Sometimes a message is picked up twice of the SQS queue, we need to safe gaurd ourselves for that.

In this PR the id for the notification is passed in and used to created the notification, which causes a integrity error.
Normally when we get a SQLAlchemy error here we send the message to the retry queue, but if the notification already exists
we just ignore it.

app/notifications/process_notifications.py

@@ -4,7 +4,7 @@ from flask import current_app
 from notifications_utils.renderers import PassThrough
 from notifications_utils.template import Template
 
-from app import DATETIME_FORMAT, redis_store
+from app import redis_store
 from app.celery import provider_tasks
 from app.clients import redis
 from app.dao.notifications_dao import dao_create_notification, dao_delete_notifications_and_history_by_id
@@ -48,8 +48,10 @@ def persist_notification(template_id,
                          created_at=None,
                          job_id=None,
                          job_row_number=None,
-                         reference=None):
+                         reference=None,
+                         notification_id=None):
     notification = Notification(
+        id=notification_id,
         template_id=template_id,
         template_version=template_version,
         to=recipient,