[RFC PATCH v2] imapd.c: imapoptions: implement idle timeout

[Thomas Jarosch]

Hi Ellie,

On Thursday, 8. September 2016 11:07:54 ellie timoney via Cyrus-devel wrote:
> I can kind of see a point about the ability to request a monotonic
> clock, such that some sysadmin changing the system time doesn't
> prematurely timeout a bunch of idle connections.  Though that doesn't
> seem likely to be a real problem in practice (a: don't do that, b: the
> clients will just reconnect in a bit anyway).

time jumps issued via NTP are a recurring source of trouble.
On our distribution we have detection logic for that and restart
quite a few services if it happens. The monotonic clock avoids that nicely.

> Anyway, the patch applies cleanly, builds fine for me, and passes our
> current tests.  I'll try and put together a couple of Cassandane tests
> for the new behaviour and see what shakes out of that.

Would it make sense to enable the timeout by default?
In the current version of the patch it's disabled (value 0).

We plan on rolling it out with a default value of three days
for our systems. That's enough to keep workstations that are left on
over the weekend happy, but short enough to clean up "forgotten" clients
idling on the INBOX/Drafts folder. There are still quite a few
Outlook 2007 installations with broken IMAP IDLE handling in the wild,
so the RFC recommended timeout of 29 minutes is unsuitable.

Cheers,
Thomas