Provide user friendly messages for db sync

Currently 'cinder-manage db sync' prints stacktrace if you
pass invalid value for 'version'.

This patch validates 'version' for its type and maximum
limit and displays a meaningful message to the user.

Handles DbMigrationError exception when database schema
file is not present in migration repository.

Closes-Bug: #1546441
Change-Id: Id3dc077b80c2b6353907a1bb5c15cefdb2eae8ed

cinder/cmd/manage.py

@@ -210,11 +210,19 @@ class DbCommands(object):
     def __init__(self):
         pass
 
-    @args('version', nargs='?', default=None,
+    @args('version', nargs='?', default=None, type=int,
           help='Database version')
     def sync(self, version=None):
         """Sync the database up to the most recent version."""
-        return db_migration.db_sync(version)
+        if version is not None and version > db.MAX_INT:
+            print(_('Version should be less than or equal to '
+                    '%(max_version)d.') % {'max_version': db.MAX_INT})
+            sys.exit(1)
+        try:
+            return db_migration.db_sync(version)
+        except db_exc.DbMigrationError as ex:
+            print("Error during database migration: %s" % ex)
+            sys.exit(1)
 
     def version(self):
         """Print the current database version."""

cinder/tests/unit/test_cmd.py

@@ -19,6 +19,7 @@ import ddt
 import fixtures
 import mock
 from oslo_config import cfg
+from oslo_db import exception as oslo_exception
 from oslo_utils import timeutils
 import six
 from six.moves import StringIO
@@ -194,7 +195,7 @@ class TestCinderManageCmd(test.TestCase):
 
     @mock.patch('cinder.db.migration.db_sync')
     def test_db_commands_sync(self, db_sync):
-        version = mock.MagicMock()
+        version = 11
         db_cmds = cinder_manage.DbCommands()
         db_cmds.sync(version=version)
         db_sync.assert_called_once_with(version)
@@ -206,6 +207,19 @@ class TestCinderManageCmd(test.TestCase):
             db_cmds.version()
             self.assertEqual(1, db_version.call_count)
 
+    def test_db_commands_upgrade_out_of_range(self):
+        version = 2147483647
+        db_cmds = cinder_manage.DbCommands()
+        exit = self.assertRaises(SystemExit, db_cmds.sync, version + 1)
+        self.assertEqual(1, exit.code)
+
+    @mock.patch("oslo_db.sqlalchemy.migration.db_sync")
+    def test_db_commands_script_not_present(self, db_sync):
+        db_sync.side_effect = oslo_exception.DbMigrationError
+        db_cmds = cinder_manage.DbCommands()
+        exit = self.assertRaises(SystemExit, db_cmds.sync, 101)
+        self.assertEqual(1, exit.code)
+
     @mock.patch('cinder.cmd.manage.DbCommands.online_migrations',
                 (mock.Mock(side_effect=((2, 2), (0, 0)), __name__='foo'),))
     def test_db_commands_online_data_migrations(self):