Thanks to @benley and @jonringer the following works
with import <nixpkgs> {};
let
vpn-slice = pkgs.python3Packages.buildPythonPackage rec {
name = "vpn-slice";
version = "v0.13";
src = pkgs.fetchFromGitHub {
owner = "dlenski";
repo = "${name}";
rev = "${version}";
sha256 = "1ibrwal80z27c2mh9hx85idmzilx6cpcmgc15z3lyz57bz0krigb";
};
propagatedBuildInputs = with pkgs.python3Packages; [ setproctitle ];
meta = {
homepage = "https://github.com/dlenski/vpn-slice";
description = "vpnc-script replacement for easy and secure split-tunnel VPN setup";
license = stdenv.lib.licenses.gpl3Plus;
maintainers = with maintainers; [ dlenski ];
};
};
in mkShell {
name = "vpn-env";
buildInputs = with pkgs.python3Packages; [ numpy toolz vpn-slice ];
shellHook = ''
echo "Whatever makes this happen."
'';
}