bocker/bocker

#!/usr/bin/env bash
set -o errexit -o nounset -o pipefail; shopt -s nullglob

btrfs_path='/var/bocker';
basename=$(which basename);	btrfs=$(which btrfs);	cat=$(which cat);
unshare=$(which unshare);	umount=$(which umount);	chroot=$(which chroot)

function CHECK_VOLUME() {
if $btrfs subvolume list "$btrfs_path" | grep -qw "$1"; then
	return 0
else
	echo "No image named '$1' exists"
	exit 1
fi
}

function INIT() {
if [[ -d "$1" ]]; then
	uuid="img_$(uuidgen)"
	$btrfs subvolume create "$btrfs_path/$uuid" > /dev/null
	cp -rf --reflink=auto "$1"/* "$btrfs_path/$uuid" > /dev/null
	echo "$uuid"
else
	echo "No directory named '$1' exists"
fi
}

function RM() {
CHECK_VOLUME "$1"
$btrfs subvolume delete "$btrfs_path/$1" > /dev/null
}

function IMAGES() {
echo -e "IMAGE_ID"
for img in "$btrfs_path"/img_*; do
	$basename "$img"
done
}

function PS() {
echo -e "CONTAINER_ID\t\t\t\t\tCOMMAND"
for ps in "$btrfs_path"/ps_*; do
	ps=$($basename "$ps")
	echo -e "$ps\t\t$($cat "$btrfs_path/$ps/$ps.cmd")"
done
}

function RUN() {
CHECK_VOLUME "$1"
uuid="ps_$(uuidgen)"
$btrfs subvolume snapshot "$btrfs_path/$1" "$btrfs_path/$uuid" > /dev/null
echo "$2" > "$btrfs_path/$uuid/$uuid.cmd"
"$unshare" -fp --mount-proc "$chroot" "$btrfs_path/$uuid" \
	/bin/sh -c "/bin/mount -t proc proc /proc && /bin/$2" \
	2>&1 | tee "$btrfs_path/$uuid/$uuid.log"
$umount "$btrfs_path/$uuid/proc"
}

function LOGS() {
CHECK_VOLUME "$1"
$cat "$btrfs_path/$1/$1.log"
}

function HELP() {
echo -e "Create an image: \n\t./bocker init <image_directory>\n"
echo -e "List images: \n\t./bocker images\n"
echo -e "Create a container: \n\t./bocker run <image_id> <command>\n"
echo -e "List containers: \n\t./bocker ps\n"
echo -e "View logs from a container: \n\t./bocker logs <container_id>\n"
echo -e "Delete an image or container: \n\t./bocker rm <image_or_container_id>\n"
exit 0
}

[[ -z "${1-}" ]] && HELP
case $1 in
	init) INIT "$2" ;;
	rm)	RM "$2" ;;
	images) IMAGES ;;
	ps) PS ;;
	run)
		IMAGE="$2"
		shift && shift
		RUN "$IMAGE" "$*"
		;;
	logs) LOGS "$2" ;;
	*) HELP ;;
esac