Merge "Add nova-manage cell_v2 delete_cell command"

nova/cmd/manage.py

@@ -1461,6 +1461,44 @@ class CellV2Commands(object):
         print(t)
         return 0
 
+    @args('--cell_uuid', metavar='<cell_uuid>', dest='cell_uuid',
+          required=True, help=_('The uuid of the cell to delete.'))
+    def delete_cell(self, cell_uuid):
+        """Delete an empty cell by the given uuid.
+
+        If the cell is not found by uuid or it is not empty (it has host or
+        instance mappings) this command will return a non-zero exit code.
+
+        Returns 0 if the empty cell is found and deleted successfully.
+        """
+        ctxt = context.get_admin_context()
+        # Find the CellMapping given the uuid.
+        try:
+            cell_mapping = objects.CellMapping.get_by_uuid(ctxt, cell_uuid)
+        except exception.CellMappingNotFound:
+            print(_('Cell with uuid %s was not found.') % cell_uuid)
+            return 1
+
+        # Check to see if there are any HostMappings for this cell.
+        host_mappings = objects.HostMappingList.get_by_cell_id(
+            ctxt, cell_mapping.id)
+        if host_mappings:
+            print(_('There are existing hosts mapped to cell with uuid %s.') %
+                  cell_uuid)
+            return 2
+
+        # Check to see if there are any InstanceMappings for this cell.
+        instance_mappings = objects.InstanceMappingList.get_by_cell_id(
+            ctxt, cell_mapping.id)
+        if instance_mappings:
+            print(_('There are existing instances mapped to cell with '
+                    'uuid %s.') % cell_uuid)
+            return 3
+
+        # There are no hosts or instances mapped to the cell so delete it.
+        cell_mapping.destroy()
+        return 0
+
 
 CATEGORIES = {
     'account': AccountCommands,

nova/tests/unit/test_nova_manage.py

@@ -1462,6 +1462,62 @@ class CellV2CommandsTestCase(test.NoDBTestCase):
 +--------+--------------------+---------------+---------------------+''',
                          output)
 
+    def test_delete_cell_not_found(self):
+        """Tests trying to delete a cell that is not found by uuid."""
+        cell_uuid = uuidutils.generate_uuid()
+        self.assertEqual(1, self.commands.delete_cell(cell_uuid))
+        output = self.output.getvalue().strip()
+        self.assertEqual('Cell with uuid %s was not found.' % cell_uuid,
+                         output)
+
+    def test_delete_cell_host_mappings_exist(self):
+        """Tests trying to delete a cell which has host mappings."""
+        cell_uuid = uuidutils.generate_uuid()
+        ctxt = context.get_admin_context()
+        # create the cell mapping
+        cm = objects.CellMapping(
+            context=ctxt, uuid=cell_uuid, database_connection='fake:///db',
+            transport_url='fake:///mq')
+        cm.create()
+        # create a host mapping in this cell
+        hm = objects.HostMapping(
+            context=ctxt, host='fake-host', cell_mapping=cm)
+        hm.create()
+        self.assertEqual(2, self.commands.delete_cell(cell_uuid))
+        output = self.output.getvalue().strip()
+        self.assertIn('There are existing hosts mapped to cell', output)
+
+    def test_delete_cell_instance_mappings_exist(self):
+        """Tests trying to delete a cell which has instance mappings."""
+        cell_uuid = uuidutils.generate_uuid()
+        ctxt = context.get_admin_context()
+        # create the cell mapping
+        cm = objects.CellMapping(
+            context=ctxt, uuid=cell_uuid, database_connection='fake:///db',
+            transport_url='fake:///mq')
+        cm.create()
+        # create an instance mapping in this cell
+        im = objects.InstanceMapping(
+            context=ctxt, instance_uuid=uuidutils.generate_uuid(),
+            cell_mapping=cm, project_id=uuidutils.generate_uuid())
+        im.create()
+        self.assertEqual(3, self.commands.delete_cell(cell_uuid))
+        output = self.output.getvalue().strip()
+        self.assertIn('There are existing instances mapped to cell', output)
+
+    def test_delete_cell_success(self):
+        """Tests trying to delete an empty cell."""
+        cell_uuid = uuidutils.generate_uuid()
+        ctxt = context.get_admin_context()
+        # create the cell mapping
+        cm = objects.CellMapping(
+            context=ctxt, uuid=cell_uuid, database_connection='fake:///db',
+            transport_url='fake:///mq')
+        cm.create()
+        self.assertEqual(0, self.commands.delete_cell(cell_uuid))
+        output = self.output.getvalue().strip()
+        self.assertEqual('', output)
+
 
 class TestNovaManageMain(test.NoDBTestCase):
     """Tests the nova-manage:main() setup code."""