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I am storing settings in json file > loading it > using eval to evaluate the stringified data.

However I am sure eval is not the best way to do it.

I would like to know if there is any better way to implement it without using eval. Any pointer will be a great help.

Below is what I have got now.

Store the settings - decision_settings.json

{
    "DecisionModelConfig": {   
        "model_type": "ModelType.RULE_BASED",
        "model_path": "DECISION_MODEL_PATH"
    }
}

Load the settings - abc.py

with open("decision_settings.json", encoding="utf-8") as settings:
    decision_settings = json.load(settings)

Use eval to evaluate the stringified input as read from json file

from abc.settings import decision_settings
from abc_pqr import ModelType
from abc_xyz import DECISION_MODEL_PATH

class DecisionModelConfig(BaseModel):
    model_type: ModelType = eval(decision_settings["DecisionModelConfig"]["model_type"])
    model_path: Path = eval(pipeline_decision_settings["DecisionModelConfig"]["model_path"])

class ModelType(str, Enum):
    RULE_BASED = "rule based"
    MACHINE_LEARNING = "machine learning"

DECISION_MODEL_PATH = PROJECT_DIR / "models" / "whatever.json"

-- EDIT --

This is what we intend to have:

class DecisionModelConfig(BaseModel):
    model_type: ModelType = ModelType.RULE_BASED
    model_path: Path = DECISION_MODEL_PATH

This is what we get if we directly use the dict keys(without eval on it) - we get the deserialized data in form of string

class DecisionModelConfig(BaseModel):
    model_type: ModelType = "ModelType.RULE_BASED"
    model_path: Path = "DECISION_MODEL_PATH"

Using eval however evaluates the string and we are good.

Soumya
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  • Do you need arbitrary Python expressions in your data? If your need is for serializing enum values only, please check https://stackoverflow.com/questions/24481852/serialising-an-enum-member-to-json – Tugrul Ates Aug 03 '22 at 04:55
  • @TugrulAtes It's not only for enum. It can have any python expressions. – Soumya Aug 03 '22 at 04:57
  • In the code you're showing us, you're evaluating a string and getting back the identical string. – Frank Yellin Aug 03 '22 at 07:02
  • @FrankYellin Thanks for your time. I have added an edit to show what we intend to get, and what we get if we directly use the dict keys(without eval on it). – Soumya Aug 03 '22 at 07:17
  • Does it need to be json? You may have a look at "Constructors, representers, resolvers" in the yaml documentation, see https://pyyaml.org/wiki/PyYAMLDocumentation – Carlos Horn Aug 03 '22 at 07:22

0 Answers0