new: added ``get_service_base_image_dir_uid_gid``.

bin/compose

@@ -394,6 +394,16 @@ _clean_docker() {
 }
 export -f _clean_docker
 
+get_service_base_image_dir_uid_gid() {
+    local service="$1" dir="$2" uid_gid
+    uid_gid=$(cached_cmd_on_base_image "$service" "stat -c '%u %g' '$dir'") || {
+        debug "Failed to query '$dir' uid in ${DARKYELLOW}$service${NORMAL} base image."
+        return 1
+    }
+    info "uid and gid from ${DARKYELLOW}$service${NORMAL}:$dir is '$uid_gid'"
+    echo "$uid_gid"
+}
+export -f get_service_base_image_dir_uid_gid
 
 are_files_locked_in_dir() {
     local dir="$1" device hdev ldev