stevedore/stevedore/enabled.py
2012-07-22 16:54:13 -04:00

44 lines
1.9 KiB
Python

from .extension import ExtensionManager
class EnabledExtensionManager(ExtensionManager):
"""An ExtensionManager that only loads plugins that pass a check function.
The check_func 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
"""
def __init__(self, namespace, check_func, invoke_on_load=False,
invoke_args=(), invoke_kwds={}):
self.check_func = check_func
super(EnabledExtensionManager, self).__init__(namespace,
invoke_on_load=invoke_on_load,
invoke_args=invoke_args,
invoke_kwds=invoke_kwds,
)
def _load_one_plugin(self, ep, invoke_on_load, invoke_args, invoke_kwds):
if not self.check_func(ep):
LOG.debug('ignoring extension %r', ep.name)
return None
return super(EnabledExtensionManager, self)._load_one_plugin(
ep, invoke_on_load, invoke_args, invoke_kwds,
)