Multiple nested scope registrations

[aspnet-hello]

From @ghost on Friday, November 13, 2015 3:18:13 PM

When doing multiple nested scopes through IServiceScopeFactory.CreateScope(), you get nested IServiceProvider instances. It doesn't, however, give access to registrations for each scope.

Therefore if you have scopes which are created further down the pipeline (with some service data only accessible from that step in the pipeline, which isn't available at the root), you can't really register services to use in there.

The sought-after structure being:
Scope (root)
- Register (root)
- Resolve (root level)
<- Scope (level 1)
- Register (level 1)
- Resolve (root level + level 1)
<- Scope (level 2)
- Register (level 2)
- Resolve (root level + level 1 + level 2)

I don't know if there's an alternative way of achieving this, but so far the documentation is scarce.

Copied from original issue: aspnet/DependencyInjection#327

[aspnet-hello]

From @Eilon on Friday, January 22, 2016 5:27:13 PM

Moving this to Backlog as we are not planning to make any changes for this at this time.

[aspnet-hello]

From @dazinator on Thursday, July 13, 2017 10:57:56 AM

I am looking at how to achieve the following.

As well as an IServiceProvider at the Application and at the RequestServices (scoped) level, I'd like have an IServiceProvider for each separate tenant of my application. The thing I can't figure out is, if I build an IServiceProvider for each tenant, how do I chain this IServiceProvider to a parent IServiceProvider such as request services - so that resolution fallsback from the tenant container to RequestServices?

[aspnet-hello]

From @dazinator on Thursday, July 13, 2017 11:04:09 AM

It would be really good if I could register some sort of generic delegate into the child container to be invoked as a fallback for whenever a service wasn't registered - in there I could defer resolution to an alternate IServiceProvider (i.e the parent one).. Is this possible?

[t03apt]

When doing multiple nested scopes through IServiceScopeFactory.CreateScope(), you get nested IServiceProvider instances. It doesn't, however, give access to registrations for each scope.

For example AutoFac has this implemented.
See: http://autofaccn.readthedocs.io/en/latest/lifetime/working-with-scopes.html#adding-registrations-to-a-lifetime-scope

using(var scope = container.BeginLifetimeScope(
  builder =>
  {
    builder.RegisterType<Override>().As<IService>();
    builder.RegisterModule<MyModule>();
  }))
{
  // The additional registrations will be available
  // only in this lifetime scope.
}

[huysentruitw]

Can we agree that this issue is closely related to #2355 ?

[davidfowl]

We have no plans to add support to child containers. We recommend you use a 3rd party container for this (like autofac)

[huysentruitw]

Yeah, too hard probably. I tried to create a pull-request for this, but it seems like we would need to refactor a very large part in order to allow this.