def _get_constrained_instance_match(self, session):
"""Returns instance and constraint of if-match criterion if present.
Checks the context associated with the session for compare-and-swap
update revision number constraints. If one is found, this returns the
instance that is constrained as well as the requested revision number
to match.
"""
context = session.info.get('using_context')
if context:
# NOTE(ralonsoh): use "pop_transaction_constraint" once implemented
criteria = context.get_transaction_constraint()
context.clear_transaction_constraint()
else:
criteria = None
if not criteria:
return None, None
match = criteria.if_revision_match
mmap = standard_attr.get_standard_attr_resource_model_map()
model = mmap.get(criteria.resource)
if not model:
msg = _("Revision matching not supported for this resource")
raise exc.BadRequest(resource=criteria.resource, msg=msg)
instance = self._find_instance_by_column_value(
session, model, 'id', criteria.resource_id)
return instance, match
def _get_constrained_instance_match(self, session):
"""Returns instance and constraint of if-match criterion if present.
Checks the context associated with the session for compare-and-swap
update revision number constraints. If one is found, this returns the
instance that is constrained as well as the requested revision number
to match.
"""
criteria = getattr(session.info.get('using_context'), '_CONSTRAINT',
None)
if not criteria:
return None, None
match = criteria['if_revision_match']
mmap = standard_attr.get_standard_attr_resource_model_map()
model = mmap.get(criteria['resource'])
if not model:
msg = _("Revision matching not supported for this resource")
raise exc.BadRequest(resource=criteria['resource'], msg=msg)
instance = self._find_instance_by_column_value(session, model, 'id',
criteria['resource_id'])
return instance, match
