Add factory helper function which returns a singleton
Not that ServiceTypes is super expensive or anything, but it's also an encapsultation of static data, so there's really no need to construct more than one of them in a program. Change-Id: I2515fd9be27421006ed22a3ab01bef8cb48196f8
This commit is contained in:
parent
b9ce5cf729
commit
f9dca6f788
|
@ -18,3 +18,24 @@ import pbr.version
|
|||
from os_service_types.service_types import ServiceTypes # flake8: noqa
|
||||
|
||||
__version__ = pbr.version.VersionInfo('os-service-types').version_string()
|
||||
_service_type_manager = None
|
||||
|
||||
|
||||
def get_service_types(*args, **kwargs):
|
||||
"""Return singleton instance of the ServiceTypes object.
|
||||
|
||||
Parameters are all passed through to the
|
||||
:class:`~os_service_types.service_types.ServiceTypes` constructor.
|
||||
|
||||
.. note::
|
||||
|
||||
Only one singleton is kept, so if instances with different parameter
|
||||
values are desired, directly calling the constructor is necessary.
|
||||
|
||||
:returns: Singleton instance of
|
||||
:class:`~os_service_types.service_types.ServiceTypes`
|
||||
"""
|
||||
global _service_type_manager
|
||||
if not _service_type_manager:
|
||||
_service_type_manager = ServiceTypes(*args, **kwargs)
|
||||
return _service_type_manager
|
||||
|
|
|
@ -0,0 +1,38 @@
|
|||
# -*- coding: utf-8 -*-
|
||||
|
||||
# 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.
|
||||
|
||||
"""
|
||||
test_singleton
|
||||
------------
|
||||
|
||||
Tests for `get_service_types` singleton factory function.
|
||||
"""
|
||||
import os_service_types
|
||||
from os_service_types.tests import base
|
||||
|
||||
|
||||
class TestSingleton(base.TestCase):
|
||||
|
||||
def setUp(self):
|
||||
super(TestSingleton, self).setUp()
|
||||
# Make an object with no network access
|
||||
self.service_types = os_service_types.get_service_types()
|
||||
|
||||
def test_singleton_same(self):
|
||||
service_types = os_service_types.get_service_types()
|
||||
self.assertTrue(service_types is self.service_types)
|
||||
|
||||
def test_singleton_different(self):
|
||||
service_types = os_service_types.ServiceTypes()
|
||||
self.assertFalse(service_types is self.service_types)
|
|
@ -0,0 +1,7 @@
|
|||
---
|
||||
features:
|
||||
- |
|
||||
Factory function ``os_service_types.get_service_types`` added. Returns
|
||||
a singleton instance of ServiceTypes. ServiceTypes is a very low cost
|
||||
object in the first place, but it does read a data file from disk and
|
||||
then the data is pretty static.
|
Loading…
Reference in New Issue