[Dovecot] dovecot/deliver ... Can't open log file /var/log/dovecot/error.log: Permission denied

[Phil Howard]

I'm getting this ...

May 10 12:45:01 eth0 postfix/local[3416]: A788D685F7: to=<
xxxxxxxx at xxxxxxxx.net>, relay=local, delay=13, delays=13/0/0/0.03,
dsn=4.3.0, status=deferred (temporary failure. Command output: Can't open
log file /var/log/dovecot/error.log: Permission denied )

So I'm looking at http://wiki.dovecot.org/LDA to see what I can do about
it.  I would have hoped some comments in the example config file would have
mentioned this and suggested a default practice solution.  Is this something
few people or many people encounter (among those using dovecot/deliver from
Postfix)?

If I do as the wiki describes and make separate log files for
dovecot/deliver to use, do I just make them owned by Postfix?  It would seem
to me a different directory might be more helpful (absent log files could be
created by having the directory permissions.  I'm also thinking in terms of
log rotations, too ... and I prefer to do log rotations by date stamping
rather than pushing sequence numbers (the legacy log rotation).

Any chance there are %-style variables I can use in log file/path names to
make log files automatically named by the date (and maybe time) ... kind of
like in a shell script I would do: `date +/path/to/tree/%Y/%m/%d.log` or
such.