change the cron-trigger execution time from localtime to UTC

When a cron-trigger is created, in the output, the created time is
shown in UTC but the next execution time is in localtime. It would
be better if both times are shown in the same timezone. This patch
changes the next execution time to UTC.

Change-Id: Icae26cef37736cb55b9a2460f16e82afdb058165
Closes-Bug: #1592164

mistral/services/triggers.py

@@ -15,6 +15,7 @@
 import croniter
 import datetime
 import six
+import time
 
 from mistral.db.v2 import api as db_api
 from mistral.engine.rpc_backend import rpc
@@ -25,14 +26,19 @@ from mistral.workbook import parser
 
 
 def get_next_execution_time(pattern, start_time):
-    return croniter.croniter(pattern, start_time).get_next(datetime.datetime)
+    local_time = croniter.croniter(pattern, start_time).get_next(
+        datetime.datetime
+    )
+    epoch_second = time.mktime(local_time.timetuple())
+    utc_time = datetime.datetime.utcfromtimestamp(epoch_second)
+    return utc_time
 
 
 # Triggers v2.
 
 def get_next_cron_triggers():
     return db_api.get_next_cron_triggers(
-        datetime.datetime.now() + datetime.timedelta(0, 2)
+        datetime.datetime.utcnow() + datetime.timedelta(0, 2)
     )
 
 
@@ -42,7 +48,10 @@ def validate_cron_trigger_input(pattern, first_time, count):
             'Pattern or first_execution_time must be specified.'
         )
     if first_time:
-        if (datetime.datetime.now() + datetime.timedelta(0, 60)) > first_time:
+        first_second = time.mktime(first_time.timetuple())
+        first_utc_time = datetime.datetime.utcfromtimestamp(first_second)
+        sum_time = datetime.datetime.utcnow() + datetime.timedelta(0, 60)
+        if sum_time > first_utc_time:
             raise exc.InvalidModelException(
                 'first_execution_time must be at least 1 minute in the future.'
             )
@@ -76,8 +85,12 @@ def create_cron_trigger(name, workflow_name, workflow_input,
 
     validate_cron_trigger_input(pattern, first_time, count)
 
+    first_utc_time = first_time
+
     if first_time:
-        next_time = first_time
+        first_second = time.mktime(first_time.timetuple())
+        first_utc_time = datetime.datetime.utcfromtimestamp(first_second)
+        next_time = first_utc_time
 
         if not (pattern or count):
             count = 1
@@ -98,7 +111,7 @@ def create_cron_trigger(name, workflow_name, workflow_input,
         values = {
             'name': name,
             'pattern': pattern,
-            'first_execution_time': first_time,
+            'first_execution_time': first_utc_time,
             'next_execution_time': next_time,
             'remaining_executions': count,
             'workflow_name': wf_def.name,

mistral/tests/unit/engine/test_cron_trigger.py

@@ -12,6 +12,7 @@
 #    See the License for the specific language governing permissions and
 #    limitations under the License.
 import datetime
+import time
 
 import mock
 from oslo_config import cfg
@@ -145,8 +146,11 @@ class ProcessCronTriggerTest(base.EngineTestCase):
             None
         )
 
+        first_second = time.mktime(first_time.timetuple())
+        first_utc_time = datetime.datetime.utcfromtimestamp(first_second)
+
         self.assertEqual(
-            first_time,
+            first_utc_time,
             cron_trigger.next_execution_time
         )
 

mistral/tests/unit/services/test_trigger_service.py

@@ -329,3 +329,9 @@ class TriggerServiceV2Test(base.DbTestCase):
         eventlet.sleep(1)
 
         return trigger_count == start_wf_mock.call_count
+
+    def test_get_next_execution_time(self):
+        pattern = '*/20 * * * *'
+        start_time = datetime.datetime(2016, 3, 22, 23, 40)
+        result = t_s.get_next_execution_time(pattern, start_time)
+        self.assertEqual(result, datetime.datetime(2016, 3, 23, 0, 0))