How to pack a Python env like venv-pack?

[njlr]

I am attempting to bundle some py_library targets so that they can be used in Spark.

Here are the steps outside of Bazel (for an environment with pyarrow and pandas):

python -m venv pyspark_venv
source pyspark_venv/bin/activate
pip install pyarrow pandas venv-pack
venv-pack -o pyspark_venv.tar.gz

Is it possible achieve this with rules_py?

I tried throwing a py_env into a pkg_tar but the folder structure ends up very different.

py_venv(
  name = "env",
  deps = [
    ":foobar",
  ],
)

pkg_tar(
  name = "bundle",
  extension = "tar.gz",
  strip_prefix = strip_prefix.from_pkg("."),
  package_dir = "/",
  srcs = [
    ":env",
  ],
  include_runfiles = True,
)

Here is what Spark has to say about packaging: https://spark.apache.org/docs/latest/api/python/user_guide/python_packaging.html