myvemail/build/run/docker-entrypoint/init.d/70-reject.sh

#!/usr/bin/env bash
# Check filters
unset filters
if [ ${MYVEMAIL_REJECT_FILTER} ]
then
	filters+=(${MYVEMAIL_REJECT_FILTER//,/ })
fi

# Notify if rejected emails were found
while true
do
	bash -c 'tail -n +0 --pid=$$ -f /var/log/mail/maillog.debug* | grep --line-buffered -F -v -f /var/log/mail/reject.log | { sed "/NOQUEUE: reject/q" && kill $$ ;}'
	grep -h "NOQUEUE: reject" /var/log/mail/maillog.debug* | grep -F -v -f /var/log/mail/reject.log >>/var/log/mail/reject.log
	if ! tail -n 1 /var/log/mail/reject.log | grep -i -q "$(printf '%s\|' ${filters[@]:-impossible-string-that-would-never-be-grepped} | sed 's|\\\|$||')"
	then
		cat <<- mail | sendmail reject@${MYVEMAIL_DOMAIN}
		From: reject@${MYVEMAIL_DOMAIN}
		To: reject@${MYVEMAIL_DOMAIN}
		Subject: Rejected email found

		$(tail -n 1 /var/log/mail/reject.log)
		mail
	fi
done >/dev/null &