Source code for heat.engine.clients

#    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.

import weakref

from oslo_config import cfg
from oslo_log import log as logging
from oslo_utils import importutils
from stevedore import enabled

from heat.common import exception
from heat.common.i18n import _
from heat.common import pluginutils

LOG = logging.getLogger(__name__)

_default_backend = "heat.engine.clients.OpenStackClients"

cloud_opts = [
               help=_("Fully qualified class name to use as "
                      "a client backend."))

[docs]class OpenStackClients(object): """Convenience class to create and cache client instances.""" def __init__(self, context): self._context = weakref.ref(context) self._clients = {} self._client_plugins = {} @property def context(self): ctxt = self._context() assert ctxt is not None, "Need a reference to the context" return ctxt
[docs] def client_plugin(self, name): global _mgr if name in self._client_plugins: return self._client_plugins[name] if _mgr and name in _mgr.names(): client_plugin = _mgr[name].plugin(self.context) self._client_plugins[name] = client_plugin return client_plugin
[docs] def client(self, name, version=None): client_plugin = self.client_plugin(name) if client_plugin: if version: return client_plugin.client(version=version) else: return client_plugin.client() if name in self._clients: return self._clients[name] # call the local method _<name>() if a real client plugin # doesn't exist method_name = '_%s' % name if callable(getattr(self, method_name, None)): client = getattr(self, method_name)() self._clients[name] = client return client LOG.warning('Requested client "%s" not found', name)
[docs]class ClientBackend(object): """Class for delaying choosing the backend client module. Delay choosing the backend client module until the client's class needs to be initialized. """ def __new__(cls, context): if cfg.CONF.cloud_backend == _default_backend: return OpenStackClients(context) else: try: return importutils.import_object(cfg.CONF.cloud_backend, context) except (ImportError, RuntimeError, cfg.NoSuchOptError) as err: msg = _('Invalid cloud_backend setting in heat.conf ' 'detected - %s') % str(err) LOG.error(msg) raise exception.Invalid(reason=msg)
Clients = ClientBackend _mgr = None
[docs]def has_client(name): return _mgr and name in _mgr.names()
[docs]def initialise(): global _mgr if _mgr: return def client_is_available(client_plugin): if not hasattr(client_plugin.plugin, 'is_available'): # if the client does not have a is_available() class method, then # we assume it wants to be always available return True # let the client plugin decide if it wants to register or not return client_plugin.plugin.is_available() _mgr = enabled.EnabledExtensionManager( namespace='heat.clients', check_func=client_is_available, invoke_on_load=False, on_load_failure_callback=pluginutils.log_fail_msg)
[docs]def list_opts(): yield None, cloud_opts