#!/bin/bash
# (c) 2012  - Bushmills
# License : GPLv2

#%# family=auto
#%# capabilities=autoconf


interval=1			# mpstat sampling interval
timeout=1200			# 20 minutes daemon watchdog timeout
watchdog=60			# test for timeout every $watchdog seconds
pluginfull="$0"                 # full name of plugin
plugin="${0##*/}"	        # name of plugin
pidfile="$MUNIN_PLUGSTATE/munin.$plugin.pid"
cache="$MUNIN_PLUGSTATE/munin.$plugin.value"
graph="$plugin"
style="AREA"
cpus=$(grep -c ^processor /proc/cpuinfo)

run_watchdog()  {                 # should also trap kill and term signals
   kill -0 $(cat $pidfile) 2> /dev/null || rm -f $pidfile
}


run_acquire()  {
   echo "$$" > $pidfile
   LANG=C mpstat -P ALL $interval |
   awk -v cpus=$cpus '$2>=0&&$2<99 {print $2, systime(), (100-$11)/cpus; system("");}' >> $cache
   rm -f $pidfile $cache
}

run_daemon()  {
   run_watchdog
   if [ -f $pidfile ]; then
      touch $pidfile
   else
      $pluginfull acquire &
   fi
}


# --------------------------------------------------------------------------

run_autoconf() {
   run=(yes no)
   type -t mpstat > /dev/null
   echo "${run[$?]}"
}

run_config() {
run_daemon
cat << EOF
graph_title $graph
graph_category 1sec
graph_vlabel average cpu use %
graph_scale no
graph_total All CPUs
update_rate 1
graph_data_size custom 1d, 10s for 1w, 1m for 1t, 5m for 1y
EOF
cpun=0
for ((i=0; i<$cpus; i++)); do
cat << EOF
cpu${cpun}.label CPU $cpun
cpu${cpun}.draw $style
cpu${cpun}.min 0
EOF
style=STACK
((cpun++))
done
}

run_fetch()  {
   run_daemon
   awk 'NF==3 {print "cpu" $1 ".value " $2 ":" $3}' $cache
   > $cache
}


run_${1:-fetch}
exit 0

# export -f functionname     export functionname to subshell, avoiding the need
#    for locating plugin for subshell calling, when process needs a different
#    pid. Instead, $SHELL -c functionname  can be used. useful for calling
#    acquire which needs a different pid than watchdog, otherwise watchdog
#    could/will kill itself when expiring before the watched process is killed.
# not a POSIX feature.