Source code for pyscaffold.extensions

Built-in extensions for PyScaffold.
import argparse
import sys
import textwrap
from typing import Callable, Iterable, List, Optional, Type

from ..actions import Action, register, unregister
from ..exceptions import ErrorLoadingExtension
from ..identification import dasherize, deterministic_sort, underscore

if sys.version_info[:2] >= (3, 8):
    # TODO: Import directly (no need for conditional) when `python_requires = >= 3.8`
    from importlib.metadata import EntryPoint, entry_points  # pragma: no cover
    from importlib_metadata import EntryPoint, entry_points  # pragma: no cover

ENTRYPOINT_GROUP = "pyscaffold.cli"

NO_LONGER_NEEDED = {"pyproject", "tox"}
"""Extensions that are no longer needed and are now part of PyScaffold itself"""

# TODO: NO_LONGER_SUPPORTED = {"no_pyproject"}

[docs]class Extension: """Base class for PyScaffold's extensions Args: name (str): How the extension should be named. Default: name of class By default, this value is used to create the activation flag in PyScaffold cli. See our docs on how to create extensions in: Also check :obj:`~pyscaffold.actions`, :obj:`~pyscaffold.structure.Structure` and :obj:`~pyscaffold.operations.ScaffoldOpts` for more details. Note: Please name your class using a CamelCase version of the name you use in the setuptools entrypoint (alternatively you will need to overwrite the ``name`` property to match the entrypoint name). """ #: When ``True`` PyScaffold will store the extension in the PyScaffold's section of #: ``setup.cfg``. Useful for updates. Set to ``False`` if the extension should not #: be re-invoked on updates. persist = True def __init__(self, name: Optional[str] = None): self._name = name or underscore(self.__class__.__name__) @property def name(self): return self._name @property def flag(self) -> str: return f"--{dasherize(}" @property def help_text(self) -> str: if self.__doc__ is None: raise NotImplementedError("Please provide a help text for your extension") doc = textwrap.dedent(self.__doc__) return doc[0].lower() + doc[1:]
[docs] def augment_cli(self, parser: argparse.ArgumentParser): """Augments the command-line interface parser. A command line argument ``--FLAG`` where FLAG=```` is added which appends ``self.activate`` to the list of extensions. As help text the docstring of the extension class is used. In most cases this method does not need to be overwritten. Args: parser: current parser object """ parser.add_argument( self.flag, dest="extensions", action="append_const", const=self, help=self.help_text, ) return self
[docs] def activate(self, actions: List[Action]) -> List[Action]: """Activates the extension by registering its functionality Args: actions (List[Action]): list of action to perform Returns: List[Action]: updated list of actions """ raise NotImplementedError(f"Extension {} has no actions registered")
#: Shortcut for :obj:`pyscaffold.actions.register` register = staticmethod(register) #: Shortcut for :obj:`pyscaffold.actions.unregister` unregister = staticmethod(unregister) def __call__(self, actions: List[Action]) -> List[Action]: """Just delegating to :obj:`self.activate`""" return self.activate(actions)
[docs]def include(*extensions: Extension) -> Type[argparse.Action]: """Create a custom :obj:`argparse.Action` that saves multiple extensions for activation. Args: *extensions: extension objects to be saved """ class IncludeExtensions(argparse.Action): """Appends the given extensions to the extensions list.""" def __call__(self, parser, namespace, values, option_string=None): ext_list = list(getattr(namespace, "extensions", [])) namespace.extensions = ext_list + list(extensions) return IncludeExtensions
[docs]def store_with(*extensions: Extension) -> Type[argparse.Action]: """Create a custom :obj:`argparse.Action` that stores the value of the given option in addition to saving the extension for activation. Args: *extensions: extension objects to be saved for activation """ class AddExtensionAndStore(include(*extensions)): # type: ignore """\ Consumes the values provided, but also appends the given extension to the extensions list. """ def __call__(self, parser, namespace, values, option_string=None): super().__call__(parser, namespace, values, option_string) setattr(namespace, self.dest, values) return AddExtensionAndStore
[docs]def iterate_entry_points(group=ENTRYPOINT_GROUP) -> Iterable[EntryPoint]: """Produces a generator yielding an EntryPoint object for each extension registered via `setuptools`_ entry point mechanism. This method can be used in conjunction with :obj:`load_from_entry_point` to filter the extensions before actually loading them. .. _setuptools: """ # noqa entries = entry_points() if hasattr(entries, "select"): # The select method was introduced in importlib_metadata 3.9 (and Python 3.10) # and the previous dict interface was declared deprecated return # type: ignore else: # TODO: Once Python 3.10 becomes the oldest version supported, this fallback and # conditional statement can be removed. return (extension for extension in entries.get(group, [])) # type: ignore
[docs]def load_from_entry_point(entry_point: EntryPoint) -> Extension: """Carefully load the extension, raising a meaningful message in case of errors""" try: return entry_point.load()( except Exception as ex: raise ErrorLoadingExtension(entry_point=entry_point) from ex
[docs]def list_from_entry_points( group: str = ENTRYPOINT_GROUP, filtering: Callable[[EntryPoint], bool] = lambda _: True, ) -> List[Extension]: """Produces a list of extension objects for each extension registered via `setuptools`_ entry point mechanism. Args: group: name of the setuptools' entry_point group where extensions is being registered filtering: function returning a boolean deciding if the entry point should be loaded and included (or not) in the final list. A ``True`` return means the extension should be included. .. _setuptools: """ # noqa return deterministic_sort( load_from_entry_point(e) for e in iterate_entry_points(group) if filtering(e) )