Install spamassassin

docker/postfix/Dockerfile

@@ -4,7 +4,7 @@ FROM tozd/postfix:ubuntu-focal
 VOLUME /etc/sympa/shared
 
 RUN apt-get update -q -q && \
- apt-get install adduser curl dnsutils openssh-client opendkim opendkim-tools --yes --force-yes && \
+ apt-get install adduser curl dnsutils openssh-client opendkim opendkim-tools spamassassin --yes --force-yes && \
  adduser --system --group mailpipe --no-create-home --home /nonexistent && \
  cp /etc/postfix/main.cf /etc/postfix/main.cf.orig && \
  cp /etc/postfix/master.cf /etc/postfix/master.cf.orig
@@ -15,4 +15,8 @@ RUN curl https://okean.com/sinokoreacidr.txt \
 	| sed -e 's/\(China\|Korea\)/REJECT Source IP blocked \1/g' \
 	> /etc/postfix/sinokorea.cidr
 
+RUN sed -i -e 's/^\(smtp.*smtpd\)$/\1 -o content_filter=spamassassin/' /etc/postfix/master.cf
+
+RUN echo 'rewrite_header Subject *****SPAM*****' >> /etc/spamassassin/local.cf
+
 COPY ./etc /etc

docker/postfix/etc/postfix/master.cf.append

@@ -14,3 +14,4 @@ sympabounce	unix	-	n	n	-	-	pipe
 sympabouncedomain	unix	-	n	n	-	-	pipe
   -o soft_bounce=yes
   flags=RF user=mailpipe:mailpipe argv=/usr/bin/ssh -i /etc/sympa/shared/id_rsa -o UserKnownHostsFile=/etc/sympa/shared/known_hosts -T sympa@sympa bouncequeue sympa@${domain}
+spamassassin unix -     n       n       -       -       pipe user=spamassassin argv=/usr/bin/spamc -f -e /usr/sbin/sendmail -oi -f ${sender} ${recipient}