#!/bin/sh

usage () {
    echo 'usage: kvmstats.sh [-u K|M|G]'
    exit 1
}

POW=$(echo 1024 ^ 3 | bc)
while echo $1 | grep -q '^-[[:alnum:]]'
do
    case $1 in
    '-u')
        case $2 in
        'K')
            POW=$(echo 1024 ^ 1 | bc)
            ;;
        'M')
            POW=$(echo 1024 ^ 2 | bc)
            ;;
        'G')
            POW=$(echo 1024 ^ 3 | bc)
            ;;
        *)
            usage
        esac
        ;;
    *)
        usage
    esac
    shift
done

# since libvirt seems to store memoy in KiB, POW must be lowered by 1
POW=$(expr $POW / 1024)

for DEP in hxselect lvs tempfile
do
    if [ -z "$(which $DEP)" ]
    then
        echo "kvmstats.sh: $DEP not found in \$PATH" 1>&2
        exit 1
    fi
done

TMPFILE=$(tempfile)
LVSOUT=$(tempfile)

lvs --units b --nosuffix >$LVSOUT

for VM in $(virsh list --all --name)
do
    VCPU=$(hxselect -c 'domain vcpu' </etc/libvirt/qemu/$VM.xml)
    RAM=$(expr $(hxselect -c 'domain memory' </etc/libvirt/qemu/$VM.xml) / $POW)
    for DEV in $(hxselect -s'\n' 'domain devices disk[device=disk] source' </etc/libvirt/qemu/$VM.xml | cut -d\" -f2)
    do
        case $DEV in
        /dev/drbd/*)
            DISK=$(cat $LVSOUT | awk "/$VM/ { ans += \$NF } END { print ans / 1024 ^ 3 }")
            ;;
        *.qcow2)
            DISK=$(du -sBG $DEV | awk '{ print substr($1, 0, length($1) - 1) }')
            ;;
        *)
            DISK=0
            esac
    done
    echo $VM $VCPU $RAM $DISK
done >$TMPFILE

(
    echo vm vcpu ram disk
    cat $TMPFILE
    awk '{ vcpu += $2; ram += $3; disk += $4 } END { print "TOTAL", vcpu, ram, disk }' <$TMPFILE
) | column -t

rm $TMPFILE $LVSOUT