# The code in this module is mostly borrowed/adapted from PyScaffold and was originally
# published under the MIT license
# The original PyScaffold license can be found in 'tests/examples/pyscaffold'
import sys
from textwrap import dedent
from typing import Any, Callable, Iterable, List, Optional, cast
from .. import __version__
from ..types import Plugin
ENTRYPOINT_GROUP = "ini2toml.processing"
try:
if sys.version_info[:2] >= (3, 8): # pragma: no cover
# TODO: Import directly (no conditional) when `python_requires = >= 3.8`
from importlib.metadata import EntryPoint, entry_points
else: # pragma: no cover
from importlib_metadata import EntryPoint, entry_points
def iterate_entry_points(group=ENTRYPOINT_GROUP) -> Iterable[EntryPoint]:
"""Produces a generator yielding an EntryPoint object for each plugin registered
via `setuptools`_ entry point mechanism.
This method can be used in conjunction with :obj:`load_from_entry_point` to
filter the plugins before actually loading them.
.. _setuptools: https://setuptools.pypa.io/en/latest/userguide/entry_point.html
""" # noqa
entries = entry_points()
if hasattr(entries, "select"):
# The select method was introduced in importlib_metadata 3.9/3.10
# and the previous dict interface was declared deprecated
select = cast(Any, getattr(entries, "select")) # typecheck gymnastic # noqa
entries_: Iterable[EntryPoint] = select(group=group)
else:
# TODO: Once Python 3.10 becomes the oldest version supported, this fallback
# and conditional statement can be removed.
entries_ = (plugin for plugin in entries.get(group, []))
return sorted(entries_, key=lambda e: e.name)
except ImportError: # pragma: no cover
from pkg_resources import EntryPoint, iter_entry_points # type: ignore
[docs]
def iterate_entry_points(group=ENTRYPOINT_GROUP) -> Iterable[EntryPoint]:
return iter_entry_points(group)
[docs]
def load_from_entry_point(entry_point: EntryPoint) -> Plugin:
"""Carefully load the plugin, raising a meaningful message in case of errors"""
try:
return entry_point.load()
except Exception as ex:
raise ErrorLoadingPlugin(entry_point=entry_point) from ex
[docs]
def list_from_entry_points(
group: str = ENTRYPOINT_GROUP,
filtering: Callable[[EntryPoint], bool] = lambda _: True,
) -> List[Plugin]:
"""Produces a list of plugin objects for each plugin registered
via `setuptools`_ entry point mechanism.
Args:
group: name of the setuptools' entry_point group where plugins 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
plugin should be included.
.. _setuptools: https://setuptools.pypa.io/en/latest/userguide/entry_point.html
""" # noqa
return [
load_from_entry_point(e) for e in iterate_entry_points(group) if filtering(e)
]
[docs]
class ErrorLoadingPlugin(RuntimeError):
"""There was an error loading '{plugin}'.
Please make sure you have installed a version of the plugin that is compatible
with {package} {version}. You can also try uninstalling it.
"""
def __init__(self, plugin: str = "", entry_point: Optional[EntryPoint] = None):
if entry_point and not plugin:
plugin = getattr(entry_point, "module", entry_point.name)
sub = dict(package=__package__, version=__version__, plugin=plugin)
msg = dedent(self.__doc__ or "").format(**sub).splitlines()
super().__init__(f"{msg[0]}\n{' '.join(msg[1:])}")