Pydantic : Comment charger et stocker un modèle dans un fichier YAML (exemple minimal)

Voici un exemple minimal de comment charger et stocker un modèle Pydantic dans un fichier YAML.

Ce code inclut de la logique pour sélectionner le premier chemin qui est inscriptible, ce qui rend facile son utilisation par ex. à la fois dans un conteneur et pour le développement local

pydantic_yaml_example.py

from pydantic import BaseModel, ValidationError, Field
import yaml
import os

class MySettings(BaseModel):
    variable1: float = Field(default=1.5, help="TODO enter your description here")
    variable2: str = Field(default="foobar", help="TODO enter your description here")

    _default_paths = ['/data/settings.yaml', './settings.yaml']

    @classmethod
    def from_yaml(cls) -> 'MySettings':
        for path in cls._default_paths.default:
            if os.path.exists(path):
                with open(path, 'r', encoding="utf-8") as f:
                    data = yaml.safe_load(f)
                return cls(**data)
        # If no files exist, return a Settings instance with default values
        print(f"None of the settings files found in {cls._default_paths}. Initializing with default values.")
        _settings = cls()
        _settings.save_to_first_writable_path()
        return _settings

    def save_to_first_writable_path(self) -> None:
        for path in self._default_paths:
            try:
                with open(path, 'w', encoding="utf-8") as f:
                    yaml.safe_dump(self.model_dump(), f)
                print(f"Settings saved to {path}")
                return
            except IOError:
                print(f"Unable to write to {path}")
        raise IOError(f"None of the paths in {self._default_paths} are writable.")

    def to_yaml(self) -> None:
        self.save_to_first_writable_path()

# Global settings singleton
global_settings = MySettings.from_yaml()

from pydantic import BaseModel, ValidationError, Field
import yaml
import os

class MySettings(BaseModel):
    variable1: float = Field(default=1.5, help="TODO enter your description here")
    variable2: str = Field(default="foobar", help="TODO enter your description here")

    _default_paths = ['/data/settings.yaml', './settings.yaml']

    @classmethod
    def from_yaml(cls) -> 'MySettings':
        for path in cls._default_paths.default:
            if os.path.exists(path):
                with open(path, 'r', encoding="utf-8") as f:
                    data = yaml.safe_load(f)
                return cls(**data)
        # If no files exist, return a Settings instance with default values
        print(f"None of the settings files found in {cls._default_paths}. Initializing with default values.")
        _settings = cls()
        _settings.save_to_first_writable_path()
        return _settings

    def save_to_first_writable_path(self) -> None:
        for path in self._default_paths:
            try:
                with open(path, 'w', encoding="utf-8") as f:
                    yaml.safe_dump(self.model_dump(), f)
                print(f"Settings saved to {path}")
                return
            except IOError:
                print(f"Unable to write to {path}")
        raise IOError(f"None of the paths in {self._default_paths} are writable.")

    def to_yaml(self) -> None:
        self.save_to_first_writable_path()

# Global settings singleton
global_settings = MySettings.from_yaml()

Une fois modifié, vous pouvez le sauvegarder en utilisant

pydantic_yaml_save.py

global_settings.save_to_first_writable_path()

global_settings.save_to_first_writable_path()