typed-settings 0.5

Typed settings based on attrs classes

Typed Settings

PoC for library for managing (typed) settings – for server processes as well as commandline programms.

Requirements

• Default settings are defined by app and can be overridden by config files, environment variables and click options.

• You define settings as attrs class with types, converters and validators.

• Attributes are basic data types (bool, int, float, str), lists of basic types, or nested settings classes.

• Settings can be loaded from multiple config files.

• Config files are allowed to contain settings for multiple apps (like pyproject.toml)

• Paths to config files have to be explicitly named. Most defaults are not useful in many cases and have to be changed anyways.

• Additional paths for config files can be specified via an environment variable. As in PATH, multiple paths are separated by a :. The last file in the list has the highest priority.

• Environment variables with a defined prefix override settings from config files. This can optionally be disabled.

• Click options for some or all settings can be generated. They are passed to the cli function as a single object (instead of individually).

• Settings must be explicitly loaded, either via typed_settings.load_settings() or via typed_settings.click_options().

• Both functions allow you to customize config file paths, prefixes et cetera.

Example

import click

import typed_settings as ts


@ts.settings
class Host:
    name: str
    port: int = ts.option(converter=int)


@ts.settings(kw_only=True)
class Settings:
    url: str
    default: int = 3
    host: Host = ts.option(converter=lambda d: Host(**d))


settings = ts.load_settings(
    settings_cls=Settings, appname='example', config_files=['settings.toml']
)
print(settings)


@click.command()
@ts.click_options(Settings, 'example', ['settings.toml'])
def main(settings):
    print(settings)


if __name__ == '__main__':
    main()