ConfigureContainer(Registry registry) not called

[CMircea]

The README says that after calling app.UseStructureMap() the runtime will look for a ConfigureContainer method, however, there isn't any code that actually does this, so the StructureMap.AspNetCore package is kinda useless on its own.

[khellang]

What are you talking about?

The package adds the UseStructureMap extension method to IWebHostBuilder.

There's no mentioning of app anywhere. The code that makes the hosting layer call Startup.ConfigureContainer is here.

The StructureMap.AspNetCore package isn't useless on its own, it's used together with StructureMap.Microsoft.DependencyInjection to integrate StructureMap with ASP.NET Core. Why would anyone create a useless package?

[CMircea]

Hmm... my bad. I don't get ConfigureContainer called on ASP.NET Core 1.0.1. Digging further into this, support for it was added in ASP.NET Core 1.1.

Here is StartupLoader for 1.0.1: https://github.com/aspnet/Hosting/blob/rel/1.0.1/src/Microsoft.AspNetCore.Hosting/Internal/StartupLoader.cs

And here is StartupLoader for 1.1: https://github.com/aspnet/Hosting/blob/rel/1.1.0/src/Microsoft.AspNetCore.Hosting/Internal/StartupLoader.cs

For 1.1 we can see on line 18 that it does look for a ConfigureContainer method, while 1.0.1 doesn't have that functionality. The StructureMap.AspNetCore package is useful only for 1.1, but this isn't mentioned anywhere. I checked and even the version isn't suggestive - it's 1.0.0, it should be the same as ASP.NET Core's version IMO (1.1). I have now seen the dependency on Microsoft.AspNetCore.Hosting.Abstractions version 1.1, but that is quite easy to miss.

I suggest documenting that StructureMap.AspNetCore only supports ASP.NET Core 1.1. It works with 1.0 only if you use the overload that takes a Registry, which isn't as useful :)

Sorry for jumping to the conclusion that the package is useful, that was my mistake and I was too harsh.

[khellang]

Sure, I'll clarify this in the documentation.

It works with 1.0 only if you use the overload that takes a Registry, which isn't as useful

What does that mean?

[CMircea]

It means that in 1.0 you can create the container in any way you fancy and call this overload of AddStructureMap: https://github.com/structuremap/StructureMap.Microsoft.DependencyInjection/blob/master/src/StructureMap.Microsoft.DependencyInjection/ServiceCollectionExtensions.cs#L12

There's no automatic support for ConfigureContainer, so you have to do the equivalent yourself, and there's two ways to integrate StructureMap:

1. Use the IServiceProvider ConfigureServices(IServiceCollection services) method, and manually return new StructureMapServiceProvider(Container).
2. Call AddStructureMap(Registry) in Configure(IApplicationBuilder app).

The first option doesn't need the StructureMap.AspNetCore package, but the second does.

I prefer the first option, as I can manually call Populate(services) and then AssertConfigurationIsValid.

[khellang]

I'm not sure what you're saying. In 1.1, which the library requires, you can, as you say, call either IWebHostBuilder.UseStructureMap, or IServiceCollection.AddStructureMap. These are equivalent. The former requires StructureMap.AspNetCore, the latter doesn't. They will both make the hosting layer call ConfigureContainer(Registry). There should be no way to use this in a 1.0 app.

The second option you have, is to manually, as you've mentioned, return an instance of IServiceProvider from the ConfigureServices(IServiceCollection) method. This works in 1.0 and doesn't require StructureMap.AspNetCore.

I'm not sure what you mean by "call AddStructureMap(Registry) in Configure(IApplicationBuilder). By the time Configure(IApplicationBuilder) is called, it's too late to call anything on the service collection. Where do you even get a service collection in that method?

[CMircea]

My bad, I mixed up IApplicationBuilder with IWebHostBuilder, I meant calling IWebHostBuilder.UseStructureMap.

There should be no way to use this in a 1.0 app.

Sure there is. Add it as a dependency, you will get Microsoft.Extensions.DependencyInjection.Abstractions version 1.1 but all other packages will be 1.0. DependencyInjection 1.1 is backwards compatible to ASP.NET Core 1.0 from what I can tell. IIRC the ASP.NET team tested StructureMap against 1.0 and only the constructor selection was a problem.

[khellang]

Oh, I see what you're saying now. You get 1.1 of the DI-specific packages, but the hosting layer remains at 1.0 and won't know what to do with the IServiceProviderFactory<T> service. That's exactly right. It's a good point that this should be mentioned in the README.

[CMircea]

Yeah, that's exactly right.

Compatibility with 1.0 should be documented, but mentioned that the StructureMap.AspNetCore package requires ASP.NET Core 1.1 :).