Python development environment

shell.nix

# first run the following
# $ niv init
# $ niv update nixpkgs -b nixpkgs-unstable
# then enter the environment by running
# $ nix-shell

let
  sources = import ./nix/sources.nix;
  pkgs = import sources.nixpkgs { };
  inherit (pkgs.lib) optional optionals;

  mach-nix = import (builtins.fetchGit {
    url = "https://github.com/DavHau/mach-nix/";
    # ref = "refs/tags/3.2.0";
    ref = "refs/heads/conda-beta";
  }) {
    condaChannelsExtra.conda-forge = [
      (builtins.fetchurl "https://conda.anaconda.org/conda-forge/linux-64/repodata.json")
      (builtins.fetchurl "https://conda.anaconda.org/conda-forge/noarch/repodata.json")
  ];  };

  customPython = mach-nix.mkPython {
    requirements = ''
      numpy
      faiss-cpu
      scikit-learn
    '';
    providers = {
      _default = "conda-forge,wheel,sdist,nixpkgs";
      scikitlearn = "conda-forge";
      faiss-cpu = "wheel";
    };
  };


in pkgs.mkShell {
  buildInputs = with pkgs;
  [ customPython
  ];
}