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
# 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
    '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',, err ) ) ) if instantiate: plugins = dict( (, ext.plugin if isinstance(ext.plugin, Plugin) else ext.plugin() ) for ext in mgr ) else: plugins = dict((, ext.plugin) for ext in mgr) return plugins