#!/bin/bash
##
## Munin plugin to return how many OpenVPN sessions are currently connected to
## an OpenVPN server.
##
## The 'openvpn_usercount' config stanza for munin-node looks like:
##
### [openvpn_usercount]
### user root
### env.statusfile "/var/log/openvpn-status.log"
##
## You can watch mutiple OpenVPN networks by aliasing openvpn_usercount script
## to "openvpn_usercount_network.vpn" where "network.vpn" is the OpenVPN
## network name.
##
### [openvpn_usercount_network.vpn]
### user root
### env.statusfile "/var/log/openvpn/network.vpn/openvpn-status.log"
##
## Original Author: Jeffrey Forman ( https://github.com/jforman )
## Enhanced by : Pierre-Yves Landuré for Biapy ( https://github.com/biapy )
##

# Compute statusfile option.
OPENVPN_STATUS_FILE="/var/log/openvpn-status.log"
if [ -n "${statusfile}" ]; then
  OPENVPN_STATUS_FILE="${statusfile}"
fi

# Check for status log existance.
if [ ! -e "${OPENVPN_STATUS_FILE}" ]; then
  echo "Error: OpenVPN status file '${OPENVPN_STATUS_FILE}' does not exist"
  exit 1
fi

# Detect VPN network name from script name.
NETWORK_NAME="$(command basename "${0}" \
    | command sed -e 's/openvpn_usercount[_]\{0,1\}//')"
if [ -n "${NETWORK_NAME}" ]; then
  NETWORK_NAME=" (${NETWORK_NAME})"
fi

case "${1}" in

  "config" )
    # Display munin-node plugin configuration.
    echo "graph_title OpenVPN Users${NETWORK_NAME}
graph_vlabel User Count
graph_category openvpn
user.label Logged In Users"
    exit 0
    ;;

  * )
    # Default action.

    # This compute the number of connected clients for all
    # status-version values.
    CLIENT_LIST_START="$(command grep --max-count=1 --line-number \
          "Connected Since" "${OPENVPN_STATUS_FILE}" \
        | command cut --delimiter=":" --field="1")"
    CLIENT_LIST_END="$(command grep --max-count=1 --line-number \
          "ROUTING[ _]TABLE" "${OPENVPN_STATUS_FILE}" \
        | command cut --delimiter=":" --field="1")"

    USER_COUNT=$((${CLIENT_LIST_END} - ${CLIENT_LIST_START} - 1))

    echo "user.value ${USER_COUNT}"
    exit 0;
    ;;
esac