How can I get logrotate dateext to reflect the log date rather than the rotation date?

My Apache logrotate config looks like this:

/var/log/http/*log {
    monthly
    dateext
    dateformat .%Y.%m
    [... rest stripped for brevity ...]
}

This works great, except that the date on the rotated filename is one period later than the period actually covered by the logs, for example error_log.2012.09 covers 2012-08-01 to 2012-08-31.

I realize that there are other options for Apache (eg. cronolog), but I have a bunch of other logs that I also need to rotate, and logrotate is really exactly what I need apart from this one issue.

Is there a way to get logrotate to use a date offset -- or, even better, figure out the previous time period -- when generating the rotated filename?

Added in 3.8.0 (although looking at the svn history, it looks like it was actually added in 3.7.9):

http://svn.fedorahosted.org/svn/logrotate/tags/r3-8-0/CHANGES

- added "dateyesterday" option (see man page)

if logrotate in your distrib doesn't have 'dateyesterday' option yet, you can use script like the following:

LOGFILE="$1"
LOGMTIME="$(env LC_ALL='C' stat $LOGFILE |awk '/^Modify/{print $2}')"
LOGSTART=$(( $(date +%Y%m%d -d "${LOGMTIME}") - 1 ))
mv $LOGFILE ${LOGFILE%-[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]}-$LOGSTART

Notes:

1. script will work right only in case of 'daily' option
2. if operating on multiple files, wrap the code block in "for LOGFILE in $@" loop.
3. sequence '-[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]' is the logrotate's default glob pattern, see description of dateext option of logrotate man.