Change this as appropriate, also eliminating these top 26 lines

Whether or not you use logrotate, you may want to adapt parts of this file to
your needs.  The postrotate script is executed by the shell after renaming (mv)
the log file.

This is not a portable piece of code, check out contrib/opendkim-reportstats
for such kind of script.  However, the first part of the script exemplifies
how to use zdkimstats-wait and zdkimstats-anon.  It assumes you have configured
zdkimfilter.conf with

  # stats_file
  # full path for a stats file about signatures verifications, including a line
  # for each non-signed message. Setting this parameter enables writing stats.
  # The default is an empty string, which disables writing stats.
  stats_file /var/log/zdkimstats/stats

Before you start submitting your data to OpenDKIM, you should create a gpg key
and send its public part to OpenDKIM.

Change "/var/log/zdkimstats" or create it.  Remember "courier" user needs to write it.
Change "YOUR POSTMASTER ADDRESS"
Change 'your secret hash prefix' _ONCE_: Never change it after you've started submitting your data.
Change "WHEREVER_YOU_HAVE" to some directory (e.g. the home directory of the "courier" user)
Change "YOUR.MTA.FQDN"

/var/log/zdkimstats/stats {
	daily
	missingok
	rotate 10
	maxage 10
	size 1
	dateext
	nocompress
	notifempty
	nocreate
	nocopy
	postrotate
		rotatedlog="stats-$(date '+%Y%m%d')"
		if cd /var/log/zdkimstats && zdkimstats-wait $rotatedlog
		then
			exec >logrotate.stdout 2>logrotate.stderr
			zdkimstats-anon -a adsp -c total \
				-p 'your secret hash prefix' \
				-x opendkim.org mipassoc.org \
				< $rotatedlog > stats.out
			zdkimstats-anon < $rotatedlog | \
				opendkim-importstats -p password

			# change these variables, if needed
			export OPENDKIM_OUTPUT=/var/www/opendkim/opendkim-report.html
			export OPENDKIM_PASSWORD=password
			opendkim-genstats

			printf 'uauthsmtp\nipostmaster@YOUR.MTA.FQDN\nMsign\n' > ctlfile &&
			printf '%s: %s\n%s: %s\n%s: %s at %s\n%s: %s\n%s: <%s.%x.%x@%s>\n\n' \
				"From" "YOUR POSTMASTER ADDRESS" \
				"To" "stats-report@opendkim.org" \
				"Subject" "opendkim-stats report from YOUR.MTA.FQDN" \
					"$(date +%s)" \
				"Date" "$(date --rfc-2822)" \
				"Message-ID" "dkimeodlog" \
					"$(date +%s)" \
					"$(date +%N)" \
					"YOUR.MTA.FQDN" > header &&
			gpg --home=WHEREVER_YOU_HAVE/.gnupg --batch --no-tty \
				--output stats.signed --clearsign stats.out &&
			cat header stats.signed > stats.eml &&
			printf 'stats.eml\nctlfile\n\nexit\n' > zbatch &&
			/usr/local/libexec/filters/zdkimfilter --batch-test < zbatch &&
			MAILSUSER=postmaster MAILSHOST=YOUR.MTA.FQDN sendmail < stats.eml &&
			rm zbatch stats.signed
		fi
	endscript
}