#!/bin/bash -
#
#### Abstract ################################################################
#
# Munin contributed plugin to measure open, locked and files being hold by
# Netatalk version 3.*;
#
#### Author ##################################################################
#
# Otavio Fernandes <otaviof@gmail.com>
# Wednesday, 01/01/2014
#

#### Functions ###############################################################
#

function afpd_full_path () {
    echo $(which afpd |head -n 1)
}

function afp_related_file_exists () {
    local afp_file_path=$1
    if [ -z "$afp_file_path" -o ! -f "$afp_file_path" ]; then
        echo "ERROR: AFP related file not found: \"${afpd_bin_path}\";" >&2
        exit 1
    fi
}

function is_netatalk_version_3 () {
    local afpd_bin_path=$1
    version_string="$(${afpd_bin_path} -version |head -n1 |grep '^afpd' |cut -d' ' -f2)"
    if [[ $version_string != 3\.* ]]; then
        cat <<EOM >&2
ERROR: Netatalk is not version 3.
  Binary: ${afpd_bin_path};
 Version: ${version_string};
EOM
        exit 1
    fi
}

function count_running_procs () {
    local afpd_bin_path=$1
    echo $(ps ax --no-headers -o command |grep "^${afpd_bin_path}" |wc -l)
}

function count_connected_users () {
    local afpd_bin_path=$1
    afpd_procs=$(ps anx --no-headers -o uid,command |grep -E "\w+\d+*\s${afpd_bin_path}" |wc -l)
    # one of those processes will be always from root user, so it's not being
    # used to externaly connect volumes, therefor being disconsider.
    echo $(echo "${afpd_procs} - 1" |bc)
}

function base_lsof () {
    local afpd_bin_path=$1
    process_name="$(basename ${afpd_bin_path})"
    excluded_fds="^DEL,^err,^jld,^ltx,^Mxx,^m86,^mem,^mmap,^pd,^rtd,^tr,^txt,^v86"
    echo "lsof -a -c ${process_name} -d ${excluded_fds}"
}

function count_locked_files () {
    local afpd_bin_path=$1
    cmd_suffix="$(base_lsof "${afpd_bin_path}")"
    echo "$(${cmd_suffix} -F -l |grep '^l[rRwWu]' |wc -l)"
}

function probe_afp_conf_file () {
    local afpd_bin_path=$1
    echo "$(${afpd_bin_path} -version 2>&1 |grep -E '^\s+afp.conf\:' |awk '{print $2}')"
}

function count_open_shares () {
    local afpd_bin_path=$1
    local afp_conf_path=$2

    mounted=0
    declare -a shares=($(grep '^path.*\=' ${afp_conf_path}  |awk -F '=' '{print $2}' |sed -E 's/^\s+//g'))
    if [ ! -z "$shares" ]; then
        # narrowing lsof results to only list configured mount directories
        cmd_lookup_prefix=$(echo ${shares[@]} |tr " " "|")
        cmd_suffix="$(base_lsof "${afpd_bin_path}")"
        mounted=$(${cmd_suffix} -F n |grep '^n' |egrep "(${cmd_lookup_prefix})" |wc -l)
    fi
    echo $mounted
}


#### Main ####################################################################
# For all routines, holds the entry points dealing with the informed parameter
# or lack of it, meaning just print out collected data.
#

case "$1" in
    config)
        # printing configuration for this plugin's produced data
        cat <<EOM
graph_title Netatalk v3 Status
graph_title Netatalk status
graph_args --logarithmic --lower-limit 0.1
graph_vlabel Number
graph_category fs
proc.label Running processes
proc.info Running AFPd processes
proc.min 0
user.label Connected users
user.info Connected users
user.min 0
lock.label Locked files
lock.info AFPd locked files
lock.min 0
share.label Open shares
share.info Netatalk open shares
share.min 0
EOM
        exit 0
    ;;
    *)
        #### Boilerplates ####################################################
        # Locating AFP related files:
        #  * Binary: Using the first result of "which" command;
        #  * Config: Using "afpd" with parameters to pring configuration file
        #            location;
        #

        AFPD_PATH="$(afpd_full_path)"
        afp_related_file_exists "${AFPD_PATH}"
        is_netatalk_version_3 "${AFPD_PATH}"

        AFP_CONF_PATH="$(probe_afp_conf_file "${AFPD_PATH}")"
        afp_related_file_exists "${AFP_CONF_PATH}"

        #### Collecting Metrics ##############################################
        #
        echo "proc.value" $(count_running_procs "${AFPD_PATH}")
        echo "user.value" $(count_connected_users "${AFPD_PATH}")
        echo "lock.value" $(count_locked_files "${AFPD_PATH}")
        echo "share.value" $(count_open_shares "${AFPD_PATH}" "${AFP_CONF_PATH}")

        exit 0
    ;;
esac

# EOF