Python项目中,一般都会有一个 requirements.txt 文件,这个文件主要是用于记录当前项目下的所有依赖包及其精确的版本号,以方便在一个新环境下更快的进行部署,那么如何自动生成该文件?

使用 pip freeze 生成


一般情况,我们可以直接使用Python下的 pip 包管理工具,来生成 requirements.txt 文件,命令如下:

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PS C:\Users\liu.ziyi> pip freeze > E:\工作\git\Portal\partner\requestments.txt

其中,D:\pycharm\requirements.txt 为生成的 requirements.txt 文件的具体路径。通过这个 pip freeze 方式生成时,会把整个Python环境下的所有包都列出生成,比较适用于Python项目为虚拟环境的情况。

使用 pipreqs 生成


可以通过第三方库 pipreqs 来生成 requirements.txt 文件,这个方式有一个好处,那就是它可以只生成我们当前Python项目中所用到的依赖包及其版本号,而不是像 pip freeze 方式一样把所有包全部列出生成。

如果使用的IDE为pycharm,请勿直接在pycharm的terminal中安装,因为此时安装地址为当前虚拟环境,会导致其他项目无法使用pipreqs命令的问题,建议使用cmd进行全局安装。

安装pipreqs

直接通过pip安装pipreqs,如果下载速度慢,请更换pip安装源,可参考xxx:

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PS C:\Users\liu.ziyi> pip install pipreqs
Looking in indexes: https://mirrors.aliyun.com/pypi/simple/
Collecting pipreqs
Using cached https://mirrors.aliyun.com/pypi/packages/9b/83/b1560948400a07ec094a15c2f64587b70e1a5ab5f7b375ba902fcab5b6Collecting yarg
Using cached https://mirrors.aliyun.com/pypi/packages/8b/90/89a2ff242ccab6a24fbab18dbbabc67c51a6f0ed01f9a0f41689dc177419/yarg-0.1.9-py2.py3-none-any.whl (19 kB)
Collecting docopt
Using cached https://mirrors.aliyun.com/pypi/packages/a2/55/8f8cab2afd404cf578136ef2cc5dfb50baa1761b68c9da1fb1e4eed343c9/docopt-0.6.2.tar.gz (25 kB)
Requirement already satisfied: requests in c:\users\liu.ziyi\appdata\local\programs\python\python38\lib\site-packages (from yarg->pipreqs) (2.24.0)
Requirement already satisfied: chardet<4,>=3.0.2 in c:\users\liu.ziyi\appdata\local\programs\python\python38\lib\site-packages (from requests->yarg->pipreqs) (3.0.4)
Requirement already satisfied: idna<3,>=2.5 in c:\users\liu.ziyi\appdata\local\programs\python\python38\lib\site-packages (from requests->yarg->pipreqs) (2.10)
Requirement already satisfied: urllib3!=1.25.0,!=1.25.1,<1.26,>=1.21.1 in c:\users\liu.ziyi\appdata\local\programs\python\python38\lib\site-packages (from requests->yarg->pipreqs) (1.25.10)
Requirement already satisfied: certifi>=2017.4.17 in c:\users\liu.ziyi\appdata\local\programs\python\python38\lib\site-packages (from requests->yarg->pipreqs) (2020.6.20)
Building wheels for collected packages: docopt
Building wheel for docopt (setup.py) ... done
Created wheel for docopt: filename=docopt-0.6.2-py2.py3-none-any.whl size=13709 sha256=7a5caddc08c4957471a8af1f2b2091297471146ef486d26ecd5453c3c660157a
Stored in directory: c:\users\liu.ziyi\appdata\local\pip\cache\wheels\fd\fc\32\7eb069c258da9a405602bec74fa3bfe46251d39e2ea2843099
Successfully built docopt
Installing collected packages: yarg, docopt, pipreqs
Successfully installed docopt-0.6.2 pipreqs-0.4.10 yarg-0.1.9

使用pipreqs

pipreqs使用起来也很容易,命令使用方式为:pipreqs + Python项目的根目录。

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PS C:\Users\liu.ziyi> pipreqs E:\工\git\Portal\partner
Traceback (most recent call last):
File "c:\users\liu.ziyi\appdata\local\programs\python\python38\lib\runpy.py", line 193, in _run_module_as_main
return _run_code(code, main_globals, None,
File "c:\users\liu.ziyi\appdata\local\programs\python\python38\lib\runpy.py", line 86, in _run_code
exec(code, run_globals)
File "C:\Users\liu.ziyi\AppData\Local\Programs\Python\Python38\Scripts\pipreqs.exe\__main__.py", line 7, in <module>
File "c:\users\liu.ziyi\appdata\local\programs\python\python38\lib\site-packages\pipreqs\pipreqs.py", line 470, in main
init(args)
File "c:\users\liu.ziyi\appdata\local\programs\python\python38\lib\site-packages\pipreqs\pipreqs.py", line 406, in init
candidates = get_all_imports(input_path,
File "c:\users\liu.ziyi\appdata\local\programs\python\python38\lib\site-packages\pipreqs\pipreqs.py", line 122, in get_all_imports
contents = f.read()
UnicodeDecodeError: 'gbk' codec can't decode byte 0xac in position 1270: illegal multibyte sequence

在执行时,可能会出现上面提示编码方式不对的情况,为解决这个问题,我们可以在执行命令中指定编码方式为 utf-8 ,如下:

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PS C:\Users\liu.ziyi> pipreqs E:\工\git\Portal\partner --encoding=utf8
INFO: Successfully saved requirements file in E:\工\git\Portal\partner\requirements.txt

如果我们Python项目的根目录中已存在 requirements.txt ,那么使用上面命令就会出现警告:

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PS C:\Users\liu.ziyi> pipreqs E:\工作\git\Portal\partner --encoding=utf8
WARNING: Requirements.txt already exists, use --force to overwrite it

警告信息中的提示,告诉我们可以使用参数 –force 来覆盖重新生成 requirements.txt ,如下:

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PS C:\Users\liu.ziyi> pipreqs E:\工\git\Portal\partner --encoding=utf8 --force

执行requirement.txt

生成 requirement.txt 后,我们查看其发现是这样的格式:

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typing_extensions==3.7.4.2
pytest==6.0.1
SQLAlchemy==1.3.18
...

那么,对于 requirement.txt 中列出的第三方库,应该如何去执行并安装呢?安装方式很简单,我们通过 pip 工具,执行命令:pip install -r requirements.txt ,该命令会把 requirements.txt 文件中列出的库依次进行安装,最后等待安装完成即可。