Tuesday, February 13, 2007

SSMTP/Getmail how-to part III

back to part II

The getmail documentation said that was the best way to automate it, and its bloody better then buling up getmail with 'daemon mode' code. But also like the documentation said if we want to 'stop' this daemon like mail checking we need a script for cron to run getmail through and program it to not run getmail if a file is pressent. Now we can do this many ways, heck we could set a enviroment variable if we want.

I've written a little script that can be run with a users cron jobs and skip over all mail or only the given account. You need one rcfile per account and you can tweak it to follow any conventions you want. My RCFiles follow the convention of getmailrc-shortaccountname, hence getmailrc-bell and getmailrc-sas for my bellsouth and sasclan accounts. This script should work on any system that has a bourneshell compatible /bin/sh. Just edit the shebang if you need to run it as another shell (such as /bin/ksh).

#!/bin/sh

# Use getmail to check my E-Mail account using the RC variable
# This script has the advantage that one can save it as another file, change
# one variable and set a cron job to check each account at different times (1
# cron job per script). Then not only use a file in their .getmail folder to
# stop all the scripts from running getmail or use a file to stop one script
# from checking its account. It also keeps a log which will be trimmed by
# another script

# Name of the getmailrc file to use
RC=getmailrc-sas

# log to a file when mail is checked
LOGFILE=${HOME}/.getmail/cronjobs.log

#
# If a nomail or nocheck file is found in ~/.getmail/ exit without checking
# else look for a no file. Where  is equal to every thing that
# comes after the getmailrc- in $RC. If none of these files exsist check mail
# using the $RC file.
#
if [ -e ${HOME}/.getmail/nomail ]
then
        LOG=$(echo "Skipping mail for $RC")
        exit 1
elif [ -e ${HOME}/.getmail/nocheck ]
then
        LOG=$(echo "Skipping mail for $RC")
        exit 1
else
        DIE=$(ls ${HOME}/.getmail| grep $RC | cut -d '-' -f 2)
        if [ -e ${HOME}/.getmail/no${DIE} ]
        then
                LOG=$(echo "You have desided not to check this mailbox - $DIE")
        else
                LOG=$(echo `date` "checked mailbox with $RC")
                getmail -r$RC
        fi
fi

# Update log with the result
echo $LOG >> $LOGFILE 2> /dev/null

if you want to use the script copy and paste it into a text file and mark it executible. I saved them as ~/.getmail/check-.sh and chmod'd them 0700

Ok, let us make a cron job, because this is allready a big long post that took me forever to write with the way my house is. I'm not detailing cron(8) so please read the handbook or read the fine manual.

I created this crontab file to run my scripts to check my accounts every 5 and 4 hours respecfully and to 'trim' my log file every week.

# rstf's crontab
SHELL=/bin/sh
PATH=/etc:/bin:/sbin:/usr/bin:/usr/sbin
HOME=/usr/home/rstf/
MAILTO=""
#
#minute hour    mday    month   wday    who     command
#
# check sas every 5hr
5     *       *       *       *       rstf    ${HOME}/.getmail/check-sas.sh
#
# check bell every 4hr
4     *       *       *       *       rstf    ${HOME}/.getmail/check-bell.sh
#
# trim log @weekly
0     0       *       *       0       rstf    ${HOME}/sh/trim-getmail-cronlog
#

The trim-getmail-cronlog script is thus

#!/bin/sh

# Rotate my logfile for running get mail via cron

LOGFILE=${HOME}/.getmail/cronjobs.log
TMPDIR=/tmp/

if [ -e $LOGFILE ]
then
        tail $LOGFILE > $TMPDIR/gmlog.$$
        rm $LOGFILE
        mv $TMPDIR/gmlog.$$ $LOGFILE
else
        exit 1
fi

To load my crontab file into crons system i.e. /var/run/tabs/${USER} all I have to do is run a simple command.

crontab ~/rstf-contrab

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