Add `get_node_network_data` method to NetworkInterface

Extends NetworkInterface with `get_node_network_data` method
providing network configuration for node NICs in form of Nova network
metadata structure (i.e. `network_data.json`). Network interface
implementations would implement their own ways of gathering network
configuration when possible.

Ironic would eventually pass network configuration to the node being
managed out-of-band.

Change-Id: I4c956c08a695fb17ec32c3e2a17cbca55148eb79
Story: 2006691
Task: 36992

ironic/drivers/base.py

@@ -1543,6 +1543,26 @@ class NetworkInterface(BaseInterface):
         """
         return False
 
+    def get_node_network_data(self, task):
+        """Return network configuration for node NICs.
+
+        Gather L2 and L3 network settings from ironic port/portgroups
+        objects and underlying network provider, then put together
+        collected data in form of Nova network metadata (`network_data.json`)
+        dict.
+
+        Ironic would eventually pass network configuration to the node
+        being managed out-of-band.
+
+        :param task: A TaskManager instance.
+        :raises: InvalidParameterValue, if the network interface configuration
+            is invalid.
+        :raises: MissingParameterValue, if some parameters are missing.
+        :returns: a dict holding network configuration information adhearing
+            Nova network metadata layout (`network_data.json`).
+        """
+        return {}
+
 
 class StorageInterface(BaseInterface, metaclass=abc.ABCMeta):
     """Base class for storage interfaces."""

ironic/tests/unit/drivers/modules/network/test_flat.py

@@ -333,3 +333,9 @@ class TestFlatInterface(db_base.DbTestCase):
         with task_manager.acquire(self.context, self.node.id) as task:
             self.assertRaises(exception.UnsupportedDriverExtension,
                               self.interface.validate_inspection, task)
+
+    def test_get_node_network_data(self):
+        with task_manager.acquire(self.context, self.node.id) as task:
+            network_data = self.interface.get_node_network_data(task)
+
+        self.assertEqual({}, network_data)

ironic/tests/unit/drivers/modules/network/test_neutron.py

@@ -853,3 +853,9 @@ class NeutronInterfaceTestCase(db_base.DbTestCase):
         with task_manager.acquire(self.context, self.node.id) as task:
             self.assertRaises(exception.UnsupportedDriverExtension,
                               self.interface.validate_inspection, task)
+
+    def test_get_node_network_data(self):
+        with task_manager.acquire(self.context, self.node.id) as task:
+            network_data = self.interface.get_node_network_data(task)
+
+        self.assertEqual({}, network_data)

ironic/tests/unit/drivers/modules/network/test_noop.py

@@ -94,3 +94,9 @@ class NoopInterfaceTestCase(db_base.DbTestCase):
     def test_remove_inspection_network(self):
         with task_manager.acquire(self.context, self.node.id) as task:
             self.interface.remove_inspection_network(task)
+
+    def test_get_node_network_data(self):
+        with task_manager.acquire(self.context, self.node.id) as task:
+            network_data = self.interface.get_node_network_data(task)
+
+        self.assertEqual({}, network_data)