Source code for heat.engine.parent_rsrc

#    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
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#    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 heat.objects import resource as resource_object

[docs]class ParentResourceProxy(object): """Proxy for the TemplateResource that owns a provider stack. This is an interface through which the Fn::ResourceFacade/resource_facade intrinsic functions in a stack can access data about the TemplateResource in the parent stack for which it was created. This API can be considered stable by third-party Function plugins, and no part of it should be changed or removed without an appropriate deprecation process. """ def __new__(cls, context, parent_resource_name, parent_stack_id): if parent_resource_name is None: return None return super(ParentResourceProxy, cls).__new__(cls) def __init__(self, context, parent_resource_name, parent_stack_id): self._context = context = parent_resource_name self._stack_id = parent_stack_id self._stack_ref = None self._parent_stack = None def _stack(self): if self._stack_ref is not None: stk = self._stack_ref() if stk is not None: return stk assert self._stack_id is not None, "Must provide parent stack or ID" from heat.engine import stack self._parent_stack = stack.Stack.load(self._context, stack_id=self._stack_id) self._stack_ref = weakref.ref(self._parent_stack) return self._parent_stack
[docs] def metadata_get(self): """Return the resource metadata.""" # If we're using an existing stack that was passed in, assume that its # resources are already in memory. If they haven't been stored to the # DB yet, this avoids an unnecessary attempt to read from it. if self._parent_stack is None: refd_stk = self._stack_ref and self._stack_ref() if refd_stk is not None: return refd_stk[].metadata_get() assert self._stack_id is not None, "Must provide parent stack or ID" # Try to read just this resource from the DB rs = resource_object.Resource.get_by_name_and_stack(self._context,, self._stack_id) if rs is not None: return rs.rsrc_metadata # Resource not stored, just return the data from the template return self.t.metadata()
@property def t(self): """The resource definition.""" stk = self._stack() return stk.t.resource_definitions(stk)[]
[docs]def use_parent_stack(parent_proxy, stack): parent_proxy._stack_ref = weakref.ref(stack) parent_proxy._parent_stack = None