as of now, swh-environment within nix:
```
$ nix-shell swh.nix
```
with:
```
$ cat swh.nix
with import <nixpkgs> {};
with pkgs.python3Packages;
let ppackages = pkgs.python3Packages;
in stdenv.mkDerivation {
name = "swhEnv";
buildInputs = [
# required packages for virtualenvwrapper and pip to work
python3Full
ppackages.virtualenv
ppackages.virtualenvwrapper
ppackages.pip
# runtime dependencies needed for the python modules pip will try
# to install. In this particular environment the python modules
# listed in the accumulated requirements.txt require the following
# packages to be installed locally in order to compile any binary
# extensions they may require.
openssl
libffi
libzip
stdenv
zlib
pkgs.systemd.lib systemd
# subvertpy needs this
apr aprutil pkgs.subversion.dev
# web (not enough)
pkgs.libxml2 lxml
];
src = null;
# ${lib.getLib pkgs.libsystemd}/lib;
shellHook =''
# set SOURCE_DATE_EPOCH so that we can use python wheels
SOURCE_DATE_EPOCH=$(date +%s)
source ${ppackages.virtualenvwrapper}/bin/virtualenvwrapper_lazy.sh
export LC_ALL=C.UTF-8
export LC_CTYPE=C.UTF-8
export LANG=C.UTF-8
# subvertpy needs this for compilation
export SVN_PREFIX=${pkgs.subversion.dev}
# libsystemd need this
export PKG_CONFIG_PATH=${pkgs.systemd.lib}/lib
mkvirtualenv -p ${python3}/bin/python3 -a $SWH_ENVIRONMENT_HOME swh2
'';
}
```
Then from within the virtualenv, install following the getting-started:
```
(swh2) $ pip install $( ./bin/pip-swh-packages --with-testing ) tox pifpaf
```