Function instantiate

monai/utils/module.py:207–261

Create an object instance or call a callable object from a class or function represented by ``_path``. `kwargs` will be part of the input arguments to the class constructor or function. The target component must be a class or a function, if not, return the component directly. Args:

(__path: str, __mode: str, **kwargs: Any)

def instantiate(__path: str, __mode: str, **kwargs: Any) -> Any:
    """
    Create an object instance or call a callable object from a class or function represented by ``_path``.
    `kwargs` will be part of the input arguments to the class constructor or function.
    The target component must be a class or a function, if not, return the component directly.

    Args:
        __path: if a string is provided, it's interpreted as the full path of the target class or function component.
            If a callable is provided, ``__path(**kwargs)`` will be invoked and returned for ``__mode="default"``.
            For ``__mode="callable"``, the callable will be returned as ``__path`` or, if ``kwargs`` are provided,
            as ``functools.partial(__path, **kwargs)`` for future invoking.

        __mode: the operating mode for invoking the (callable) ``component`` represented by ``__path``:

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

        kwargs: keyword arguments to the callable represented by ``__path``.

    """
    from monai.utils.enums import CompInitMode

    component = locate(__path) if isinstance(__path, str) else __path
    if component is None:
        raise ModuleNotFoundError(f"Cannot locate class or function path: '{__path}'.")
    m = look_up_option(__mode, CompInitMode)
    try:
        if kwargs.pop("_debug_", False) or run_debug:
            warnings.warn(
                f"\n\npdb: instantiating component={component}, mode={m}\n"
                f"See also Debugger commands documentation: https://docs.python.org/3/library/pdb.html\n"
            )
            breakpoint()
        if not callable(component):
            warnings.warn(f"Component {component} is not callable when mode={m}.")
            return component
        if m == CompInitMode.DEFAULT:
            return component(**kwargs)
        if m == CompInitMode.CALLABLE:
            return partial(component, **kwargs) if kwargs else component
        if m == CompInitMode.DEBUG:
            warnings.warn(
                f"\n\npdb: instantiating component={component}, mode={m}\n"
                f"See also Debugger commands documentation: https://docs.python.org/3/library/pdb.html\n"
            )
            return pdb.runcall(component, **kwargs)
    except Exception as e:
        raise RuntimeError(
            f"Failed to instantiate component '{__path}' with keywords: {','.join(kwargs.keys())}"
            f"\n set '_mode_={CompInitMode.DEBUG}' to enter the debugging mode."
        ) from e

    warnings.warn(f"Component to instantiate must represent a valid class or function, but got {__path}.")
    return component


def get_full_type_name(typeobj):