If the notification ends up in the retry queue and the delivery app is restarted the notification will get sent twice.
This is because when the app is restarted another message will be in the retry queue as message available which is a
duplicate of the one in the queue that is a message in flight.
This should complete https://www.pivotaltracker.com/story/show/121844427
10 seconds, 1 minute, 5 minutes, 1 hour and 4 hours.
Total elapsed wait is max 5 hours 6 minutes and 10 seconds.
Changed visibility window of SQS to be 4 hours 10 seconds, longer the max retry period.
- 2 separate tasks - DB and Provider
- DB to persist notification
- Provider to contact provider
- Each piece has separate retries
- Provider retries have configured back-off