+version () {
+ echo "$@" | awk -F. '{ printf("%d%03d%03d%03d\n", $1,$2,$3,$4); }'
+}
+
+# Support for docker versions older than 17.05.
+# See https://github.com/moby/moby/issues/32457
+if [[ $(version "$(docker version --format '{{.Server.Version}}')") < $(version "17.05") ]]; then
+ tmp_file="${DOCKER_FILE}.tmp"
+ trap "rm -f ${tmp_file}" EXIT
+
+ cp -f ${DOCKER_FILE} ${tmp_file}
+ DOCKER_FILE=${tmp_file}
+ sed --in-place "s|ARG DOCKER_FROM||" ${tmp_file}
+ sed --in-place "s|\${DOCKER_FROM}|${DOCKER_FROM}|" ${tmp_file}
+fi
+