[Duplicity-talk] Best way to find the date and time of the latest backup in a collection

[Aaron]

Hello everyone,

Sorry I have been so quiet lately. Things have been busy and I have been 
doing a lot with ZFS rather than Duplicity. I do still use Duplicity for 
a few things, though. One of those is to do the backups of my 
Mail-in-a-box installation. I was hoping I could ask what the best way 
was for me to find the date of the latest duplicity backup to add an 
alert into prometheus.

I have mail-in-a-box backing up to cloud storage using the built-in 
duplicity backup. I copy that back somewhere and then run a verify, with 
prometheus monitoring telling me if it has been too long since the 
verify successfully completed. I noticed today that this has been 
completing successfully even when the the backups were not copying 
properly. It seems that this is because the verify completes, it is just 
verifying a backup that is a month old. I would therefore like to add an 
additional prometheus check that the last backup is not more than x days 
old. To do that, I need to extract the date of the latest backup.

I could do:

duplicity collection-status file:///[location] | grep "Chain end time:"
Chain end time: Thu Sep  5 03:09:10 2024
Chain end time: Fri Sep  6 03:09:12 2024

convert those to datetimes and use the latest of them, but is there a 
better way?

I saw there was a new --jsonstat argument, which sounded promising, but 
does that need to be used as part of the backup process to work 
correctly? Unfortunately I cannot change the backup arguments because 
that side is built into mail-in-a-box.

Kind regards,

Aaron