Validates the period compatibility of reprocessing dates

Problem description
===================

The reprocess API is accepting time windows that are
not compatible with the configured collection period
which causes some reprocessings to be endless or
generating different values based on the time window
the user inputs.

Proposal
========

We propose to add a validation in the reprocess API
to deny users to schedule a reprocess using a not
compatible time window and suggest the nearest valid
time window that the user can schedule a reprocess.

Change-Id: I24745a612bbd4714a7793df1deced671c1d1c26a

cloudkitty/api/v2/task/reprocess.py

@@ -11,6 +11,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 #
+from datetime import timedelta
 from datetimerange import DateTimeRange
 import flask
 from oslo_log import log
@@ -24,6 +25,7 @@ from cloudkitty import storage_state
 from cloudkitty.storage_state.models import ReprocessingScheduler
 from cloudkitty.utils import tz as tzutils
 from cloudkitty.utils import validation as validation_utils
+from oslo_config import cfg
 
 
 LOG = log.getLogger(__name__)
@@ -91,6 +93,29 @@ class ReprocessSchedulerPostApi(base.BaseResource):
 
         return {}, 202
 
+    @staticmethod
+    def get_date_period_overflow(date):
+        return int(date.timestamp() % cfg.CONF.collect.period)
+
+    @staticmethod
+    def get_valid_period_date(date):
+        return date - timedelta(
+            seconds=ReprocessSchedulerPostApi.get_date_period_overflow(date))
+
+    @staticmethod
+    def get_overflow_from_dates(start, end):
+        start_overflow = ReprocessSchedulerPostApi.get_date_period_overflow(
+            start)
+        end_overflow = ReprocessSchedulerPostApi.get_date_period_overflow(end)
+        if start_overflow or end_overflow:
+            valid_start = ReprocessSchedulerPostApi.get_valid_period_date(
+                start)
+            valid_end = ReprocessSchedulerPostApi.get_valid_period_date(end)
+            if valid_start == valid_end:
+                valid_end += timedelta(seconds=cfg.CONF.collect.period)
+
+            return [str(valid_start), str(valid_end)]
+
     @staticmethod
     def validate_inputs(
             end_reprocess_time, reason, scope_ids, start_reprocess_time):
@@ -107,6 +132,14 @@ class ReprocessSchedulerPostApi(base.BaseResource):
                 "start reprocessing timestamp [%s]."
                 % (start_reprocess_time, end_reprocess_time))
 
+        periods_overflows = ReprocessSchedulerPostApi.get_overflow_from_dates(
+            start_reprocess_time, end_reprocess_time)
+        if periods_overflows:
+            raise http_exceptions.BadRequest(
+                "The provided reprocess time window does not comply with "
+                "the configured collector period. A valid time window "
+                "near the provided one is %s" % periods_overflows)
+
     @staticmethod
     def validate_scope_ids(scope_ids):
         option_all_selected = False

cloudkitty/tests/api/v2/task/test_reprocess.py

@@ -31,9 +31,10 @@ class TestReprocessSchedulerPostApi(tests.TestCase):
         self.scope_ids = ["some-other-scope-id",
                           "5e56cb64-4980-4466-9fce-d0133c0c221e"]
 
-        self.start_reprocess_time = tzutils.localized_now()
+        self.start_reprocess_time = self.endpoint.get_valid_period_date(
-        self.end_reprocess_time =\
+            tzutils.localized_now())
-            self.start_reprocess_time + datetime.timedelta(hours=1)
+        self.end_reprocess_time = self.endpoint.get_valid_period_date(
+            self.start_reprocess_time + datetime.timedelta(hours=1))
 
         self.reason = "We are testing the reprocess API."
 
@@ -100,6 +101,54 @@ class TestReprocessSchedulerPostApi(tests.TestCase):
             self.end_reprocess_time, self.reason, self.scope_ids,
             self.start_reprocess_time)
 
+    def test_validate_inputs_different_from_configured_period(self):
+        original_end_reprocess_time = self.end_reprocess_time
+
+        self.end_reprocess_time += datetime.timedelta(seconds=1)
+
+        expected_message = "400 Bad Request: The provided reprocess time " \
+                           "window does not comply with the configured" \
+                           " collector period. A valid time window near " \
+                           "the provided one is ['%s', '%s']" % (
+                               self.start_reprocess_time,
+                               original_end_reprocess_time)
+
+        expected_message = re.escape(expected_message)
+
+        self.assertRaisesRegex(http_exceptions.BadRequest, expected_message,
+                               self.endpoint.validate_inputs,
+                               self.end_reprocess_time, self.reason,
+                               self.scope_ids, self.start_reprocess_time)
+
+        self.end_reprocess_time = original_end_reprocess_time
+        self.endpoint.validate_inputs(
+            self.end_reprocess_time, self.reason, self.scope_ids,
+            self.start_reprocess_time)
+
+    def test_validate_time_window_smaller_than_configured_period(self):
+        start = datetime.datetime(year=2022, day=22, month=2, hour=10,
+                                  minute=10, tzinfo=tzutils._LOCAL_TZ)
+        end = datetime.datetime(year=2022, day=22, month=2, hour=10,
+                                minute=20, tzinfo=tzutils._LOCAL_TZ)
+        expected_start = datetime.datetime(year=2022, day=22, month=2, hour=10,
+                                           tzinfo=tzutils._LOCAL_TZ)
+        expected_end = datetime.datetime(year=2022, day=22, month=2, hour=11,
+                                         tzinfo=tzutils._LOCAL_TZ)
+
+        expected_message = "400 Bad Request: The provided reprocess time " \
+                           "window does not comply with the configured" \
+                           " collector period. A valid time window near " \
+                           "the provided one is ['%s', '%s']" % (
+                               expected_start,
+                               expected_end)
+
+        expected_message = re.escape(expected_message)
+
+        self.assertRaisesRegex(http_exceptions.BadRequest, expected_message,
+                               self.endpoint.validate_inputs,
+                               end, self.reason,
+                               self.scope_ids, start)
+
     def test_check_if_there_are_invalid_scopes(self):
         all_scopes = self.generate_all_scopes_object()
 

releasenotes/notes/add-new-validation-to-not-allow-reprocessing-with-incompatible-timewindows-5a44802f20bce4f2.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Add a validation to not allow users to schedule reprocesses via
+    ``POST`` request on ``/v2/task/reprocesses`` using a time window not
+    compatible with the configured ``period`` in the collector.