Idempotence (GSI-626)

[TheByronHimes]

New Model

There is a new model, NotificationRecord. It has two fields: hash_sum (str) and sent (bool).

No changes were made to the event subscriber. It still passes the notification event as it did before.
Inside the Notifier instance, the notification event is used to generate a NotificationRecord.
The hash sum from the record is used to determine if the notification has been encountered before, and
whether or not it was successfully sent.
If the notification has been seen before, the operation is complete.
If not, the record is added to the database.
The notification is then sent out, and afterwards the record is updated with sent set to True.

New methods for Notifier

A few private methods were added to the Notifier class:

• _ensure_not_sent(hash_sum) -> bool
• _create_notification_record(notification) -> NotificationRecord
• _register_new_notification(NotificationRecord) -> None

Tests

Unit tests were created to verify that the above new methods work as expected. There is a single tests that covers the three methods above, and then a general idempotence test. The latter naturally tests the transmission capability, so the old test_transmission test case was removed.

[mephenor]

There are some minor issues that should be addressed, but the rest looks good.

[coveralls]

Pull Request Test Coverage Report for Build 8142443883

Details

• 47 of 47 (100.0%) changed or added relevant lines in 6 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+4.0%) to 80.159%

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Totals
Change from base Build 7558586254:	4.0%
Covered Lines:	202
Relevant Lines:	252

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💛 - Coveralls

[mephenor]

One small thing can still be improved