Support the API for managing external gateways

Relevant Neutron core change:
https://review.opendev.org/c/openstack/neutron/+/873593

Co-Authored-by: Frode Nordahl <frode.nordahl@canonical.com>
Partial-Bug: #2002687
Change-Id: Idedce3c0ae6f4239ff3c1df35dc1b9af0add0a58

doc/source/user/proxies/network.rst

@@ -39,6 +39,8 @@ Router Operations
   :members: create_router, update_router, delete_router, get_router,
             find_router, routers,
             add_gateway_to_router, remove_gateway_from_router,
+            add_external_gateways, update_external_gateways,
+            remove_external_gateways,
             add_interface_to_router, remove_interface_from_router,
             add_extra_routes_to_router, remove_extra_routes_from_router,
             create_conntrack_helper, update_conntrack_helper,

openstack/network/v2/_proxy.py

@@ -4099,6 +4099,42 @@ class Proxy(proxy.Proxy):
         router = self._get_resource(_router.Router, router)
         return router.remove_gateway(self, **body)
 
+    def add_external_gateways(self, router, body):
+        """Add router external gateways
+
+        :param router: Either the router ID or an instance of
+            :class:`~openstack.network.v2.router.Router`
+        :param body: Body containing the external_gateways parameter.
+        :returns: Router with added gateways
+        :rtype: :class:`~openstack.network.v2.router.Router`
+        """
+        router = self._get_resource(_router.Router, router)
+        return router.add_external_gateways(self, body)
+
+    def update_external_gateways(self, router, body):
+        """Update router external gateways
+
+        :param router: Either the router ID or an instance of
+            :class:`~openstack.network.v2.router.Router`
+        :param body: Body containing the external_gateways parameter.
+        :returns: Router with updated gateways
+        :rtype: :class:`~openstack.network.v2.router.Router`
+        """
+        router = self._get_resource(_router.Router, router)
+        return router.update_external_gateways(self, body)
+
+    def remove_external_gateways(self, router, body):
+        """Remove router external gateways
+
+        :param router: Either the router ID or an instance of
+            :class:`~openstack.network.v2.router.Router`
+        :param body: Body containing the external_gateways parameter.
+        :returns: Router without the removed gateways
+        :rtype: :class:`~openstack.network.v2.router.Router`
+        """
+        router = self._get_resource(_router.Router, router)
+        return router.remove_external_gateways(self, body)
+
     def routers_hosting_l3_agents(self, router, **query):
         """Return a generator of L3 agent hosting a router
 

openstack/network/v2/router.py

@@ -177,6 +177,52 @@ class Router(_base.NetworkResource, tag.TagMixin):
         resp = session.put(url, json=body)
         return resp.json()
 
+    def add_external_gateways(self, session, body):
+        """Add external gateways to a router.
+
+        :param session: The session to communicate through.
+        :type session: :class:`~keystoneauth1.adapter.Adapter`
+        :param dict body: The body requested to be updated on the router
+
+        :returns: The body of the response as a dictionary.
+        """
+        url = utils.urljoin(self.base_path, self.id, 'add_external_gateways')
+        resp = session.put(url, json=body)
+        self._translate_response(resp)
+        return self
+
+    def update_external_gateways(self, session, body):
+        """Update external gateways of a router.
+
+        :param session: The session to communicate through.
+        :type session: :class:`~keystoneauth1.adapter.Adapter`
+        :param dict body: The body requested to be updated on the router
+
+        :returns: The body of the response as a dictionary.
+        """
+        url = utils.urljoin(
+            self.base_path, self.id, 'update_external_gateways'
+        )
+        resp = session.put(url, json=body)
+        self._translate_response(resp)
+        return self
+
+    def remove_external_gateways(self, session, body):
+        """Remove external gateways from a router.
+
+        :param session: The session to communicate through.
+        :type session: :class:`~keystoneauth1.adapter.Adapter`
+        :param dict body: The body requested to be updated on the router
+
+        :returns: The body of the response as a dictionary.
+        """
+        url = utils.urljoin(
+            self.base_path, self.id, 'remove_external_gateways'
+        )
+        resp = session.put(url, json=body)
+        self._translate_response(resp)
+        return self
+
 
 class L3AgentRouter(Router):
     resource_key = 'router'

openstack/tests/unit/network/v2/test_proxy.py

@@ -1511,6 +1511,48 @@ class TestNetworkRouter(TestNetworkProxy):
         )
         mock_get.assert_called_once_with(router.Router, "FAKE_ROUTER")
 
+    @mock.patch.object(proxy_base.Proxy, '_get_resource')
+    @mock.patch.object(router.Router, 'add_external_gateways')
+    def test_add_external_gateways(self, mock_add, mock_get):
+        x_router = router.Router.new(id="ROUTER_ID")
+        mock_get.return_value = x_router
+
+        self._verify(
+            "openstack.network.v2.router.Router.add_external_gateways",
+            self.proxy.add_external_gateways,
+            method_args=["FAKE_ROUTER", "bar"],
+            expected_args=[self.proxy, "bar"],
+        )
+        mock_get.assert_called_once_with(router.Router, "FAKE_ROUTER")
+
+    @mock.patch.object(proxy_base.Proxy, '_get_resource')
+    @mock.patch.object(router.Router, 'update_external_gateways')
+    def test_update_external_gateways(self, mock_remove, mock_get):
+        x_router = router.Router.new(id="ROUTER_ID")
+        mock_get.return_value = x_router
+
+        self._verify(
+            "openstack.network.v2.router.Router.update_external_gateways",
+            self.proxy.update_external_gateways,
+            method_args=["FAKE_ROUTER", "bar"],
+            expected_args=[self.proxy, "bar"],
+        )
+        mock_get.assert_called_once_with(router.Router, "FAKE_ROUTER")
+
+    @mock.patch.object(proxy_base.Proxy, '_get_resource')
+    @mock.patch.object(router.Router, 'remove_external_gateways')
+    def test_remove_external_gateways(self, mock_remove, mock_get):
+        x_router = router.Router.new(id="ROUTER_ID")
+        mock_get.return_value = x_router
+
+        self._verify(
+            "openstack.network.v2.router.Router.remove_external_gateways",
+            self.proxy.remove_external_gateways,
+            method_args=["FAKE_ROUTER", "bar"],
+            expected_args=[self.proxy, "bar"],
+        )
+        mock_get.assert_called_once_with(router.Router, "FAKE_ROUTER")
+
     def test_router_hosting_l3_agents_list(self):
         self.verify_list(
             self.proxy.routers_hosting_l3_agents,