Controller driver base and pod project driver

This patch adds stevedore-based driver support to the controller and
implements a driver to determine OpenStack project ID used to create
pod ports.

Change-Id: I0002ce1c1f7985955b7f66902dcf5386db212a1a
Partially-Implements: blueprint kuryr-k8s-integration

kuryr_kubernetes/config.py

@@ -33,12 +33,20 @@ k8s_opts = [
     cfg.StrOpt('api_root',
         help=_("The root URL of the Kubernetes API"),
         default=os.environ.get('K8S_API', 'http://localhost:8080')),
+    cfg.StrOpt('pod_project_driver',
+        help=_("The driver to determine OpenStack project for pod ports"),
+        default='default'),
 ]
 
+neutron_defaults = [
+    cfg.StrOpt('project',
+        help=_("Default OpenStack project ID for Kubernetes resources")),
+]
 
 CONF = cfg.CONF
 CONF.register_opts(kuryr_k8s_opts)
 CONF.register_opts(k8s_opts, group='kubernetes')
+CONF.register_opts(neutron_defaults, group='neutron_defaults')
 
 CONF.register_opts(lib_config.core_opts)
 CONF.register_opts(lib_config.binding_opts, 'binding')

kuryr_kubernetes/controller/drivers/base.py

@@ -0,0 +1,95 @@
+# Copyright (c) 2016 Mirantis, Inc.
+# All Rights Reserved.
+#
+#    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.
+
+import abc
+import six
+
+from kuryr.lib._i18n import _LE
+from oslo_log import log as logging
+from stevedore import driver as stv_driver
+
+from kuryr_kubernetes import config
+
+LOG = logging.getLogger(__name__)
+
+_DRIVER_NAMESPACE_BASE = 'kuryr_kubernetes.controller.drivers'
+_DRIVER_MANAGERS = {}
+
+
+class DriverBase(object):
+    """Base class for controller drivers.
+
+    Subclasses must define an *ALIAS* attribute that is used to find a driver
+    implementation by `get_instance` class method which utilises
+    `stevedore.driver.DriverManager` with the namespace set to
+    'kuryr_kubernetes.controller.drivers.*ALIAS*' and the name of
+    the driver determined from the '[kubernetes]/*ALIAS*_driver' configuration
+    parameter.
+
+    Usage example:
+
+        @six.add_metaclass(abc.ABCMeta)
+        class SomeDriverInterface(DriverBase):
+            ALIAS = 'driver_alias'
+
+            @abc.abstractmethod
+            def some_method(self):
+                pass
+
+        driver = SomeDriverInterface.get_instance()
+        driver.some_method()
+    """
+
+    @classmethod
+    def get_instance(cls):
+        """Get an implementing driver instance."""
+
+        alias = cls.ALIAS
+
+        try:
+            manager = _DRIVER_MANAGERS[alias]
+        except KeyError:
+            name = config.CONF.kubernetes[alias + '_driver']
+            manager = stv_driver.DriverManager(
+                namespace="%s.%s" % (_DRIVER_NAMESPACE_BASE, alias),
+                name=name,
+                invoke_on_load=True)
+            _DRIVER_MANAGERS[alias] = manager
+
+        driver = manager.driver
+        if not isinstance(driver, cls):
+            raise TypeError(_LE("Invalid %(alias)r driver type: %(driver)s, "
+                                "must be a subclass of %(type)s") % {
+                'alias': alias,
+                'driver': driver.__class__.__name__,
+                'type': cls})
+        return driver
+
+
+@six.add_metaclass(abc.ABCMeta)
+class PodProjectDriver(DriverBase):
+    """Provides an OpenStack project ID for Kubernetes Pod ports."""
+
+    ALIAS = 'pod_project'
+
+    @abc.abstractmethod
+    def get_project(self, pod):
+        """Get an OpenStack project ID for Kubernetes Pod ports.
+
+        :param pod: dict containing Kubernetes Pod object
+        :return: project ID
+        """
+
+        raise NotImplementedError()

kuryr_kubernetes/controller/drivers/default_project.py

@@ -0,0 +1,35 @@
+# Copyright (c) 2016 Mirantis, Inc.
+# All Rights Reserved.
+#
+#    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 oslo_config import cfg
+
+from kuryr_kubernetes import config
+from kuryr_kubernetes.controller.drivers import base
+
+
+class DefaultPodProjectDriver(base.PodProjectDriver):
+    """Provides project ID for Pod port based on a configuration option."""
+
+    def get_project(self, pod):
+        project_id = config.CONF.neutron_defaults.project
+
+        if not project_id:
+            # NOTE(ivc): this option is only required for
+            # DefaultPodProjectDriver and its subclasses, but it may be
+            # optional for other drivers (e.g. when each namespace has own
+            # project)
+            raise cfg.RequiredOptError('project', 'neutron_defaults')
+
+        return project_id

kuryr_kubernetes/tests/unit/controller/drivers/test_base.py

@@ -0,0 +1,83 @@
+# Copyright (c) 2016 Mirantis, Inc.
+# All Rights Reserved.
+#
+#    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.
+
+import abc
+import mock
+import six
+
+from kuryr_kubernetes.controller.drivers import base as d_base
+from kuryr_kubernetes.tests import base as test_base
+
+
+@six.add_metaclass(abc.ABCMeta)
+class _TestDriver(d_base.DriverBase):
+    ALIAS = 'test_alias'
+
+    @abc.abstractmethod
+    def test(self):
+        raise NotImplementedError()
+
+
+class TestDriverBase(test_base.TestCase):
+
+    @mock.patch.object(d_base, '_DRIVER_MANAGERS')
+    @mock.patch('kuryr_kubernetes.config.CONF')
+    @mock.patch('stevedore.driver.DriverManager')
+    def test_get_instance(self, m_stv_mgr, m_cfg, m_mgrs):
+        m_drv = mock.MagicMock(spec=_TestDriver)
+        m_mgr = mock.MagicMock()
+        m_mgr.driver = m_drv
+        m_mgrs.__getitem__.return_value = m_mgr
+
+        self.assertEqual(m_drv, _TestDriver.get_instance())
+        m_cfg.assert_not_called()
+        m_stv_mgr.assert_not_called()
+
+    @mock.patch.object(d_base, '_DRIVER_MANAGERS')
+    @mock.patch('kuryr_kubernetes.config.CONF')
+    @mock.patch('stevedore.driver.DriverManager')
+    def test_get_instance_not_loaded(self, m_stv_mgr, m_cfg, m_mgrs):
+        alias = _TestDriver.ALIAS
+        cfg_name = '%s_driver' % (alias)
+        drv_name = 'driver_impl'
+        namespace = '%s.%s' % (d_base._DRIVER_NAMESPACE_BASE, alias)
+        m_cfg.kubernetes.__getitem__.return_value = drv_name
+        m_drv = mock.MagicMock(spec=_TestDriver)
+        m_mgr = mock.MagicMock()
+        m_mgr.driver = m_drv
+        m_stv_mgr.return_value = m_mgr
+        m_mgrs.__getitem__.side_effect = KeyError
+
+        self.assertEqual(m_drv, _TestDriver.get_instance())
+        m_cfg.kubernetes.__getitem__.assert_called_with(cfg_name)
+        m_stv_mgr.assert_called_with(namespace=namespace, name=drv_name,
+                                     invoke_on_load=True)
+        m_mgrs.__setitem__.assert_called_once_with(alias, m_mgr)
+
+    @mock.patch.object(d_base, '_DRIVER_MANAGERS')
+    @mock.patch('kuryr_kubernetes.config.CONF')
+    @mock.patch('stevedore.driver.DriverManager')
+    def test_get_instance_invalid_type(self, m_stv_mgr, m_cfg, m_mgrs):
+        class _InvalidDriver(object):
+            pass
+
+        m_drv = mock.MagicMock(spec=_InvalidDriver)
+        m_mgr = mock.MagicMock()
+        m_mgr.driver = m_drv
+        m_mgrs.__getitem__.return_value = m_mgr
+
+        self.assertRaises(TypeError, _TestDriver.get_instance)
+        m_cfg.assert_not_called()
+        m_stv_mgr.assert_not_called()

kuryr_kubernetes/tests/unit/controller/drivers/test_default_project.py

@@ -0,0 +1,39 @@
+# Copyright (c) 2016 Mirantis, Inc.
+# All Rights Reserved.
+#
+#    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.
+
+import mock
+
+from oslo_config import cfg
+
+from kuryr_kubernetes.controller.drivers import default_project
+from kuryr_kubernetes.tests import base as test_base
+
+
+class TestDefaultPodProjectDriver(test_base.TestCase):
+
+    @mock.patch('kuryr_kubernetes.config.CONF')
+    def test_get_project(self, m_cfg):
+        project_id = mock.sentinel.project_id
+        pod = mock.sentinel.pod
+        m_cfg.neutron_defaults.project = project_id
+        driver = default_project.DefaultPodProjectDriver()
+
+        self.assertEqual(project_id, driver.get_project(pod))
+
+    def test_get_project_not_set(self):
+        pod = mock.sentinel.pod
+        driver = default_project.DefaultPodProjectDriver()
+
+        self.assertRaises(cfg.RequiredOptError, driver.get_project, pod)

requirements.txt

@@ -13,3 +13,4 @@ oslo.serialization>=1.10.0 # Apache-2.0
 oslo.service>=1.10.0 # Apache-2.0
 oslo.utils>=3.16.0 # Apache-2.0
 six>=1.9.0 # MIT
+stevedore>=1.17.1 # Apache-2.0

setup.cfg

@@ -26,6 +26,9 @@ oslo.config.opts =
 console_scripts =
     kuryr-k8s-controller = kuryr_kubernetes.cmd.eventlet.controller:start
 
+kuryr_kubernetes.controller.drivers.pod_project =
+    default = kuryr_kubernetes.controller.drivers.default_project:DefaultPodProjectDriver
+
 [files]
 packages =
     kuryr_kubernetes