MONAI Bundle as an isolated python library

[surajpaib]

Is your feature request related to a problem? Please describe.
MONAI Bundle can be used to configure a wide range of workflows, and I see that a few issues are open for configuring it in simpler/ non-Pytorch environments.

Project-MONAI/tutorials#1454
Project-MONAI/tutorials#1453

On that note, earlier this year, for a traditional ML project based on optuna, I attempted to configure my search strategies using monai bundle. However, the issue was that the bundle is tied to MONAI core, which comes with a huge set of dependencies such as pytorch (~700MB), cudnn (~700MB), cublas (~400MB), nccl (~200MB), cuparse (~200MB), etc.

Describe the solution you'd like
If I want to use a bundle for other non-pytorch projects, it seems counterintuitive for end-users to download such heavy dependencies.

Is there a plan to release the bundle as a standalone?

I personally think this would be amazing as the bundle (with its config parser, resolvers, and CLI overrides) can be a very useful tool for several workflows beyond MONAI-based deep learning. For example, this could be a potential replacement for the more complex Hydra (which we used earlier and abandoned in favor of MONAI bundle).

[KumoLiu]

Hi @surajpaib, thanks for your interest here!
It may be hard to decouple the bundle from MONAI. You could specify your own JSON or YAML file.