Python

From the docs:

svcs (pronounced services) is a dependency container for Python. It gives you a central place to register factories for types/interfaces and then imperatively acquire instances of those types with automatic cleanup and health checks.

It’s suitable for implementing Inversion of Control using either dependency injection or service location while not requiring global state, decorators, or mangling of function signatures.

Personally I don't know if I will ever need such a tool; I don't really do web framework-y work right now. But I have a ton of respect for Hynek and enjoy his other projects and his blog posts, so if you need something like this I can recommend it on that basis.