[Question] Limit possible values of config fields using Literal?

[hoangthienan95]

🐛 Bug

Description

Is it possible to limit the possible values of a field in a config yaml file using type hints? I want to limit the values of the STEP_NAME variable in step1.yaml to only 2 values: "extract_info" and "run_ovp"

I tried using the Literal["extract_info", "run_ovp"] type but it threw an error. When the type was str it worked fine

Checklist

• [ X] I checked on the latest version of Hydra
• [ X] I created a minimal repro (See this for tips).

To reproduce

** Minimal Code/Config snippet to reproduce **
Directory structure:

├── conf
│   ├── hydra_all_confs
│   │   ├── config.yaml
│   │   └── step
│   │       └── step1.yaml
├── hydra_test_app.py

Content of hydra_test_app.py

import logging
from dataclasses import dataclass
import os
from typing import Literal, Union
from enum import Enum

from omegaconf import DictConfig, OmegaConf, MISSING
import hydra
from hydra.core.config_store import ConfigStore


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


# +
@dataclass
class step1:
    STEP_NAME: Literal["extract_info", "run_ovp", "???"] = MISSING #read this from step1.yaml and limit the step name to 2 possible values

@dataclass
class Config:
    step = MISSING


# -

cs = ConfigStore.instance()

cs.store(name="config", node=Config)
cs.store(group="step", name="step1", node=step1)

@hydra.main(config_path='conf/hydra_all_confs', config_name="config")
def my_app(cfg: DictConfig) -> None:
    log.debug(cfg)
    log.info(OmegaConf.to_yaml(cfg))
    log.info("Working directory : {}".format(os.getcwd()))


if __name__ == "__main__":
    my_app()

Content of config.yaml

defaults:
 - step: ??? #want user to provide this at run time

** Stack trace/error message **

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-26-89e95316894d> in <module>
      1 cs.store(name="config", node=Config)
----> 2 cs.store(group="step", name="step1", node=step1)

/lab/corradin_biobank/FOR_AN/OVP/2019_MSGWAS_OVGen_GWAS_PAIR_RUN/corradin_ovp_kedro/.venv/lib/python3.8/site-packages/hydra/core/config_store.py in store(self, name, node, group, package, provider)
     83             name = f"{name}.yaml"
     84         assert isinstance(cur, dict)
---> 85         cfg = OmegaConf.structured(node)
     86         cur[name] = ConfigNode(
     87             name=name, node=cfg, group=group, package=package, provider=provider

/lab/corradin_biobank/FOR_AN/OVP/2019_MSGWAS_OVGen_GWAS_PAIR_RUN/corradin_ovp_kedro/.venv/lib/python3.8/site-packages/omegaconf/omegaconf.py in structured(obj, parent)
    138     @staticmethod
    139     def structured(obj: Any, parent: Optional[BaseContainer] = None) -> Any:
--> 140         return OmegaConf.create(obj, parent)
    141 
    142     @staticmethod

/lab/corradin_biobank/FOR_AN/OVP/2019_MSGWAS_OVGen_GWAS_PAIR_RUN/corradin_ovp_kedro/.venv/lib/python3.8/site-packages/omegaconf/omegaconf.py in create(obj, parent)
    175         obj: Any = _EMPTY_MARKER_, parent: Optional[BaseContainer] = None
    176     ) -> Union[DictConfig, ListConfig]:
--> 177         return OmegaConf._create_impl(obj=obj, parent=parent)
    178 
    179     @staticmethod

/lab/corradin_biobank/FOR_AN/OVP/2019_MSGWAS_OVGen_GWAS_PAIR_RUN/corradin_ovp_kedro/.venv/lib/python3.8/site-packages/omegaconf/omegaconf.py in _create_impl(obj, parent)
    219                     else:
    220                         key_type, element_type = get_dict_key_value_types(ref_type)
--> 221                     return DictConfig(
    222                         content=obj,
    223                         parent=parent,

/lab/corradin_biobank/FOR_AN/OVP/2019_MSGWAS_OVGen_GWAS_PAIR_RUN/corradin_ovp_kedro/.venv/lib/python3.8/site-packages/omegaconf/dictconfig.py in __init__(self, content, key, parent, ref_type, key_type, element_type, is_optional)
     72 
     73         if is_structured_config(content) or is_structured_config(ref_type):
---> 74             self._set_value(content)
     75             if is_structured_config_frozen(content) or is_structured_config_frozen(
     76                 ref_type

/lab/corradin_biobank/FOR_AN/OVP/2019_MSGWAS_OVGen_GWAS_PAIR_RUN/corradin_ovp_kedro/.venv/lib/python3.8/site-packages/omegaconf/dictconfig.py in _set_value(self, value)
    540             if is_structured_config(value):
    541                 self._metadata.object_type = None
--> 542                 data = get_structured_config_data(value)
    543                 for k, v in data.items():
    544                     self.__setitem__(k, v)

/lab/corradin_biobank/FOR_AN/OVP/2019_MSGWAS_OVGen_GWAS_PAIR_RUN/corradin_ovp_kedro/.venv/lib/python3.8/site-packages/omegaconf/_utils.py in get_structured_config_data(obj)
    316 def get_structured_config_data(obj: Any) -> Dict[str, Any]:
    317     if is_dataclass(obj):
--> 318         return get_dataclass_data(obj)
    319     elif is_attr_class(obj):
    320         return get_attr_data(obj)

/lab/corradin_biobank/FOR_AN/OVP/2019_MSGWAS_OVGen_GWAS_PAIR_RUN/corradin_ovp_kedro/.venv/lib/python3.8/site-packages/omegaconf/_utils.py in get_dataclass_data(obj)
    259             )
    260             format_and_raise(node=None, key=None, value=value, cause=e, msg=str(e))
--> 261         d[name] = _maybe_wrap(
    262             ref_type=type_, is_optional=is_optional, key=name, value=value, parent=None
    263         )

/lab/corradin_biobank/FOR_AN/OVP/2019_MSGWAS_OVGen_GWAS_PAIR_RUN/corradin_ovp_kedro/.venv/lib/python3.8/site-packages/omegaconf/omegaconf.py in _maybe_wrap(ref_type, key, value, is_optional, parent)
    762         return value
    763     else:
--> 764         return _node_wrap(
    765             type_=ref_type,
    766             parent=parent,

/lab/corradin_biobank/FOR_AN/OVP/2019_MSGWAS_OVGen_GWAS_PAIR_RUN/corradin_ovp_kedro/.venv/lib/python3.8/site-packages/omegaconf/omegaconf.py in _node_wrap(type_, parent, is_optional, value, key, ref_type)
    727     elif type_ == Any or type_ is None:
    728         node = AnyNode(value=value, key=key, parent=parent, is_optional=is_optional)
--> 729     elif issubclass(type_, Enum):
    730         node = EnumNode(
    731             enum_type=type_,

TypeError: issubclass() arg 1 must be a class

Expected Behavior

System information

• Hydra Version :
• Python version :
• Virtual environment type and version :
• Operating system :

Additional context

Add any other context about the problem here.

[omry]

Literals are not supported by OmegaConf. use an Enum.

See feature request in omry/omegaconf#422.