Autofac RegisterAssemblyOpenGenericTypes matching query

Question

I'm attempting to register all open generic components I tag with a custom attribute. The query finds the class correctly but the interface is not registered properly. I'm able to register and resolve the component fine using RegisterGeneric

**Working: **

/// <inheritdoc />
[GenericTransient]
public sealed class RetryPolicyService<TResult> : IRetryPolicyService<TResult>
{...
}

builder.RegisterGeneric(typeof(RetryPolicyService<>))
                .As(typeof(IRetryPolicyService<>))
                .InstancePerDependency();

Not Working:

builder.RegisterAssemblyOpenGenericTypes(Assembly.GetExecutingAssembly())
                .Where(t =>
                    t.GetCustomAttribute<GenericTransientAttribute>() != null)
                .As(t => t.GetInterfaces()[0]);

Not Working:

 builder.RegisterAssemblyOpenGenericTypes(Assembly.GetExecutingAssembly())
                .Where(t =>
                    t.GetCustomAttribute<GenericTransientAttribute>() != null)
                .AsImplementedInterfaces();

Break Point

The expectation is to be able to inject IRetryPolicyService into objects. Again its working as expected when I register the type specifically.

private readonly IHttpClientService _httpClient;
private readonly IRetryPolicyService<HttpResponseMessage> _retryPolicy;

public ServiceController(
    IHttpClientService httpClient,
    IRetryPolicyService<HttpResponseMessage> retryPolicy)
{
    _httpClient = httpClient;
    _retryPolicy = retryPolicy;
    _retryPolicy.CreatePolicy(5, times => TimeSpan.FromMilliseconds(times * 1000));
}

Answer 1

The following simplified example works fine. If you uncomment GenericTransient attribute on the second service then controller will get its instance (last registration wins). And the retryPolicies variable will get 2 instances.

The first variant (with GetInterfaces()) also worked after adding .GetGenericTypeDefinition().

using Autofac;
using System.Reflection;

namespace Console.Core6
{
    internal class Program
    {
        static void Main(string[] args)
        {
            var builder = new ContainerBuilder();

            builder.RegisterAssemblyOpenGenericTypes(Assembly.GetExecutingAssembly())
                .Where(t => t.GetCustomAttribute<GenericTransientAttribute>() != null)
                .AsImplementedInterfaces();

            builder.RegisterAssemblyOpenGenericTypes(Assembly.GetExecutingAssembly())
                .Where(t => t.GetCustomAttribute<GenericTransientAttribute>() != null)
                .As(t => t.GetInterfaces()[0].GetGenericTypeDefinition());

            builder.RegisterType<ServiceController>().InstancePerDependency();

            var container = builder.Build();
            var controller = container.Resolve<ServiceController>();
            var retryPolicies = container.Resolve<IEnumerable<IRetryPolicyService<HttpResponseMessage>>>();
        }
    }

    internal class GenericTransientAttribute : Attribute
    { }

    public interface IRetryPolicyService<TResult>
    { }

    [GenericTransient]
    public sealed class RetryPolicyService<TResult> : IRetryPolicyService<TResult>
    {}

    //[GenericTransient]
    public sealed class RetryPolicyService2<TResult> : IRetryPolicyService<TResult>
    {}

    public class ServiceController
    {
        private readonly IRetryPolicyService<HttpResponseMessage> _retryPolicy;

        public ServiceController(IRetryPolicyService<HttpResponseMessage> retryPolicy)
        {
            _retryPolicy = retryPolicy;
        }
    }
}