Class Application

traitlets/config/application.py:152–1082

A singleton application with full configuration support.

class Application(SingletonConfigurable):
    """A singleton application with full configuration support."""

    # The name of the application, will usually match the name of the command
    # line application
    name: str | Unicode[str, str | bytes] = Unicode("application")

    # The description of the application that is printed at the beginning
    # of the help.
    description: str | Unicode[str, str | bytes] = Unicode("This is an application.")
    # default section descriptions
    option_description: str | Unicode[str, str | bytes] = Unicode(option_description)
    keyvalue_description: str | Unicode[str, str | bytes] = Unicode(keyvalue_description)
    subcommand_description: str | Unicode[str, str | bytes] = Unicode(subcommand_description)

    python_config_loader_class = PyFileConfigLoader
    json_config_loader_class = JSONFileConfigLoader

    # The usage and example string that goes at the end of the help string.
    examples: str | Unicode[str, str | bytes] = Unicode()

    # A sequence of Configurable subclasses whose config=True attributes will
    # be exposed at the command line.
    classes: ClassesType = []

    def _classes_inc_parents(
        self, classes: ClassesType | None = None
    ) -> t.Generator[type[Configurable], None, None]:
        """Iterate through configurable classes, including configurable parents

        :param classes:
            The list of classes to iterate; if not set, uses :attr:`classes`.

        Children should always be after parents, and each class should only be
        yielded once.
        """
        if classes is None:
            classes = self.classes

        seen = set()
        for c in classes:
            # We want to sort parents before children, so we reverse the MRO
            for parent in reversed(c.mro()):
                if issubclass(parent, Configurable) and (parent not in seen):
                    seen.add(parent)
                    yield parent

    # The version string of this application.
    version: str | Unicode[str, str | bytes] = Unicode("0.0")

    # the argv used to initialize the application
    argv: list[str] | List[str] = List()

    # Whether failing to load config files should prevent startup
    raise_config_file_errors = Bool(TRAITLETS_APPLICATION_RAISE_CONFIG_FILE_ERROR)

    # The log level for the application
    log_level = Enum(