#!/bin/bash
# 'getCurrentStat bash for sh' simultaneously on many target.
# Sample of distributing POSIX shell commands through many hosts, using ssh
# then get/retrieve all outputs, format and print them using bash V5+
# More complex, but more robust than 'getCurrentStat to sort' alternative
# (C) 2023-2024 Felix Hauri - felix@f-hauri.ch
# Licensed under terms of GPL v3. www.gnu.org

## Note: Host list is ignored if arguments (list of user@hosts) are submited!!
## To use an external file replace the following by: exec {hostList}</path/file
exec {hostList}<<EOHostList
#   Target: user@host-or-ip	Text full description

    pi@192.168.1.7		Private NAS
    user@somewhere.not		My web server
    root@10.1.33.4		Private backup through vpn
EOHostList

percent() { # usage: percent <value> <ref val> [varname]
    local p=000$(( ${1}00000/$2 ))
    # shellcheck disable=SC2059 disable=SC2086
    printf ${3+-v} $3 %.2f ${p::-3}.${p: -3}
}
textSize(){ # usage: textSize <value> [varname]
    local i=$(( $1 >= 1<<50 ? 5 : $1 >= 1<<40 ? 4 : $1 >= 1<<30 ? 3 :
		$1 >= 1<<20 ? 2 : $1 > 1023 ? 1 : 0 )) a=(K M G T P)
    # shellcheck disable=SC1105 disable=SC2210 disable=SC2035
    (( i > 4 ? i+=-2 : 0 )) && a=( "${a[@]:2}" ) && set -- $(( $1>>20 )) "$2"
    local r=00$(( 1000 * $1 / ( 1024**i ) ))
    # shellcheck disable=SC2059 disable=SC2086
    printf -v $2 %.2f%s ${r::-3}.${r: -3} ${a[i]}
}
collectCpuMemDiskStat() { # Collect infos and format print them
    export LC_ALL=C
    # shellcheck disable=SC2046
    echo "$1" $( # order position , host name
	hostname
	 ) $(  # uptime,  idle time
	cat /proc/uptime
	 ) $(  # mem total, mem used, swap total, swap used
	free | sed '1d;s/^.*: *\([[:digit:]]\+\) \+\([[:digit:]]\+\) .*/\1 \2/'
	 ) $(  # disk total, disk used
	df -PkT |
	     awk '
		BEGIN{ tot=0;use=0;};
		END{ print tot,use;};
		/ ext| xfs| reiser| ntfs| vfat| fat| btrfs/{
		    tot+=$3 ; use+=$4;
		};'
	 ) $(  # number of cpus * cores
	grep -c processor /proc/cpuinfo
	 ) $(  # model of rapsberry if raspberry or else of CPU
	if [ -d "/sys/firmware/devicetree/base" ]; then # It's a Raspberry Pi
	    tr \\0 \\n  < /sys/firmware/devicetree/base/model
	else
	    sed -e '/^model name/{s/.*: *//;s/([^)]*)//g;q;};d' </proc/cpuinfo
	fi
	 )
}
run1ssh() {
    local target=${1} string=${2} thisFd
    order+=1
    exec {thisFd}<> >(:) # open This File descriptor, but not linked to ssh
    # This method is reliable as long expected output stay small.
    # For bigger ouput, consider using a file, even through compression!
    ssh "$host" sh  < <(
	declare -f collectCpuMemDiskStat
	printf 'collectCpuMemDiskStat %q %q\n' "$order" "$target"
    ) >&$thisFd &
    allFDs[$!]=$thisFd
    targets[$!]=${target#*.*.}
    text[$!]=${string}
}

declare -i order allFDs pid amtot=0 adtot=0 \
	mtot muse stot suse dtot duse ncpu start=${EPOCHREALTIME/.} end

if (($#)); then
    for host; do
	run1ssh "$host"{,}
    done
else
    while read -ru $hostList host desc; do
	case $host in
	    \#*|'' ) ;;
	    * ) run1ssh "$host" "$desc" ;;
	esac
    done
fi
printf '%-13s %-35s %7s %7s %7s %7s %7s %7s %8s %s\n' \
       Host Model Mem Disk CPU Mem Swap Disk ReqTime Description
while (( ${#allFDs[@]} )); do
    printf >&2 '\rCurrent run %d: \47%s\47\e[K' ${#allFDs[@]} "${targets[*]}"
    wait -n -p pid "${!allFDs[@]}"
    if ((pid)); then
	read -ru ${allFDs[pid]} \
	     order host upt idl mtot muse stot suse dtot duse ncpu model
	end=${EPOCHREALTIME/.}
	unset "allFDs[pid]" "targets[pid]"
	elap=00000$((  end - start ))
	percent $(( ${upt/.} * ncpu - ${idl/.} )) $(( ${upt/.} * ncpu )) pcpu
	percent $muse $mtot pmem
	percent $suse $stot pswap
	percent $duse $dtot pdsk
	textSize $mtot hmem
	textSize $dtot hdsk
	amtot+=mtot adtot+=dtot
	# shellcheck disable=SC2154
	printf -v out[$order] \
	       '%-13s %-35s %7s %7s %6.2f%% %6.2f%% %6.2f%% %6.2f%% %7.4fs %s' \
	       "$host" "${model::35}" "$hmem" "$hdsk" "$pcpu" "$pmem" "$pswap" \
	       "$pdsk" "${elap::-6}.${elap: -6}" "${text[pid]}"
    fi
done
end=${EPOCHREALTIME/.}
elap=00000$((  end - start ))
printf >&2 '\r\e[K'
printf "%s\n" "${out[@]}"
textSize $amtot hmem
textSize $adtot hdsk
printf '%-49s%8s%8s%40.4fs\n' Total "$hmem" "$hdsk" "${elap::-6}.${elap: -6}"