Updates after review

- Modified the services_dao to return an int instead of a datetime to
make usage easier and removed the BST function on year as it is not
relevant for year
- Improved tests do there is less logic by ordering the result so there
is less reliance on the template id
- Renamed variable in stats_template_usage_by_month_dao.py to make it
consistent with the method

app/celery/scheduled_tasks.py

@@ -410,13 +410,13 @@ def check_job_status():
 
 @notify_celery.task(name='daily-stats-template_usage_by_month')
 @statsd(namespace="tasks")
-def daily_stats_template_usage_my_month():
+def daily_stats_template_usage_by_month():
     results = dao_fetch_monthly_historical_stats_by_template()
 
     for result in results:
         insert_or_update_stats_for_template(
             result.template_id,
-            result.month.month,
-            result.year.year,
+            result.month,
+            result.year,
             result.count
         )

app/config.py

@@ -244,7 +244,7 @@ class Config(object):
         },
         'daily-stats-template_usage_by_month': {
             'task': 'daily-stats-template_usage_by_month',
-            'schedule': crontab(hour=00, minute=50),
+            'schedule': crontab(hour=0, minute=50),
             'options': {'queue': QueueNames.PERIODIC}
         }
     }

app/dao/services_dao.py

@@ -40,7 +40,7 @@ from app.models import (
 )
 from app.service.statistics import format_monthly_template_notification_stats
 from app.statsd_decorators import statsd
-from app.utils import get_london_month_from_utc_column, get_london_midnight_in_utc, get_london_year_from_utc_column
+from app.utils import get_london_month_from_utc_column, get_london_midnight_in_utc
 from app.dao.annual_billing_dao import dao_insert_annual_billing
 
 DEFAULT_SERVICE_PERMISSIONS = [
@@ -525,13 +525,13 @@ def dao_fetch_active_users_for_service(service_id):
 @statsd(namespace="dao")
 def dao_fetch_monthly_historical_stats_by_template():
     month = get_london_month_from_utc_column(NotificationHistory.created_at)
-    year = get_london_year_from_utc_column(NotificationHistory.created_at)
+    year = func.date_trunc("year", NotificationHistory.created_at)
     end_date = datetime.combine(date.today(), time.min)
 
     return db.session.query(
         NotificationHistory.template_id,
-        month.label('month'),
-        year.label('year'),
+        extract('month', month).label('month'),
+        extract('year', year).label('year'),
         func.count().label('count')
     ).filter(
         NotificationHistory.created_at < end_date

app/dao/stats_template_usage_by_month_dao.py

@@ -15,10 +15,10 @@ def insert_or_update_stats_for_template(template_id, month, year, count):
         }
     )
     if result == 0:
-        new_sms_sender = StatsTemplateUsageByMonth(
+        monthly_stats = StatsTemplateUsageByMonth(
             template_id=template_id,
             month=month,
             year=year,
             count=count
         )
-        db.session.add(new_sms_sender)
+        db.session.add(monthly_stats)

app/utils.py

@@ -71,23 +71,7 @@ def get_london_month_from_utc_column(column):
     """
     return func.date_trunc(
         "month",
-        func.timezone("Europe/London", func.timezone("UTC", column))
-    )
-
-
-def get_london_year_from_utc_column(column):
-    """
-     Where queries need to count notifications by month it needs to be
-     the month in BST (British Summer Time).
-     The database stores all timestamps as UTC without the timezone.
-      - First set the timezone on created_at to UTC
-      - then convert the timezone to BST (or Europe/London)
-      - lastly truncate the datetime to month with which we can group
-        queries
-    """
-    return func.date_trunc(
-        "month",
-        func.timezone("Europe/London", func.timezone("UTC", column))
+        func.timezone("Europe/London", column)
     )