【Python】虚拟环境的创建和使用

Pipenv管理Python虚拟环境

一、pipenv介绍

简单说，pipenv就是把pip和virtualenv包装起来的一个便携工具，它会自动为您的项目创建和管理virtualenv，以及在安装/卸载软件包时添加/删除Pipfile中的软件包。

使用pipenv管理python环境虚拟环境的优势：

  • 不再需要分开使用pip和virtualenv，合并到了一起

  • 不再需要管理requirements.txt，pipenv install xxx安装包时自动生成版本号、Hash值、包依赖关系到Pipfile和Pipfile.lock，并且可以手工编辑以区分开发环境和生产环境

  • 使用Hash校验安装的包，有利于主动暴露安全问题

  • 使用最新版本的依赖项，以最大限度地降低过时组件带来的安全风险

  • 可以图形化显示包之间的依赖关系（pipenv graph）

  • 通过加载.env文件简化开发工作流程

二、安装pipenv

首先，确保你已经正确安装python3和pip3

[[email protected] ~]# python3 -V Python 3.7.2 [[email protected] ~]# pip3 -V pip 19.0.1 from /usr/local/python3/lib/python3.7/site-packages/pip (python 3.7) [[email protected] ~]#

然后，Linux下pip3 install pipenv，Mac下brew install pipenv

[[email protected] ~]# pip3 install pipenv Looking in indexes: http://mirrors.aliyun.com/pypi/simple/ Collecting pipenv  Downloading http://mirrors.aliyun.com/pypi/packages/13/b4/3ffa55f77161cff9a5220f162670f7c5eb00df52e00939e203f601b0f579/pipenv-2018.11.26-py3-none-any.whl (5.2MB) 100% |████████████████████████████████| 5.2MB 4.0MB/s Requirement already satisfied: certifi in /usr/local/python3/lib/python3.7/site-packages (from pipenv) (2018.11.29) Requirement already satisfied: setuptools>=36.2.1 in /usr/local/python3/lib/python3.7/site-packages (from pipenv) (40.6.2) Requirement already satisfied: pip>=9.0.1 in /usr/local/python3/lib/python3.7/site-packages (from pipenv) (18.1) Requirement already satisfied: virtualenv in /usr/local/python3/lib/python3.7/site-packages (from pipenv) (16.2.0) Requirement already satisfied: virtualenv-clone>=0.2.5 in /usr/local/python3/lib/python3.7/site-packages (from pipenv) (0.4.0) Installing collected packages: pipenv Successfully installed pipenv-2018.11.26 [[email protected] ~]#

pipenv依赖psutil, virtualenv-clone, pew, certifi, urllib3, chardet, requests, mccabe, pyflakes, pycodestyle, flake8等第三方模块，pipenv有很漂亮的彩色终端界面。

三、Pipfile和Pipfile.lock

  • Pipfile, 简明地显示项目环境和依赖包

[[source]] name = "pypi" url = "https://mirrors.aliyun.com/pypi/simple/"  # 指定国内pip源，不然会慢死人的 verify_ssl = true [dev-packages]  # 开发环境 [packages]  # 生产环境 requests = "*"  # *表示最新版本 django = "*" [requires] python_version = "3.7"  # python版本

  • Pipfile.lock, 详细记录环境依赖，并且利用了Hash算法保证了它完整对应关系

{  "_meta": { "hash": { "sha256": "d737a1ef2f8b591f86cd0fa6a8cb48918f742d60df2a394ebc3d23aff4748999" }, "pipfile-spec": 6, "requires": { "python_version": "3.7" }, "sources": [ { "name": "pypi", "url": "https://pypi.org/simple", "verify_ssl": true } ] }, "default": { "certifi": { "hashes": [ "sha256:47f9c83ef4c0c621eaef743f133f09fa8a74a9b75f037e8624f83bd1b6626cb7", "sha256:993f830721089fef441cdfeb4b2c8c9df86f0c63239f06bd025a76a7daddb033" ], "version": "==2018.11.29" }, "chardet": { "hashes": [ "sha256:84ab92ed1c4d4f16916e05906b6b75a6c0fb5db821cc65e70cbd64a3e2a5eaae", "sha256:fc323ffcaeaed0e0a02bf4d117757b98aed530d9ed4531e3e15460124c106691" ], "version": "==3.0.4" }, "django": { "hashes": [ "sha256:a32c22af23634e1d11425574dce756098e015a165be02e4690179889b207c7a8", "sha256:d6393918da830530a9516bbbcbf7f1214c3d733738779f06b0f649f49cc698c3" ], "index": "pypi", "version": "==2.1.5" }, "idna": { "hashes": [ "sha256:c357b3f628cf53ae2c4c05627ecc484553142ca23264e593d327bcde5e9c3407", "sha256:ea8b7f6188e6fa117537c3df7da9fc686d485087abf6ac197f9c46432f7e4a3c" ], "version": "==2.8" }, "pytz": { "hashes": [ "sha256:32b0891edff07e28efe91284ed9c31e123d84bea3fd98e1f72be2508f43ef8d9", "sha256:d5f05e487007e29e03409f9398d074e158d920d36eb82eaf66fb1136b0c5374c" ], "version": "==2018.9" }, "requests": { "hashes": [ "sha256:502a824f31acdacb3a35b6690b5fbf0bc41d63a24a45c4004352b0242707598e", "sha256:7bf2a778576d825600030a110f3c0e3e8edc51dfaafe1c146e39a2027784957b" ], "index": "pypi", "version": "==2.21.0" }, "urllib3": { "hashes": [ "sha256:61bf29cada3fc2fbefad4fdf059ea4bd1b4a86d2b6d15e1c7c0b582b9752fe39", "sha256:de9529817c93f27c8ccbfead6985011db27bd0ddfcdb2d86f3f663385c6a9c22" ], "version": "==1.24.1" } }, "develop": {} }

四、虚拟环境管理

4.1 创建虚拟环境

进入项目的文件夹，直接pipenv install xxx安装你需要的包，就会在当前文件夹下创建虚拟环境，生成Pipfile和Pipfile.lock

[[email protected] ~]# cd myproject/ [[email protected] myproject]# pipenv install requests Creating a virtualenv for this project… Pipfile: /root/myproject/Pipfile Using /usr/local/python3/bin/python3.7 (3.7.2) to create virtualenv… ⠸ Creating virtual environment...Already using interpreter /usr/local/python3/bin/python3.7 Using base prefix '/usr/local/python3' New python executable in /root/.local/share/virtualenvs/myproject-zKJX12a5/bin/python3.7 Also creating executable in /root/.local/share/virtualenvs/myproject-zKJX12a5/bin/python Installing setuptools, pip, wheel... done. ✔ Successfully created virtual environment! Virtualenv location: /root/.local/share/virtualenvs/myproject-zKJX12a5 Creating a Pipfile for this project… Installing requests… ✔ Installation Succeeded Pipfile.lock not found, creating… Locking [dev-packages] dependencies… Locking [packages] dependencies… ✔ Success! Updated Pipfile.lock (444a6d)! Installing dependencies from Pipfile.lock (444a6d)…  ▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉ 5/5 — 00:00:04 To activate this project's virtualenv, run pipenv shell. Alternatively, run a command inside the virtualenv with pipenv run. [[email protected] myproject]# ll -al total 12 drwxr-xr-x.  2 root root   39 Jan 31 14:09 . dr-xr-x---. 17 root root 4096 Jan 31 14:08 .. -rw-r--r--.  1 root root  153 Jan 31 14:09 Pipfile -rw-r--r--.  1 root root 1914 Jan 31 14:09 Pipfile.lock [[email protected] myproject]#

如果需要指定python版本的话

$ pipenv --three # 泛指python的版本 $ pipenv --python 3.7 # 或者，特指某个python版本 $ pipenv --python <path/to/python> # 或者，特指某个位置的python

4.2 进入/退出/删除虚拟环境

[[email protected] myproject]# pipenv shell  # 进入虚拟环境 Launching subshell in virtual environment…  . /root/.local/share/virtualenvs/myproject-zKJX12a5/bin/activate [[email protected] myproject]#  . /root/.local/share/virtualenvs/myproject-zKJX12a5/bin/activate (myproject) [[email protected] myproject]# exit  # 退出虚拟环境 exit [[email protected] myproject]# pipenv --rm  # 删除整个环境 Removing virtualenv (/root/.local/share/virtualenvs/myproject-zKJX12a5)… [[email protected] myproject]#

有几点需要注意：

  • 平时安装和卸载包的时候不需要先进入或退出虚拟环境，直接在项目文件下pipenv install/uninstall xxx就行了

  • 退出虚拟环境不要deactivate，请使用exit，否则下次pipenv进入的时候就会报如下错

[[email protected] myproject]# pipenv shell Shell for UNKNOWN_VIRTUAL_ENVIRONMENT already activated. No action taken to avoid nested environments. [[email protected] myproject]#

  • pipenv --rm并不会删除生成的Pipfile和Pipfile.lock

4.3 管理开发环境

通常有一些Python包只在你的开发环境中需要，而不是在生产环境中，例如单元测试包。 Pipenv使用–dev标志区分两个环境。也就是说一个–dev参数，帮你在同一个虚拟环境中又区分出了开发和非开发环境。

$ pipenv install --dev pytest

在虚拟环境中运行命令，使用run参数，提供要运行的命令：

$ pipenv run python manage.py runserver

这将使用当前虚拟环境关联的Python解释器，执行命令。或者简单的执行脚本：

$ pipenv run python your_script.py

如果你不想每次运行Python时都输入这么多字符，可以在shell中设置一个别名，例如：

$ alias prp="pipenv run python"

冻结Pipfile，相当于将项目所使用的第三方库列表进行打包输出，类似于virtualenv中生成requirements.txt文件。通过更新Pipfile.lock来冻结库名称及其版本，以及其依赖关系的列表。需要使用lock参数：

[[email protected] myproject]# pipenv lock Locking [dev-packages] dependencies… Locking [packages] dependencies… ✔ Success! Updated Pipfile.lock (748999)! [[email protected] myproject]#

定位项目路径、虚拟环境、Python解释器，显示依赖关系，卸载包

[[email protected] myproject]# pipenv --where  # 定位项目路径 /root/myproject [[email protected] myproject]# pipenv --venv  # 定位虚拟环境 /root/.local/share/virtualenvs/myproject-zKJX12a5 [[email protected] myproject]# pipenv --py  # 定位Python解释器 /root/.local/share/virtualenvs/myproject-zKJX12a5/bin/python [[email protected] myproject]# pipenv graph  # 显示依赖关系 atomicwrites==1.2.1 attrs==18.2.0 Django==2.1.5  - pytz [required: Any, installed: 2018.9] more-itertools==5.0.0  - six [required: >=1.0.0,<2.0.0, installed: 1.12.0] py==1.7.0 requests==2.21.0  - certifi [required: >=2017.4.17, installed: 2018.11.29] - chardet [required: >=3.0.2,<3.1.0, installed: 3.0.4] - idna [required: >=2.5,<2.9, installed: 2.8] - urllib3 [required: >=1.21.1,<1.25, installed: 1.24.1] [[email protected] myproject]# pipenv uninstall --all  # 卸载所有包 Un-installing all [dev-packages] and [packages]… Found 12 installed package(s), purging… Uninstalling Django-2.1.5:  Successfully uninstalled Django-2.1.5 ...略... Environment now purged and fresh! [[email protected] myproject]#

4.4 有个大坑等你跳

pipenv有个缺点，lock不稳定而且时间非常长，所以安装包的时候记得加上--skip-lock，在最后开发完成要提交到仓库的时候再pipenv lock。希望将来的版本能够优化。

[[email protected] myproject]# pipenv install django --skip-lock Installing django… ✔ Installation Succeeded Installing dependencies from Pipfile…  ▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉▉ 2/2 — 00:00:02 [[email protected] myproject]#

五、常用命令汇总

pipenv具有下列的选项：

$ pipenv Usage: pipenv [OPTIONS] COMMAND [ARGS]... Options: --where 显示项目文件所在路径 --venv 显示虚拟环境实际文件所在路径 --py 显示虚拟环境Python解释器所在路径 --envs 显示虚拟环境的选项变量 --rm 删除虚拟环境 --bare 最小化输出 --completion 完整输出 --man 显示帮助页面 --three / --two 使用Python 3/2创建虚拟环境（注意本机已安装的Python版本） --python TEXT 指定某个Python版本作为虚拟环境的安装源 --site-packages 附带安装原Python解释器中的第三方库 --jumbotron An easter egg, effectively. --version 版本信息 -h, --help 帮助信息

pipenv可使用的命令参数：

Commands: check 检查安全漏洞 graph 显示当前依赖关系图信息 install 安装虚拟环境或者第三方库 lock 锁定并生成Pipfile.lock文件 open 在编辑器中查看一个库 run 在虚拟环境中运行命令 shell 进入虚拟环境 uninstall 卸载一个库 update 卸载当前所有的包，并安装它们的最新版本

六、在线练习

Pipenv playground是官方的在线练习网站：https://rootnroll.com/d/pipenv/，非常棒！

【Python】虚拟环境的创建和使用

[文章参考]

快速入门Python 最新最流行的pipenv虚拟环境

Pipenv: Python Dev Workflow for Humans

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