Password should be prompted once

There's a corner case where password may be requested twice. In a fresh
environment, when schemas have not be downloaded for v2, the client will
ask for a password to download the schemas and then it'll ask for the
password again to run the actual command. This happens because we parse
the CLI arguments twice to make sure we're parsing them for the right
client version.

This patch checks if the password is unset in the newly parsed arguments
and if it's been set in the previously parsed ones. In this case it
keeps the set password. I believe this approach is safer than re-using
the already parsed arguements which may have been parsed for a different
API version (might happen because we fallback to v1 if v2 is not
available).

Change-Id: I080253170e3e84a90363e5bb494cf137895fe2e7
Closes-bug: #1488892

glanceclient/shell.py

@@ -659,6 +659,13 @@ class OpenStackImagesShell(object):
         # Parse args again and call whatever callback was selected
         args = subcommand_parser.parse_args(argv)
 
+        # NOTE(flaper87): Make sure we re-use the password input if we
+        # have one. This may happen if the schemas were downloaded in
+        # this same command. Password will be asked to download the
+        # schemas and then for the operations below.
+        if not args.os_password and options.os_password:
+            args.os_password = options.os_password
+
         # Short-circuit and deal with help command right away.
         if args.func == self.do_help:
             self.do_help(args)

glanceclient/tests/unit/test_shell.py

@@ -291,7 +291,7 @@ class ShellTest(testutils.TestCase):
         self.assertRaises(ks_exc.ConnectionRefused,
                           glance_shell.main, ['image-list'])
         # Make sure we are actually prompted.
-        mock_getpass.assert_called_with('OS Password: ')
+        mock_getpass.assert_called_once_with('OS Password: ')
 
     @mock.patch('sys.stdin', side_effect=mock.MagicMock)
     @mock.patch('getpass.getpass', side_effect=EOFError)