how does hydra manages timezone when it creates output directories?

Question

I have a .yaml configuration file which looks like:

key: value

hydra:
  run:
    dir: ./data_fetcher/hydra_outputs/${now:%Y-%m-%d}/${now:%H-%M-%S}

with a python file main.py:

import hydra

@hydra.main(config_path="data_fetcher/config", config_name="config")
def main(cfg: DictConfig):
    pass

if __name__ == "__main__":
    main()

When running main.py an output directory is created according to the current date and time.

How does Hydra get the current time ? is it possible to change the timezone ?

Answer 1

Hydra is registering a simple OmegaConf custom resolver here with a line like:

register("now", lambda pattern: strftime(pattern, localtime()))

You can register your own custom resolver with a different name before @hydra.main() runs that will do what you want.

• Read about custom resolvers in the OmegaConf documentation.
• Read about how to get time in a different time zone here.

You can also file a feature request to add support for time zone to the ${now:...} custom resolve in Hydra. a PR would be appreciated. For example, ${now:...} can support an optional second parameter for the time zone.