Stop silently ignoring invalid 'server create --hint' options

The '--hint' option for 'server create' expects a key-value pair like so:

  openstack server create --hint group=245e1dfe-2d0e-4139-80a9-fce124948896 ...

However, the command doesn't complain if this isn't the case, meaning
typos like the below aren't indicated to the user:

  openstack server create --hint 245e1dfe-2d0e-4139-80a9-fce124948896

Due to how we'd implemented this here, this ultimately results in us
POSTing the following as part of the body to 'os-servers':

  {
    ...
    "OS-SCH-HNT:scheduler_hints": {
      "245e1dfe-2d0e-4139-80a9-fce124948896": null
    }
    ...
  }

Which is unfortunately allowed and ignored by nova due to the use of
'additionalProperties' in the schema [1]

Do what we do for loads of other options and explicitly fail on invalid
values. This involves adding a new argparse action since none of those
defined in osc-lib work for us. This is included here to ease
backporting of the fix but will be moved to osc-lib in a future patch.

[1] https://github.com/openstack/nova/blob/19.0.0/nova/api/openstack/compute/schemas/servers.py#L142-L146

Change-Id: I9e96d2978912c8dfeadae4a782c481a17cd7e348
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>
Story: #2006628
Task: #36840
Related-Bug: #1845322

openstackclient/compute/v2/server.py

@@ -201,6 +201,36 @@ def _prep_server_detail(compute_client, image_client, server, refresh=True):
     return info
 
 
+# TODO(stephenfin): Migrate this to osc-lib
+class KeyValueAppendAction(argparse.Action):
+    """A custom action to parse arguments as key=value pairs
+
+    Ensures that ``dest`` is a dict and values are lists of strings.
+    """
+
+    def __call__(self, parser, namespace, values, option_string=None):
+        # Make sure we have an empty dict rather than None
+        if getattr(namespace, self.dest, None) is None:
+            setattr(namespace, self.dest, {})
+
+        # Add value if an assignment else remove it
+        if '=' in values:
+            key, value = values.split('=', 1)
+            # NOTE(qtang): Prevent null key setting in property
+            if '' == key:
+                msg = _("Property key must be specified: %s")
+                raise argparse.ArgumentTypeError(msg % str(values))
+
+            dest = getattr(namespace, self.dest)
+            if key in dest:
+                dest[key].append(value)
+            else:
+                dest[key] = [value]
+        else:
+            msg = _("Expected 'key=value' type, but got: %s")
+            raise argparse.ArgumentTypeError(msg % str(values))
+
+
 class AddFixedIP(command.Command):
     _description = _("Add fixed IP address to server")
 
@@ -689,8 +719,8 @@ class CreateServer(command.ShowOne):
         parser.add_argument(
             '--hint',
             metavar='<key=value>',
-            action='append',
-            default=[],
+            action=KeyValueAppendAction,
+            default={},
             help=_('Hints for the scheduler (optional extension)'),
         )
         parser.add_argument(
@@ -986,16 +1016,12 @@ class CreateServer(command.ShowOne):
                 security_group_names.append(sg['name'])
 
         hints = {}
-        for hint in parsed_args.hint:
-            key, _sep, value = hint.partition('=')
-            # NOTE(vish): multiple copies of the same hint will
-            #             result in a list of values
-            if key in hints:
-                if isinstance(hints[key], six.string_types):
-                    hints[key] = [hints[key]]
-                hints[key] += [value]
+        for key, values in parsed_args.hint.items():
+            # only items with multiple values will result in a list
+            if len(values) == 1:
+                hints[key] = values[0]
             else:
-                hints[key] = value
+                hints[key] = values
 
         # What does a non-boolean value for config-drive do?
         # --config-drive argument is either a volume id or

openstackclient/tests/unit/compute/v2/test_server.py

@@ -860,7 +860,7 @@ class TestServerCreate(TestServer):
             ('key_name', 'keyname'),
             ('property', {'Beta': 'b'}),
             ('security_group', ['securitygroup']),
-            ('hint', ['a=b', 'a=c']),
+            ('hint', {'a': ['b', 'c']}),
             ('config_drive', False),
             ('server_name', self.new_server.name),
         ]
@@ -2060,6 +2060,29 @@ class TestServerCreate(TestServer):
                           self.cmd.take_action,
                           parsed_args)
 
+    def test_server_create_invalid_hint(self):
+        # Not a key-value pair
+        arglist = [
+            '--image', 'image1',
+            '--flavor', 'flavor1',
+            '--hint', 'a0cf03a5-d921-4877-bb5c-86d26cf818e1',
+            self.new_server.name,
+        ]
+        self.assertRaises(argparse.ArgumentTypeError,
+                          self.check_parser,
+                          self.cmd, arglist, [])
+
+        # Empty key
+        arglist = [
+            '--image', 'image1',
+            '--flavor', 'flavor1',
+            '--hint', '=a0cf03a5-d921-4877-bb5c-86d26cf818e1',
+            self.new_server.name,
+        ]
+        self.assertRaises(argparse.ArgumentTypeError,
+                          self.check_parser,
+                          self.cmd, arglist, [])
+
     def test_server_create_with_description_api_newer(self):
 
         # Description is supported for nova api version 2.19 or above