Merge "Raise NovaException for missing/empty machine-id"

nova/tests/unit/virt/libvirt/test_driver.py

@@ -3761,27 +3761,44 @@ class LibvirtConnTestCase(test.NoDBTestCase):
 
         self._test_get_guest_config_sysinfo_serial(theuuid)
 
+    @contextlib.contextmanager
+    def patch_exists(self, result):
+        real_exists = os.path.exists
+
+        def fake_exists(filename):
+            if filename == "/etc/machine-id":
+                return result
+            return real_exists(filename)
+
+        with mock.patch.object(os.path, "exists") as mock_exists:
+            mock_exists.side_effect = fake_exists
+            yield mock_exists
+
     def test_get_guest_config_sysinfo_serial_os(self):
         self.flags(sysinfo_serial="os", group="libvirt")
-
-        real_open = builtins.open
+        theuuid = "56b40135-a973-4eb3-87bb-a2382a3e6dbc"
         with contextlib.nested(
-                mock.patch.object(builtins, "open"),
-        ) as (mock_open, ):
-            theuuid = "56b40135-a973-4eb3-87bb-a2382a3e6dbc"
-
-            def fake_open(filename, *args, **kwargs):
-                if filename == "/etc/machine-id":
-                    h = mock.MagicMock()
-                    h.read.return_value = theuuid
-                    h.__enter__.return_value = h
-                    return h
-                return real_open(filename, *args, **kwargs)
-
-            mock_open.side_effect = fake_open
-
+                mock.patch('__builtin__.open',
+                    mock.mock_open(read_data=theuuid)),
+                self.patch_exists(True)):
             self._test_get_guest_config_sysinfo_serial(theuuid)
 
+    def test_get_guest_config_sysinfo_serial_os_empty_machine_id(self):
+        self.flags(sysinfo_serial="os", group="libvirt")
+        with contextlib.nested(
+                mock.patch('__builtin__.open', mock.mock_open(read_data="")),
+                self.patch_exists(True)):
+            self.assertRaises(exception.NovaException,
+                    self._test_get_guest_config_sysinfo_serial,
+                    None)
+
+    def test_get_guest_config_sysinfo_serial_os_no_machine_id_file(self):
+        self.flags(sysinfo_serial="os", group="libvirt")
+        with self.patch_exists(False):
+            self.assertRaises(exception.NovaException,
+                    self._test_get_guest_config_sysinfo_serial,
+                    None)
+
     def test_get_guest_config_sysinfo_serial_auto_hardware(self):
         self.flags(sysinfo_serial="auto", group="libvirt")
 

nova/virt/libvirt/driver.py

@@ -3396,10 +3396,19 @@ class LibvirtDriver(driver.ComputeDriver):
         systemd based containers and can be provided by other
         init systems too, since it is just a plain text file.
         """
+        if not os.path.exists("/etc/machine-id"):
+            msg = _("Unable to get host UUID: /etc/machine-id does not exist")
+            raise exception.NovaException(msg)
+
         with open("/etc/machine-id") as f:
             # We want to have '-' in the right place
             # so we parse & reformat the value
-            return str(uuid.UUID(f.read().split()[0]))
+            lines = f.read().split()
+            if not lines:
+                msg = _("Unable to get host UUID: /etc/machine-id is empty")
+                raise exception.NovaException(msg)
+
+            return str(uuid.UUID(lines[0]))
 
     def _get_host_sysinfo_serial_auto(self):
         if os.path.exists("/etc/machine-id"):