fix(console,computes): an unreachable host is named as the cause, not an empty list

The console page of a VM whose host does not answer said "Fail to get
console. Please check the console configuration of your VM." and logged
nothing. It now shows the connection error (to users who do not see the
hosts, that the host cannot be reached) and logs it with the VM and host.

A host's Storage, Networks, Interfaces, Filters and Secrets pages showed
the connection error and also "This host has no ...". The list is None
when it was not read, and the page shows only the error.

console/tests/test_views.py

@@ -14,7 +14,7 @@ from django.conf import settings
 from django.test import TestCase, override_settings
 from django.urls import reverse
 from instances.models import Instance
-from libvirt import libvirtError
+from vrtManager.util import ConnectionFailed
 from lxml import html
 
 
@@ -323,16 +323,26 @@ class ConsoleViewsTestCase(TestCase):
                 self.assertEqual("This console listens only on its host" in response.content.decode(), refused)
 
     @patch("console.views.wvmInstance")
-    def test_console_libvirt_error_fallback(self, mock_wvm):
-        mock_wvm.side_effect = libvirtError("Connection to libvirtd failed")
+    def test_a_host_that_cannot_be_reached_is_named_as_the_cause_and_logged(self, mock_wvm):
+        # not "check the console configuration of your VM": the VM was never read
+        mock_wvm.side_effect = ConnectionFailed("Connection Failed: %(host)s did not answer within 5 s", host="192.0.2.10")
+        for user, shown in ((self.admin_user, "Connection Failed: 192.0.2.10 did not answer within 5 s"),
+                            (self.alice, "The host of this virtual machine cannot be reached right now.")):
+            with self.subTest(user.username):
+                self.client.force_login(user)
+                with self.assertLogs("console.views", "WARNING") as logs:
+                    response = self.client.get(self.url)
+                self.assertTemplateUsed(response, "console-error.html")
+                self.assertEqual(str(response.context["console_error"]), shown)
+                self.assertIn("Console of vm-alpha on", logs.output[0])
+                self.assertIn("192.0.2.10 did not answer", logs.output[0])
 
+    @patch("console.views.wvmInstance")
+    def test_a_vm_without_a_readable_console_points_to_its_console_settings(self, mock_wvm):
+        mock_wvm.return_value.get_console_type.side_effect = IndexError
         self.client.force_login(self.admin_user)
-        url = self.url
-        response = self.client.get(url)
-
-        self.assertEqual(response.status_code, 200)
-        self.assertTemplateUsed(response, "console-error.html")
-        self.assertIsNotNone(response.context["console_error"])
+        response = self.client.get(self.url)
+        self.assertIn("check the console configuration", str(response.context["console_error"]))
 
     def test_an_unknown_vm_gives_the_superuser_an_error_page(self):
         self.client.force_login(self.admin_user)

console/views.py

@@ -2,6 +2,7 @@
 
 import functools
 import json
+import logging
 from pathlib import Path
 
 from appsettings.settings import app_settings
@@ -12,9 +13,13 @@ from django.utils.translation import gettext_lazy as _
 from instances.models import Instance
 from instances.utils import can_open_console
 from libvirt import libvirtError
+from operations.utils import safe_text
 from vrtManager.connection import CONN_TCP, CONN_TLS
 from vrtManager.instance import wvmInstance
 from vrtManager.util import is_loopback
+from webvirtcloud.middleware import error_text
+
+logger = logging.getLogger(__name__)
 
 # one file a layout, written by dev/console_layout.py
 LAYOUTS_DIR = Path(__file__).resolve().parent / "layouts"
@@ -60,7 +65,11 @@ def console(request, compute_id, uuid):
         unreachable = instance.compute.type in (CONN_TCP, CONN_TLS) and bool(
             conn.get_console_socket() or is_loopback(conn.get_console_listener_addr())
         )
-    except (libvirtError, ValueError, IndexError):
+    except libvirtError as err:
+        # the host or the VM could not be read: the page says that, not to check the console settings
+        logger.warning("Console of %s on %s: %s", instance.name, instance.compute.name, safe_text(err))
+        return render(request, "console-error.html", {"instance": instance, "console_error": error_text(request, err)})
+    except (ValueError, IndexError):
         running = unreachable = False
         console_type = None
         console_passwd = None