cronjob: notify users when over quota

[tiborsimko]

We are running periodic quota updater and periodic system status reporter cron jobs. This calculate user CPU and Disk storage quotas.

We could introduce an optional feature in order to notify users when they are over their quotas.

This could be part of the existing quota updater or system status updater (rather than a fully new cronjob).

Here is a draft template:

Dear John Doe:

It appears that you are using 1234 GiB out of 456 GiB of the storage quota on
reana.cern.ch shared disk. You may not be able to run new workflows when you
are over quota.

Please consider deleting your unnecessary files or unnecessary workflow runs
using techniques described in:
<https://docs.reana.io/advanced-usage/user-quotas/#what-to-do-when-quotas-are-exceeded>

If you do need to use temporarily more disk space than the storage quota limit
in order to run your workflows, please get in touch with us at
<[email protected]>.

Best regards,

REANA notification system

Beware of sending too many of these messages though; it could get over board quickly. We may need to amend DB model to store somewhere an information that this user has already been notified, and not send more than 1 reminder per month.

A beyond-MVP bonus point would be to start sending these emails when user approach 90% of their storage quota (with a softer message, so we would have to have two or three outgoing email templates).

(Another possible complication could be, when a user was over quota and deleted some files and went below the quota, that we may want to send another notification that everything is in order now and that the new workflows can be started. Dunno if that is really necessary though; most probably it is not.)