Pydantic Settings

BaseSettings

BaseSettings(
    __pydantic_self__,
    _case_sensitive: bool | None = None,
    _nested_model_default_partial_update: (
        bool | None
    ) = None,
    _env_prefix: str | None = None,
    _env_file: DotenvType | None = ENV_FILE_SENTINEL,
    _env_file_encoding: str | None = None,
    _env_ignore_empty: bool | None = None,
    _env_nested_delimiter: str | None = None,
    _env_parse_none_str: str | None = None,
    _env_parse_enums: bool | None = None,
    _cli_prog_name: str | None = None,
    _cli_parse_args: (
        bool | list[str] | tuple[str, ...] | None
    ) = None,
    _cli_settings_source: (
        CliSettingsSource[Any] | None
    ) = None,
    _cli_parse_none_str: str | None = None,
    _cli_hide_none_type: bool | None = None,
    _cli_avoid_json: bool | None = None,
    _cli_enforce_required: bool | None = None,
    _cli_use_class_docs_for_groups: bool | None = None,
    _cli_exit_on_error: bool | None = None,
    _cli_prefix: str | None = None,
    _cli_flag_prefix_char: str | None = None,
    _cli_implicit_flags: bool | None = None,
    _cli_ignore_unknown_args: bool | None = None,
    _secrets_dir: PathType | None = None,
    **values: Any
)

Bases: BaseModel

Base class for settings, allowing values to be overridden by environment variables.

This is useful in production for secrets you do not wish to save in code, it plays nicely with docker(-compose), Heroku and any 12 factor app design.

All the below attributes can be set via model_config.

Parameters:

Name	Type	Description	Default
_case_sensitive	bool | None	Whether environment and CLI variable names should be read with case-sensitivity. Defaults to None.	None
_nested_model_default_partial_update	bool | None	Whether to allow partial updates on nested model default object fields. Defaults to False.	None
_env_prefix	str | None	Prefix for all environment variables. Defaults to None.	None
_env_file	DotenvType | None	The env file(s) to load settings values from. Defaults to Path(''), which means that the value from model_config['env_file'] should be used. You can also pass None to indicate that environment variables should not be loaded from an env file.	ENV_FILE_SENTINEL
_env_file_encoding	str | None	The env file encoding, e.g. 'latin-1'. Defaults to None.	None
_env_ignore_empty	bool | None	Ignore environment variables where the value is an empty string. Default to False.	None
_env_nested_delimiter	str | None	The nested env values delimiter. Defaults to None.	None
_env_parse_none_str	str | None	The env string value that should be parsed (e.g. "null", "void", "None", etc.) into None type(None). Defaults to None type(None), which means no parsing should occur.	None
_env_parse_enums	bool | None	Parse enum field names to values. Defaults to None., which means no parsing should occur.	None
_cli_prog_name	str | None	The CLI program name to display in help text. Defaults to None if _cli_parse_args is None. Otherwse, defaults to sys.argv[0].	None
_cli_parse_args	bool | list[str] | tuple[str, ...] | None	The list of CLI arguments to parse. Defaults to None. If set to True, defaults to sys.argv[1:].	None
_cli_settings_source	CliSettingsSource[Any] | None	Override the default CLI settings source with a user defined instance. Defaults to None.	None
_cli_parse_none_str	str | None	The CLI string value that should be parsed (e.g. "null", "void", "None", etc.) into None type(None). Defaults to _env_parse_none_str value if set. Otherwise, defaults to "null" if _cli_avoid_json is False, and "None" if _cli_avoid_json is True.	None
_cli_hide_none_type	bool | None	Hide None values in CLI help text. Defaults to False.	None
_cli_avoid_json	bool | None	Avoid complex JSON objects in CLI help text. Defaults to False.	None
_cli_enforce_required	bool | None	Enforce required fields at the CLI. Defaults to False.	None
_cli_use_class_docs_for_groups	bool | None	Use class docstrings in CLI group help text instead of field descriptions. Defaults to False.	None
_cli_exit_on_error	bool | None	Determines whether or not the internal parser exits with error info when an error occurs. Defaults to True.	None
_cli_prefix	str | None	The root parser command line arguments prefix. Defaults to "".	None
_cli_flag_prefix_char	str | None	The flag prefix character to use for CLI optional arguments. Defaults to '-'.	None
_cli_implicit_flags	bool | None	Whether bool fields should be implicitly converted into CLI boolean flags. (e.g. --flag, --no-flag). Defaults to False.	None
_cli_ignore_unknown_args	bool | None	Whether to ignore unknown CLI args and parse only known ones. Defaults to False.	None
_secrets_dir	PathType | None	The secret files directory or a sequence of directories. Defaults to None.	None

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/main.py

def __init__(
    __pydantic_self__,
    _case_sensitive: bool | None = None,
    _nested_model_default_partial_update: bool | None = None,
    _env_prefix: str | None = None,
    _env_file: DotenvType | None = ENV_FILE_SENTINEL,
    _env_file_encoding: str | None = None,
    _env_ignore_empty: bool | None = None,
    _env_nested_delimiter: str | None = None,
    _env_parse_none_str: str | None = None,
    _env_parse_enums: bool | None = None,
    _cli_prog_name: str | None = None,
    _cli_parse_args: bool | list[str] | tuple[str, ...] | None = None,
    _cli_settings_source: CliSettingsSource[Any] | None = None,
    _cli_parse_none_str: str | None = None,
    _cli_hide_none_type: bool | None = None,
    _cli_avoid_json: bool | None = None,
    _cli_enforce_required: bool | None = None,
    _cli_use_class_docs_for_groups: bool | None = None,
    _cli_exit_on_error: bool | None = None,
    _cli_prefix: str | None = None,
    _cli_flag_prefix_char: str | None = None,
    _cli_implicit_flags: bool | None = None,
    _cli_ignore_unknown_args: bool | None = None,
    _secrets_dir: PathType | None = None,
    **values: Any,
) -> None:
    # Uses something other than `self` the first arg to allow "self" as a settable attribute
    super().__init__(
        **__pydantic_self__._settings_build_values(
            values,
            _case_sensitive=_case_sensitive,
            _nested_model_default_partial_update=_nested_model_default_partial_update,
            _env_prefix=_env_prefix,
            _env_file=_env_file,
            _env_file_encoding=_env_file_encoding,
            _env_ignore_empty=_env_ignore_empty,
            _env_nested_delimiter=_env_nested_delimiter,
            _env_parse_none_str=_env_parse_none_str,
            _env_parse_enums=_env_parse_enums,
            _cli_prog_name=_cli_prog_name,
            _cli_parse_args=_cli_parse_args,
            _cli_settings_source=_cli_settings_source,
            _cli_parse_none_str=_cli_parse_none_str,
            _cli_hide_none_type=_cli_hide_none_type,
            _cli_avoid_json=_cli_avoid_json,
            _cli_enforce_required=_cli_enforce_required,
            _cli_use_class_docs_for_groups=_cli_use_class_docs_for_groups,
            _cli_exit_on_error=_cli_exit_on_error,
            _cli_prefix=_cli_prefix,
            _cli_flag_prefix_char=_cli_flag_prefix_char,
            _cli_implicit_flags=_cli_implicit_flags,
            _cli_ignore_unknown_args=_cli_ignore_unknown_args,
            _secrets_dir=_secrets_dir,
        )
    )

settings_customise_sources classmethod

settings_customise_sources(
    settings_cls: type[BaseSettings],
    init_settings: PydanticBaseSettingsSource,
    env_settings: PydanticBaseSettingsSource,
    dotenv_settings: PydanticBaseSettingsSource,
    file_secret_settings: PydanticBaseSettingsSource,
) -> tuple[PydanticBaseSettingsSource, ...]

Define the sources and their order for loading the settings values.

Parameters:

Name	Type	Description	Default
settings_cls	type[BaseSettings]	The Settings class.	required
init_settings	PydanticBaseSettingsSource	The InitSettingsSource instance.	required
env_settings	PydanticBaseSettingsSource	The EnvSettingsSource instance.	required
dotenv_settings	PydanticBaseSettingsSource	The DotEnvSettingsSource instance.	required
file_secret_settings	PydanticBaseSettingsSource	The SecretsSettingsSource instance.	required

Returns:

Type	Description
tuple[PydanticBaseSettingsSource, ...]	A tuple containing the sources and their order for loading the settings values.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/main.py

@classmethod
def settings_customise_sources(
    cls,
    settings_cls: type[BaseSettings],
    init_settings: PydanticBaseSettingsSource,
    env_settings: PydanticBaseSettingsSource,
    dotenv_settings: PydanticBaseSettingsSource,
    file_secret_settings: PydanticBaseSettingsSource,
) -> tuple[PydanticBaseSettingsSource, ...]:
    """
    Define the sources and their order for loading the settings values.

    Args:
        settings_cls: The Settings class.
        init_settings: The `InitSettingsSource` instance.
        env_settings: The `EnvSettingsSource` instance.
        dotenv_settings: The `DotEnvSettingsSource` instance.
        file_secret_settings: The `SecretsSettingsSource` instance.

    Returns:
        A tuple containing the sources and their order for loading the settings values.
    """
    return init_settings, env_settings, dotenv_settings, file_secret_settings

CliApp

A utility class for running Pydantic BaseSettings, BaseModel, or pydantic.dataclasses.dataclass as CLI applications.

run staticmethod

run(
    model_cls: type[T],
    cli_args: (
        list[str]
        | Namespace
        | SimpleNamespace
        | dict[str, Any]
        | None
    ) = None,
    cli_settings_source: (
        CliSettingsSource[Any] | None
    ) = None,
    cli_exit_on_error: bool | None = None,
    cli_cmd_method_name: str = "cli_cmd",
    **model_init_data: Any
) -> T

Runs a Pydantic BaseSettings, BaseModel, or pydantic.dataclasses.dataclass as a CLI application. Running a model as a CLI application requires the cli_cmd method to be defined in the model class.

Parameters:

Name	Type	Description	Default
model_cls	type[T]	The model class to run as a CLI application.	required
cli_args	list[str] | Namespace | SimpleNamespace | dict[str, Any] | None	The list of CLI arguments to parse. If cli_settings_source is specified, this may also be a namespace or dictionary of pre-parsed CLI arguments. Defaults to sys.argv[1:].	None
cli_settings_source	CliSettingsSource[Any] | None	Override the default CLI settings source with a user defined instance. Defaults to None.	None
cli_exit_on_error	bool | None	Determines whether this function exits on error. If model is subclass of BaseSettings, defaults to BaseSettings cli_exit_on_error value. Otherwise, defaults to True.	None
cli_cmd_method_name	str	The CLI command method name to run. Defaults to "cli_cmd".	'cli_cmd'
model_init_data	Any	The model init data.	{}

Returns:

Type	Description
T	The ran instance of model.

Raises:

Type	Description
SettingsError	If model_cls is not subclass of BaseModel or pydantic.dataclasses.dataclass.
SettingsError	If model_cls does not have a cli_cmd entrypoint defined.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/main.py

@staticmethod
def run(
    model_cls: type[T],
    cli_args: list[str] | Namespace | SimpleNamespace | dict[str, Any] | None = None,
    cli_settings_source: CliSettingsSource[Any] | None = None,
    cli_exit_on_error: bool | None = None,
    cli_cmd_method_name: str = 'cli_cmd',
    **model_init_data: Any,
) -> T:
    """
    Runs a Pydantic `BaseSettings`, `BaseModel`, or `pydantic.dataclasses.dataclass` as a CLI application.
    Running a model as a CLI application requires the `cli_cmd` method to be defined in the model class.

    Args:
        model_cls: The model class to run as a CLI application.
        cli_args: The list of CLI arguments to parse. If `cli_settings_source` is specified, this may
            also be a namespace or dictionary of pre-parsed CLI arguments. Defaults to `sys.argv[1:]`.
        cli_settings_source: Override the default CLI settings source with a user defined instance.
            Defaults to `None`.
        cli_exit_on_error: Determines whether this function exits on error. If model is subclass of
            `BaseSettings`, defaults to BaseSettings `cli_exit_on_error` value. Otherwise, defaults to
            `True`.
        cli_cmd_method_name: The CLI command method name to run. Defaults to "cli_cmd".
        model_init_data: The model init data.

    Returns:
        The ran instance of model.

    Raises:
        SettingsError: If model_cls is not subclass of `BaseModel` or `pydantic.dataclasses.dataclass`.
        SettingsError: If model_cls does not have a `cli_cmd` entrypoint defined.
    """

    if not (is_pydantic_dataclass(model_cls) or is_model_class(model_cls)):
        raise SettingsError(
            f'Error: {model_cls.__name__} is not subclass of BaseModel or pydantic.dataclasses.dataclass'
        )

    cli_settings = None
    cli_parse_args = True if cli_args is None else cli_args
    if cli_settings_source is not None:
        if isinstance(cli_parse_args, (Namespace, SimpleNamespace, dict)):
            cli_settings = cli_settings_source(parsed_args=cli_parse_args)
        else:
            cli_settings = cli_settings_source(args=cli_parse_args)
    elif isinstance(cli_parse_args, (Namespace, SimpleNamespace, dict)):
        raise SettingsError('Error: `cli_args` must be list[str] or None when `cli_settings_source` is not used')

    model_init_data['_cli_parse_args'] = cli_parse_args
    model_init_data['_cli_exit_on_error'] = cli_exit_on_error
    model_init_data['_cli_settings_source'] = cli_settings
    if not issubclass(model_cls, BaseSettings):

        class CliAppBaseSettings(BaseSettings, model_cls):  # type: ignore
            model_config = SettingsConfigDict(
                alias_generator=AliasGenerator(lambda s: s.replace('_', '-')),
                nested_model_default_partial_update=True,
                case_sensitive=True,
                cli_hide_none_type=True,
                cli_avoid_json=True,
                cli_enforce_required=True,
                cli_implicit_flags=True,
            )

        model = CliAppBaseSettings(**model_init_data)
        model_init_data = {}
        for field_name, field_info in model.model_fields.items():
            model_init_data[_field_name_for_signature(field_name, field_info)] = getattr(model, field_name)

    return CliApp._run_cli_cmd(model_cls(**model_init_data), cli_cmd_method_name, is_required=False)

run_subcommand staticmethod

run_subcommand(
    model: PydanticModel,
    cli_exit_on_error: bool | None = None,
    cli_cmd_method_name: str = "cli_cmd",
) -> PydanticModel

Runs the model subcommand. Running a model subcommand requires the cli_cmd method to be defined in the nested model subcommand class.

Parameters:

Name	Type	Description	Default
model	PydanticModel	The model to run the subcommand from.	required
cli_exit_on_error	bool | None	Determines whether this function exits with error if no subcommand is found. Defaults to model_config cli_exit_on_error value if set. Otherwise, defaults to True.	None
cli_cmd_method_name	str	The CLI command method name to run. Defaults to "cli_cmd".	'cli_cmd'

Returns:

Type	Description
PydanticModel	The ran subcommand model.

Raises:

Type	Description
SystemExit	When no subcommand is found and cli_exit_on_error=True (the default).
SettingsError	When no subcommand is found and cli_exit_on_error=False.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/main.py

@staticmethod
def run_subcommand(
    model: PydanticModel, cli_exit_on_error: bool | None = None, cli_cmd_method_name: str = 'cli_cmd'
) -> PydanticModel:
    """
    Runs the model subcommand. Running a model subcommand requires the `cli_cmd` method to be defined in
    the nested model subcommand class.

    Args:
        model: The model to run the subcommand from.
        cli_exit_on_error: Determines whether this function exits with error if no subcommand is found.
            Defaults to model_config `cli_exit_on_error` value if set. Otherwise, defaults to `True`.
        cli_cmd_method_name: The CLI command method name to run. Defaults to "cli_cmd".

    Returns:
        The ran subcommand model.

    Raises:
        SystemExit: When no subcommand is found and cli_exit_on_error=`True` (the default).
        SettingsError: When no subcommand is found and cli_exit_on_error=`False`.
    """

    subcommand = get_subcommand(model, is_required=True, cli_exit_on_error=cli_exit_on_error)
    return CliApp._run_cli_cmd(subcommand, cli_cmd_method_name, is_required=True)

SettingsConfigDict

Bases: ConfigDict

pyproject_toml_depth instance-attribute

pyproject_toml_depth: int

Number of levels up from the current working directory to attempt to find a pyproject.toml file.

This is only used when a pyproject.toml file is not found in the current working directory.

pyproject_toml_table_header instance-attribute

pyproject_toml_table_header: tuple[str, ...]

Header of the TOML table within a pyproject.toml file to use when filling variables. This is supplied as a tuple[str, ...] instead of a str to accommodate for headers containing a ..

For example, toml_table_header = ("tool", "my.tool", "foo") can be used to fill variable values from a table with header [tool."my.tool".foo].

To use the root table, exclude this config setting or provide an empty tuple.

CliSettingsSource

CliSettingsSource(
    settings_cls: type[BaseSettings],
    cli_prog_name: str | None = None,
    cli_parse_args: (
        bool | list[str] | tuple[str, ...] | None
    ) = None,
    cli_parse_none_str: str | None = None,
    cli_hide_none_type: bool | None = None,
    cli_avoid_json: bool | None = None,
    cli_enforce_required: bool | None = None,
    cli_use_class_docs_for_groups: bool | None = None,
    cli_exit_on_error: bool | None = None,
    cli_prefix: str | None = None,
    cli_flag_prefix_char: str | None = None,
    cli_implicit_flags: bool | None = None,
    cli_ignore_unknown_args: bool | None = None,
    case_sensitive: bool | None = True,
    root_parser: Any = None,
    parse_args_method: Callable[..., Any] | None = None,
    add_argument_method: (
        Callable[..., Any] | None
    ) = ArgumentParser.add_argument,
    add_argument_group_method: (
        Callable[..., Any] | None
    ) = ArgumentParser.add_argument_group,
    add_parser_method: (
        Callable[..., Any] | None
    ) = _SubParsersAction.add_parser,
    add_subparsers_method: (
        Callable[..., Any] | None
    ) = ArgumentParser.add_subparsers,
    formatter_class: Any = RawDescriptionHelpFormatter,
)

Bases: EnvSettingsSource, Generic[T]

Source class for loading settings values from CLI.

Note

A CliSettingsSource connects with a root_parser object by using the parser methods to add settings_cls fields as command line arguments. The CliSettingsSource internal parser representation is based upon the argparse parsing library, and therefore, requires the parser methods to support the same attributes as their argparse library counterparts.

Parameters:

Name	Type	Description	Default
cli_prog_name	str | None	The CLI program name to display in help text. Defaults to None if cli_parse_args is None. Otherwse, defaults to sys.argv[0].	None
cli_parse_args	bool | list[str] | tuple[str, ...] | None	The list of CLI arguments to parse. Defaults to None. If set to True, defaults to sys.argv[1:].	None
cli_parse_none_str	str | None	The CLI string value that should be parsed (e.g. "null", "void", "None", etc.) into None type(None). Defaults to "null" if cli_avoid_json is False, and "None" if cli_avoid_json is True.	None
cli_hide_none_type	bool | None	Hide None values in CLI help text. Defaults to False.	None
cli_avoid_json	bool | None	Avoid complex JSON objects in CLI help text. Defaults to False.	None
cli_enforce_required	bool | None	Enforce required fields at the CLI. Defaults to False.	None
cli_use_class_docs_for_groups	bool | None	Use class docstrings in CLI group help text instead of field descriptions. Defaults to False.	None
cli_exit_on_error	bool | None	Determines whether or not the internal parser exits with error info when an error occurs. Defaults to True.	None
cli_prefix	str | None	Prefix for command line arguments added under the root parser. Defaults to "".	None
cli_flag_prefix_char	str | None	The flag prefix character to use for CLI optional arguments. Defaults to '-'.	None
cli_implicit_flags	bool | None	Whether bool fields should be implicitly converted into CLI boolean flags. (e.g. --flag, --no-flag). Defaults to False.	None
cli_ignore_unknown_args	bool | None	Whether to ignore unknown CLI args and parse only known ones. Defaults to False.	None
case_sensitive	bool | None	Whether CLI "--arg" names should be read with case-sensitivity. Defaults to True. Note: Case-insensitive matching is only supported on the internal root parser and does not apply to CLI subcommands.	True
root_parser	Any	The root parser object.	None
parse_args_method	Callable[..., Any] | None	The root parser parse args method. Defaults to argparse.ArgumentParser.parse_args.	None
add_argument_method	Callable[..., Any] | None	The root parser add argument method. Defaults to argparse.ArgumentParser.add_argument.	add_argument
add_argument_group_method	Callable[..., Any] | None	The root parser add argument group method. Defaults to argparse.ArgumentParser.add_argument_group.	add_argument_group
add_parser_method	Callable[..., Any] | None	The root parser add new parser (sub-command) method. Defaults to argparse._SubParsersAction.add_parser.	add_parser
add_subparsers_method	Callable[..., Any] | None	The root parser add subparsers (sub-commands) method. Defaults to argparse.ArgumentParser.add_subparsers.	add_subparsers
formatter_class	Any	A class for customizing the root parser help text. Defaults to argparse.RawDescriptionHelpFormatter.	RawDescriptionHelpFormatter

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def __init__(
    self,
    settings_cls: type[BaseSettings],
    cli_prog_name: str | None = None,
    cli_parse_args: bool | list[str] | tuple[str, ...] | None = None,
    cli_parse_none_str: str | None = None,
    cli_hide_none_type: bool | None = None,
    cli_avoid_json: bool | None = None,
    cli_enforce_required: bool | None = None,
    cli_use_class_docs_for_groups: bool | None = None,
    cli_exit_on_error: bool | None = None,
    cli_prefix: str | None = None,
    cli_flag_prefix_char: str | None = None,
    cli_implicit_flags: bool | None = None,
    cli_ignore_unknown_args: bool | None = None,
    case_sensitive: bool | None = True,
    root_parser: Any = None,
    parse_args_method: Callable[..., Any] | None = None,
    add_argument_method: Callable[..., Any] | None = ArgumentParser.add_argument,
    add_argument_group_method: Callable[..., Any] | None = ArgumentParser.add_argument_group,
    add_parser_method: Callable[..., Any] | None = _SubParsersAction.add_parser,
    add_subparsers_method: Callable[..., Any] | None = ArgumentParser.add_subparsers,
    formatter_class: Any = RawDescriptionHelpFormatter,
) -> None:
    self.cli_prog_name = (
        cli_prog_name if cli_prog_name is not None else settings_cls.model_config.get('cli_prog_name', sys.argv[0])
    )
    self.cli_hide_none_type = (
        cli_hide_none_type
        if cli_hide_none_type is not None
        else settings_cls.model_config.get('cli_hide_none_type', False)
    )
    self.cli_avoid_json = (
        cli_avoid_json if cli_avoid_json is not None else settings_cls.model_config.get('cli_avoid_json', False)
    )
    if not cli_parse_none_str:
        cli_parse_none_str = 'None' if self.cli_avoid_json is True else 'null'
    self.cli_parse_none_str = cli_parse_none_str
    self.cli_enforce_required = (
        cli_enforce_required
        if cli_enforce_required is not None
        else settings_cls.model_config.get('cli_enforce_required', False)
    )
    self.cli_use_class_docs_for_groups = (
        cli_use_class_docs_for_groups
        if cli_use_class_docs_for_groups is not None
        else settings_cls.model_config.get('cli_use_class_docs_for_groups', False)
    )
    self.cli_exit_on_error = (
        cli_exit_on_error
        if cli_exit_on_error is not None
        else settings_cls.model_config.get('cli_exit_on_error', True)
    )
    self.cli_prefix = cli_prefix if cli_prefix is not None else settings_cls.model_config.get('cli_prefix', '')
    self.cli_flag_prefix_char = (
        cli_flag_prefix_char
        if cli_flag_prefix_char is not None
        else settings_cls.model_config.get('cli_flag_prefix_char', '-')
    )
    self._cli_flag_prefix = self.cli_flag_prefix_char * 2
    if self.cli_prefix:
        if cli_prefix.startswith('.') or cli_prefix.endswith('.') or not cli_prefix.replace('.', '').isidentifier():  # type: ignore
            raise SettingsError(f'CLI settings source prefix is invalid: {cli_prefix}')
        self.cli_prefix += '.'
    self.cli_implicit_flags = (
        cli_implicit_flags
        if cli_implicit_flags is not None
        else settings_cls.model_config.get('cli_implicit_flags', False)
    )
    self.cli_ignore_unknown_args = (
        cli_ignore_unknown_args
        if cli_ignore_unknown_args is not None
        else settings_cls.model_config.get('cli_ignore_unknown_args', False)
    )

    case_sensitive = case_sensitive if case_sensitive is not None else True
    if not case_sensitive and root_parser is not None:
        raise SettingsError('Case-insensitive matching is only supported on the internal root parser')

    super().__init__(
        settings_cls,
        env_nested_delimiter='.',
        env_parse_none_str=self.cli_parse_none_str,
        env_parse_enums=True,
        env_prefix=self.cli_prefix,
        case_sensitive=case_sensitive,
    )

    root_parser = (
        _CliInternalArgParser(
            cli_exit_on_error=self.cli_exit_on_error,
            prog=self.cli_prog_name,
            description=None if settings_cls.__doc__ is None else dedent(settings_cls.__doc__),
            formatter_class=formatter_class,
            prefix_chars=self.cli_flag_prefix_char,
        )
        if root_parser is None
        else root_parser
    )
    self._connect_root_parser(
        root_parser=root_parser,
        parse_args_method=parse_args_method,
        add_argument_method=add_argument_method,
        add_argument_group_method=add_argument_group_method,
        add_parser_method=add_parser_method,
        add_subparsers_method=add_subparsers_method,
        formatter_class=formatter_class,
    )

    if cli_parse_args not in (None, False):
        if cli_parse_args is True:
            cli_parse_args = sys.argv[1:]
        elif not isinstance(cli_parse_args, (list, tuple)):
            raise SettingsError(
                f'cli_parse_args must be List[str] or Tuple[str, ...], recieved {type(cli_parse_args)}'
            )
        self._load_env_vars(parsed_args=self._parse_args(self.root_parser, cli_parse_args))

root_parser property

root_parser: T

The connected root parser instance.

DotEnvSettingsSource

DotEnvSettingsSource(
    settings_cls: type[BaseSettings],
    env_file: DotenvType | None = ENV_FILE_SENTINEL,
    env_file_encoding: str | None = None,
    case_sensitive: bool | None = None,
    env_prefix: str | None = None,
    env_nested_delimiter: str | None = None,
    env_ignore_empty: bool | None = None,
    env_parse_none_str: str | None = None,
    env_parse_enums: bool | None = None,
)

Bases: EnvSettingsSource

Source class for loading settings values from env files.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def __init__(
    self,
    settings_cls: type[BaseSettings],
    env_file: DotenvType | None = ENV_FILE_SENTINEL,
    env_file_encoding: str | None = None,
    case_sensitive: bool | None = None,
    env_prefix: str | None = None,
    env_nested_delimiter: str | None = None,
    env_ignore_empty: bool | None = None,
    env_parse_none_str: str | None = None,
    env_parse_enums: bool | None = None,
) -> None:
    self.env_file = env_file if env_file != ENV_FILE_SENTINEL else settings_cls.model_config.get('env_file')
    self.env_file_encoding = (
        env_file_encoding if env_file_encoding is not None else settings_cls.model_config.get('env_file_encoding')
    )
    super().__init__(
        settings_cls,
        case_sensitive,
        env_prefix,
        env_nested_delimiter,
        env_ignore_empty,
        env_parse_none_str,
        env_parse_enums,
    )

EnvSettingsSource

EnvSettingsSource(
    settings_cls: type[BaseSettings],
    case_sensitive: bool | None = None,
    env_prefix: str | None = None,
    env_nested_delimiter: str | None = None,
    env_ignore_empty: bool | None = None,
    env_parse_none_str: str | None = None,
    env_parse_enums: bool | None = None,
)

Bases: PydanticBaseEnvSettingsSource

Source class for loading settings values from environment variables.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def __init__(
    self,
    settings_cls: type[BaseSettings],
    case_sensitive: bool | None = None,
    env_prefix: str | None = None,
    env_nested_delimiter: str | None = None,
    env_ignore_empty: bool | None = None,
    env_parse_none_str: str | None = None,
    env_parse_enums: bool | None = None,
) -> None:
    super().__init__(
        settings_cls, case_sensitive, env_prefix, env_ignore_empty, env_parse_none_str, env_parse_enums
    )
    self.env_nested_delimiter = (
        env_nested_delimiter if env_nested_delimiter is not None else self.config.get('env_nested_delimiter')
    )
    self.env_prefix_len = len(self.env_prefix)

    self.env_vars = self._load_env_vars()

get_field_value

get_field_value(
    field: FieldInfo, field_name: str
) -> tuple[Any, str, bool]

Gets the value for field from environment variables and a flag to determine whether value is complex.

Parameters:

Name	Type	Description	Default
field	FieldInfo	The field.	required
field_name	str	The field name.	required

Returns:

Type	Description
tuple[Any, str, bool]	A tuple contains the key, value if the file exists otherwise None, and a flag to determine whether value is complex.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def get_field_value(self, field: FieldInfo, field_name: str) -> tuple[Any, str, bool]:
    """
    Gets the value for field from environment variables and a flag to determine whether value is complex.

    Args:
        field: The field.
        field_name: The field name.

    Returns:
        A tuple contains the key, value if the file exists otherwise `None`, and
            a flag to determine whether value is complex.
    """

    env_val: str | None = None
    for field_key, env_name, value_is_complex in self._extract_field_info(field, field_name):
        env_val = self.env_vars.get(env_name)
        if env_val is not None:
            break

    return env_val, field_key, value_is_complex

prepare_field_value

prepare_field_value(
    field_name: str,
    field: FieldInfo,
    value: Any,
    value_is_complex: bool,
) -> Any

Prepare value for the field.

• Extract value for nested field.
• Deserialize value to python object for complex field.

Parameters:

Name	Type	Description	Default
field	FieldInfo	The field.	required
field_name	str	The field name.	required

Returns:

Type	Description
Any	A tuple contains prepared value for the field.

Raises:

Type	Description
ValuesError	When There is an error in deserializing value for complex field.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def prepare_field_value(self, field_name: str, field: FieldInfo, value: Any, value_is_complex: bool) -> Any:
    """
    Prepare value for the field.

    * Extract value for nested field.
    * Deserialize value to python object for complex field.

    Args:
        field: The field.
        field_name: The field name.

    Returns:
        A tuple contains prepared value for the field.

    Raises:
        ValuesError: When There is an error in deserializing value for complex field.
    """
    is_complex, allow_parse_failure = self._field_is_complex(field)
    if self.env_parse_enums:
        enum_val = _annotation_enum_name_to_val(field.annotation, value)
        value = value if enum_val is None else enum_val

    if is_complex or value_is_complex:
        if isinstance(value, EnvNoneType):
            return value
        elif value is None:
            # field is complex but no value found so far, try explode_env_vars
            env_val_built = self.explode_env_vars(field_name, field, self.env_vars)
            if env_val_built:
                return env_val_built
        else:
            # field is complex and there's a value, decode that as JSON, then add explode_env_vars
            try:
                value = self.decode_complex_value(field_name, field, value)
            except ValueError as e:
                if not allow_parse_failure:
                    raise e

            if isinstance(value, dict):
                return deep_update(value, self.explode_env_vars(field_name, field, self.env_vars))
            else:
                return value
    elif value is not None:
        # simplest case, field is not complex, we only need to add the value if it was found
        return value

next_field

next_field(
    field: FieldInfo | Any | None,
    key: str,
    case_sensitive: bool | None = None,
) -> FieldInfo | None

Find the field in a sub model by key(env name)

By having the following models:

```py
class SubSubModel(BaseSettings):
    dvals: Dict

class SubModel(BaseSettings):
    vals: list[str]
    sub_sub_model: SubSubModel

class Cfg(BaseSettings):
    sub_model: SubModel
```

Then

next_field(sub_model, 'vals') Returns the vals field of SubModel class next_field(sub_model, 'sub_sub_model') Returns sub_sub_model field of SubModel class

Parameters:

Name	Type	Description	Default
field	FieldInfo | Any | None	The field.	required
key	str	The key (env name).	required
case_sensitive	bool | None	Whether to search for key case sensitively.	None

Returns:

Type	Description
FieldInfo | None	Field if it finds the next field otherwise None.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def next_field(
    self, field: FieldInfo | Any | None, key: str, case_sensitive: bool | None = None
) -> FieldInfo | None:
    """
    Find the field in a sub model by key(env name)

    By having the following models:

        ```py
        class SubSubModel(BaseSettings):
            dvals: Dict

        class SubModel(BaseSettings):
            vals: list[str]
            sub_sub_model: SubSubModel

        class Cfg(BaseSettings):
            sub_model: SubModel
        ```

    Then:
        next_field(sub_model, 'vals') Returns the `vals` field of `SubModel` class
        next_field(sub_model, 'sub_sub_model') Returns `sub_sub_model` field of `SubModel` class

    Args:
        field: The field.
        key: The key (env name).
        case_sensitive: Whether to search for key case sensitively.

    Returns:
        Field if it finds the next field otherwise `None`.
    """
    if not field:
        return None

    annotation = field.annotation if isinstance(field, FieldInfo) else field
    if origin_is_union(get_origin(annotation)) or isinstance(annotation, WithArgsTypes):
        for type_ in get_args(annotation):
            type_has_key = self.next_field(type_, key, case_sensitive)
            if type_has_key:
                return type_has_key
    elif is_model_class(annotation) or is_pydantic_dataclass(annotation):
        fields = _get_model_fields(annotation)
        # `case_sensitive is None` is here to be compatible with the old behavior.
        # Has to be removed in V3.
        for field_name, f in fields.items():
            for _, env_name, _ in self._extract_field_info(f, field_name):
                if case_sensitive is None or case_sensitive:
                    if field_name == key or env_name == key:
                        return f
                elif field_name.lower() == key.lower() or env_name.lower() == key.lower():
                    return f
    return None

explode_env_vars

explode_env_vars(
    field_name: str,
    field: FieldInfo,
    env_vars: Mapping[str, str | None],
) -> dict[str, Any]

Process env_vars and extract the values of keys containing env_nested_delimiter into nested dictionaries.

This is applied to a single field, hence filtering by env_var prefix.

Parameters:

Name	Type	Description	Default
field_name	str	The field name.	required
field	FieldInfo	The field.	required
env_vars	Mapping[str, str | None]	Environment variables.	required

Returns:

Type	Description
dict[str, Any]	A dictionary contains extracted values from nested env values.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def explode_env_vars(self, field_name: str, field: FieldInfo, env_vars: Mapping[str, str | None]) -> dict[str, Any]:
    """
    Process env_vars and extract the values of keys containing env_nested_delimiter into nested dictionaries.

    This is applied to a single field, hence filtering by env_var prefix.

    Args:
        field_name: The field name.
        field: The field.
        env_vars: Environment variables.

    Returns:
        A dictionary contains extracted values from nested env values.
    """
    is_dict = lenient_issubclass(get_origin(field.annotation), dict)

    prefixes = [
        f'{env_name}{self.env_nested_delimiter}' for _, env_name, _ in self._extract_field_info(field, field_name)
    ]
    result: dict[str, Any] = {}
    for env_name, env_val in env_vars.items():
        if not any(env_name.startswith(prefix) for prefix in prefixes):
            continue
        # we remove the prefix before splitting in case the prefix has characters in common with the delimiter
        env_name_without_prefix = env_name[self.env_prefix_len :]
        _, *keys, last_key = env_name_without_prefix.split(self.env_nested_delimiter)
        env_var = result
        target_field: FieldInfo | None = field
        for key in keys:
            target_field = self.next_field(target_field, key, self.case_sensitive)
            if isinstance(env_var, dict):
                env_var = env_var.setdefault(key, {})

        # get proper field with last_key
        target_field = self.next_field(target_field, last_key, self.case_sensitive)

        # check if env_val maps to a complex field and if so, parse the env_val
        if (target_field or is_dict) and env_val:
            if target_field:
                is_complex, allow_json_failure = self._field_is_complex(target_field)
            else:
                # nested field type is dict
                is_complex, allow_json_failure = True, True
            if is_complex:
                try:
                    env_val = self.decode_complex_value(last_key, target_field, env_val)  # type: ignore
                except ValueError as e:
                    if not allow_json_failure:
                        raise e
        if isinstance(env_var, dict):
            if last_key not in env_var or not isinstance(env_val, EnvNoneType) or env_var[last_key] == {}:
                env_var[last_key] = env_val

    return result

InitSettingsSource

InitSettingsSource(
    settings_cls: type[BaseSettings],
    init_kwargs: dict[str, Any],
    nested_model_default_partial_update: bool | None = None,
)

Bases: PydanticBaseSettingsSource

Source class for loading values provided during settings class initialization.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def __init__(
    self,
    settings_cls: type[BaseSettings],
    init_kwargs: dict[str, Any],
    nested_model_default_partial_update: bool | None = None,
):
    self.init_kwargs = init_kwargs
    super().__init__(settings_cls)
    self.nested_model_default_partial_update = (
        nested_model_default_partial_update
        if nested_model_default_partial_update is not None
        else self.config.get('nested_model_default_partial_update', False)
    )

JsonConfigSettingsSource

JsonConfigSettingsSource(
    settings_cls: type[BaseSettings],
    json_file: PathType | None = DEFAULT_PATH,
    json_file_encoding: str | None = None,
)

Bases: InitSettingsSource, ConfigFileSourceMixin

A source class that loads variables from a JSON file

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def __init__(
    self,
    settings_cls: type[BaseSettings],
    json_file: PathType | None = DEFAULT_PATH,
    json_file_encoding: str | None = None,
):
    self.json_file_path = json_file if json_file != DEFAULT_PATH else settings_cls.model_config.get('json_file')
    self.json_file_encoding = (
        json_file_encoding
        if json_file_encoding is not None
        else settings_cls.model_config.get('json_file_encoding')
    )
    self.json_data = self._read_files(self.json_file_path)
    super().__init__(settings_cls, self.json_data)

PydanticBaseSettingsSource

PydanticBaseSettingsSource(
    settings_cls: type[BaseSettings],
)

Bases: ABC

Abstract base class for settings sources, every settings source classes should inherit from it.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def __init__(self, settings_cls: type[BaseSettings]):
    self.settings_cls = settings_cls
    self.config = settings_cls.model_config
    self._current_state: dict[str, Any] = {}
    self._settings_sources_data: dict[str, dict[str, Any]] = {}

current_state property

current_state: dict[str, Any]

The current state of the settings, populated by the previous settings sources.

settings_sources_data property

settings_sources_data: dict[str, dict[str, Any]]

The state of all previous settings sources.

get_field_value abstractmethod

get_field_value(
    field: FieldInfo, field_name: str
) -> tuple[Any, str, bool]

Gets the value, the key for model creation, and a flag to determine whether value is complex.

This is an abstract method that should be overridden in every settings source classes.

Parameters:

Name	Type	Description	Default
field	FieldInfo	The field.	required
field_name	str	The field name.	required

Returns:

Type	Description
tuple[Any, str, bool]	A tuple contains the key, value and a flag to determine whether value is complex.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

@abstractmethod
def get_field_value(self, field: FieldInfo, field_name: str) -> tuple[Any, str, bool]:
    """
    Gets the value, the key for model creation, and a flag to determine whether value is complex.

    This is an abstract method that should be overridden in every settings source classes.

    Args:
        field: The field.
        field_name: The field name.

    Returns:
        A tuple contains the key, value and a flag to determine whether value is complex.
    """
    pass

field_is_complex

field_is_complex(field: FieldInfo) -> bool

Checks whether a field is complex, in which case it will attempt to be parsed as JSON.

Parameters:

Name	Type	Description	Default
field	FieldInfo	The field.	required

Returns:

Type	Description
bool	Whether the field is complex.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def field_is_complex(self, field: FieldInfo) -> bool:
    """
    Checks whether a field is complex, in which case it will attempt to be parsed as JSON.

    Args:
        field: The field.

    Returns:
        Whether the field is complex.
    """
    return _annotation_is_complex(field.annotation, field.metadata)

prepare_field_value

prepare_field_value(
    field_name: str,
    field: FieldInfo,
    value: Any,
    value_is_complex: bool,
) -> Any

Prepares the value of a field.

Parameters:

Name	Type	Description	Default
field_name	str	The field name.	required
field	FieldInfo	The field.	required
value	Any	The value of the field that has to be prepared.	required
value_is_complex	bool	A flag to determine whether value is complex.	required

Returns:

Type	Description
Any	The prepared value.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def prepare_field_value(self, field_name: str, field: FieldInfo, value: Any, value_is_complex: bool) -> Any:
    """
    Prepares the value of a field.

    Args:
        field_name: The field name.
        field: The field.
        value: The value of the field that has to be prepared.
        value_is_complex: A flag to determine whether value is complex.

    Returns:
        The prepared value.
    """
    if value is not None and (self.field_is_complex(field) or value_is_complex):
        return self.decode_complex_value(field_name, field, value)
    return value

decode_complex_value

decode_complex_value(
    field_name: str, field: FieldInfo, value: Any
) -> Any

Decode the value for a complex field

Parameters:

Name	Type	Description	Default
field_name	str	The field name.	required
field	FieldInfo	The field.	required
value	Any	The value of the field that has to be prepared.	required

Returns:

Type	Description
Any	The decoded value for further preparation

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def decode_complex_value(self, field_name: str, field: FieldInfo, value: Any) -> Any:
    """
    Decode the value for a complex field

    Args:
        field_name: The field name.
        field: The field.
        value: The value of the field that has to be prepared.

    Returns:
        The decoded value for further preparation
    """
    return json.loads(value)

PyprojectTomlConfigSettingsSource

PyprojectTomlConfigSettingsSource(
    settings_cls: type[BaseSettings],
    toml_file: Path | None = None,
)

Bases: TomlConfigSettingsSource

A source class that loads variables from a pyproject.toml file.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def __init__(
    self,
    settings_cls: type[BaseSettings],
    toml_file: Path | None = None,
) -> None:
    self.toml_file_path = self._pick_pyproject_toml_file(
        toml_file, settings_cls.model_config.get('pyproject_toml_depth', 0)
    )
    self.toml_table_header: tuple[str, ...] = settings_cls.model_config.get(
        'pyproject_toml_table_header', ('tool', 'pydantic-settings')
    )
    self.toml_data = self._read_files(self.toml_file_path)
    for key in self.toml_table_header:
        self.toml_data = self.toml_data.get(key, {})
    super(TomlConfigSettingsSource, self).__init__(settings_cls, self.toml_data)

SecretsSettingsSource

SecretsSettingsSource(
    settings_cls: type[BaseSettings],
    secrets_dir: PathType | None = None,
    case_sensitive: bool | None = None,
    env_prefix: str | None = None,
    env_ignore_empty: bool | None = None,
    env_parse_none_str: str | None = None,
    env_parse_enums: bool | None = None,
)

Bases: PydanticBaseEnvSettingsSource

Source class for loading settings values from secret files.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def __init__(
    self,
    settings_cls: type[BaseSettings],
    secrets_dir: PathType | None = None,
    case_sensitive: bool | None = None,
    env_prefix: str | None = None,
    env_ignore_empty: bool | None = None,
    env_parse_none_str: str | None = None,
    env_parse_enums: bool | None = None,
) -> None:
    super().__init__(
        settings_cls, case_sensitive, env_prefix, env_ignore_empty, env_parse_none_str, env_parse_enums
    )
    self.secrets_dir = secrets_dir if secrets_dir is not None else self.config.get('secrets_dir')

find_case_path classmethod

find_case_path(
    dir_path: Path, file_name: str, case_sensitive: bool
) -> Path | None

Find a file within path's directory matching filename, optionally ignoring case.

Parameters:

Name	Type	Description	Default
dir_path	Path	Directory path.	required
file_name	str	File name.	required
case_sensitive	bool	Whether to search for file name case sensitively.	required

Returns:

Type	Description
Path | None	Whether file path or None if file does not exist in directory.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

@classmethod
def find_case_path(cls, dir_path: Path, file_name: str, case_sensitive: bool) -> Path | None:
    """
    Find a file within path's directory matching filename, optionally ignoring case.

    Args:
        dir_path: Directory path.
        file_name: File name.
        case_sensitive: Whether to search for file name case sensitively.

    Returns:
        Whether file path or `None` if file does not exist in directory.
    """
    for f in dir_path.iterdir():
        if f.name == file_name:
            return f
        elif not case_sensitive and f.name.lower() == file_name.lower():
            return f
    return None

get_field_value

get_field_value(
    field: FieldInfo, field_name: str
) -> tuple[Any, str, bool]

Gets the value for field from secret file and a flag to determine whether value is complex.

Parameters:

Name	Type	Description	Default
field	FieldInfo	The field.	required
field_name	str	The field name.	required

Returns:

Type	Description
tuple[Any, str, bool]	A tuple contains the key, value if the file exists otherwise None, and a flag to determine whether value is complex.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def get_field_value(self, field: FieldInfo, field_name: str) -> tuple[Any, str, bool]:
    """
    Gets the value for field from secret file and a flag to determine whether value is complex.

    Args:
        field: The field.
        field_name: The field name.

    Returns:
        A tuple contains the key, value if the file exists otherwise `None`, and
            a flag to determine whether value is complex.
    """

    for field_key, env_name, value_is_complex in self._extract_field_info(field, field_name):
        # paths reversed to match the last-wins behaviour of `env_file`
        for secrets_path in reversed(self.secrets_paths):
            path = self.find_case_path(secrets_path, env_name, self.case_sensitive)
            if not path:
                # path does not exist, we currently don't return a warning for this
                continue

            if path.is_file():
                return path.read_text().strip(), field_key, value_is_complex
            else:
                warnings.warn(
                    f'attempted to load secret file "{path}" but found a {path_type_label(path)} instead.',
                    stacklevel=4,
                )

    return None, field_key, value_is_complex

TomlConfigSettingsSource

TomlConfigSettingsSource(
    settings_cls: type[BaseSettings],
    toml_file: PathType | None = DEFAULT_PATH,
)

Bases: InitSettingsSource, ConfigFileSourceMixin

A source class that loads variables from a TOML file

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def __init__(
    self,
    settings_cls: type[BaseSettings],
    toml_file: PathType | None = DEFAULT_PATH,
):
    self.toml_file_path = toml_file if toml_file != DEFAULT_PATH else settings_cls.model_config.get('toml_file')
    self.toml_data = self._read_files(self.toml_file_path)
    super().__init__(settings_cls, self.toml_data)

YamlConfigSettingsSource

YamlConfigSettingsSource(
    settings_cls: type[BaseSettings],
    yaml_file: PathType | None = DEFAULT_PATH,
    yaml_file_encoding: str | None = None,
)

Bases: InitSettingsSource, ConfigFileSourceMixin

A source class that loads variables from a yaml file

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def __init__(
    self,
    settings_cls: type[BaseSettings],
    yaml_file: PathType | None = DEFAULT_PATH,
    yaml_file_encoding: str | None = None,
):
    self.yaml_file_path = yaml_file if yaml_file != DEFAULT_PATH else settings_cls.model_config.get('yaml_file')
    self.yaml_file_encoding = (
        yaml_file_encoding
        if yaml_file_encoding is not None
        else settings_cls.model_config.get('yaml_file_encoding')
    )
    self.yaml_data = self._read_files(self.yaml_file_path)
    super().__init__(settings_cls, self.yaml_data)

get_subcommand

get_subcommand(
    model: PydanticModel,
    is_required: bool = True,
    cli_exit_on_error: bool | None = None,
) -> Optional[PydanticModel]

Get the subcommand from a model.

Parameters:

Name	Type	Description	Default
model	PydanticModel	The model to get the subcommand from.	required
is_required	bool	Determines whether a model must have subcommand set and raises error if not found. Defaults to True.	True
cli_exit_on_error	bool | None	Determines whether this function exits with error if no subcommand is found. Defaults to model_config cli_exit_on_error value if set. Otherwise, defaults to True.	None

Returns:

Type	Description
Optional[PydanticModel]	The subcommand model if found, otherwise None.

Raises:

Type	Description
SystemExit	When no subcommand is found and is_required=True and cli_exit_on_error=True (the default).
SettingsError	When no subcommand is found and is_required=True and cli_exit_on_error=False.

Source code in .venv/lib/python3.12/site-packages/pydantic_settings/sources.py

def get_subcommand(
    model: PydanticModel, is_required: bool = True, cli_exit_on_error: bool | None = None
) -> Optional[PydanticModel]:
    """
    Get the subcommand from a model.

    Args:
        model: The model to get the subcommand from.
        is_required: Determines whether a model must have subcommand set and raises error if not
            found. Defaults to `True`.
        cli_exit_on_error: Determines whether this function exits with error if no subcommand is found.
            Defaults to model_config `cli_exit_on_error` value if set. Otherwise, defaults to `True`.

    Returns:
        The subcommand model if found, otherwise `None`.

    Raises:
        SystemExit: When no subcommand is found and is_required=`True` and cli_exit_on_error=`True`
            (the default).
        SettingsError: When no subcommand is found and is_required=`True` and
            cli_exit_on_error=`False`.
    """

    model_cls = type(model)
    if cli_exit_on_error is None and is_model_class(model_cls):
        model_default = model_cls.model_config.get('cli_exit_on_error')
        if isinstance(model_default, bool):
            cli_exit_on_error = model_default
    if cli_exit_on_error is None:
        cli_exit_on_error = True

    subcommands: list[str] = []
    for field_name, field_info in _get_model_fields(model_cls).items():
        if _CliSubCommand in field_info.metadata:
            if getattr(model, field_name) is not None:
                return getattr(model, field_name)
            subcommands.append(field_name)

    if is_required:
        error_message = (
            f'Error: CLI subcommand is required {{{", ".join(subcommands)}}}'
            if subcommands
            else 'Error: CLI subcommand is required but no subcommands were found.'
        )
        raise SystemExit(error_message) if cli_exit_on_error else SettingsError(error_message)

    return None