Allow multiple binding drivers

In before, only one binding driver is allowed. This patch introduces
a new config to support multiple binding drivers. The first use case
is to allow SR-IOV binding to be co-existed with other binding.

* Rename the config 'driver' to 'default_driver' in 'binding' group.
  This is for making it clear that it is allowed to have more than
  one type of bindings.
* Introduce a new config called 'enabled_drivers'.
* Allow client to pass a driver name to port_bind and port_unbind.
  If this parameter is None, kuryr will load the default driver.

Partial-Implements: blueprint sriov-binding
Change-Id: I14b23379de9f2459ba97d5d82dfdb51553370cb1

kuryr/lib/binding/__init__.py

@@ -12,9 +12,17 @@
 from oslo_config import cfg
 from oslo_utils import importutils
 
+from kuryr.lib import exceptions
+
+
+def _verify_driver(driver):
+    if driver.__name__ not in cfg.CONF.binding.enabled_drivers:
+        raise exceptions.DriverNotEnabledException(
+            'Driver %s is not enabled' % driver.__name__)
+
 
 def port_bind(endpoint_id, port, subnets, network=None, vm_port=None,
-              segmentation_id=None, **kwargs):
+              segmentation_id=None, driver=None, **kwargs):
     """Binds the Neutron port to the network interface on the host.
 
     :param endpoint_id:   the ID of the endpoint as string
@@ -29,30 +37,39 @@ def port_bind(endpoint_id, port, subnets, network=None, vm_port=None,
                          port of a container which is running inside this Nova
                          instance (either ipvlan/macvlan or a subport).
     :param segmentation_id: ID of the segment for container traffic isolation)
+    :param driver:       the binding driver name
     :param kwargs:       Additional driver-specific arguments
     :returns: the tuple of the names of the veth pair and the tuple of stdout
               and stderr returned by processutils.execute invoked with the
               executable script for binding
     :raises: kuryr.common.exceptions.VethCreationFailure,
+             kuryr.common.exceptions.DriverNotEnabledException,
              processutils.ProcessExecutionError
     """
-    driver = importutils.import_module(cfg.CONF.binding.driver)
+    driver = importutils.import_module(
+        driver or cfg.CONF.binding.default_driver)
+    _verify_driver(driver)
+
     return driver.port_bind(endpoint_id, port, subnets, network=network,
                             vm_port=vm_port,
                             segmentation_id=segmentation_id,
                             **kwargs)
 
 
-def port_unbind(endpoint_id, neutron_port, **kwargs):
+def port_unbind(endpoint_id, neutron_port, driver=None, **kwargs):
     """Unbinds the Neutron port from the network interface on the host.
 
     :param endpoint_id: the ID of the Docker container as string
     :param neutron_port: a port dictionary returned from python-neutronclient
+    :param driver:       the binding driver name
     :param kwargs:       Additional driver-specific arguments
     :returns: the tuple of stdout and stderr returned by processutils.execute
               invoked with the executable script for unbinding
-    :raises: processutils.ProcessExecutionError, pyroute2.NetlinkError
+    :raises: processutils.ProcessExecutionError, pyroute2.NetlinkError,
+             kuryr.common.exceptions.DriverNotEnabledException,
     """
-    driver = importutils.import_module(cfg.CONF.binding.driver)
+    driver = importutils.import_module(
+        driver or cfg.CONF.binding.default_driver)
+    _verify_driver(driver)
 
     return driver.port_unbind(endpoint_id, neutron_port, **kwargs)

kuryr/lib/config.py

@@ -68,9 +68,13 @@ binding_opts = [
                default='eth',
                help=_('The name prefix of the veth endpoint put inside the '
                       'container.')),
-    cfg.StrOpt('driver',
+    cfg.StrOpt('default_driver',
                default='kuryr.lib.binding.drivers.veth',
+               deprecated_name='driver',
                help=_('Driver to use for binding and unbinding ports.')),
+    cfg.ListOpt('enabled_drivers',
+                default=['kuryr.lib.binding.drivers.veth'],
+                help=_('Drivers to use for binding and unbinding ports.')),
     cfg.StrOpt('link_iface',
                default='',
                help=_('Specifies the name of the Nova instance interface to '

kuryr/lib/exceptions.py

@@ -118,3 +118,11 @@ class AddressInUseException(KuryrException):
     This exception is thrown when a specific address is requested and the
     requested ip address already exists and is used.
     """
+
+
+class DriverNotEnabledException(KuryrException):
+    """Exception represents the binding driver is not enabled.
+
+    This exception is thrown when kuryr tries to load a specific binding driver
+    but the driver is not enabled.
+    """

kuryr/lib/segmentation_type_drivers/__init__.py

@@ -22,7 +22,7 @@ _driver = ""
 def _get_driver():
     global _driver
     if not _driver:
-        driver_name = cfg.CONF.binding.driver.rsplit('.', 1)[1]
+        driver_name = cfg.CONF.binding.default_driver.rsplit('.', 1)[1]
 
         # REVISIT(vikasc): Need to remove this if check
         if driver_name == 'vlan':

kuryr/tests/unit/binding/__init__.py

@@ -0,0 +1,32 @@
+# 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 oslo_utils import importutils
+
+from kuryr.lib import binding
+from kuryr.lib import exceptions
+from kuryr.tests.unit import base
+
+
+class TestBinding(base.TestCase):
+    """Unit tests for binding module"""
+
+    def test__verify_driver(self):
+        cfg.CONF.set_override('enabled_drivers',
+                              ['kuryr.lib.binding.drivers.veth'],
+                              group='binding')
+        driver = importutils.import_module('kuryr.lib.binding.drivers.veth')
+        binding._verify_driver(driver)  # assert no exception raise
+        driver = importutils.import_module('kuryr.lib.binding.drivers.vlan')
+        self.assertRaises(exceptions.DriverNotEnabledException,
+                          binding._verify_driver, driver)

kuryr/tests/unit/segmentation_type_drivers/test_vlan.py

@@ -29,7 +29,7 @@ class VlanSegmentationDriverTest(base.TestCase):
 
     def setUp(self):
         super(VlanSegmentationDriverTest, self).setUp()
-        cfg.CONF.binding.driver = 'kuryr.lib.binding.drivers.vlan'
+        cfg.CONF.binding.default_driver = 'kuryr.lib.binding.drivers.vlan'
 
     def test_allocate_segmentation_id(self):
         vlan_seg_driver = vlan.SegmentationDriver()

kuryr/tests/unit/test_config.py

@@ -30,4 +30,4 @@ class ConfigurationTest(base.TestCase):
         self.assertEqual('baremetal',
                          cfg.CONF.deployment_type)
         self.assertEqual('kuryr.lib.binding.drivers.veth',
-                         cfg.CONF.binding.driver)
+                         cfg.CONF.binding.default_driver)

releasenotes/notes/multiple-binding-driver-512a6a7f620c758e.yaml

@@ -0,0 +1,11 @@
+---
+features:
+  - |
+    Add support for multiple binding drivers. Introduce a new config
+    called 'enabled_drivers' which specifies a list of binding drivers
+    allowed to use.
+deprecations:
+  - |
+    Rename the config 'driver' to 'default_driver' in 'binding' group.
+    This is for making it clear that it is allowed to have more than
+    one type of bindings.