stevedore/stevedore/enabled.py
Chris Yeoh b617873a99 Update docstrings for map exception propagation
Updates docstrings related to map exception propagation
and the history.rst file
2013-06-21 13:55:00 +09:30

58 lines
2.1 KiB
Python

import logging
from .extension import ExtensionManager
LOG = logging.getLogger(__name__)
class EnabledExtensionManager(ExtensionManager):
"""Loads only plugins that pass a check function.
The check_func argument should return a boolean, with ``True``
indicating that the extension should be loaded and made available
and ``False`` indicating that the extension should be ignored.
:param namespace: The namespace for the entry points.
:type namespace: str
:param check_func: Function to determine which extensions to load.
:type check_func: callable
:param invoke_on_load: Boolean controlling whether to invoke the
object returned by the entry point after the driver is loaded.
:type invoke_on_load: bool
:param invoke_args: Positional arguments to pass when invoking
the object returned by the entry point. Only used if invoke_on_load
is True.
:type invoke_args: tuple
:param invoke_kwds: Named arguments to pass when invoking
the object returned by the entry point. Only used if invoke_on_load
is True.
:type invoke_kwds: dict
:param propagate_map_exceptions: Boolean controlling whether exceptions
are propagated up through the map call or whether they are logged and
then ignored
:type invoke_on_load: bool
"""
def __init__(self, namespace, check_func, invoke_on_load=False,
invoke_args=(), invoke_kwds={},
propagate_map_exceptions=False):
self.check_func = check_func
super(EnabledExtensionManager, self).__init__(
namespace,
invoke_on_load=invoke_on_load,
invoke_args=invoke_args,
invoke_kwds=invoke_kwds,
propagate_map_exceptions=propagate_map_exceptions,
)
def _load_one_plugin(self, ep, invoke_on_load, invoke_args, invoke_kwds):
ext = super(EnabledExtensionManager, self)._load_one_plugin(
ep, invoke_on_load, invoke_args, invoke_kwds,
)
if ext and not self.check_func(ext):
LOG.debug('ignoring extension %r', ep.name)
return None
return ext