Created basic Autofac integration.

src/AbpDesk/AbpDesk.Web.Mvc/AbpDeskWebMvcModule.cs

@@ -1,5 +1,7 @@
 using AbpDesk.EntityFrameworkCore;
 using AbpDesk.Web.Mvc.Navigation;
+using AbpDesk.Web.Mvc.Temp;
+using Autofac;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Configuration;
@@ -42,6 +44,8 @@ namespace AbpDesk.Web.Mvc
             services.AddMvc();
 
             services.AddAssemblyOf<AbpDeskWebMvcModule>();
+
+            services.GetContainerBuilder().RegisterType<MyClassToTestAutofacCustomRegistration>();
         }
 
         public override void OnApplicationInitialization(ApplicationInitializationContext context)

src/AbpDesk/AbpDesk.Web.Mvc/Controllers/HomeController.cs

@@ -1,11 +1,12 @@
-using Microsoft.AspNetCore.Mvc;
+using AbpDesk.Web.Mvc.Temp;
+using Microsoft.AspNetCore.Mvc;
 using Volo.Abp.AspNetCore.Mvc;
 
 namespace AbpDesk.Web.Mvc.Controllers
 {
     public class HomeController : AbpController
     {
-        public IActionResult Index()
+        public IActionResult Index(MyClassToTestAutofacCustomRegistration obj)
         {
             return View();
         }

src/AbpDesk/AbpDesk.Web.Mvc/Startup.cs

@@ -1,20 +1,16 @@
-using System;
+using System.IO;
-using System.IO;
-using Autofac;
-using Autofac.Extensions.DependencyInjection;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Serilog;
+using Volo.Abp;
 using Volo.Abp.Modularity.PlugIns;
 
 namespace AbpDesk.Web.Mvc
 {
     public class Startup
     {
-        public IContainer ApplicationContainer { get; private set; }
-
         private readonly IHostingEnvironment _env;
 
         public Startup(IHostingEnvironment env)
@@ -22,10 +18,12 @@ namespace AbpDesk.Web.Mvc
             _env = env;
         }
 
-        public IServiceProvider ConfigureServices(IServiceCollection services)
+        public void ConfigureServices(IServiceCollection services)
         {
             services.AddApplication<AbpDeskWebMvcModule>(options =>
             {
+                options.UseAutofac();
+
                 /* @halil: I added Abp.MongoDb package as a dependency to the main application in order to use the blog plugin.
                  * Otherwise, we should add all dependencies (Recursively) into plugin folder
                  * and load in correct order. We should carefully think on that problem in the future.
@@ -36,11 +34,6 @@ namespace AbpDesk.Web.Mvc
                         @"../Web_PlugIns/")
                 );
             });
-
-            var builder = new ContainerBuilder();
-            builder.Populate(services);
-            ApplicationContainer = builder.Build();
-            return new AutofacServiceProvider(ApplicationContainer);
         }
 
         public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IApplicationLifetime appLifetime)
@@ -54,8 +47,6 @@ namespace AbpDesk.Web.Mvc
                     .CreateLogger()
                 );
 
-            appLifetime.ApplicationStopped.Register(() => ApplicationContainer.Dispose());
-
             app.InitializeApplication();
         }
     }

src/AbpDesk/AbpDesk.Web.Mvc/Temp/MyClassToTestAutofacCustomRegistration.cs

@@ -0,0 +1,7 @@
+namespace AbpDesk.Web.Mvc.Temp
+{
+    /* Will be removed later */
+    public class MyClassToTestAutofacCustomRegistration
+    {
+    }
+}

src/Volo.Abp.Autofac/Volo.Abp.Autofac.csproj

@@ -16,4 +16,8 @@
     <PackageReference Include="Autofac.Extensions.DependencyInjection" Version="4.1.0" />
   </ItemGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\Volo.Abp\Volo.Abp.csproj" />
+  </ItemGroup>
+
 </Project>

src/Volo.Abp.Autofac/Volo/Abp/AbpApplicationCreationOptionsAutofacExtensions.cs

@@ -0,0 +1,30 @@
+using Autofac;
+using JetBrains.Annotations;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Volo.Abp
+{
+    public static class AbpApplicationCreationOptionsAutofacExtensions
+    {
+        public static void UseAutofac(this AbpApplicationCreationOptions options)
+        {
+            var builder = new ContainerBuilder();
+            options.Services.AddObjectAccessor(builder);
+            options.Services.AddSingleton((IServiceProviderFactory<ContainerBuilder>) new AbpAutofacServiceProviderFactory(builder));
+        }
+
+        [NotNull]
+        public static ContainerBuilder GetContainerBuilder([NotNull] this IServiceCollection services)
+        {
+            Check.NotNull(services, nameof(services));
+
+            var builder = services.GetObjectOrNull<ContainerBuilder>();
+            if (builder == null)
+            {
+                throw new AbpException($"Could not find ContainerBuilder. Be sure that you have called {nameof(UseAutofac)} method before!");
+            }
+
+            return builder;
+        }
+    }
+}

src/Volo.Abp.Autofac/Volo/Abp/AbpAutofacServiceProviderFactory.cs

@@ -0,0 +1,39 @@
+using System;
+using Autofac;
+using Autofac.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Volo.Abp
+{
+    /// <summary>
+    /// A factory for creating a <see cref="T:Autofac.ContainerBuilder" /> and an <see cref="T:System.IServiceProvider" />.
+    /// </summary>
+    public class AbpAutofacServiceProviderFactory : IServiceProviderFactory<ContainerBuilder>
+    {
+        private readonly ContainerBuilder _builder;
+
+        public AbpAutofacServiceProviderFactory(ContainerBuilder builder)
+        {
+            _builder = builder;
+        }
+
+        /// <summary>
+        /// Creates a container builder from an <see cref="T:Microsoft.Extensions.DependencyInjection.IServiceCollection" />.
+        /// </summary>
+        /// <param name="services">The collection of services</param>
+        /// <returns>A container builder that can be used to create an <see cref="T:System.IServiceProvider" />.</returns>
+        public ContainerBuilder CreateBuilder(IServiceCollection services)
+        {
+            AutofacRegistration.Populate(_builder, services);
+
+            return _builder;
+        }
+
+        public IServiceProvider CreateServiceProvider(ContainerBuilder containerBuilder)
+        {
+            Check.NotNull(containerBuilder, nameof(containerBuilder));
+
+            return new AutofacServiceProvider(containerBuilder.Build());
+        }
+    }
+}

src/Volo.Abp/Microsoft/Extensions/DependencyInjection/ServiceCollectionObjectAccessorExtensions.cs

@@ -39,5 +39,17 @@ namespace Microsoft.Extensions.DependencyInjection
 
             return accessor;
         }
+
+        public static T GetObjectOrNull<T>(this IServiceCollection services)
+            where T : class 
+        {
+            return services.GetSingletonInstanceOrNull<IObjectAccessor<T>>()?.Value;
+        }
+
+        public static T GetObject<T>(this IServiceCollection services)
+            where T : class
+        {
+            return services.GetObjectOrNull<T>() ?? throw new Exception($"Could not find an object of {typeof(T).AssemblyQualifiedName} in services. Be sure that you have used AddObjectAccessor before!");
+        }
     }
 }

src/Volo.Abp/Volo/Abp/AbpApplication.cs

@@ -26,7 +26,7 @@ namespace Volo.Abp
 
             StartupModuleType = startupModuleType;
 
-            var options = new AbpApplicationCreationOptions();
+            var options = new AbpApplicationCreationOptions(services);
             optionsAction?.Invoke(options);
 
             services.AddCoreAbpServices(this);

src/Volo.Abp/Volo/Abp/AbpApplicationCreationOptions.cs

@@ -1,4 +1,5 @@
 using JetBrains.Annotations;
+using Microsoft.Extensions.DependencyInjection;
 using Volo.Abp.Modularity.PlugIns;
 
 namespace Volo.Abp
@@ -6,10 +7,14 @@ namespace Volo.Abp
     public class AbpApplicationCreationOptions
     {
         [NotNull]
-        public PlugInSourceList PlugInSources { get; private set; }
+        public IServiceCollection Services { get; }
 
-        public AbpApplicationCreationOptions()
+        [NotNull]
+        public PlugInSourceList PlugInSources { get; }
+
+        public AbpApplicationCreationOptions([NotNull] IServiceCollection services)
         {
+            Services = Check.NotNull(services, nameof(services));
             PlugInSources = new PlugInSourceList();
         }
     }