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.

tests/app/notifications/test_process_notification.py

@@ -1,4 +1,5 @@
 import datetime
+import uuid
 
 import pytest
 from boto3.exceptions import Boto3Error
@@ -108,7 +109,7 @@ def test_persist_notification_with_optionals(sample_job, sample_api_key, mocker)
     assert Notification.query.count() == 0
     assert NotificationHistory.query.count() == 0
     mocked_redis = mocker.patch('app.notifications.process_notifications.redis_store.incr')
-
+    n_id = uuid.uuid4()
     created_at = datetime.datetime(2016, 11, 11, 16, 8, 18)
     persist_notification(template_id=sample_job.template.id,
                          template_version=sample_job.template.version,
@@ -120,11 +121,13 @@ def test_persist_notification_with_optionals(sample_job, sample_api_key, mocker)
                          created_at=created_at,
                          job_id=sample_job.id,
                          job_row_number=10,
-                         reference="ref from client")
+                         reference="ref from client",
+                         notification_id=n_id)
     assert Notification.query.count() == 1
     assert NotificationHistory.query.count() == 1
     persisted_notification = Notification.query.all()[0]
-    assert persisted_notification.job_id == sample_job.id
+    assert persisted_notification.id == n_id
+    persisted_notification.job_id == sample_job.id
     assert persisted_notification.job_row_number == 10
     assert persisted_notification.created_at == created_at
     mocked_redis.assert_called_once_with(str(sample_job.service_id) + "-2016-01-01-count")