Parallelise status aggregation by service and day

This follows a similar approach as [1]. Recently we've seen lots
of errors from this task, which we think are a consequence of it
doing too much work and tripping Celery's visibility timeout.

While we can optimise the query [2], it's likely the errors will
return as the number of live services grows. Parallelising the
aggregation now will make it more futureproof.

[1]: https://github.com/alphagov/notifications-api/pull/3397
[2]: https://github.com/alphagov/notifications-api/pull/3417

app/celery/reporting_tasks.py

@@ -91,54 +91,58 @@ def create_nightly_notification_status():
 
     yesterday = convert_utc_to_bst(datetime.utcnow()).date() - timedelta(days=1)
 
-    for notification_type in [SMS_TYPE, EMAIL_TYPE, LETTER_TYPE]:
-        days = 10 if notification_type == LETTER_TYPE else 4
+    for (service_id,) in db.session.query(Service.id):
+        for notification_type in [SMS_TYPE, EMAIL_TYPE, LETTER_TYPE]:
+            days = 10 if notification_type == LETTER_TYPE else 4
 
-        for i in range(days):
-            process_day = yesterday - timedelta(days=i)
+            for i in range(days):
+                process_day = yesterday - timedelta(days=i)
 
-            create_nightly_notification_status_for_day.apply_async(
-                kwargs={'process_day': process_day.isoformat(), 'notification_type': notification_type},
-                queue=QueueNames.REPORTING
-            )
-            current_app.logger.info(
-                f"create-nightly-notification-status-for-day task created "
-                f"for {notification_type} and {process_day}"
-            )
+                create_nightly_notification_status_for_service_and_day.apply_async(
+                    kwargs={
+                        'process_day': process_day.isoformat(),
+                        'notification_type': notification_type,
+                        'service_id': service_id,
+                    },
+                    queue=QueueNames.REPORTING
+                )
+                current_app.logger.info(
+                    f"create-nightly-notification-status-for-day task created "
+                    f"for {service_id}, {notification_type} and {process_day}"
+                )
 
 
-@notify_celery.task(name="create-nightly-notification-status-for-day")
-def create_nightly_notification_status_for_day(process_day, notification_type):
+@notify_celery.task(name="create-nightly-notification-status-for-service-and-day")
+def create_nightly_notification_status_for_service_and_day(process_day, service_id, notification_type):
     process_day = datetime.strptime(process_day, "%Y-%m-%d").date()
     current_app.logger.info(
         f'create-nightly-notification-status-for-day task started '
-        f'for {notification_type} and {process_day}'
+        f'for {service_id}, {notification_type} and {process_day}'
     )
 
-    for (service_id,) in db.session.query(Service.id):
-        start = datetime.utcnow()
-        transit_data = fetch_status_data_for_service_and_day(
-            process_day=process_day,
-            notification_type=notification_type,
-            service_id=service_id,
-        )
+    start = datetime.utcnow()
+    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 fetch '
-            f'for {process_day} and {notification_type}: '
-            f'data fetched in {(end - start).seconds} seconds'
-        )
+    end = datetime.utcnow()
+    current_app.logger.info(
+        f'create-nightly-notification-status-for-day task fetch '
+        f'for {service_id}, {process_day} and {notification_type}: '
+        f'data fetched in {(end - start).seconds} seconds'
+    )
 
-        update_fact_notification_status(
-            transit_data=transit_data,
-            process_day=process_day,
-            notification_type=notification_type,
-            service_id=service_id
-        )
+    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 finished '
-            f'for {process_day} and {notification_type}: '
-            f'{len(transit_data)} rows updated'
-        )
+    current_app.logger.info(
+        f'create-nightly-notification-status-for-day task finished '
+        f'for {service_id}, {process_day} and {notification_type}: '
+        f'{len(transit_data)} rows updated'
+    )

tests/app/celery/test_reporting_tasks.py

@@ -10,7 +10,7 @@ from app.celery.reporting_tasks import (
     create_nightly_billing,
     create_nightly_billing_for_day,
     create_nightly_notification_status,
-    create_nightly_notification_status_for_day,
+    create_nightly_notification_status_for_service_and_day,
 )
 from app.config import QueueNames
 from app.dao.fact_billing_dao import get_rate
@@ -62,8 +62,8 @@ def test_create_nightly_billing_triggers_tasks_for_days(notify_api, mocker, day_
 
 
 @freeze_time('2019-08-01')
-def test_create_nightly_notification_status_triggers_tasks_for_days(notify_api, mocker):
-    mock_celery = mocker.patch('app.celery.reporting_tasks.create_nightly_notification_status_for_day')
+def test_create_nightly_notification_status_triggers_tasks(notify_api, sample_service, mocker):
+    mock_celery = mocker.patch('app.celery.reporting_tasks.create_nightly_notification_status_for_service_and_day')
     create_nightly_notification_status()
 
     assert mock_celery.apply_async.call_count == (
@@ -77,13 +77,21 @@ def test_create_nightly_notification_status_triggers_tasks_for_days(notify_api,
         [SMS_TYPE, EMAIL_TYPE, LETTER_TYPE]
     ):
         mock_celery.apply_async.assert_any_call(
-            kwargs={'process_day': process_date, 'notification_type': notification_type},
+            kwargs={
+                'process_day': process_date,
+                'notification_type': notification_type,
+                'service_id': sample_service.id,
+            },
             queue=QueueNames.REPORTING
         )
 
     for process_date in ['2019-07-27', '2019-07-26', '2019-07-25', '2019-07-24', '2019-07-23', '2019-07-22']:
         mock_celery.apply_async.assert_any_call(
-            kwargs={'process_day': process_date, 'notification_type': LETTER_TYPE},
+            kwargs={
+                'process_day': process_date,
+                'notification_type': LETTER_TYPE,
+                'service_id': sample_service.id,
+            },
             queue=QueueNames.REPORTING
         )
 
@@ -501,7 +509,7 @@ def test_create_nightly_billing_for_day_update_when_record_exists(
     assert records[0].updated_at
 
 
-def test_create_nightly_notification_status_for_day(notify_db_session):
+def test_create_nightly_notification_status_for_service_and_day(notify_db_session):
     first_service = create_service(service_name='First Service')
     first_template = create_template(service=first_service)
     second_service = create_service(service_name='second Service')
@@ -532,9 +540,9 @@ def test_create_nightly_notification_status_for_day(notify_db_session):
 
     assert len(FactNotificationStatus.query.all()) == 0
 
-    create_nightly_notification_status_for_day(str(process_day), 'sms')
-    create_nightly_notification_status_for_day(str(process_day), 'email')
-    create_nightly_notification_status_for_day(str(process_day), 'letter')
+    create_nightly_notification_status_for_service_and_day(str(process_day), first_service.id, 'sms')
+    create_nightly_notification_status_for_service_and_day(str(process_day), second_service.id, 'email')
+    create_nightly_notification_status_for_service_and_day(str(process_day), third_service.id, 'letter')
 
     new_fact_data = FactNotificationStatus.query.order_by(
         FactNotificationStatus.notification_type
@@ -569,13 +577,13 @@ def test_create_nightly_notification_status_for_day(notify_db_session):
     assert new_fact_data[2].key_type == KEY_TYPE_NORMAL
 
 
-def test_create_nightly_notification_status_for_day_overwrites_old_data(notify_db_session):
+def test_create_nightly_notification_status_for_service_and_day_overwrites_old_data(notify_db_session):
     first_service = create_service(service_name='First Service')
     first_template = create_template(service=first_service)
     create_notification(template=first_template, status='delivered')
 
     process_day = date.today()
-    create_nightly_notification_status_for_day(str(process_day), 'sms')
+    create_nightly_notification_status_for_service_and_day(str(process_day), first_service.id, 'sms')
 
     new_fact_data = FactNotificationStatus.query.order_by(
         FactNotificationStatus.bst_date,
@@ -586,7 +594,7 @@ def test_create_nightly_notification_status_for_day_overwrites_old_data(notify_d
     assert new_fact_data[0].notification_count == 1
 
     create_notification(template=first_template, status='delivered')
-    create_nightly_notification_status_for_day(str(process_day), 'sms')
+    create_nightly_notification_status_for_service_and_day(str(process_day), first_service.id, 'sms')
 
     updated_fact_data = FactNotificationStatus.query.order_by(
         FactNotificationStatus.bst_date,
@@ -599,7 +607,7 @@ def test_create_nightly_notification_status_for_day_overwrites_old_data(notify_d
 
 # the job runs at 12:30am London time. 04/01 is in BST.
 @freeze_time('2019-04-01T23:30')
-def test_create_nightly_notification_status_for_day_respects_bst(sample_template):
+def test_create_nightly_notification_status_for_service_and_day_respects_bst(sample_template):
     create_notification(sample_template, status='delivered', created_at=datetime(2019, 4, 1, 23, 0))  # too new
 
     create_notification(sample_template, status='created', created_at=datetime(2019, 4, 1, 22, 59))
@@ -607,7 +615,7 @@ def test_create_nightly_notification_status_for_day_respects_bst(sample_template
 
     create_notification(sample_template, status='delivered', created_at=datetime(2019, 3, 31, 22, 59))  # too old
 
-    create_nightly_notification_status_for_day('2019-04-01', 'sms')
+    create_nightly_notification_status_for_service_and_day('2019-04-01', sample_template.service_id, 'sms')
 
     noti_status = FactNotificationStatus.query.order_by(FactNotificationStatus.bst_date).all()
     assert len(noti_status) == 1