Friendlier option for providing dict key arguments

Several CLI commands require providing dictionary arguments. These
arguments are currently provided as:

--argument-name "key1=<value1,key2=value2,...>"

Although the value fields are optional, it requires the user to
at least provide input in the form "key=". This is not very intuitive
and often confusing.

In this patch we preseve the current convention of providing the
dictionary arguments, but we enhance the parsing logic to also accept only
keys as arguments. The values are assumed as empty strings in such cases
and the appropriate dictonary is constructed and passed to the backend. So,
the following new syntax is also supported:

--argument-name "key1<,key2,...>"

This is a backward compatible change to the CLI.

Change-Id: I0f4c15b02c151a5f4facb2881fb0c11896a7e39c
Closes-bug: 1504912

gbpclient/common/utils.py

@@ -0,0 +1,31 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+#
+
+
+def str2dict(strdict):
+    """Convert key1=value1,key2=value2,... string into dictionary.
+
+    :param strdict: key1=value1,key2=value2
+    Note: This implementation overrides the original implementation
+    in the neutronclient such that it is no longer required to append
+    the key with a = to specify a corresponding empty value. For example,
+    key1=value1,key2,key3=value3
+    key1
+    key1,key2
+    will also be supported and converted to a dictionary with empty
+    values for the relevant keys.
+    """
+    if not strdict:
+        return {}
+    return dict([kv.split('=', 1) if '=' in kv else [kv, ""]
+                 for kv in strdict.split(',')])

gbpclient/gbp/v2_0/groupbasedpolicy.py

@@ -14,11 +14,12 @@
 import logging
 import string
 
-from neutronclient.common import utils
 from neutronclient.i18n import _
 from neutronclient.neutron import v2_0 as neutronV20
 from oslo.serialization import jsonutils
 
+from gbpclient.common import utils
+
 
 def _format_network_service_params(net_svc_policy):
     try:

gbpclient/tests/unit/test_utils.py

@@ -0,0 +1,39 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import testtools
+
+from gbpclient.common import utils
+
+
+class TestUtils(testtools.TestCase):
+    def test_string_to_dictionary(self):
+        input_str = 'key1'
+        expected = {'key1': ''}
+        self.assertEqual(expected, utils.str2dict(input_str))
+        input_str = 'key1,key2'
+        expected = {'key1': '', 'key2': ''}
+        self.assertEqual(expected, utils.str2dict(input_str))
+        input_str = 'key1=value1,key2'
+        expected = {'key1': 'value1', 'key2': ''}
+        self.assertEqual(expected, utils.str2dict(input_str))
+        input_str = 'key1=value1,key2=value2'
+        expected = {'key1': 'value1', 'key2': 'value2'}
+        self.assertEqual(expected, utils.str2dict(input_str))
+
+    def test_none_string_to_dictionary(self):
+        input_str = ''
+        expected = {}
+        self.assertEqual(expected, utils.str2dict(input_str))
+        input_str = None
+        expected = {}
+        self.assertEqual(expected, utils.str2dict(input_str))