Script to run with cron to update vnstati output

vnstat-update.command

#!/usr/bin/env bash

# Fail on any error
set -e

# Debug
# set -x

###########################################################################
####### Set below as appropropriate for your environment ##################
####### IFACE is the interface (use `ifconfig` to get the name) ###########
####### WEB_DIR is where vnstat files will be output ######################
####### USER is the user vnstat will be run as ############################
###########################################################################
IFACE='en0'
WEB_DIR='/path/to/my/webdir'
USER='_www'

PATH=/usr/local/bin:$PATH
CWD=$(pwd)

#########################################################

function cleanup {
    cd "$CWD"
    exit 1
}
trap 'cleanup' SIGHUP SIGINT SIGTERM ERR

#########################################################

sudo -u ${USER} bash <<EOF

# Fail on any error
set -e

# Debug
# set -x

if [[ ! "\$(whoami)" == "${USER}" ]]; then
    echo "Must be run as ${USER}, you are \$(whoami)"
    exit 1
fi

cd "${WEB_DIR}"
vnstati -i ${IFACE} -vs -o vnstat.png
vnstati -i ${IFACE} -d  -o vnstat_d.png
vnstati -i ${IFACE} -m  -o vnstat_m.png
vnstat --xml > vnstat.xml

echo "vnstati files successfully generated in ${WEB_DIR}"

EOF