#!/bin/sh
# -*- sh -*-

# shellcheck disable=SC2046

: << =cut

=head1 NAME

memory - Plugin to measure memory on osx.

=head1 NOTES

This plugin runs the vm_stat command once per interval, to discover memory usage on OSX.

=head1 LICENSE

GPLv2

=head1 MAGIC MARKERS

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

=cut

if [ "$1" = "autoconf" ]; then
    if [ "$(uname)" = "Darwin" ]; then
        echo yes
        exit 0
    else
        echo "no (uname does not report 'Darwin')"
        exit 0
    fi
fi

dehumanise() {
    echo "$1" | sed -e "s/K/*1024/g;s/M/*1024*1024/;s/G/*1024*1024*1024/;s/T/*1024*1024*1024*1024/"
}

if [ "$1" = "config" ]; then
        echo 'graph_title Memory'
        echo "graph_order wired app compressed cached free swap_used swap_free"
        echo "graph_args --base 1024 -r --lower-limit 0"
        echo 'graph_vlabel Bytes'
        echo 'graph_category system'
        echo 'wired.label wired'
        echo 'wired.draw AREASTACK'
        echo 'wired.min 0'
        echo 'wired.info Wired memory'
        echo 'app.label app'
        echo 'app.draw AREASTACK'
        echo 'app.min 0'
        echo "app.info Application memory"
        echo 'compressed.label compressed'
        echo 'compressed.draw AREASTACK'
        echo 'compressed.min 0'
        echo 'compressed.info Compressed memory'
        echo 'cached.label cached'
        echo 'cached.draw AREASTACK'
        echo 'cached.min 0'
        echo 'cached.info Cached memory'
        echo 'free.label free'
        echo 'free.draw AREASTACK'
        echo 'free.min 0'
        echo 'free.info Free memory'
        echo 'swap_used.label swap_used'
        echo 'swap_used.draw AREASTACK'
        echo 'swap_used.min 0'
        echo 'swap_used.info Swap used'
        echo 'swap_free.label swap_free'
        echo 'swap_free.draw AREASTACK'
        echo 'swap_free.min 0'
        echo 'swap_free.info Swap free'

        exit 0
fi

PAGESIZE=$(pagesize)
VMSTATINFO=$(vm_stat)
MEM_FREE=$(echo "$VMSTATINFO" | awk '/Pages free: / { print substr($3, 1, length($3)-1) }')
MEM_WIRED=$(echo "$VMSTATINFO" | awk '/Pages wired down: / { print substr($4, 1, length($4)-1) }')
MEM_ANONYMOUS=$(echo "$VMSTATINFO" | awk '/Anonymous pages: / { print substr($3, 1, length($3)-1) }')
MEM_PURGEABLE=$(echo "$VMSTATINFO" | awk '/Pages purgeable: / { print substr($3, 1, length($3)-1) }')
MEM_COMPRESSED=$(echo "$VMSTATINFO" | awk '/Pages occupied by compressor: / { print substr($5, 1, length($5)-1) }')
MEM_FILEBACKED=$(echo "$VMSTATINFO" | awk '/File-backed pages: / { print substr($3, 1, length($3)-1) }')
#
MEM_APP=$( echo "$MEM_ANONYMOUS $MEM_PURGEABLE" | awk '{ print $1 - $2 }')
MEM_CACHED=$( echo "$MEM_FILEBACKED $MEM_PURGEABLE" | awk '{ print $1 + $2 }')
#
SWAPINFO=$(sysctl vm.swapusage)
SWAP_USED=$(echo "$SWAPINFO" | awk '/vm.swapusage: / { print substr($7, 1, length($7)) }')
SWAP_FREE=$(echo "$SWAPINFO" | awk '/vm.swapusage: / { print substr($10, 1, length($10)) }')
#
echo "wired.value" $(( MEM_WIRED * PAGESIZE ))
echo "app.value" $(( MEM_APP * PAGESIZE ))
echo "compressed.value" $(( MEM_COMPRESSED * PAGESIZE ))
echo "cached.value" $(( MEM_CACHED * PAGESIZE ))
echo "free.value" $(( MEM_FREE * PAGESIZE ))
echo "swap_used.value" $( dehumanise "$SWAP_USED" | bc )
echo "swap_free.value" $( dehumanise "$SWAP_FREE" | bc )