[Dovecot] Quota handling - v2 - updated FR

[Charles Marcus]

This revised proposal for a Feature Request is the result of my desire
to implement quotas, but not have the attendant headaches that
inevitably accompany its implementation.

Ralf Hildebrandt wrote:
> I have to face it, my users are retards:

Is there any other kind of user?  ;)

<snip>

> Thus I need a feature in dovecot that will tell them via email:
>
> Level1: "You ALMOST exceeded your quota, you're at 90% now"
> Level2: "You're very close to exceededin your quota, you're at 95%
> now"
> Level3: "Would you please clean up now? You're at 99% now"

What I'd *really* like to see implemented is something along the lines
outlined below - but of course, this will depend entirely on whether or
not Timo thinks it is doable - or desirable...

I'm thinking this would be best handled by the Quota plug-in - either as 
part of the current one, or as a separate/different one...

*** 1. Have a 'special' user-specific folder (by special, I mean like 
the Drafts, Sent, Templates folders) that dovecot controls. For purposes 
of this FR, call it the 'over-quota' folder.

Question: could the .tmp folder be used for this? No sense in 
reinventing the wheel if necessary... and then if someone migrated from 
dovecot to something else, and messages were left in there from an 
over-quota condition, that other solution would most likely just move 
these to .new the first time it ran, right?

Or, possibly, could dovecot create a new one maybe, .oqt (for 
over-quota), and store the queued messages there until the over-quota 
condition was rectified?

Anyway, the main thing is, this folder should be essentially hidden from 
the user so they do *not* have access to it, and should temporarily hold 
messages that come in that are unable to be delivered due to an 
over-quota condition.

*** 2. Make dovecot aware of and use a special 'Quota Status' message 
that it uses to inform a user that they are over quota. This message 
should be able to be customized, with variables (like, for example, it 
should list the messages that are currently being prevented from being 
moved to the Inbox - including, optionally, the Subject, the sender, 
date/time, attachments, size, etc - as well as provide general quota 
information (ie, how close to or over quota they are, and how much 
they'd need to delete or move to Local Folders to allow delivery of all 
of the messages being held), and lastly, any custom information the 
System Admin wanted to provide - like, maybe, specific instructions for 
how to move messages to Local Folders, how to request additional storage 
allowance, etc.

*** 3. When user is over quota, have LDA deliver to the folder 
referenced above (# 1) - (yes, accept the message for final delivery 
from the sending mta), and then update the Quota Status message and move 
it to the Inbox.

Optionally, a bounce/notification could be generated to the sender, 
informing them that their message is being 'held in queue' or something 
to that effect, due to the recipient being over-quota.

*** 4. Once the user deletes enough mail to come back under quota, 
dovecot would then move messages from the 'over-quota' folder to his Inbox.

Ok, again, am willing to hear *valid* reasons how/why this is a terrible 
idea... :)

-- 

Best regards,

Charles