Headache from postfix

Earlier I wrote a post on how postfix could be used in a mail integration solution. This was a result on a project that I'm doing using postfix to catch mail and transfer it via a bash-shell script, through mq to BPEL PM using the mq-adapter.

I added a logging construction in the script that give me a nice mechanism to do some logging:

...
TRUE=1
FALSE=0
...
#Logging variables
LOG_ENABLED=$TRUE
#LOG_ENABLED=$FALSE
LOG_DIR=/tmp/log
LOG_FILENAME=$LOG_DIR/routescript.log
#Check log dir and create it if it does not exist.
check_logdir(){
if [ "$LOG_ENABLED" -eq $TRUE ]; then
  if [ -d $LOG_DIR ]; then
    #log a seperation line
    log
  else
    mkdir $LOG_DIR
  fi
fi
}
#Function to display usage
usage(){
  SCRIPT_PARAMETERS=" -q queuename -s sender -r receiver";
  USAGE="Usage: `basename $0` $SCRIPT_PARAMETERS";
  echo $USAGE;
}
#Log
log(){
  if [ "$LOG_ENABLED" -eq $TRUE ]; then
    TEXT="$1 ""$2"
    echo $TEXT >>$LOG_FILENAME;
  fi
}
# First check logdir
check_logdir

#Do the rest of the script logic

It works nicely, but the solution described in the earlier post works only for mails with one receipient. This was caused by the flag 'D' in the transport-line of the master.cf:
The 'D' flag prepends a message with a property line with the receipient.

# 2010-02-10, M. van den Akker: Setup transport routescript for passing message to a bash-script
routescript   unix  -       n       n       -       -       pipe
flags=FDq. user=smtpuser argv=/bin/bash -c /home/smtpuser/routescript.sh -s $sender -r $recipient -q $nexthop

Besides removing this flag, also the argument parsing of the script should be adapted, to support for multiple receipients:

ARG_NR=0;
until [ -z "$1" ]
do
  ARG_NR=$(($ARG_NR+1));
  log "Argument $ARG_NR: " $1
  case $1 in
    "-s") PARAM=$1;;
    "-r") PARAM=$1;;
    "-q") PARAM=$1;;
    * )  case $PARAM in
            "-s") SENDER=$1;
                  log "Sender: " $SENDER;;
            "-r") RECEIVER=$1;
                  log "Receiver: " $RECEIVER;
                  if  [ -z "$RECEIVER_LIST" ]
                  then
                    RECEIVER_LIST=$RECEIVER;
                  else
                    RECEIVER_LIST="$RECEIVER_LIST,$RECEIVER";
                  fi
                  log "Receiverlist: " $RECEIVER_LIST;;
            "-q") FQN_QUEUE_NAME=$1;
                  log "Queue: " $FQN_QUEUE_NAME;;
            * ) usage;
            exit $E_WRONG_ARGS;;
         esac;;
  esac;
shift 1;
done;
#Log Parameters.
log "SENDER: " $SENDER
log "RECEIVER_LIST: " $RECEIVER_LIST
log "FQN_QUEUE_NAME: " $FQN_QUEUE_NAME

But implementing this I got the strange behaviour that posfix did call my script but the script did not get any arguments! Logging like the following gave me 0 arguments:

# Check Arguments
log "Number of arguments:  $#"
log "Arguments:  $*"

Yesterday and this morning I tried and figured and thought until my brains got nearly overheated. But since all my configs seemed alright and even the version I knew they worked, it finally stroke me that it had to with the commandline to call the script.

And I finally had it. It was due to the nasty '-c' option after '/bin/bash'!

It probably got there through an example I used. And it was removed in the test environments, but apparently not in my examples and documentation. So it also came into my earlier post. The option toggles the spawn of a new bash-session for the script. The arguments got into the 'parent' session but not into the 'child'-session that runs the script. Removing the '-c'option would do the trick.

Furthermore I moved the $receiver argument to the end since it can expand to more arguments. Although the script would not have problems with it, I found it saver.

So the resulting (correct) line in the master.cf should be:

routemq   unix  -       n       n       -       -       pipe
flags=Fq. user=smtpbridge argv=/bin/bash  /home/smtpbridge/routemq.sh -q $nexthop -s $sender -r $recipient