Add oneline_string validators

Those new validators are used to validate extra_dhcp_opt's opt_name and
opt_value fields to not allow multi-line strings to be set there.

Related-Bug: #1939733
Change-Id: I4dc3a09847205a660dc966d8eabccb4946f9bbc6

neutron_lib/api/definitions/extra_dhcp_opt.py

@@ -33,9 +33,9 @@ EXTRA_DHCP_OPT_KEY_SPECS = [
                     'type:values': [4, 6],
                     'required': False}},
     # key spec if opt_name not in _VALID_BLANK_EXTRA_DHCP_OPTS
-    {'opt_name': {'type:not_empty_string': DHCP_OPT_NAME_MAX_LEN,
+    {'opt_name': {'type:oneline_not_empty_string': DHCP_OPT_NAME_MAX_LEN,
                   'required': True},
-     'opt_value': {'type:not_empty_string_or_none':
+     'opt_value': {'type:oneline_not_empty_string_or_none':
                    DHCP_OPT_VALUE_MAX_LEN,
                    'required': True},
      'ip_version': {'convert_to': converters.convert_to_int,

neutron_lib/api/validators/__init__.py

@@ -256,6 +256,36 @@ def validate_list_of_unique_strings(data, max_len=None):
     return _validate_list_of_unique_strings(data, max_len=max_len)
 
 
+def validate_oneline_not_empty_string(data, max_len=None):
+    """Validate data is a non-empty string without newline character.
+
+    :param data: The data to validate.
+    :param max_len: An optional cap on the length of the string.
+    :returns: None if the data is a string without newline character,
+        otherwise a human readable message indicating why validation failed.
+    """
+    msg = validate_not_empty_string(data, max_len=max_len)
+    if msg:
+        return msg
+    if len(data.splitlines()) > 1:
+        msg = _("Multi-line string is not allowed: '%s'") % data
+        LOG.debug(msg)
+        return msg
+
+
+def validate_oneline_not_empty_string_or_none(data, max_len=None):
+    """Validate data is a non-empty string without newline character or None.
+
+    :param data: The data to validate.
+    :param max_len: An optional cap on the length of the string data.
+    :returns: None if the data is None or a valid string without newline
+        character, otherwise a human readable message indicating why
+        validation failed.
+    """
+    if data is not None:
+        return validate_oneline_not_empty_string(data, max_len=max_len)
+
+
 def validate_boolean(data, valid_values=None):
     """Validate data is a python bool compatible object.
 
@@ -1232,6 +1262,10 @@ validators = {'type:dict': validate_dict,
               'type:not_empty_string': validate_not_empty_string,
               'type:not_empty_string_or_none':
               validate_not_empty_string_or_none,
+              'type:oneline_not_empty_string':
+              validate_oneline_not_empty_string,
+              'type:oneline_not_empty_string_or_none':
+              validate_oneline_not_empty_string_or_none,
               'type:subnet': validate_subnet,
               'type:subnet_list': validate_subnet_list,
               'type:subnet_or_none': validate_subnet_or_none,

neutron_lib/tests/unit/api/validators/test_validators.py

@@ -222,6 +222,59 @@ class TestAttributeValidation(base.BaseTestCase):
         msg = validators.validate_list_of_unique_strings(data, None)
         self.assertIsNone(msg)
 
+    def test_validate_oneline_not_empty_string(self):
+        data = "Test"
+        msg = validators.validate_oneline_not_empty_string(data, None)
+        self.assertIsNone(msg)
+
+        data = "Test but this is too long"
+        max_len = 4
+        msg = validators.validate_oneline_not_empty_string(data, max_len)
+        self.assertEqual(
+            "'%s' exceeds maximum length of %s" % (data, max_len),
+            msg)
+
+        data = "First line\nsecond line"
+        msg = validators.validate_oneline_not_empty_string(data, None)
+        self.assertEqual(
+            "Multi-line string is not allowed: '%s'" % data,
+            msg)
+
+        data = ""
+        msg = validators.validate_oneline_not_empty_string(data, None)
+        self.assertEqual(
+            "'%s' Blank strings are not permitted" % data,
+            msg)
+
+    def test_validate_oneline_not_empty_string_or_none(self):
+        data = "Test"
+        msg = validators.validate_oneline_not_empty_string_or_none(data, None)
+        self.assertIsNone(msg)
+
+        data = None
+        msg = validators.validate_oneline_not_empty_string_or_none(data, None)
+        self.assertIsNone(msg)
+
+        data = "Test but this is too long"
+        max_len = 4
+        msg = validators.validate_oneline_not_empty_string_or_none(
+            data, max_len)
+        self.assertEqual(
+            "'%s' exceeds maximum length of %s" % (data, max_len),
+            msg)
+
+        data = "First line\nsecond line"
+        msg = validators.validate_oneline_not_empty_string_or_none(data, None)
+        self.assertEqual(
+            "Multi-line string is not allowed: '%s'" % data,
+            msg)
+
+        data = ""
+        msg = validators.validate_oneline_not_empty_string(data, None)
+        self.assertEqual(
+            "'%s' Blank strings are not permitted" % data,
+            msg)
+
     def test_validate_boolean(self):
         msg = validators.validate_boolean(True)
         self.assertIsNone(msg)

releasenotes/notes/Add-oneline-string-validator-aa4e1ccad9d8d5c8.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - |
+    New API validators ``validate_oneline_not_empty_string`` and
+    ``validate_oneline_not_empty_string_or_none`` are added. Those validators
+    are now used to validate ``opt_name`` and ``opt_value`` fields of
+    the extra_dhcp_opt so strings with newline character are not valid for
+    dhcp extra option's name nor value.