Fix InfluxDB storage's "_point_to_dataframe_entry" method

This fixes the "_point_to_dataframe_entry" method by checking if the
"metadata" and "groupby" attributes of points returned by the influxdb
client are not None.

Change-Id: Ic7e482fad3ad05026fa14412acb577fe7a02045c
(cherry picked from commit 0259fe458c)

cloudkitty/storage/v2/influx.py

@@ -270,8 +270,10 @@ class InfluxStorage(v2_storage.BaseStorage):
 
     @staticmethod
     def _point_to_dataframe_entry(point):
-        groupby = point.pop('groupby').split('|')
+        groupby = (point.pop('groupby', None) or '').split('|')
-        metadata = point.pop('metadata').split('|')
+        groupby = [g for g in groupby if g]
+        metadata = (point.pop('metadata', None) or '').split('|')
+        metadata = [m for m in metadata if m]
         return {
             'vol': {
                 'unit': point['unit'],

cloudkitty/tests/storage/v2/test_influxdb.py

@@ -0,0 +1,55 @@
+# Copyright 2019 Objectif Libre
+#
+#    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.
+#
+from cloudkitty.storage.v2.influx import InfluxStorage
+from cloudkitty.tests import TestCase
+
+
+class TestInfluxDBStorage(TestCase):
+
+    def setUp(self):
+        super(TestInfluxDBStorage, self).setUp()
+        self.point = {
+            'unit': 'banana',
+            'qty': 42,
+            'price': 1.0,
+            'groupby': 'one|two',
+            'metadata': '1|2',
+            'one': '1',
+            'two': '2',
+            '1': 'one',
+            '2': 'two',
+        }
+
+    def test_point_to_dataframe_entry_valid_point(self):
+        self.assertEqual(
+            InfluxStorage._point_to_dataframe_entry(self.point), {
+                'vol': {'unit': 'banana', 'qty': 42},
+                'rating': {'price': 1.0},
+                'groupby': {'one': '1', 'two': '2'},
+                'metadata': {'1': 'one', '2': 'two'},
+            }
+        )
+
+    def test_point_to_dataframe_entry_invalid_groupby_metadata(self):
+        self.point['groupby'] = 'a'
+        self.point['metadata'] = None
+        self.assertEqual(
+            InfluxStorage._point_to_dataframe_entry(self.point), {
+                'vol': {'unit': 'banana', 'qty': 42},
+                'rating': {'price': 1.0},
+                'groupby': {'a': ''},
+                'metadata': {}
+            }
+        )