Dependency Injection into Autofac Module in .NET Core 3.0

Question

I am quite new to creating and registering modules but I am trying to get a better understanding of the process as a whole. Currently I am trying to inject a dependency into an autofac module but I think the problem is that autofac registers its modules before the dependency injection can take place. Here is my my security module:

 public class SecurityModule : Module
{
    private readonly IConfiguration configuration;

    public SecurityModule(IConfiguration configuration)
    {
        this.configuration = configuration;
    }

    protected override void Load(ContainerBuilder builder)
    {
        builder.RegisterType<TeamManager>()
          .WithParameter("tenantName", this.configuration["TenantName"])
          .InstancePerDependency();
    }
}

Here is the section in program.cs where I register the module:

    public static IHostBuilder CreateHostBuilder(string[] args)
    {
        return Host.CreateDefaultBuilder(args)
            .UseServiceProviderFactory(new AutofacServiceProviderFactory())
            .ConfigureContainer<ContainerBuilder>(builder =>
            {
                builder.RegisterAssemblyModules(typeof(Startup).Assembly);
                builder.RegisterModule<LoggingModule>();
                builder.RegisterModule(new ConfigurationModule(args));
                builder.RegisterModule<CXDatabaseModule>();
                builder.RegisterModule<SecurityModule>();
            })
            .ConfigureLogging(logging =>
            {
                logging.ClearProviders();
                logging.AddLog4Net();
            })
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.ConfigureKestrel(options =>
                {
                    options.Limits.MaxRequestBodySize = 209715200;
                });

                webBuilder.UseStartup<Startup>();
            })
            .UseNServiceBus((configuration, container) =>
            {
                return CreateStartableEndpoint(configuration, container);
            });
    }

And this is the error I am receiving. Is there possibly a way to specify that this module should be registered at a later stage ? Or am I missing a vital bit of information?

DependencyResolutionException: None of the constructors found with 'Autofac.Core.Activators.Reflection.DefaultConstructorFinder' on type 'inQuba.CX.Web.Api.AutofacIntegration.SecurityModule' can be invoked with the available services and parameters: Cannot resolve parameter 'Microsoft.Extensions.Configuration.IConfiguration configuration' of constructor 'Void .ctor(Microsoft.Extensions.Configuration.IConfiguration)'.

@Changemyminds I've updated the question with my CreateHostBuilder method. — Damian, Aug 05 '20 at 03:22

score 0 · Answer 1 · answered Aug 05 '20 at 05:44

Just only fixed SecurityModule.
You can create IConfiguration in your SecurityModule by Load method.
Remove the SecurityModule constructor and IConfiguration field.

public class SecurityModule : Module
{
    protected override void Load(ContainerBuilder builder)
    {
        // create configuration by your appsettings.json
        var configurationBuilder = new ConfigurationBuilder();
        configurationBuilder.AddJsonFile("appsettings.json");
        var configuration = configurationBuilder.Build();

        builder.RegisterType<TeamManager>()
          .WithParameter("tenantName", configuration["TenantName"])
          .InstancePerDependency();
    }
}

Note: builder.RegisterModule<TModule>() where TModule is a new constraint mean you must have a public parameter-less default constructor.

Dependency Injection into Autofac Module in .NET Core 3.0

1 Answers1