nova/nova/objects/host_mapping.py
Dan Smith bb7c6ebb56 Move to proper target_cell calling convention
When target_cell was originally written, the intent was to yield the
context that should be used. It currently mutates the input context,
which means you don't have to actually use the yielded one, because
we have a lot of stuff that would break otherwise. This fixes all the
current uses of it to be proper, and adjusts tests accordingly. This
is separate from changing target_cell's behavior to not mutate the
input context specifically to isolate the mechanical changes from ones
that actually need different behavior.

In addition to code that was already using target_cell() but not
depending on the yielded context, the _create_block_device_mapping()
method in conductor/manager.py was still depending on the shared
context switching to target the BDM objects on create. Since these
were prepared with the context prior to having determined where the
instanace was going to end up, we need to explicitly target the
object context on create (like the rest of the boot workflow does
for other objects in schedule_and_build_instances()).

Related to blueprint cells-aware-api

Change-Id: I35206e665f2c81531a2269dd66f8c5c0df834245
2017-05-23 08:12:42 -07:00

233 lines
8.7 KiB
Python

# 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
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# 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 sqlalchemy.orm import joinedload
from nova import context
from nova.db.sqlalchemy import api as db_api
from nova.db.sqlalchemy import api_models
from nova import exception
from nova.i18n import _
from nova.objects import base
from nova.objects import cell_mapping
from nova.objects import fields
def _cell_id_in_updates(updates):
cell_mapping_obj = updates.pop("cell_mapping", None)
if cell_mapping_obj:
updates["cell_id"] = cell_mapping_obj.id
def _apply_updates(context, db_mapping, updates):
db_mapping.update(updates)
db_mapping.save(context.session)
# NOTE: This is done because a later access will trigger a lazy load
# outside of the db session so it will fail. We don't lazy load
# cell_mapping on the object later because we never need a HostMapping
# without the CellMapping.
db_mapping.cell_mapping
return db_mapping
@base.NovaObjectRegistry.register
class HostMapping(base.NovaTimestampObject, base.NovaObject):
# Version 1.0: Initial version
VERSION = '1.0'
fields = {
'id': fields.IntegerField(read_only=True),
'host': fields.StringField(),
'cell_mapping': fields.ObjectField('CellMapping'),
}
def _get_cell_mapping(self):
with db_api.api_context_manager.reader.using(self._context) as session:
cell_map = (session.query(api_models.CellMapping)
.join(api_models.HostMapping)
.filter(api_models.HostMapping.host == self.host)
.first())
if cell_map is not None:
return cell_mapping.CellMapping._from_db_object(
self._context, cell_mapping.CellMapping(), cell_map)
def _load_cell_mapping(self):
self.cell_mapping = self._get_cell_mapping()
def obj_load_attr(self, attrname):
if attrname == 'cell_mapping':
self._load_cell_mapping()
@staticmethod
def _from_db_object(context, host_mapping, db_host_mapping):
for key in host_mapping.fields:
db_value = db_host_mapping.get(key)
if key == "cell_mapping":
# NOTE(dheeraj): If cell_mapping is stashed in db object
# we load it here. Otherwise, lazy loading will happen
# when .cell_mapping is accessed later
if not db_value:
continue
db_value = cell_mapping.CellMapping._from_db_object(
host_mapping._context, cell_mapping.CellMapping(),
db_value)
setattr(host_mapping, key, db_value)
host_mapping.obj_reset_changes()
host_mapping._context = context
return host_mapping
@staticmethod
@db_api.api_context_manager.reader
def _get_by_host_from_db(context, host):
db_mapping = (context.session.query(api_models.HostMapping)
.options(joinedload('cell_mapping'))
.filter(api_models.HostMapping.host == host)).first()
if not db_mapping:
raise exception.HostMappingNotFound(name=host)
return db_mapping
@base.remotable_classmethod
def get_by_host(cls, context, host):
db_mapping = cls._get_by_host_from_db(context, host)
return cls._from_db_object(context, cls(), db_mapping)
@staticmethod
@db_api.api_context_manager.writer
def _create_in_db(context, updates):
db_mapping = api_models.HostMapping()
return _apply_updates(context, db_mapping, updates)
@base.remotable
def create(self):
changes = self.obj_get_changes()
# cell_mapping must be mapped to cell_id for create
_cell_id_in_updates(changes)
db_mapping = self._create_in_db(self._context, changes)
self._from_db_object(self._context, self, db_mapping)
@staticmethod
@db_api.api_context_manager.writer
def _save_in_db(context, obj, updates):
db_mapping = context.session.query(api_models.HostMapping).filter_by(
id=obj.id).first()
if not db_mapping:
raise exception.HostMappingNotFound(name=obj.host)
return _apply_updates(context, db_mapping, updates)
@base.remotable
def save(self):
changes = self.obj_get_changes()
# cell_mapping must be mapped to cell_id for updates
_cell_id_in_updates(changes)
db_mapping = self._save_in_db(self._context, self, changes)
self._from_db_object(self._context, self, db_mapping)
self.obj_reset_changes()
@staticmethod
@db_api.api_context_manager.writer
def _destroy_in_db(context, host):
result = context.session.query(api_models.HostMapping).filter_by(
host=host).delete()
if not result:
raise exception.HostMappingNotFound(name=host)
@base.remotable
def destroy(self):
self._destroy_in_db(self._context, self.host)
@base.NovaObjectRegistry.register
class HostMappingList(base.ObjectListBase, base.NovaObject):
# Version 1.0: Initial version
VERSION = '1.0'
fields = {
'objects': fields.ListOfObjectsField('HostMapping'),
}
@staticmethod
@db_api.api_context_manager.reader
def _get_by_cell_id_from_db(context, cell_id):
return (context.session.query(api_models.HostMapping)
.options(joinedload('cell_mapping'))
.filter(api_models.HostMapping.cell_id == cell_id)).all()
@base.remotable_classmethod
def get_by_cell_id(cls, context, cell_id):
db_mappings = cls._get_by_cell_id_from_db(context, cell_id)
return base.obj_make_list(context, cls(), HostMapping, db_mappings)
def _check_and_create_host_mappings(ctxt, cm, compute_nodes, status_fn):
host_mappings = []
for compute in compute_nodes:
status_fn(_("Checking host mapping for compute host "
"'%(host)s': %(uuid)s") %
{'host': compute.host, 'uuid': compute.uuid})
try:
HostMapping.get_by_host(ctxt, compute.host)
except exception.HostMappingNotFound:
status_fn(_("Creating host mapping for compute host "
"'%(host)s': %(uuid)s") %
{'host': compute.host, 'uuid': compute.uuid})
host_mapping = HostMapping(
ctxt, host=compute.host,
cell_mapping=cm)
host_mapping.create()
host_mappings.append(host_mapping)
compute.mapped = 1
compute.save()
return host_mappings
def discover_hosts(ctxt, cell_uuid=None, status_fn=None):
# TODO(alaski): If this is not run on a host configured to use the API
# database most of the lookups below will fail and may not provide a
# great error message. Add a check which will raise a useful error
# message about running this from an API host.
from nova import objects
if not status_fn:
status_fn = lambda x: None
if cell_uuid:
cell_mappings = [objects.CellMapping.get_by_uuid(ctxt, cell_uuid)]
else:
cell_mappings = objects.CellMappingList.get_all(ctxt)
status_fn(_('Found %s cell mappings.') % len(cell_mappings))
host_mappings = []
for cm in cell_mappings:
if cm.is_cell0():
status_fn(_('Skipping cell0 since it does not contain hosts.'))
continue
if 'name' in cm and cm.name:
status_fn(_("Getting compute nodes from cell '%(name)s': "
"%(uuid)s") % {'name': cm.name,
'uuid': cm.uuid})
else:
status_fn(_("Getting compute nodes from cell: %(uuid)s") %
{'uuid': cm.uuid})
with context.target_cell(ctxt, cm) as cctxt:
compute_nodes = objects.ComputeNodeList.get_all_by_not_mapped(
cctxt, 1)
status_fn(_('Found %(num)s unmapped computes in cell: %(uuid)s') %
{'num': len(compute_nodes),
'uuid': cm.uuid})
added_hm = _check_and_create_host_mappings(cctxt, cm,
compute_nodes,
status_fn)
host_mappings.extend(added_hm)
return host_mappings