network: Add --advertise-host argument to "add subnet"

The parameter sets a boolean for the
"openstack router add subnet" command. If "--advertise-host" is passed
then the REST request contains "advertise_host": "true" in the body
according the spec [1].

There is a conditional handling of that parameter because of the
openstacksdk dependency. Once openstacksdk gets implemented the
parameter and is released, we should remove the condition and
pass the parameter directly to the add_interface_to_router method

Related-Bug: #2144617
Assisted-By: Claude Opus 4.6

[1] https://opendev.org/openstack/neutron-specs/src/branch/master/specs/2026.2/bgp_evpn_type_5_route_support.rst#changes-to-cli-and-rest-api

Change-Id: I7b760ad963901eb149e3149057aed17e654af0aa
Signed-off-by: Jakub Libosvar <libosvar@redhat.com>

Author: cubeek

openstackclient/network/v2/router.py

@@ -367,15 +367,36 @@ def get_parser(self, prog_name: str) -> argparse.ArgumentParser:
             metavar='<subnet>',
             help=_("Subnet to be added (name or ID)"),
         )
+        parser.add_argument(
+            '--advertise-host',
+            action='store_true',
+            default=False,
+            dest='advertise_host',
+            help=_(
+                "Mark the subnet's prefixes to be advertised as host "
+                "routes within the router's EVPN VNI. "
+                "Only valid for EVPN routers."
+            ),
+        )
         return parser
 
     def take_action(self, parsed_args: argparse.Namespace) -> None:
         client = self.app.client_manager.network
         subnet = client.find_subnet(parsed_args.subnet, ignore_missing=False)
-        client.add_interface_to_router(
-            client.find_router(parsed_args.router, ignore_missing=False),
-            subnet=subnet.id,
-        )
+        if parsed_args.advertise_host:
+            # TODO(evpn): switch to client.add_interface_to_router() once
+            # openstacksdk supports the advertise_host parameter.
+            router = client.find_router(
+                parsed_args.router, ignore_missing=False
+            )
+            router.add_interface(
+                client, subnet_id=subnet.id, advertise_host=True
+            )
+        else:
+            client.add_interface_to_router(
+                client.find_router(parsed_args.router, ignore_missing=False),
+                subnet=subnet.id,
+            )
 
 
 class AddExtraRoutesToRouter(command.ShowOne):

openstackclient/tests/unit/network/v2/test_router.py

@@ -86,6 +86,7 @@ def setUp(self):
 
         self.network_client.find_router.return_value = self._router
         self.network_client.find_subnet.return_value = self._subnet
+        self._router.add_interface = mock.Mock()
 
         self.cmd = router.AddSubnetToRouter(self.app, None)
 
@@ -119,6 +120,49 @@ def test_add_subnet_required_options(self):
 
         self.assertIsNone(result)
 
+    def test_add_subnet_with_advertise_host(self):
+        arglist = [
+            self._router.id,
+            self._router.subnet,
+            '--advertise-host',
+        ]
+        verifylist = [
+            ('router', self._router.id),
+            ('subnet', self._router.subnet),
+            ('advertise_host', True),
+        ]
+        parsed_args = self.check_parser(self.cmd, arglist, verifylist)
+
+        result = self.cmd.take_action(parsed_args)
+        self._router.add_interface.assert_called_once_with(
+            self.network_client,
+            subnet_id=self._subnet.id,
+            advertise_host=True,
+        )
+        self.network_client.add_interface_to_router.assert_not_called()
+
+        self.assertIsNone(result)
+
+    def test_add_subnet_without_advertise_host(self):
+        arglist = [
+            self._router.id,
+            self._router.subnet,
+        ]
+        verifylist = [
+            ('router', self._router.id),
+            ('subnet', self._router.subnet),
+            ('advertise_host', False),
+        ]
+        parsed_args = self.check_parser(self.cmd, arglist, verifylist)
+
+        result = self.cmd.take_action(parsed_args)
+        self.network_client.add_interface_to_router.assert_called_once_with(
+            self._router, subnet=self._subnet.id
+        )
+        self._router.add_interface.assert_not_called()
+
+        self.assertIsNone(result)
+
 
 class TestCreateRouter(TestRouter):
     # The new router created.