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utils.config.configuration

Configuration Objects​

class Configuration()

Encapsulates configuration settings and their fallback default values.

Settings can be loaded from a configuration file (in TOML format) or provided as environment variables (see below).

All settings are accessed by an identifier of type SettingID, which represents settings in a path-like format; General.Debug, for example, refers to a setting called Debug in the ``General` section.

A corresponding configuration file would look like this::

[General] Debug = True

A setting identifier is translated to its corresponding environment variable name by replacing all dots (.) with underscores (_), prepending a prefix (defaults to 'RDS'), as well as making everything uppercase::

General.Debug -> RDS_GENERAL_DEBUG

Notes:

When accessing a setting value, a default value must always be present. This means that before a setting can be accessed, a default value must be added using add_defaults.

__init__​

def __init__(env_prefix: str = "RDS")

Arguments:

  • env_prefix - The prefix to use when generating the environment variable name of a setting.

load​

def load(filename: str) -> None

Loads settings from a TOML file.

Arguments:

  • filename - The file to load.

Raises:

  • FileNotFoundError - If the specified file doesn't exist or couldn't be opened.

add_defaults​

def add_defaults(defaults: typing.Dict[SettingID, typing.Any]) -> None

Adds default values for settings, merging the new defaults into the existing ones.

Arguments:

  • defaults - A dictionary containing the new default values.

Notes:

It is always necessary to add a default value for a setting before accessing it.

value​

def value(key: SettingID) -> typing.Any

Gets the value of a setting.

The value is first looked up in the environment variables. If not found, the loaded settings are searched. If that also fails, the defaults are used.

Arguments:

  • key - The identifier of the setting.

Returns:

The value of the setting.

Raises:

  • KeyError - The setting identifier was not found in the defaults.

value_with_default​

def value_with_default(key: SettingID, default: typing.Any) -> typing.Any

Gets the value of a setting.

The value is first looked up in the environment variables. If not found, the loaded settings are searched.

Arguments:

  • key - The identifier of the setting.
  • default - The default fallback value.

Returns:

The value of the setting.

settings_file​

@property
def settings_file() -> str

The name of the currently loaded settings file.