nix_importer.py

# Import python packages which are installed in the nix store

# Note you NEED this if you install it via environment.systemPackages
# E.g environment.systemPackages = with pkgs; [ python27Packages.tensorflowWithCuda ]

# You DON'T NEED this if you do it like this: 
# python-with-my-packages = pkgs.python27.withPackages (ps: with ps; [ tensorflowWithCuda]);
# environment.systemPackages = [ python-with-my-packages ]

import sys
from os.path import join


def import_nix(nix_store_path="/nix/store/y83iqaaq13k23lgyppbkaf4l6ilpsmjx-python2.7-tensorflow-gpu-1.14.0/"):
    python_version = "python2.7"  # replace with automatic call to get version of interpreter
    sys.path.append(join(nix_store_path, "lib", python_version, "site-packages"))
    propagated_build_inputs = "nix-support/propagated-build-inputs"
    f = open(join(nix_store_path, propagated_build_inputs))
    content = f.read()
    f.close()

    # skip last entry as it's just the path to python itself
    # example:/nix/store/q20xz6iq493vha5425cbr4l6q190b39i-python-2.7.17
    propagated_paths = content.split(" ")[:-2]

    for p in propagated_paths:
        # Recursively do this for all dependencies
        import_nix(p)