How can I define an owner to an empty_dir using container_image or container_layer from bazel rules_docker?
In a BUILD file, the attribute you're looking for is ownername. See the pkg_tar reference documentation documentation for more details. Also, I don't think you can pass it directly to container_image, you have to create a separate pkg_tar first. Like this:
pkg_tar( name = "with_empty_dirs_tar", empty_dirs = [ "etc", "foo", "bar", ], ownername = "nginx.nginx",)container_image( name = "with_empty_dirs", tars = [":with_empty_dirs_tar"],)In general, container_image has a subset of pkg_tar as direct attributes to make simple forms of adding files, but for complex use cases you should create a pkg_tar yourself for full access to all of its features for adding/arranging files and setting their ownership.
The names you see in that PR is a variable in a Python helper tool which the BUILD file rules use as part of the implementation. There's a layer of abstraction between what you write in a BUILD file and that Python code.