Rewrite task to aggregate status by service

This is a step towards parallelising the task by service and day.

app/celery/reporting_tasks.py

@@ -3,7 +3,7 @@ from datetime import datetime, timedelta
 from flask import current_app
 from notifications_utils.timezones import convert_utc_to_bst
 
-from app import notify_celery
+from app import db, notify_celery
 from app.config import QueueNames
 from app.cronitor import cronitor
 from app.dao.fact_billing_dao import (
@@ -11,10 +11,10 @@ from app.dao.fact_billing_dao import (
     update_fact_billing,
 )
 from app.dao.fact_notification_status_dao import (
-    fetch_notification_status_for_day,
+    fetch_status_data_for_service_and_day,
     update_fact_notification_status,
 )
-from app.models import EMAIL_TYPE, LETTER_TYPE, SMS_TYPE
+from app.models import EMAIL_TYPE, LETTER_TYPE, SMS_TYPE, Service
 
 
 @notify_celery.task(name="create-nightly-billing")
@@ -124,15 +124,26 @@ def create_nightly_notification_status_for_day(process_day, notification_type):
         f'create-nightly-notification-status-for-day task for {process_day} type {notification_type}: started'
     )
 
+    for (service_id,) in db.session.query(Service.id):
         start = datetime.utcnow()
-    transit_data = fetch_notification_status_for_day(process_day=process_day, notification_type=notification_type)
+        transit_data = fetch_status_data_for_service_and_day(
+            process_day=process_day,
+            notification_type=notification_type,
+            service_id=service_id,
+        )
+
         end = datetime.utcnow()
         current_app.logger.info(
             f'create-nightly-notification-status-for-day task for {process_day} type {notification_type}: '
             f'data fetched in {(end - start).seconds} seconds'
         )
 
-    update_fact_notification_status(transit_data, process_day, notification_type)
+        update_fact_notification_status(
+            transit_data=transit_data,
+            process_day=process_day,
+            notification_type=notification_type,
+            service_id=service_id
+        )
 
         current_app.logger.info(
             f'create-nightly-notification-status-for-day task for {process_day} type {notification_type}: '

app/dao/fact_notification_status_dao.py

@@ -1,6 +1,5 @@
 from datetime import datetime, time, timedelta
 
-from flask import current_app
 from notifications_utils.timezones import convert_bst_to_utc
 from sqlalchemy import Date, case, func
 from sqlalchemy.dialects.postgresql import insert
@@ -36,19 +35,15 @@ from app.utils import (
 )
 
 
-def fetch_notification_status_for_day(process_day, notification_type):
+def fetch_status_data_for_service_and_day(process_day, service_id, notification_type):
     start_date = convert_bst_to_utc(datetime.combine(process_day, time.min))
     end_date = convert_bst_to_utc(datetime.combine(process_day + timedelta(days=1), time.min))
 
-    current_app.logger.info("Fetch ft_notification_status for {} to {}".format(start_date, end_date))
+    # query notifications or notification_history for the day, depending on their data retention
-
+    service = Service.query.get(service_id)
-    all_data_for_process_day = []
-    services = Service.query.all()
-    # for each service query notifications or notification_history for the day, depending on their data retention
-    for service in services:
     table = get_notification_table_to_use(service, notification_type, process_day, has_delete_task_run=False)
 
-        data_for_service_and_type = query_for_fact_status_data(
+    return query_for_fact_status_data(
         table=table,
         start_date=start_date,
         end_date=end_date,
@@ -56,10 +51,6 @@ def fetch_notification_status_for_day(process_day, notification_type):
         service_id=service.id
     )
 
-        all_data_for_process_day += data_for_service_and_type
-
-    return all_data_for_process_day
-
 
 def query_for_fact_status_data(table, start_date, end_date, notification_type, service_id):
     query = db.session.query(
@@ -86,18 +77,19 @@ def query_for_fact_status_data(table, start_date, end_date, notification_type, s
 
 
 @autocommit
-def update_fact_notification_status(data, process_day, notification_type):
+def update_fact_notification_status(transit_data, process_day, notification_type, service_id):
     table = FactNotificationStatus.__table__
     FactNotificationStatus.query.filter(
         FactNotificationStatus.bst_date == process_day,
-        FactNotificationStatus.notification_type == notification_type
+        FactNotificationStatus.notification_type == notification_type,
+        FactNotificationStatus.service_id == service_id,
     ).delete()
 
-    for row in data:
+    for row in transit_data:
         stmt = insert(table).values(
             bst_date=process_day,
             template_id=row.template_id,
-            service_id=row.service_id,
+            service_id=service_id,
             job_id=row.job_id,
             notification_type=notification_type,
             key_type=row.key_type,