LG-752 Verify by mail / undeliverable as addressed processing

[stevegsa]

Why: We need to track whether a user has an undeliverable address when they attempt to verify by mail.

How: Download the USPS undeliverable address otp/codes from their sftp site daily. Add a bounced_at field to usps_confirmation_codes and add an index on otp fingerprint. For each code find the entry by otp fingerprint, set the bounced_at timestamp, and send an email notification to the user. Use locking to prevent a user from being notified twice.

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[stevegsa]

Schema:

[jmhooper]

We tell people to sign in and follow instructions, but the instructions they see will them to enter the code we couldn't send them, right? Should we build in something, either here or in another PR, that shows users something if their letter bounced?

[stevegsa]

The GUI and this email verbiage is up in the air right now. I guess depending on where we go with the GUI will drive what we say here. Docauth currently does not have a way to change the address so we would need to add a new flow for that.

[jmhooper]

Okay, cool. Those are all things we can handle outside this PR once we know what needs to happen.

[jmhooper]

The file we get here is just a list of OTPs?

[stevegsa]

correct

[jmhooper]

Huh, well that makes this easy then