Improve the timestamp validation of ceilometer API

Currently, ceilometer API is lack of timestamp validation. Timestamp in
query should be checked if it can be parsed to iso timestamp, and raise
explicit exception if not.

Change-Id: I02cb2f30b00bde46bf8a0e4e161a0e2ce9d44c09
Closes-bug: #1270394

ceilometer/api/controllers/v2.py

@@ -590,8 +590,8 @@ def _get_query_timestamps(args=None):
     query_end: Final timestamp to use for query
     end_timestamp: end_timestamp parameter from request
     search_offset: search_offset parameter from request
-
     """
+
     if args is None:
         return {'query_start': None,
                 'query_end': None,
@@ -600,23 +600,25 @@ def _get_query_timestamps(args=None):
                 'search_offset': 0}
     search_offset = int(args.get('search_offset', 0))
 
+    def _parse_timestamp(timestamp):
+        if not timestamp:
+            return None
+        try:
+            iso_timestamp = timeutils.parse_isotime(timestamp)
+            iso_timestamp = iso_timestamp.replace(tzinfo=None)
+        except ValueError:
+            raise wsme.exc.InvalidInput('timestamp', timestamp,
+                                        'invalid timestamp format')
+        return iso_timestamp
+
     start_timestamp = args.get('start_timestamp')
-    if start_timestamp:
-        start_timestamp = timeutils.parse_isotime(start_timestamp)
-        start_timestamp = start_timestamp.replace(tzinfo=None)
-        query_start = (start_timestamp -
-                       datetime.timedelta(minutes=search_offset))
-    else:
-        query_start = None
-
     end_timestamp = args.get('end_timestamp')
-    if end_timestamp:
-        end_timestamp = timeutils.parse_isotime(end_timestamp)
-        end_timestamp = end_timestamp.replace(tzinfo=None)
-        query_end = end_timestamp + datetime.timedelta(minutes=search_offset)
-    else:
-        query_end = None
-
+    start_timestamp = _parse_timestamp(start_timestamp)
+    end_timestamp = _parse_timestamp(end_timestamp)
+    query_start = start_timestamp - datetime.timedelta(
+        minutes=search_offset) if start_timestamp else None
+    query_end = end_timestamp + datetime.timedelta(
+        minutes=search_offset) if end_timestamp else None
     return {'query_start': query_start,
             'query_end': query_end,
             'start_timestamp': start_timestamp,

ceilometer/tests/api/v2/test_query.py

@@ -321,3 +321,15 @@ class TestQueryToKwArgs(tests_base.BaseTestCase):
                                           storage.SampleFilter.__init__)
             for o in ['user', 'project', 'resource']:
                 self.assertEqual('fake_%s_id' % o, kwargs.get(o))
+
+    def test_timestamp_validation(self):
+        q = [api.Query(field='timestamp',
+                       op='le',
+                       value='123')]
+
+        exc = self.assertRaises(
+            wsme.exc.InvalidInput,
+            api._query_to_kwargs, q, storage.SampleFilter.__init__)
+        expected_exc = wsme.exc.InvalidInput('timestamp', '123',
+                                             'invalid timestamp format')
+        self.assertEqual(str(expected_exc), str(exc))