Filter ML2Plugin mech driver supported extensions

Each mechanism driver loaded in the ML2Plugin can provide what
extensions are supported. By default, any mech driver can support
all extensions.

This extension filtering is done during the plugin initialization.
If any requested extension is not supported, it will be silently
removed from the loaded extensions.

Depends-On: https://review.opendev.org/#/c/743519
Related-Bug: #1888829

Change-Id: Id4809d4f3c4e13a93f9160df3618f8602b57437c

neutron/plugins/ml2/drivers/mech_agent.py

@@ -49,6 +49,7 @@ class AgentMechanismDriverBase(api.MechanismDriver, metaclass=abc.ABCMeta):
         :param agent_type: Constant identifying agent type in agents_db
         :param supported_vnic_types: The binding:vnic_type values we can bind
         """
+        super(AgentMechanismDriverBase, self).__init__()
         self.agent_type = agent_type
         self.supported_vnic_types = supported_vnic_types
 

neutron/plugins/ml2/plugin.py

@@ -223,7 +223,7 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
             sg_rpc.disable_security_group_extension_by_config(aliases)
             vlantransparent._disable_extension_by_config(aliases)
             filter_validation._disable_extension_by_config(aliases)
-            self._aliases = aliases
+            self._aliases = self._filter_extensions_by_mech_driver(aliases)
         return self._aliases
 
     def __new__(cls, *args, **kwargs):
@@ -288,6 +288,17 @@ class Ml2Plugin(db_base_plugin_v2.NeutronDbPluginV2,
                         driver=extension_driver, service_plugin=service_plugin
                     )
 
+    def _filter_extensions_by_mech_driver(self, aliases):
+        """Return the supported extensions by the loaded mech drivers"""
+        if not self.mechanism_manager.ordered_mech_drivers:
+            return aliases
+
+        supported_extensions = set([])
+        for mech_driver in self.mechanism_manager.ordered_mech_drivers:
+            supported_extensions |= mech_driver.obj.supported_extensions(
+                set(aliases))
+        return list(supported_extensions)
+
     @registry.receives(resources.PORT,
                        [provisioning_blocks.PROVISIONING_COMPLETE])
     def _port_provisioned(self, rtype, event, trigger, payload=None):

neutron/tests/unit/plugins/ml2/drivers/mechanism_logger.py

@@ -25,6 +25,9 @@ class LoggerMechanismDriver(api.MechanismDriver):
 
     Generally used for testing and debugging.
     """
+    def __init__(self, *args, **kwargs):
+        super(LoggerMechanismDriver, self).__init__(*args, **kwargs)
+        self._supported_extensions = set()
 
     def initialize(self):
         pass
@@ -140,3 +143,8 @@ class LoggerMechanismDriver(api.MechanismDriver):
                  "%(segments)s, candidate hosts %(hosts)s ",
                  {'segments': segments, 'hosts': candidate_hosts})
         return set()
+
+    def supported_extensions(self, extensions):
+        if self._supported_extensions:
+            return extensions & self._supported_extensions
+        return extensions

neutron/tests/unit/plugins/ml2/drivers/mechanism_test.py

@@ -32,6 +32,7 @@ class TestMechanismDriver(api.MechanismDriver):
     def __init__(self, *args, **kwargs):
         super(TestMechanismDriver, self).__init__(*args, **kwargs)
         self._supported_vnic_types = ('test_mechanism_driver_vnic_type', )
+        self._supported_extensions = set([])
 
     def initialize(self):
         self.bound_ports = set()
@@ -267,6 +268,11 @@ class TestMechanismDriver(api.MechanismDriver):
     def get_standard_device_mappings(self, agent):
         return {}
 
+    def supported_extensions(self, extensions):
+        if self._supported_extensions:
+            return extensions & self._supported_extensions
+        return extensions
+
 
 class TestMechanismDriverWithAgent(mech_agent.AgentMechanismDriverBase,
                                    TestMechanismDriver):

neutron/tests/unit/plugins/ml2/test_plugin.py

@@ -166,6 +166,24 @@ class TestMl2BulkToggleWithoutBulkless(Ml2PluginV2TestCase):
         self.assertFalse(self._skip_native_bulk)
 
 
+class TestMl2FilterExtensions(Ml2PluginV2TestCase):
+
+    _mechanism_drivers = ['logger', 'test']
+
+    def test__filter_extensions_by_mech_driver(self):
+        extension_aliases = ['ext1', 'ext2', 'ext3', 'ext4', 'ext5']
+        supported_aliases = [{'ext0', 'ext1', 'ext2'},
+                             {'ext4', 'ext5', 'ext6'}]
+        for idx, mech_driver in enumerate(
+                self.plugin.mechanism_manager.ordered_mech_drivers):
+            mech_driver.obj._supported_extensions = supported_aliases[idx]
+
+        supported_extensions = sorted(
+            self.plugin._filter_extensions_by_mech_driver(extension_aliases))
+        self.assertEqual(['ext1', 'ext2', 'ext4', 'ext5'],
+                         supported_extensions)
+
+
 class TestMl2BasicGet(test_plugin.TestBasicGet,
                       Ml2PluginV2TestCase):
     pass