fix(networks): a network QoS rate that is not a whole number is refused

A network's QoS form whose rate was not a whole number (abc, 1.5) made
wvmNetwork.set_qos raise a ValueError that the view did not catch: the
request ended in a server error. The page's pattern stops this in a
browser, but the server must refuse it too. set_qos now says "QoS rates
must be whole numbers", and the view reports that, as it does a libvirt
error, and goes back to the network's page.

networks/tests/test_network_qos.py

@@ -0,0 +1,26 @@
+"""A network QoS the user typed wrong is refused with a message on the
+network's page, not a server error."""
+
+from unittest.mock import patch
+
+import libvirt
+from computes.models import Compute
+from django.contrib.auth import get_user_model
+from django.contrib.messages import get_messages
+from django.test import TestCase
+from django.urls import reverse
+
+
+class NetworkQosTests(TestCase):
+    def test_a_rate_that_is_not_a_whole_number_is_refused(self):
+        conn = libvirt.open("test:///default")
+        self.addCleanup(conn.close)
+        compute = Compute.objects.create(name="qos-test", hostname="localhost", login="", password="", type=4)
+        self.client.force_login(get_user_model().objects.create_superuser("qos", "qos@example.com", "pw"))
+        url = reverse("network", args=[compute.id, "default"])
+        for rates in ({"qos_average": "abc"}, {"qos_average": "1", "qos_peak": "1.5"}):
+            with self.subTest(rates=rates), \
+                 patch("vrtManager.connection.connection_manager.get_connection", return_value=conn):
+                response = self.client.post(url, {"set_qos": "", "qos_direction": "inbound", **rates})
+                self.assertRedirects(response, url, fetch_redirect_response=False)
+                self.assertIn("QoS rates must be whole numbers", [str(m) for m in get_messages(response.wsgi_request)])

networks/views.py

@@ -247,8 +247,8 @@ def network(request, compute_id, pool):
                         request,
                         _("%(qos_dir)s QoS is set") % {"qos_dir": qos_dir.capitalize()},
                     )
-            except libvirtError as lib_err:
-                messages.error(request, lib_err)
+            except (libvirtError, ValueError) as err:
+                messages.error(request, err)
             return HttpResponseRedirect(request.get_full_path())
         if "unset_qos" in request.POST:
             qos_dir = request.POST.get("qos_direction", "")

vrtManager/network.py

@@ -356,9 +356,10 @@ class wvmNetwork(wvmConnect):
         if direction not in ("inbound", "outbound"):
             raise ValueError("Direction must be inbound or outbound")
 
-        average = int(average)
-        peak = int(peak)
-        burst = int(burst)
+        try:
+            average, peak, burst = int(average), int(peak), int(burst)
+        except ValueError:
+            raise ValueError("QoS rates must be whole numbers")
 
         xml = f"<{direction} average='{average}' peak='{peak}' burst='{burst}'/>"
         tree = etree.fromstring(self._XMLDesc(0))