Source code for lago.plugins
#!/usr/bin/env python
#
# Copyright 2014 Red Hat, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#
# Refer to the README and COPYING files for full details of the license
#
"""
"""
from stevedore import ExtensionManager
import logging
LOGGER = logging.getLogger(__name__)
#: Map of plugin type string -> setuptools entry point
PLUGIN_ENTRY_POINTS = {
'cli': 'lago.plugins.cli',
'out': 'lago.plugins.output',
'vm': 'lago.plugins.vm',
'vm-service': 'lago.plugins.vm_service',
'vm-provider': 'lago.plugins.vm_provider',
}
[docs]class PluginError(Exception):
pass
[docs]class NoSuchPluginError(PluginError):
pass
[docs]class Plugin(object):
"""
Base class for all the plugins
"""
pass
[docs]def load_plugins(namespace, instantiate=True):
"""
Loads all the plugins for the given namespace
Args:
namespace(str): Namespace string, as in the setuptools entry_points
instantiate(bool): If true, will instantiate the plugins too
Returns:
dict of str, object: Returns the list of loaded plugins
"""
mgr = ExtensionManager(
namespace=namespace,
on_load_failure_callback=(
lambda _, ep, err: LOGGER.
debug('Could not load %r: %s', ep.name, err)
)
)
if instantiate:
plugins = dict(
(
ext.name, ext.plugin if isinstance(ext.plugin, Plugin) else
ext.plugin()
) for ext in mgr
)
else:
plugins = dict((ext.name, ext.plugin) for ext in mgr)
return plugins