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diff --git a/doc/languages-frameworks/python.md b/doc/languages-frameworks/python.md index 48d9e0a0952f9..3f5d500620bb3 100644 --- a/doc/languages-frameworks/python.md +++ b/doc/languages-frameworks/python.md @@ -804,6 +804,55 @@ If you want to create a Python environment for development, then the recommended method is to use `nix-shell`, either with or without the `python.buildEnv` function. +### How to consume python modules using pip in a virtualenv like I am used to on other Operating Systems ? + +This is an example of a `default.nix` for a `nix-shell`, which allows to consume a `virtualenv` environment, +and install python modules through `pip` the traditional way. + +Create this `default.nix` file, together with a `requirements.txt` and simply execute `nix-shell`. + +``` +with import <nixpkgs> {}; +with pkgs.python27Packages; + +stdenv.mkDerivation { + name = "impurePythonEnv"; + buildInputs = [ + # these packages are required for virtualenv and pip to work: + # + python27Full + python27Packages.virtualenv + python27Packages.pip + # the following packages are related to the dependencies of your python + # project. + # In this particular example the python modules listed in the + # requirements.tx require the following packages to be installed locally + # in order to compile any binary extensions they may require. + # + taglib + openssl + git + libxml2 + libxslt + libzip + stdenv + zlib ]; + src = null; + shellHook = '' + # set SOURCE_DATE_EPOCH so that we can use python wheels + SOURCE_DATE_EPOCH=$(date +%s) + virtualenv --no-setuptools venv + export PATH=$PWD/venv/bin:$PATH + pip install -r requirements.txt + ''; +} +``` + +Note that the `pip install` is an imperative action. So every time `nix-shell` +is executed it will attempt to download the python modules listed in +requirements.txt. However these will be cached locally within the `virtualenv` +folder and not downloaded again. + ## Contributing |