if we're served a 429, put the item on the retry queue and retry the
same as if the service returned a 5xx. 429 is commonly returned for rate
limit exceeding, and retrying on a delay is a typical response to that.
This adds the `template_id` and `template_version` fields to the data
sent to services from the `send_delivery_status_to_service` task.
We need to account for the task not being passed these fields at first
since there might be tasks retrying which don't have that data. Once all
tasks have been called with the new fields we can then update the code
to assume they are always there.
Since we only send delivery status callbacks for SMS and emails, I've
removed the tests where we call that task with letters.
At the moment, if a service callback fails, it will get put on the retry queue.
This causes a potential problem though:
If a service's callback server goes down, we may generate a lot of retries and
this may then put a lot of items on the retry queue. The retry queue is also
responsible for other important parts of Notify such as retrying message
delivery and we don't want a service's callback server going down to have an
impact on the rest of Notify.
Putting the retries on a different queue means that tasks get processed
faster than if they were put back on the same 'service-callbacks' queue.
Which means the sent_at date for the notification could be empty causing the service callback to fail.
- Allow code to work if notification.sent_at or updated_at is None
- Update calls to send_delivery_status_to_service to send the data encrypted so that the task does not need to use the db.
Which means we can remove the need to request the data from the database.
In order for the PR to be backwards compatible I have added an optional parameter "encrypted_status_update".
If this is not None then the new code is called.
The next PR will send the encrypted data to this task.
A final PR will remove the code that uses the database to get the notification and service callback api.
