[Feature Request] Permit user-defined arguments if needed

🚀 Feature Request

Motivation

Is your feature request related to a problem? Please describe.

Because hydra defines argparse.ArgumentParser internally, user cannot add own new parser.

Pitch

Describe the solution you’d like

I added a new param(user_arg_parser) to the hydra.main decorator. Then my_app function can receive the additional args param passed through Hydra.

parser = argparse.ArgumentParser(add_help=False)
parser.add_argument("--user_arg", type=str, help="This is user's argument")

@hydra.main(config_path="config/config.yaml", user_arg_parser=parser)
def my_app(cfg, args):
    print(cfg.pretty())

Describe alternatives you’ve considered

Are you willing to open a pull request? (See CONTRIBUTING) Yes.

Additional context

Add any other context or screenshots about the feature request here. You can also record a video

[jungerm2]

Thank you that makes sense. In the case where we have multiple (2+) mutually exclusive args, multiple entry points is probably better design anyways…

[omry]

@jungerm2: There is a different issue for allowing a different config file: #386 . As for tow different run modes: If those are really mutually exclusive, the work around for now is to have two different entry point. train.py:

@hydra.main(config_path="train.yaml")
def train(cfg):
  ..

test.py:

@hydra.main(config_path="test.yaml")
def test(cfg):
  ..

If you actually do want to share most of the config, you create a mode parameter in your config:

config.yaml:

defaults:
  - model: foo
  - dataset: bar

mode: train 

then the code can behave differently based on the mode.