Class Loader

invoke/loader.py:14–96

Abstract class defining how to find/import a session's base `.Collection`. .. versionadded:: 1.0

class Loader:
    """
    Abstract class defining how to find/import a session's base `.Collection`.

    .. versionadded:: 1.0
    """

    def __init__(self, config: Optional["Config"] = None) -> None:
        """
        Set up a new loader with some `.Config`.

        :param config:
            An explicit `.Config` to use; it is referenced for loading-related
            config options. Defaults to an anonymous ``Config()`` if none is
            given.
        """
        if config is None:
            config = Config()
        self.config = config

    def find(self, name: str) -> Optional[ModuleSpec]:
        """
        Implementation-specific finder method seeking collection ``name``.

        Must return a ModuleSpec valid for use by `importlib`, which is
        typically a name string followed by the contents of the 3-tuple
        returned by `importlib.util.module_from_spec` (``name``, ``loader``,
        ``origin``.)

        For a sample implementation, see `.FilesystemLoader`.

        .. versionadded:: 1.0
        """
        raise NotImplementedError

    def load(self, name: Optional[str] = None) -> Tuple[ModuleType, str]:
        """
        Load and return collection module identified by ``name``.

        This method requires a working implementation of `.find` in order to
        function.

        In addition to importing the named module, it will add the module's
        parent directory to the front of `sys.path` to provide normal Python
        import behavior (i.e. so the loaded module may load local-to-it modules
        or packages.)

        :returns:
            Two-tuple of ``(module, directory)`` where ``module`` is the
            collection-containing Python module object, and ``directory`` is
            the string path to the directory the module was found in.

        .. versionadded:: 1.0
        """
        if name is None:
            name = self.config.tasks.collection_name
        spec = self.find(name)
        if spec and spec.loader and spec.origin: