<package id="Autofac" version="4.9.2" targetFramework="net471" />
<package id="Autofac.Multitenant" version="4.2.0" targetFramework="net471" />

using Autofac;
using Autofac.Multitenant;

namespace ConsoleAutoFacTenants
{
    class Program
    {
        static void Main(string[] args)
        {
            var builder = new ContainerBuilder();
            builder.RegisterType<GeneralReader>().As<IReader>().InstancePerDependency();
            var appContainer = builder.Build();

            var tenantIdentifier = new AutomationTenantStrategy();
            var mtc = new MultitenantContainer(tenantIdentifier, appContainer);

            mtc.ConfigureTenant("1", b => b.RegisterType<SpecificReader>().As<IReader>().InstancePerDependency());

            // expected
            var reader1 = mtc.Resolve<IReader>();
            System.Diagnostics.Debug.Assert(reader1.Name == "General");

            // unexpected result in debug.assert, assumed that reader2 would resolve type SpecificReader
            var childScoped = mtc.Resolve<ILifetimeScope>();
            tenantIdentifier.TenantId = "1";
            var reader2 = childScoped.Resolve<IReader>();
            System.Diagnostics.Debug.Assert(reader2.Name == "Specific");
        }
    }
    internal sealed class AutomationTenantStrategy : ITenantIdentificationStrategy
    {
        public object TenantId { get; set; }
        public bool TryIdentifyTenant(out object tenantId)
        {
            var activeTenant = this.TenantId;
            if (TenantId == null)
            {
                tenantId = null;
                return false;
            }
            tenantId = activeTenant;
            return true;
        }
    }
    public interface IReader
    {
        string Name { get; }
    }
    public sealed class GeneralReader : IReader
    {
        public string Name => "General";
    }
    public sealed class SpecificReader : IReader
    {
        public string Name => "Specific";
    }
}