[Feature Request] How to give cfg to class __init__ by using hydra.utils.instantiate ?

🚀 Feature Request

Motivation

From this tutorial, I can give defined params (host, user, password, database) to my class. But what if I want to give cfg to my class ?

Pitch

Describe the solution you’d like

config.yaml:

defaults:
  - dataset: mnist_dataset
  - model: mnist_model

mnist_model.yaml:

model:
  name: mnist
  class: BaseModel  # The path may wrong. But in general, I will load class BaseModel 
  params:
    # I don't know how to define cfg in this params

class BaseModel:
    def __init__(self, cfg):
        self.cfg= cfg
        self.logger = cfg.log

   def shape():
        print(self.cfg.cur_dir) 
        print(self.cfg.prj_dir ) 

@hydra.main(config_path="configs/train.yaml", strict=False)
def main(cfg: DictConfig) -> None:

    # A logger for this file
    cfg.log = logging.getLogger(__name__)

    cfg.cur_dir = os.getcwd()
    cfg.prj_dir = hydra.utils.get_original_cwd()

    log.info(f"\n{cfg.pretty()}")

    if cfg.model.name=="mnist":
        mnist = hydra.utils.instantiate(cfg.model) # Loading BaseModel but how to give cfg to BaseModel ?
        mnist.shape()

p/s: I know that we can add ${dataset} to BaseModel

model:
  name: mnist
  class: BaseModel  # The path may wrong. But in general, I will load class BaseModel 
  params:
    cfg: ${dataset}

or

mnist = BaseModel(cfg)

But I just wonder if we can give cfg to class BaseModel by using hydra.utils.instantiate ?

Sorry for my silly question. You can close if it’s not correct.

[omry]

import hydra
from omegaconf import OmegaConf


class BaseModel:
    def __init__(self, cfg):
        self.cfg = cfg

    def shape(self):
        print("cfg.name:", self.cfg.name)


if __name__ == "__main__":
    cfg = OmegaConf.create(
        {"name": "mnist", "model": {"class": "__main__.BaseModel", "params": {}}}
    )

    model = hydra.utils.instantiate(cfg.model, cfg)
    model.shape()

[omry]

The cfg here is the cfg: DictConfig in main()

No. it’s not and can’t be. Why do you think the cfg in the model params should be the top level config? this would create a circular reference in the config and makes no sense at all.

If your BaseModel needs access to the whole config, you can pass pass it directly when you instantiate:

instantiate(cfg.model, cfg)

Keep in mind that this is an indication of problematic design. you are breaking encapsulation here. You want to allow the minimal access to BaseModel to what it needs. I am sure it doesn’t really need the whole config.