iiab/roles/openvpn/templates/announcer.j2

#!/bin/bash -x
# Small daemon to identify this machine to the OpenVPN server

HANDLE=
UUID=
if [ -f /etc/iiab/openvpn_handle ]; then
    # Option #1: Source directly from /etc/iiab/local_vars.yml in future?
    # Option #2
    HANDLE=`cat /etc/iiab/openvpn_handle`

# Sourcing a variable from ~4 different places is a recipe for total confusion
# (or worse!)  Far better to make variable openvpn_handle and file
# /etc/iiab/openvpn_handle "obligatory" (EMPTY STRING "" IS TOLERATED, IN WHICH
# CASE OPENVPN SERVER TRIES TO USE /etc/iiab/uuid BELOW, IN LIEU OF HANDLE...)

# CLARIF: "systemctl restart openvpn" still works tolerably even if the above
# is defied, auto-starting child service openvpn@xscenet per usual
# (e.g. if /etc/iiab/openvpn_handle is deleted by accident!)

#else
#    # Option #3: Dangerous to invoke hypothetical variables :(
#    source {{ iiab_env_file }}
#    # Option #4: CAUSED FAILURES IN AUGUST 2018, invoking stale variable from {{ iiab_ini_file }}, but safer now that relegated to #4 ?
#    if [ -z "$HANDLE" ]; then
#        HANDLE=`cat {{ iiab_ini_file }} | gawk \
#        '{ if((toupper($1) == "HANDLE") && ($2 == "=")) { print $3;}}'`
#    fi
fi
HANDLE=${HANDLE// /_}
if [ -f /etc/iiab/uuid ]; then
    UUID=`cat /etc/iiab/uuid`
fi

SERVER=/usr/bin/ncat
ID=`printf "HANDLE = %s|UUID = %s" $HANDLE $UUID`
# August 2018: Removal of trailing slash tested on Raspbian, Ubuntu 18.04 & Ubuntu 16.04
#ID=`printf "HANDLE = %s|UUID = %s|" $HANDLE $UUID`

# Start the daemon which will serve the handle on demand
{% if is_debuntu %}
$SERVER -l -k -p1705 --exec "/bin/echo $ID" &
{% else %}
source /etc/init.d/functions
PID_FILE=/var/run/openvpn/announce.pid
daemon --pidfile=${PID_FILE} $SERVER "-l -k -p1705 --exec \"/usr/bin/echo $ID\"" &
#daemon --pidfile=${PID_FILE} $SERVER "-l -k -p1705 --exec \"/usr/bin/echo $(printf 'HANDLE = %s|UUID = %s' $HANDLE $UUID)\"" &
{% endif %}