Specifying a config file

 

It can get tedious to type all those command line arguments. You can solve it by creating a configuration file next to my_app.py. Hydra configuration files are yaml files and should have the .yaml file extension.

config.yaml

db: 
  driver: mysql
  user: omry
  password: secret

Specify the config name by passing a config_name parameter to the @hydra.main() decorator. Note that you should omit the .yaml extension.

my_app.py

@hydra.main(config_name='config')
def my_app(cfg):
    print(OmegaConf.to_yaml(cfg))

config.yaml is loaded automatically when you run your application.

$ python my_app.py
db:
  driver: mysql
  user: omry
  password: secret

You can override values in the loaded config from the command line.
Note the lack of the + prefix.

$ python my_app.py db.user=root db.password=1234
db:
  driver: mysql
  user: root
  password: 1234

You can enable tab completion for your Hydra applications.