Class ConfigComponent

monai/bundle/config_item.py:164–292

Subclass of :py:class:`monai.bundle.ConfigItem`, this class uses a dictionary with string keys to represent a component of `class` or `function` and supports instantiation. Currently, three special keys (strings surrounded by ``_``) are defined and interpreted beyond the regular litera

class ConfigComponent(ConfigItem, Instantiable):
    """
    Subclass of :py:class:`monai.bundle.ConfigItem`, this class uses a dictionary with string keys to
    represent a component of `class` or `function` and supports instantiation.

    Currently, three special keys (strings surrounded by ``_``) are defined and interpreted beyond the regular literals:

        - class or function identifier of the python module, specified by ``"_target_"``,
          indicating a monai built-in Python class or function such as ``"LoadImageDict"``,
          or a full module name, e.g. ``"monai.transforms.LoadImageDict"``, or a callable, e.g. ``"$@model.forward"``.
        - ``"_requires_"`` (optional): specifies reference IDs (string starts with ``"@"``) or ``ConfigExpression``
          of the dependencies for this ``ConfigComponent`` object. These dependencies will be
          evaluated/instantiated before this object is instantiated.  It is useful when the
          component doesn't explicitly depend on the other `ConfigItems` via its arguments,
          but requires the dependencies to be instantiated/evaluated beforehand.
        - ``"_disabled_"`` (optional): a flag to indicate whether to skip the instantiation.
        - ``"_desc_"`` (optional): free text descriptions of the component for code readability.
        - ``"_mode_"`` (optional): operating mode for invoking the callable ``component`` defined by ``"_target_"``:

            - ``"default"``: returns ``component(**kwargs)``
            - ``"callable"``: returns ``component`` or, if ``kwargs`` are provided, ``functools.partial(component, **kwargs)``
            - ``"debug"``: returns ``pdb.runcall(component, **kwargs)``

    Other fields in the config content are input arguments to the python module.

    .. code-block:: python

        from monai.bundle import ComponentLocator, ConfigComponent

        locator = ComponentLocator(excludes=["modules_to_exclude"])
        config = {
            "_target_": "LoadImaged",
            "keys": ["image", "label"]
        }

        configer = ConfigComponent(config, id="test", locator=locator)
        image_loader = configer.instantiate()
        print(image_loader)  # <monai.transforms.io.dictionary.LoadImaged object at 0x7fba7ad1ee50>

    Args:
        config: content of a config item.
        id: name of the current config item, defaults to empty string.
        locator: a ``ComponentLocator`` to convert a module name string into the actual python module.
            if `None`, a ``ComponentLocator(excludes=excludes)`` will be used.
        excludes: if ``locator`` is None, create a new ``ComponentLocator`` with ``excludes``.
            See also: :py:class:`monai.bundle.ComponentLocator`.

    """

    non_arg_keys = {"_target_", "_disabled_", "_requires_", "_desc_", "_mode_"}

    def __init__(
        self,
        config: Any,
        id: str = "",
        locator: ComponentLocator | None = None,
        excludes: Sequence[str] | str | None = None,
    ) -> None: