What's the recommended way to access settings loaded from previous sources?

[AndreuCodina]

My BaseSettings uses 2 settings sources: env_settings and Azure Key Vault.

class ApplicationSettings(BaseSettings):
    @classmethod
    def settings_customise_sources(
        cls,
        settings_cls: Any,
        init_settings: PydanticBaseSettingsSource,
        env_settings: PydanticBaseSettingsSource,
        dotenv_settings: PydanticBaseSettingsSource,
        file_secret_settings: PydanticBaseSettingsSource,
    ) -> Tuple[PydanticBaseSettingsSource]:
        return (
            env_settings,
            AzureKeyVaultSettingsSource(
                settings_cls,
                os.environ['AZURE_KEY_VAULT__URL'],
                DefaultAzureCredential()
            ),
        )

In a .env file I have the URL to access to Azure Key Vault:

AZURE_KEY_VAULT="https://my-resource.vault.azure.net/"

And then in ApplicationSettings I need to use the URL provided by env_settings to configure the Azure Key Vault setting source.

In ASP.NET Core we can do this because each setting source loads the settings in a common place, and they're loaded one by one. For example:

builder.Configuration.AddJsonFile("...");

var keyVaultUrl = builder.Configuration.GetValue<string>("AzureKeyVault");

builder.Configuration.AddAzureKeyVault(keyVaultUrl, ...);

[hramezani]

In pydantic-settings V2(current major version), you can't access the values loaded by other settings sources.
There is an open issue for that.

You can have a different settings class for this and load it before.

class AzureKeyVaultSettings(BaseSettings):
    url: str


class ApplicationSettings(BaseSettings):
    @classmethod
    def settings_customise_sources(
        cls,
        settings_cls: Any,
        init_settings: PydanticBaseSettingsSource,
        env_settings: PydanticBaseSettingsSource,
        dotenv_settings: PydanticBaseSettingsSource,
        file_secret_settings: PydanticBaseSettingsSource,
    ) -> Tuple[PydanticBaseSettingsSource]:
        s = AzureKeyVaultSettings()
        return (
            env_settings,
            AzureKeyVaultSettingsSource(
                settings_cls,
                s.url,
                DefaultAzureCredential()
            ),
        )