Ability to combine multiple containers

[maciej]

Hi,

I'd like to be able to combine multiple containers together. Instead of having a single container assembled within the main function I'd like to have one for each package and them combine them in main().
Currently I have to export every constructor or provider function to have it accessible from where I want to build the container. That's not great. I'd like some of those constructors to be package-private.
I believe there is currently no way to achieve that in dig, but please correct me if I'm wrong!

I'm inspired by Guice's modules https://github.com/google/guice/wiki/GettingStarted. Guice's users were encouraged to have a single "module" (a similar construct to the container) for every package. Modules would we later assembled when creating the "injector".

Do you think such a feature would make sense for dig?

[abhinav]

Hello! We agree that that is a great idea which is why we built Fx on top
of Dig to make that possible!

We intended Dig to be the lower level library on top of which we could build a
more opinionated framework. Dig handles the dependency resolution,
instantiation, etc. with a few primitives (the container, dig.In/Out, etc.).
Fx builds on top of that with opinions on how you should structure your
application, and enables composition of modules produced by different packages.

Please check out Fx and see if it fits your needs. We recommend the
heavily commented package-level example test on https://godoc.org/go.uber.org/fx
as a starting point.