Encapsulate some port properties in the PortContext

Bindings to host or status may need further encapsulation
to avoid exposing mechanism drivers to underlying DB model
details. This was particularly true in the case of the
l2pop mech driver.

As a result, some docstrings were reworded, and the newly
introduced properties used directly in the mech drivers.

Partially-implements: blueprint neutron-ovs-dvr
Supports blueprint: ml2-hierarchical-port-binding

Change-Id: If2a373ef04d19b164585fb4bde4fe6e0cfaf43be

neutron/plugins/ml2/driver_api.py

@@ -149,21 +149,23 @@ class NetworkContext(object):
 
     @abc.abstractproperty
     def current(self):
-        """Return the current state of the network.
+        """Return the network in its current configuration.
 
-        Return the current state of the network, as defined by
+        Return the network, as defined by NeutronPluginBaseV2.
-        NeutronPluginBaseV2.create_network and all extensions in the
+        create_network and all extensions in the ml2 plugin, with
-        ml2 plugin.
+        all its properties 'current' at the time the context was
+        established.
         """
         pass
 
     @abc.abstractproperty
     def original(self):
-        """Return the original state of the network.
+        """Return the network in its original configuration.
 
-        Return the original state of the network, prior to a call to
+        Return the network, with all its properties set to their
-        update_network. Method is only valid within calls to
+        original values prior to a call to update_network. Method is
-        update_network_precommit and update_network_postcommit.
+        only valid within calls to update_network_precommit and
+        update_network_postcommit.
         """
         pass
 
@@ -185,21 +187,23 @@ class SubnetContext(object):
 
     @abc.abstractproperty
     def current(self):
-        """Return the current state of the subnet.
+        """Return the subnet in its current configuration.
 
-        Return the current state of the subnet, as defined by
+        Return the subnet, as defined by NeutronPluginBaseV2.
-        NeutronPluginBaseV2.create_subnet and all extensions in the
+        create_subnet and all extensions in the ml2 plugin, with
-        ml2 plugin.
+        all its properties 'current' at the time the context was
+        established.
         """
         pass
 
     @abc.abstractproperty
     def original(self):
-        """Return the original state of the subnet.
+        """Return the subnet in its original configuration.
 
-        Return the original state of the subnet, prior to a call to
+        Return the subnet, with all its properties set to their
-        update_subnet. Method is only valid within calls to
+        original values prior to a call to update_subnet. Method is
-        update_subnet_precommit and update_subnet_postcommit.
+        only valid within calls to update_subnet_precommit and
+        update_subnet_postcommit.
         """
         pass
 
@@ -216,21 +220,37 @@ class PortContext(object):
 
     @abc.abstractproperty
     def current(self):
-        """Return the current state of the port.
+        """Return the port in its current configuration.
 
-        Return the current state of the port, as defined by
+        Return the port, as defined by NeutronPluginBaseV2.
-        NeutronPluginBaseV2.create_port and all extensions in the ml2
+        create_port and all extensions in the ml2 plugin, with
-        plugin.
+        all its properties 'current' at the time the context was
+        established.
         """
         pass
 
     @abc.abstractproperty
     def original(self):
-        """Return the original state of the port.
+        """Return the port in its original configuration.
 
-        Return the original state of the port, prior to a call to
+        Return the port, with all its properties set to their
-        update_port. Method is only valid within calls to
+        original values prior to a call to update_port. Method is
-        update_port_precommit and update_port_postcommit.
+        only valid within calls to update_port_precommit and
+        update_port_postcommit.
+        """
+        pass
+
+    @abc.abstractproperty
+    def status(self):
+        """Return the status of the current port."""
+        pass
+
+    @abc.abstractproperty
+    def original_status(self):
+        """Return the status of the original port.
+
+        The method is only valid within calls to update_port_precommit and
+        update_port_postcommit.
         """
         pass
 
@@ -254,6 +274,20 @@ class PortContext(object):
         """
         pass
 
+    @abc.abstractproperty
+    def host(self):
+        """Return the host associated with the 'current' port."""
+        pass
+
+    @abc.abstractproperty
+    def original_host(self):
+        """Return the host associated with the 'original' port.
+
+        Method is only valid within calls to update_port_precommit
+        and update_port_postcommit.
+        """
+        pass
+
     @abc.abstractproperty
     def bound_driver(self):
         """Return the currently bound mechanism driver name."""

neutron/plugins/ml2/driver_context.py

@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from neutron.extensions import portbindings
 from neutron.openstack.common import jsonutils
 from neutron.plugins.ml2 import db
 from neutron.plugins.ml2 import driver_api as api
@@ -93,6 +94,14 @@ class PortContext(MechanismDriverContext, api.PortContext):
     def original(self):
         return self._original_port
 
+    @property
+    def status(self):
+        return self._port['status']
+
+    @property
+    def original_status(self):
+        return self._original_port['status']
+
     @property
     def network(self):
         return self._network_context
@@ -112,6 +121,14 @@ class PortContext(MechanismDriverContext, api.PortContext):
                 if segment[api.ID] == self._original_bound_segment_id:
                     return segment
 
+    @property
+    def host(self):
+        return self._port.get(portbindings.HOST_ID)
+
+    @property
+    def original_host(self):
+        return self._original_port.get(portbindings.HOST_ID)
+
     @property
     def bound_driver(self):
         return self._binding.driver

neutron/plugins/ml2/drivers/arista/mechanism_arista.py

@@ -19,7 +19,6 @@ import jsonrpclib
 from oslo.config import cfg
 
 from neutron.common import constants as n_const
-from neutron.extensions import portbindings
 from neutron.openstack.common import log as logging
 from neutron.plugins.ml2.common import exceptions as ml2_exc
 from neutron.plugins.ml2 import driver_api
@@ -801,7 +800,7 @@ class AristaDriver(driver_api.MechanismDriver):
         port = context.current
         device_id = port['device_id']
         device_owner = port['device_owner']
-        host = port[portbindings.HOST_ID]
+        host = context.host
 
         # device_id and device_owner are set on VM boot
         is_vm_boot = device_id and device_owner
@@ -822,7 +821,7 @@ class AristaDriver(driver_api.MechanismDriver):
         port = context.current
         device_id = port['device_id']
         device_owner = port['device_owner']
-        host = port[portbindings.HOST_ID]
+        host = context.host
 
         # device_id and device_owner are set on VM boot
         is_vm_boot = device_id and device_owner
@@ -885,7 +884,7 @@ class AristaDriver(driver_api.MechanismDriver):
 
         device_id = port['device_id']
         device_owner = port['device_owner']
-        host = port[portbindings.HOST_ID]
+        host = context.host
         is_vm_boot = device_id and device_owner
 
         if host and is_vm_boot:
@@ -926,7 +925,7 @@ class AristaDriver(driver_api.MechanismDriver):
         """Delete information about a VM and host from the DB."""
         port = context.current
 
-        host_id = port[portbindings.HOST_ID]
+        host_id = context.host
         device_id = port['device_id']
         tenant_id = port['tenant_id']
         network_id = port['network_id']
@@ -947,7 +946,7 @@ class AristaDriver(driver_api.MechanismDriver):
         """
         port = context.current
         device_id = port['device_id']
-        host = port[portbindings.HOST_ID]
+        host = context.host
         port_id = port['id']
         network_id = port['network_id']
         tenant_id = port['tenant_id']

neutron/plugins/ml2/drivers/cisco/apic/mechanism_apic.py

@@ -93,7 +93,7 @@ class APICMechanismDriver(api.MechanismDriver):
             # Not a compute port, return
             return
 
-        host = port.get(portbindings.HOST_ID)
+        host = context.host
         # Check host that the dhcp agent is running on
         filters = {'device_owner': 'network:dhcp',
                    'network_id': network}

neutron/plugins/ml2/drivers/cisco/nexus/mech_cisco_nexus.py

@@ -155,8 +155,7 @@ class CiscoNexusMechanismDriver(api.MechanismDriver):
 
     def _is_vm_migration(self, context):
         if not context.bound_segment and context.original_bound_segment:
-            return (context.current.get(portbindings.HOST_ID) !=
+            return context.host != context.original_host
-                    context.original.get(portbindings.HOST_ID))
 
     def _port_action(self, port, segment, func):
         """Verify configuration and then process event."""

neutron/plugins/ml2/drivers/l2pop/mech_driver.py

@@ -48,7 +48,8 @@ class L2populationMechanismDriver(api.MechanismDriver,
                  ip['ip_address']] for ip in port['fixed_ips']]
 
     def delete_port_postcommit(self, context):
-        fanout_msg = self._update_port_down(context, context.current)
+        fanout_msg = self._update_port_down(
+            context, context.current, context.host)
         if fanout_msg:
             self.L2populationAgentNotify.remove_fdb_entries(
                 self.rpc_ctx, fanout_msg)
@@ -67,7 +68,8 @@ class L2populationMechanismDriver(api.MechanismDriver,
     def _fixed_ips_changed(self, context, orig, port, diff_ips):
         orig_ips, port_ips = diff_ips
 
-        port_infos = self._get_port_infos(context, orig)
+        port_infos = self._get_port_infos(
+            context, orig, context.original_host)
         if not port_infos:
             return
         agent, agent_ip, segment, port_fdb_entries = port_infos
@@ -96,30 +98,34 @@ class L2populationMechanismDriver(api.MechanismDriver,
         diff_ips = self._get_diff_ips(orig, port)
         if diff_ips:
             self._fixed_ips_changed(context, orig, port, diff_ips)
-        if (port['binding:host_id'] != orig['binding:host_id']
+        if (context.host != context.original_host
-            and port['status'] == const.PORT_STATUS_ACTIVE
+            and context.status == const.PORT_STATUS_ACTIVE
             and not self.migrated_ports.get(orig['id'])):
             # The port has been migrated. We have to store the original
             # binding to send appropriate fdb once the port will be set
             # on the destination host
-            self.migrated_ports[orig['id']] = orig
+            self.migrated_ports[orig['id']] = (
-        elif port['status'] != orig['status']:
+                (orig, context.original_host))
-            if port['status'] == const.PORT_STATUS_ACTIVE:
+        elif context.status != context.original_status:
+            if context.status == const.PORT_STATUS_ACTIVE:
                 self._update_port_up(context)
-            elif port['status'] == const.PORT_STATUS_DOWN:
+            elif context.status == const.PORT_STATUS_DOWN:
-                fdb_entries = self._update_port_down(context, port)
+                fdb_entries = self._update_port_down(
+                    context, port, context.host)
                 self.L2populationAgentNotify.remove_fdb_entries(
                     self.rpc_ctx, fdb_entries)
-            elif port['status'] == const.PORT_STATUS_BUILD:
+            elif context.status == const.PORT_STATUS_BUILD:
                 orig = self.migrated_ports.pop(port['id'], None)
                 if orig:
-                    # this port has been migrated : remove its entries from fdb
+                    original_port = orig[0]
-                    fdb_entries = self._update_port_down(context, orig)
+                    original_host = orig[1]
+                    # this port has been migrated: remove its entries from fdb
+                    fdb_entries = self._update_port_down(
+                        context, original_port, original_host)
                     self.L2populationAgentNotify.remove_fdb_entries(
                         self.rpc_ctx, fdb_entries)
 
-    def _get_port_infos(self, context, port):
+    def _get_port_infos(self, context, port, agent_host):
-        agent_host = port['binding:host_id']
         if not agent_host:
             return
 
@@ -150,14 +156,14 @@ class L2populationMechanismDriver(api.MechanismDriver,
         return agent, agent_ip, segment, fdb_entries
 
     def _update_port_up(self, context):
-        port_context = context.current
+        port = context.current
-        port_infos = self._get_port_infos(context, port_context)
+        agent_host = context.host
+        port_infos = self._get_port_infos(context, port, agent_host)
         if not port_infos:
             return
         agent, agent_ip, segment, port_fdb_entries = port_infos
 
-        agent_host = port_context['binding:host_id']
+        network_id = port['network_id']
-        network_id = port_context['network_id']
 
         session = db_api.get_session()
         agent_active_ports = self.get_agent_network_active_port_count(
@@ -209,14 +215,13 @@ class L2populationMechanismDriver(api.MechanismDriver,
         self.L2populationAgentNotify.add_fdb_entries(self.rpc_ctx,
                                                      other_fdb_entries)
 
-    def _update_port_down(self, context, port_context):
+    def _update_port_down(self, context, port, agent_host):
-        port_infos = self._get_port_infos(context, port_context)
+        port_infos = self._get_port_infos(context, port, agent_host)
         if not port_infos:
             return
         agent, agent_ip, segment, port_fdb_entries = port_infos
 
-        agent_host = port_context['binding:host_id']
+        network_id = port['network_id']
-        network_id = port_context['network_id']
 
         session = db_api.get_session()
         agent_active_ports = self.get_agent_network_active_port_count(

neutron/tests/unit/ml2/_test_mech_agent.py

@@ -59,6 +59,14 @@ class FakePortContext(api.PortContext):
     def original(self):
         return None
 
+    @property
+    def status(self):
+        return 'DOWN'
+
+    @property
+    def original_status(self):
+        return None
+
     @property
     def network(self):
         return self._network_context
@@ -74,6 +82,14 @@ class FakePortContext(api.PortContext):
     def original_bound_segment(self):
         return None
 
+    @property
+    def host(self):
+        return ''
+
+    @property
+    def original_host(self):
+        return None
+
     @property
     def bound_driver(self):
         return None

neutron/tests/unit/ml2/drivers/arista/test_arista_mechanism_driver.py

@@ -18,6 +18,7 @@ from oslo.config import cfg
 
 from neutron.common import constants as n_const
 import neutron.db.api as ndb
+from neutron.extensions import portbindings
 from neutron.plugins.ml2.drivers.arista import db
 from neutron.plugins.ml2.drivers.arista import exceptions as arista_exc
 from neutron.plugins.ml2.drivers.arista import mechanism_arista as arista
@@ -723,3 +724,11 @@ class FakePortContext(object):
     @property
     def network(self):
         return self._network_context
+
+    @property
+    def host(self):
+        return self._port.get(portbindings.HOST_ID)
+
+    @property
+    def original_host(self):
+        return self._original_port.get(portbindings.HOST_ID)

neutron/tests/unit/ml2/drivers/cisco/apic/test_cisco_apic_mechanism_driver.py

@@ -19,6 +19,7 @@ import mock
 
 from oslo.config import cfg
 
+from neutron.extensions import portbindings
 from neutron.plugins.ml2.drivers.cisco.apic import mechanism_apic as md
 from neutron.plugins.ml2.drivers import type_vlan  # noqa
 from neutron.tests import base
@@ -224,3 +225,11 @@ class FakePortContext(object):
 
     def set_binding(self, segment_id, vif_type, cap_port_filter):
         pass
+
+    @property
+    def host(self):
+        return self._port.get(portbindings.HOST_ID)
+
+    @property
+    def original_host(self):
+        return self._original_port.get(portbindings.HOST_ID)