def get_engine(database='main', context=None):
if database == 'main':
return db_session.get_engine(context=context)
if database == 'api':
return db_session.get_api_engine()
if database == 'placement':
return placement_db.get_placement_engine()
def _count_compute_resource_providers():
"""Returns the number of compute resource providers in the API database
The resource provider count is filtered based on resource providers
which have inventories records for the VCPU resource class, which is
assumed to only come from the ResourceTracker in compute nodes.
"""
# TODO(mriedem): If/when we support a separate placement database this
# will need to change to just use the REST API.
# Get the VCPU resource class ID for filtering.
vcpu_rc_id = fields.ResourceClass.STANDARD.index(
fields.ResourceClass.VCPU)
# The inventories table has a unique constraint per resource provider
# and resource class, so we can simply count the number of inventories
# records for the given resource class and those will uniquely identify
# the number of resource providers we care about.
meta = MetaData(bind=placement_db.get_placement_engine())
inventories = Table('inventories', meta, autoload=True)
return select([sqlfunc.count()]).select_from(inventories).where(
inventories.c.resource_class_id == vcpu_rc_id).scalar()
def _count_compute_resource_providers():
"""Returns the number of compute resource providers in the API database
The resource provider count is filtered based on resource providers
which have inventories records for the VCPU resource class, which is
assumed to only come from the ResourceTracker in compute nodes.
"""
# TODO(mriedem): If/when we support a separate placement database this
# will need to change to just use the REST API.
# Get the VCPU resource class ID for filtering.
vcpu_rc_id = fields.ResourceClass.STANDARD.index(
fields.ResourceClass.VCPU)
# The inventories table has a unique constraint per resource provider
# and resource class, so we can simply count the number of inventories
# records for the given resource class and those will uniquely identify
# the number of resource providers we care about.
meta = MetaData(bind=placement_db.get_placement_engine())
inventories = Table('inventories', meta, autoload=True)
return select([sqlfunc.count()]).select_from(
inventories).where(
inventories.c.resource_class_id == vcpu_rc_id).scalar()
