From: John Jetmore <jetmore@cinergycom.com>
Date: Wed, 24 Sep 2003 13:12:58 -0500 (CDT)

I'm sure that everyone who's interested in something like this has already
come up with their own way to do this, but here's my solution:

When I moved from smail to exim I built a program that took individual
config pieces stripped all the comments and built a config file.  As a
bonus, it also runs exim -C <testfile> -bV on the new file and reports any
config errors before copying it over the old config.  In addition to just
being familiar in general w/ all the files being broken up according to
their major categories, I also got the benfit of being able to have config
pieces that were easily updatable (just replace the whole file and rebuild
the configure file).

The script has some site-specific stuff hard coded, but it's easily
fixable.  Essentially in my exim configd I have a directory called
subconfigure, which can contain directories named \d\d.\w+.  Mine
currently contains:
10.general/  30.routers/     50.retry/    70.authenticators/
20.acls/     40.transports/  60.rewrite/  80.local_scan/

Each of these directories can contain files in the form \d\d.\w+.  For
instance, my 30.routers contains:
00.begin              80.l_user_delivery_normal   _50.l_mx
10.r_forcepaths       _12.r_static_route_junk     _60.l_psp
15.r_stalemail        _17.r_internal_route        _72.l_aliases_list
33.r_mailrtrd_router  _20.r_conditionalforce      _74.l_aliases_isp
40.r_standard         _31.r_mailrtrd_bypass_spam  _76.l_aliases_mer
70.l_aliases          _39.r_smarthost             _80.l_user_delivery_isp

those files prefixed by "_" will not be used to build the live configure
file.  They are "turned off".  This allows me to keep a general list of
configure pieces that are easily updatable but not necessarily every rule
is used on every machine.  Not every file contains a single router - for
instance 60.l_psp is our virtual hosting solution and contains 10 routers.
They're just grouped by logical role.

All of these sub pieces are built in to the configure file w/ a shell
script called mkconfigure, inline below.  Again, my assumption is that
anyone who wants a system like this built it for themselves, but it
would be kind of fun to flesh this script out to be more generic.
Maybe post it and some samples on a webpage.  Or no one responds to this
and I shut up about it =).

This system is way overkill for some people (for instance, my home machine
uses a single configure file because I don't do that much special with
it), but it's useful in a larger system role.

--John

mkconfigure:

#!/bin/ksh

# I have found that our custom set up of exim's configure file is overly
# confusing.  To help alleviate this, I have broken the file out into its
# core pieces (general, tansports, directors, routers, retry, rewrite, and
# authentication), and then each of those into logical sub-pieces (SIS,
# for instance.  This program is to take all of those sub pieces and put
# them back together into the file that exim understands.

# No one should every touch the 'configure' file from now on, one should
# instead manipulate the files in the subconfigure directory and run this
# program

# jetmore 20011119

EXIMD=$1
CONFIGSUFF=$2

if [ "X$EXIMD" == "X" ] ; then
  EXIMD=/local/exim
fi
if [ ! -d "$EXIMD" ] ; then
  echo "$EXIMD is not a directory" >&2
  exit 1
fi
ETCD=$EXIMD/etc
SUBCD=$ETCD/subconfigure$CONFIGSUFF
CONFIGF=$ETCD/configure$CONFIGSUFF

if [ ! -d $SUBCD ] ; then
  echo "$SUBCD is not a directory" >&2
  exit 1
fi

GREP=/bin/grep

# initialize the temporary config file in case some trash got left around
cat /dev/null > $CONFIGF.t

# print the banner to the temp config file
echo                                                             >> $CONFIGF.t
echo "#########################################################" >> $CONFIGF.t
echo "# DO NOT DIRECTLY MANIPULATE THIS FILE                   " >> $CONFIGF.t
echo "#                                                        " >> $CONFIGF.t
echo "# if you need to make configuration change, do so in     " >> $CONFIGF.t
echo "# $SUBCD and run the mkconfigure"                          >> $CONFIGF.t
echo "# command.  Changes made to this file will be lost       " >> $CONFIGF.t
echo "#                                                        " >> $CONFIGF.t
echo "# See jetmore w/ questions                               " >> $CONFIGF.t
echo "#########################################################" >> $CONFIGF.t
echo                                                             >> $CONFIGF.t

# get the major categories
for CAT in $SUBCD/[0-9]*
do
    # print which category we're in
    echo                                                         >> $CONFIGF.t
    echo "## major category $CAT"                                >> $CONFIGF.t
    echo                                                         >> $CONFIGF.t

    # get the subcategories
    for SUBCAT in $CAT/[0-9]*
    do
        # print which sub category we're in
        echo "## sub category $SUBCAT"                           >> $CONFIGF.t
        echo                                                     >> $CONFIGF.t

        # place the contents of any non-comment line into the configure file
        $GREP -v "^ *#" $SUBCAT                                  >> $CONFIGF.t
        echo                                                     >> $CONFIGF.t
    done
done

# check and make sure there aren't any typos in the new config file
$EXIMD/bin/exim -C $CONFIGF.t -bV > $CONFIGF.test 2>&1
if [ "$?" -eq "1" ] ; then
    #/bin/rm $CONFIGF.t
    echo
    echo "There is a problem with the configure file.  "
    echo "moving paniclog to paniclog.mkfail"
    echo "$CONFIGF.test has details:"
    echo
    echo #####################################################################
    cat $CONFIGF.test
    echo #####################################################################
    echo
    echo "$CONFIGF not changed!"
    /bin/mv -f /log/exim/paniclog /log/exim/paniclog.mkfail
    exit 1
fi
/bin/rm $CONFIGF.test

/bin/mv $CONFIGF.t $CONFIGF
echo "$CONFIGF updated successfully."
echo "Don't forget to HUP the mail daemon"
exit 0