperTests.cs: line 88
--InvalidOperationException
   at Autofac.Core.Activators.ProvidedInstance.ProvidedInstanceActivator.ActivateInstance(IComponentContext context, IEnumerable`1 parameters)
   at Autofac.Core.Resolving.InstanceLookup.Activate(IEnumerable`1 parameters)
   at Autofac.Core.Resolving.InstanceLookup.<Execute>b__0()
   at Autofac.Core.Lifetime.LifetimeScope.GetOrCreateAndShare(Guid id, Func`1 creator)
   at Autofac.Core.Resolving.InstanceLookup.Execute()
   at Autofac.Core.Resolving.ResolveOperation.GetOrCreateInstance(ISharingLifetimeScope currentOperationScope, IComponentRegistration registration, IEnumerable`1 parameters)
   at Autofac.Core.Resolving.ResolveOperation.ResolveComponent(IComponentRegistration registration, IEnumerable`1 parameters)
   at Autofac.Core.Resolving.ResolveOperation.Execute(IComponentRegistration registration, IEnumerable`1 parameters)

有什么想法吗？

Answer 1

需要注意的是，Update() 在 Autofac 的较新版本中被标记为已过时，不应使用。有关更多说明，请参阅https://github.com/autofac/Autofac/issues/811#issuecomment-270246744。

列出的一些解决此问题的建议是：

• 传递 ContainerBuilder 而不是 IContainer
• 向子范围添加注册
• 使用 Lambdas
• 使用模块
• 使用条件注册（4.4.0 中的新功能）

基本上.. 如果可能的话，不要以 2 个容器结束。

Answer 2

您可以使用自定义IRegistrationSource。此接口包含一个 RegistrationsFor 方法，该方法返回特定 IService 的 IComponentRegistration 列表

public class CrossContainerRegistrationSource : IRegistrationSource
{
    public CrossContainerRegistrationSource(IComponentContext componentContext)
    {
        this._componentContext = componentContext;
    }

    private readonly IComponentContext _componentContext;

    public Boolean IsAdapterForIndividualComponents
    {
        get
        {
            return false;
        }
    }

    public IEnumerable<IComponentRegistration> RegistrationsFor(Service service, 
        Func<Service, IEnumerable<IComponentRegistration>> registrationAccessor)
    {
        return this._componentContext.ComponentRegistry.RegistrationsFor(service);
    }
}

你可以这样使用它：

container2.ComponentRegistry.AddRegistrationSource(new CrossContainerRegistrationSource(container1));

但是要小心这个解决方案，当您使用复杂的范围场景时，它可能会引入问题。

Answer 3

是的，这是可能的。

var existingContainer = new ContainerBuilder();
// Add registrations to existing container.

var newContainerBuilder = new ContainerBuilder();
// Add registrations to new container.

newContainterBuilder.Update(existingContainer);

update 方法本质上是将existingContainer 的内容合并到newContainerBuilder 中。

编辑 - 如果使用 IContainer

如果您已经将ContainerBuilder 构建到IContainer 中，则ContainerBuilder 的Update 方法能够接受IContainer 作为输入。但在这种情况下，已经构建的容器现在将包含所有注册，并且新的 ContainerBuilder 可能会超出范围。

var builtContainer = existingContainer.Build();

var newContainerBuilder = new ContainerBuilder();
// Add registrations to new container.

newContainterBuilder.Update(builtContainer);

Answer 4

谢谢大家的回答， 最终我根据自己的需要做了一些更具体的事情：

public void Merge(this IContainer container1, IContainer container2)
{ 
    var newBuilder = new ContainerBuilder();
    newBuilder.RegisterInstance(container2.Resolve<ISomeService1>()).AsImplementedInterfaces();
    newBuilder.RegisterInstance(container2.Resolve<ISomeService2>()).AsImplementedInterfaces();

    newBuilder.Update(container1);
    return container1;
}