dockerlite

#!/bin/sh
set -e

_dl_error () {
    echo "error: $*" >/dev/stderr
    exit 1
}

_dl_warning () {
    echo "warning: $*" >/dev/stderr
}

_dl_info () {
    echo "info: $*" >/dev/stderr
}

_dl_resolve () {
    CLASS=$1
    NEEDLE=$2
    cd $DOCKERLITE_ROOT/$CLASS
    # Check exact match first
    [ -d $NEEDLE/rootfs ] && { echo $NEEDLE ; return ; }
    # Check prefix match on the ID
    FOUND=""
    for DIR in $NEEDLE*
    do
	[ -d $DIR/rootfs ] && FOUND=1$FOUND
    done
    case "$FOUND" in 
	1)
	    echo $DIR
	    return
	    ;;
	1*)
	    _dl_error "more than one match for $NEEDLE found in $CLASS"
	    ;;
    esac
    # Check names
    # (if no container has a name tag, grep will show a warning,
    # so we send that to /dev/null)
    grep -q "^$NEEDLE$" */metadata/name 2>/dev/null && {
	ls -t $(grep -l "^$NEEDLE$" */metadata/name) | head -n 1 | cut -d/ -f1
	return
    }
    # Check if we asked LAST
    [ "$2" = "LAST" ] && {
	ls -t | head -n 1
	return
    }
    _dl_error "no match for $NEEDLE found in $CLASS"
}

_dl_mkid () { head -c 20 /dev/urandom | sha1sum | cut -d" " -f1 ; }
_dl_zerohash () { sha1sum /dev/null | cut -d" " -f1 ; }
_dl_cgroup () {
    CID=$1
    NONFATAL=$2
    MNT=$(grep ^cgroup.*devices /proc/mounts | cut -d" " -f2 | head -n1)
    [ "$MNT" ] || _dl_error "cannot find cgroup mount point"
    [ -d $MNT/lxc/$CID ] && { echo $MNT/lxc/$CID ; return ; }
    [ -d $MNT/$CID ] && { echo $MNT/$CID ; return ; }
    [ "$NONFATAL" ] || _dl_error "cannot find cgroup for container $CID"
}
eval "_dl_sourcedir () { echo $(dirname $(readlink -f "$0")); }"

_dl_btrfs () {
    btrfs "$@" >/dev/null || _dl_error "problem with btrfs"
}

HELP="dockerlite - a modular containerization engine"
_dl_cmd () {
    HELP="$(printf "%s\n%-10s %s\n\n" "$HELP" "$1" "$2")"
}

cd $(_dl_sourcedir)
. ./dockerlite.conf
for CMD in lib/dockerlite-*.sh
do
    . ./$CMD
done

[ "$DOCKERLITE_DEBUG" ] && set -x
if [ "$1" ]
then
	CMD="$1"
	shift
else
	CMD=help
fi
FUN=_dl_$CMD
type -t $FUN | grep -q function || _dl_error "invalid command"
$FUN "$@"