TMSS-435: processed review comments. Use constant DEFAULT_INTER_OBSERVATION_GAP

SAS/TMSS/services/scheduling/lib/dynamic_scheduling.py

@@ -39,6 +39,9 @@ from threading import Thread, Event
 
 from lofar.sas.tmss.services.scheduling.constraints import *
 
+# LOFAR needs to have a gap in between observations to (re)initialize hardware.
+DEFAULT_INTER_OBSERVATION_GAP = timedelta(seconds=60)
+
 def get_schedulable_scheduling_units() -> [models.SchedulingUnitBlueprint]:
     '''get a list of all schedulable scheduling_units'''
     defined_independend_subtasks = models.Subtask.independent_subtasks().filter(state__value='defined')
@@ -104,7 +107,7 @@ def schedule_next_scheduling_unit() -> models.SchedulingUnitBlueprint:
     schedulable_units = get_schedulable_scheduling_units()
 
     # estimate the lower_bound_start_time
-    lower_bound_start_time = get_min_earliest_possible_start_time(schedulable_units, datetime.utcnow() + timedelta(seconds=90))
+    lower_bound_start_time = get_min_earliest_possible_start_time(schedulable_units, datetime.utcnow() + DEFAULT_INTER_OBSERVATION_GAP)
 
     # estimate the upper_bound_stop_time, which may give us a small timewindow before any next scheduled unit, or a default window of a day
     try:
@@ -189,8 +192,8 @@ def assign_start_stop_times_to_schedulable_scheduling_units(lower_bound_start_ti
             logger.info("mid-term schedule: next scheduling unit id=%s '%s' start_time=%s", scheduling_unit.id, scheduling_unit.name, start_time)
             update_subtasks_start_times_for_scheduling_unit(scheduling_unit, start_time)
 
-            # keep track of the previous
-            lower_bound_start_time = scheduling_unit.stop_time
+            # keep track of the lower_bound_start_time based on last sub.stoptime and gap
+            lower_bound_start_time = scheduling_unit.stop_time + DEFAULT_INTER_OBSERVATION_GAP
 
             scheduling_units.remove(scheduling_unit)
         else:
@@ -251,7 +254,7 @@ class TMSSSchedulingUnitBlueprintDynamicSchedulingMessageHandler(TMSSEventMessag
                 try:
                     logger.info("Updating dynamic schedule....")
                     scheduled_unit = schedule_next_scheduling_unit()
-                    assign_start_stop_times_to_schedulable_scheduling_units(lower_bound_start_time=scheduled_unit.stop_time if scheduled_unit else None)
+                    assign_start_stop_times_to_schedulable_scheduling_units(lower_bound_start_time=scheduled_unit.stop_time+DEFAULT_INTER_OBSERVATION_GAP if scheduled_unit else None)
                     logger.info("Updating dynamic schedule.... finished")
                 except Exception as e:
                     logger.exception(str(e))