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# Copyright 2011 VMware, Inc
# All Rights Reserved.
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
from collections import defaultdict
from neutron_lib.plugins import constants as lib_const
from neutron_lib.plugins import directory
from neutron_lib.utils import runtime
from oslo_config import cfg
from oslo_log import log as logging
import oslo_messaging
from oslo_service import periodic_task
from oslo_utils import excutils
from osprofiler import profiler
import six
from neutron._i18n import _
from neutron.common import utils
from neutron.plugins.common import constants
LOG = logging.getLogger(__name__)
CORE_PLUGINS_NAMESPACE = 'neutron.core_plugins'
class ManagerMeta(profiler.TracedMeta, type(periodic_task.PeriodicTasks)):
class Manager(periodic_task.PeriodicTasks):
__trace_args__ = {"name": "rpc"}
# Set RPC API version to 1.0 by default.
target = oslo_messaging.Target(version='1.0')
def __init__(self, host=None):
if not host:
host = = host
conf = getattr(self, "conf", cfg.CONF)
super(Manager, self).__init__(conf)
def periodic_tasks(self, context, raise_on_error=False):
self.run_periodic_tasks(context, raise_on_error=raise_on_error)
def init_host(self):
"""Handle initialization if this is a standalone service.
Child classes should override this method.
def after_start(self):
"""Handler post initialization stuff.
Child classes can override this method.
def validate_post_plugin_load():
"""Checks if the configuration variables are valid.
If the configuration is invalid then the method will return an error
message. If all is OK then it will return None.
if ('dhcp_agents_per_network' in cfg.CONF and
cfg.CONF.dhcp_agents_per_network <= 0):
msg = _("dhcp_agents_per_network must be >= 1. '%s' "
"is invalid.") % cfg.CONF.dhcp_agents_per_network
return msg
def validate_pre_plugin_load():
"""Checks if the configuration variables are valid.
If the configuration is invalid then the method will return an error
message. If all is OK then it will return None.
if cfg.CONF.core_plugin is None:
msg = _('Neutron core_plugin not configured!')
return msg
class NeutronManager(object):
"""Neutron's Manager class.
Neutron's Manager class is responsible for parsing a config file and
instantiating the correct plugin that concretely implements
neutron_plugin_base class.
# TODO(armax): use of the singleton pattern for this class is vestigial,
# and it is mainly relied on by the unit tests. It is safer to get rid
# of it once the entire codebase (neutron + subprojects) has switched
# entirely to using the plugins directory.
_instance = None
__trace_args__ = {"name": "rpc"}
def __init__(self, options=None, config_file=None):
# If no options have been provided, create an empty dict
if not options:
options = {}
msg = validate_pre_plugin_load()
if msg:
raise Exception(msg)
# NOTE(jkoelker) Testing for the subclass with the __subclasshook__
# breaks tach monitoring. It has been removed
# intentionally to allow v2 plugins to be monitored
# for performance metrics.
plugin_provider = cfg.CONF.core_plugin"Loading core plugin: %s", plugin_provider)
# NOTE(armax): keep hold of the actual plugin object
plugin = self._get_plugin_instance(CORE_PLUGINS_NAMESPACE,
directory.add_plugin(lib_const.CORE, plugin)
msg = validate_post_plugin_load()
if msg:
raise Exception(msg)
# load services from the core plugin first
# Used by pecan WSGI
self.resource_plugin_mappings = {}
self.resource_controller_mappings = {}
self.path_prefix_resource_mappings = defaultdict(list)
def load_class_for_provider(namespace, plugin_provider):
"""Loads plugin using alias or class name
:param namespace: namespace where alias is defined
:param plugin_provider: plugin alias or class name
:returns: plugin that is loaded
:raises ImportError: if fails to load plugin
return runtime.load_class_by_alias_or_classname(namespace,
except ImportError:
with excutils.save_and_reraise_exception():
LOG.error("Plugin '%s' not found.", plugin_provider)
def _get_plugin_instance(self, namespace, plugin_provider):
plugin_class = self.load_class_for_provider(namespace, plugin_provider)
return plugin_class()
def _load_services_from_core_plugin(self, plugin):
"""Puts core plugin in service_plugins for supported services."""
LOG.debug("Loading services supported by the core plugin")
# supported service types are derived from supported extensions
for ext_alias in getattr(plugin, "supported_extension_aliases", []):
if ext_alias in constants.EXT_TO_SERVICE_MAPPING:
service_type = constants.EXT_TO_SERVICE_MAPPING[ext_alias]
directory.add_plugin(service_type, plugin)"Service %s is supported by the core plugin",
def _get_default_service_plugins(self):
"""Get default service plugins to be loaded."""
core_plugin = directory.get_plugin()
if core_plugin.has_native_datastore():
return constants.DEFAULT_SERVICE_PLUGINS.keys()
return []
def _load_service_plugins(self):
"""Loads service plugins.
Starts from the core plugin and checks if it supports
advanced services then loads classes provided in configuration.
plugin_providers = cfg.CONF.service_plugins
LOG.debug("Loading service plugins: %s", plugin_providers)
for provider in plugin_providers:
if provider == '':
continue"Loading Plugin: %s", provider)
plugin_inst = self._get_plugin_instance('neutron.service_plugins',
# only one implementation of svc_type allowed
# specifying more than one plugin
# for the same type is a fatal exception
# TODO(armax): simplify this by moving the conditional into the
# directory itself.
plugin_type = plugin_inst.get_plugin_type()
if directory.get_plugin(plugin_type):
raise ValueError(_("Multiple plugins for service "
"%s were configured") % plugin_type)
directory.add_plugin(plugin_type, plugin_inst)
# search for possible agent notifiers declared in service plugin
# (needed by agent management extension)
plugin = directory.get_plugin()
if (hasattr(plugin, 'agent_notifiers') and
hasattr(plugin_inst, 'agent_notifiers')):
# disable incompatible extensions in core plugin if any
utils.disable_extension_by_service_plugin(plugin, plugin_inst)
LOG.debug("Successfully loaded %(type)s plugin. "
"Description: %(desc)s",
{"type": plugin_type,
"desc": plugin_inst.get_plugin_description()})
def _create_instance(cls):
if not cls.has_instance():
cls._instance = cls()
def has_instance(cls):
return cls._instance is not None
def clear_instance(cls):
cls._instance = None
def get_instance(cls):
# double checked locking
if not cls.has_instance():
return cls._instance
def set_plugin_for_resource(cls, resource, plugin):
cls.get_instance().resource_plugin_mappings[resource] = plugin
def get_plugin_for_resource(cls, resource):
return cls.get_instance().resource_plugin_mappings.get(resource)
def set_controller_for_resource(cls, resource, controller):
cls.get_instance().resource_controller_mappings[resource] = controller
def get_controller_for_resource(cls, resource):
resource = resource.replace('_', '-')
res_ctrl_mappings = cls.get_instance().resource_controller_mappings
# If no controller is found for resource, try replacing dashes with
# underscores
return res_ctrl_mappings.get(
res_ctrl_mappings.get(resource.replace('-', '_')))
# TODO(blogan): This isn't used by anything else other than tests and
# probably should be removed
def get_service_plugin_by_path_prefix(cls, path_prefix):
service_plugins = directory.get_unique_plugins()
for service_plugin in service_plugins:
plugin_path_prefix = getattr(service_plugin, 'path_prefix', None)
if plugin_path_prefix and plugin_path_prefix == path_prefix:
return service_plugin
def add_resource_for_path_prefix(cls, resource, path_prefix):
resources = cls.get_instance().path_prefix_resource_mappings[
return resources
def get_resources_for_path_prefix(cls, path_prefix):
return cls.get_instance().path_prefix_resource_mappings[path_prefix]
def init():
"""Call to load the plugins (core+services) machinery."""
if not directory.is_loaded():