[Spambayes] sb_filter.py eats mail when used in postfix content_filter

[Fred Smith]

On Wed, Apr 24, 2013 at 10:15:22PM -0400, EMF wrote:
> OS:  CentOS 6.4 x86_64
> Postfix package:  postfix-2.6.6-2.2.el6_1.x86_64
> Spambayes package:  spambayes-1.1-0.2.a6.el6.noarch
> 
> All right, I've hit a brick wall with my integration of spambayes
> and postfix.  I based my build combining Jonathan St. Andre's
> instructions at http://spambayes.sourceforge.net/server_side.html,
> with a few tweaks from the Postfix side in
> http://www.postfix.org/FILTER_README.html --- mostly because I'm
> going to extend the logic.
> 
> I've successfully trained spambayes with about 12,000 each spam and
> ham, creating a database in /var/spambayes/filter.db.
> 
> Running a captured message through sb_filter.py from the command
> line works flawlessly:
> -----------------------------------------
> $ whoami
> filter
> $ cat /tmp/msg.7440 | /usr/bin/sb_filter.py -d /var/spambayes/filter.db -f
> Return-Path: <emf at amhran.net>
> Received: from amhran.net (3wg23q1.amhran.net [192.168.1.160])
>         by courier.amhran.net (Postfix) with ESMTP id CFF223E
>         for <emf at amhran.net>; Wed, 24 Apr 2013 21:28:34 -0400 (EDT)
> From: "EMF" <emf at amhran.net>
> To: "EMF" <emf at amhran.net>
> Subject: Testing
> X-Spambayes-Classification: ham; 0.17
> 
> SB Test
> $
> -----------------------------------------
> 
> Here are the lines from postfix's master.cf (which are very
> straightforward):
> -----------------------------------------
> smtp      inet  n       -       n       -       -       smtpd
>      -o content_filter=filter:dummy
> filter unix  -   n   n   -   -   pipe
>      flags=Rq user=filter
>      argv=/usr/local/bin/spamfilter.sh -f ${sender} -- ${recipient}
> -----------------------------------------
> 
> Spamfilter.sh sends the mail just fine if it consists of this:
> -----------------------------------------
>     cat > /tmp/msg.$$
>     /usr/sbin/sendmail -i $@ < /tmp/msg.$$
> -----------------------------------------
> but not if it contains this:
> -----------------------------------------
>     cat > /tmp/msg.$$
>     cat /tmp/msg.$$ | /usr/bin/sb_filter.py -d
> /var/spambayes/filter.db -f > /tmp/new.$$
>     /usr/sbin/sendmail -i $@ < /tmp/new.$$
> -----------------------------------------
> 
> In the latter case --- msg.$$ contains the message, but new.$$ is a
> zero-length file, and thus what comes through on the far end is an
> empty message.  Interestingly, I get this in syslog.log:
> -----------------------------------------
> Apr 24 21:28:35 courier abrt: detected unhandled Python exception in
> '/usr/bin/sb_filter.py'
> Apr 24 21:28:35 courier abrt: can't communicate with ABRT daemon, is
> it running? [Errno 13] Permission denied
> -----------------------------------------
> 
> How can I capture the exception?  What's being called by
> sb_filter.py at the command line that isn't available when run
> inside the content_filter?

Well, I'm not intimate with the innards of the spambayes components,
but if a program behaves differently on commandline than it does
in its own normal environment, I'd guess there's something different 
about the system environment: PATH, LD_LIBRARY_PATH, etc., etc.,
etc.


-- 
---- Fred Smith -- fredex at fcshome.stoneham.ma.us -----------------------------
                       I can do all things through Christ 
                              who strengthens me.
------------------------------ Philippians 4:13 -------------------------------