尝试将 NixOS 未打包的 pytest-bdd 添加到 shell.nix 环境

Question

我想创建一个简单的 python 项目，nixos 文档很有帮助。 所以我有一个shell.nix文件，其内容如下：

with import <nixpkgs> {};

(
  python3.withPackages (ps: [ps.ipython ps.flask ps.pytest])
).env

然后我在项目文件夹上运行nix-shell ，一切似乎都很好。

我遇到的问题是我想添加pytest-bdd但似乎没有为 NixOS 打包，因为nix search pytest-bdd不返回任何结果。

所以我尝试使用行为而不是pytest-bdd ，因为它已经为 NixOS 打包，但不幸的是，行为二进制文件不可用，而ipython和flask是。 并且行为文档统计了一个二进制文件应该可用。

所以我决定为pytest-bdd尝试一种不同的方法，并按照https://nixos.org/nixpkgs/manual/#python上的示例（15.17.1.2.1。打包库）。

with import <nixpkgs> {};

(
  let
    my_pytestbdd = python37.pkgs.buildPythonPackage rec {
      pname = "pytest-bdd";
      version = "3.2.1";

      src = python37.pkgs.fetchPypi {
        inherit pname version;
        sha256 = "1ibyr40g3p6xbx1m59as3s9spyadz8wyc7zwqyzibphrw4pkvrqp";
      };

      doCheck = false;

      meta = {
        homepage = "https://github.com/pytest-dev/pytest-bdd/";
        description = "BDD library for the py.test runner";
      };
    };

  in python37.withPackages (ps: [ps.ipython ps.flask ps.pytest ps.glob2 my_pytestbdd])
).env

我被这个消息卡住了：

Processing ./pytest_bdd-3.2.1-py2.py3-none-any.whl
Collecting glob2 (from pytest-bdd==3.2.1)
  ERROR: Could not find a version that satisfies the requirement glob2 (from pytest-bdd==3.2.1) (from versions: none)
ERROR: No matching distribution found for glob2 (from pytest-bdd==3.2.1)
builder for '/nix/store/d94madfidxgn5r0k9kivfidn4p2cvyjk-python3.7-pytest-bdd-3.2.1.drv' failed with exit code 1
cannot build derivation '/nix/store/ypc7hpylzvmxx8lmk5cfg8jfhrfalzgn-python3-3.7.5-env.drv': 1 dependencies couldn't be built
error: build of '/nix/store/ypc7hpylzvmxx8lmk5cfg8jfhrfalzgn-python3-3.7.5-env.drv' failed

Answer 1

解决方案

因此，经过大量时间浏览文档后，我设法获得了一个我想分享的可行解决方案，以避免人们遇到我所经历的同样痛苦。

这是我的shell.nix文件：

with import <nixpkgs> {};

(
  let
    my_pytestbdd = python37.pkgs.buildPythonPackage rec {
      pname = "pytest-bdd";
      version = "3.2.1";

      src = python37.pkgs.fetchPypi {
        inherit pname version;
    sha256 = "1ibyr40g3p6xbx1m59as3s9spyadz8wyc7zwqyzibphrw4pkvrqp";
      };

      buildInputs = [ python37.pkgs.glob2 python37.pkgs.parse python37.pkgs.six 
python37.pkgs.py python37.pkgs.parse-type python37.pkgs.Mako python37.pkgs.pytest ];

      doCheck = false;

      meta = {
        homepage = "https://github.com/pytest-dev/pytest-bdd/";
        description = "BDD library for the py.test runner";
      };
    };

  in python37.withPackages (ps: [ps.ipython ps.flask ps.pytest my_pytestbdd])
).env

并运行nix-shell成功创建了环境。

Answer 2

如果你很高兴只使用requirements.txt文件，你可以弯曲 nix 以使用 virtualenv 以正常方式工作，请参见下面的 default.nix：

with import <nixpkgs> {};
with pkgs.python37Packages;

stdenv.mkDerivation {
  name = "impurePythonEnv1d";
  buildInputs = [
    taglib
    openssl
    git
    libxml2
    libzip
    python37Full
    python37Packages.virtualenv
    stdenv
    libffi
    zlib ];
  src = null;
  shellHook = ''
    unset http_proxy
    export GIT_SSL_CAINFO=/etc/ssl/certs/ca-bundle.crt
    SOURCE_DATE_EPOCH=$(date +%s)
    virtualenv --no-setuptools venv
    source venv/bin/activate
    pip install jedi
    pip install ipython==5.2.0
    pip install pylint
    pip install flake8
    pip install -r requirements.txt
  '';
}

然后创建一个requirements.txt并对其进行nix-shell