Support alternative value resolution for BaseSettings

[ofek]

https://github.com/pydantic/pydantic/issues/1676

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Feature Request

My use case is I'm reading a toml config file and passing what is read directly to the model constructor. However, I have no way to allow users env var or .env overrides.

Essentially, configs persisted to disk cannot benefit from BaseSettings.

[Viicos]

Hi @ofek, the way I'm currently doing it can be found here (basically defining a custom source, and rearranging the order in customise_sources). The only drawback is that I can't specify the filename (it is read from an envvar), but this might be useful still for your use case.

[alextremblay]

I've got a working implementation here that might be of interest:

https://github.com/uoft-networking/tools/blob/b1c67d6ce8def1b67af5b3ca08fe7357f595bb68/projects/core/uoft_core/__init__.py#L1209

The codebase is a mess, but it works.

Among other things it:

• reads config from env vars
• reads config from user-level and system-wide config files in yaml, toml, json, and ini formats
• reads config from toml-formatted secrets stored in pass

If there's interest, I'd love to be able to clean it up and merge into pydantic-settings.

Right now I'm in the process of updating it to pydantic V2

[hramezani]

It is possible to have a custom settings source class beside the internal pydantic-settings source classes.

You can find the related docs here : https://docs.pydantic.dev/latest/concepts/pydantic_settings/#customise-settings-sources

[ofek]

Awesome, thank you!