Nix + Python + nanomsg

default.nix

####################################################################################
#   Nix shell for nix-powered environments
#   This is like `virtualenv`, but with fine-defined system dependencies
####################################################################################
rec {
    nanomsg-py = pythonPackages.buildPythonPackage {
        name = "nanomsg-1.0";
        src = pkgs.fetchurl { url = "https://pypi.python.org/packages/0b/b1/3037e0e380d5fab2824e69a59bd374da402c0cef264ccb3fe5d71c230c4b/nanomsg-1.0.tar.gz"; sha256 = "843be41258219d9d319cf434a68cac7669834ab9c993ea4bab5b3d87f62a7a13"; };
        doCheck = false;
        buildInputs = [ pkgs.nanomsg ];
        patchPhase = ''
            sed -i "s|LoadLibrary('libnanomsg.so')|LoadLibrary('${pkgs.nanomsg}/lib/libnanomsg.so')|g" ./_nanomsg_ctypes/__init__.py
            sed -i "s|LoadLibrary('libnanoconfig.so')|LoadLibrary('${pkgs.nanomsg}/lib/libnanoconfig.so')|g" ./setup.py
            sed -i "s|LoadLibrary('libnanoconfig.so')|LoadLibrary('${pkgs.nanomsg}/lib/libnanoconfig.so')|g" ./_nanomsg_ctypes/__init__.py
        '';
    };

    shell = pythonPackages.buildPythonApplication {
        name = "shared-env";
        buildInputs = (with pkgs; [
            postgresql
            libffi
            bashInteractive
            nanomsg-py
        ]) ++ (with pythonPackages; [
            ipython
        ]);
        phases = [ "unpackPhase" ];
        unpackPhase = '' echo "You should run this in nix-shell, not nix-build!  '';
        shellHook = ''
            echo 'Entering shared environmnet'
            echo 'Run "init" to download requirements'
            set -v

            alias pip="PIP_PREFIX='$(pwd)/build/pip_packages' \pip"
            export PYTHONPATH="$(pwd)/build/pip_packages/lib/python2.7/site-packages:$PYTHONPATH"
            unset SOURCE_DATE_EPOCH
            set +v

            function init {
                pip install -e .
            }
        '';
    };
}