Linux 强制 python 使用旧版本的模块（比我现在安装的版本）
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Force python to use an older version of module (than what I have installed now)
提问by Mike Pennington
My employer has a dedicated module1we use for internal unit / system test; however, the author of this module no longer works here and I have been asked to test some devices with it.
我的雇主有一个专门的模块1，我们用于内部单元/系统测试；然而，这个模块的作者不再在这里工作，我被要求用它测试一些设备。
The problem is that pyfoorequires an ancient version of twisted(v8.2.0) and it imports twistedin 33 different files. I tried running pyfoo's unit tests under v11.0.0 and I don't even see TCP SYN packets2. Unfortunately, I have already got twisted v11.0.0installed on my lab linux server and I have my own code that depends on it.
问题是它pyfoo需要一个古老的twisted(v8.2.0)版本，它导入twisted了 33 个不同的文件。我尝试pyfoo在 v11.0.0 下运行单元测试，我什至没有看到 TCP SYN 数据包2。不幸的是，我已经在我的实验室 linux 服务器上安装了Twisted v11.0.0，并且我有自己的代码依赖于它。
I have been wracking my brain for a way around this, but I can only come up with the following options:
我一直在绞尽脑汁想办法解决这个问题，但我只能想出以下选项：
Option A. Install a new version of python, install virtualenv, and then install an old version of twistedunder the virtualenv. Only run the tests requiring pyfoounder this new version of python.
选项A。安装新版本的python，安装virtualenv，然后twisted在virtualenv. 只运行pyfoo在这个新版本的 python 下需要的测试。
Option B. Edit all 33 of the files with the following: DIR = '../'; sys.path.insert(0, DIR)and install the old version of python in the appropriate directory below the source.
选项B。使用以下内容编辑所有 33 个文件：DIR = '../'; sys.path.insert(0, DIR)并将旧版本的 python 安装在源代码下的相应目录中。
Option C. Attempt to fix pyfooto use v11.0.03
选项C。尝试修复pyfoo使用 v11.0.0 3
Are there any options I am missing? Is there a more elegant way to solve this problem, besides Option A, above?
有没有我缺少的选项？除了上面的选项A之外，还有没有更优雅的方法来解决这个问题？
END-NOTES:尾注：
- Let's call it
pyfoofor sake of argument - The unit tests connect to one of our local lab servers and exercises basic telnet functionality
- This option is almost a non-starter...
pyfoois not trivial, and I have a short deadline for this work.
pyfoo为了争论，让我们称之为- 单元测试连接到我们的本地实验室服务器之一并练习基本的 telnet 功能
- 这个选项几乎
pyfoo是不可能的……不是微不足道的，而且我有一个很短的期限来完成这项工作。
采纳答案by SingleNegationElimination
A better version of option B. would be to replace
选项 B 的更好版本是替换
import twisted
by
经过
import pkg_resources
pkg_resources.require("Twisted==8.2.0")
import twisted
which will arrange for the correct version of twisted to be imported, so long as it's installed, and raises an exception otherwise. This is a more portable solution.
这将安排导入正确版本的扭曲，只要它已安装，否则引发异常。这是一个更便携的解决方案。
This won't work, though (nor would any other variaton of option B), if twisted gets imported before the pkg_resources.requiregets called; twistedwill already be in sys.modules
但是，如果pkg_resources.require在调用之前导入了twisted，这将不起作用（选项B 的任何其他变体也不会）；twisted已经在sys.modules
OP Edit: Minor syntax correction, per pkg_resourcesdocs
OP 编辑：根据文档进行少量语法更正pkg_resources
回答by Gerrat
I can't tell you what is best in your situation, but you might be able to consider:
我无法告诉您在您的情况下什么是最好的，但您可以考虑：
Option D: run it in a virtual machine (eg. with Windows 7)
选项 D：在虚拟机中运行（例如使用 Windows 7）
Option E: install old version of python/twisted on another machine
选项 E：在另一台机器上安装旧版本的 python/twisted
回答by jmetz
If SingleNegationElimination's solution doesn't work, be aware that you don't need to replace all 33 instances of the import; you only need to modify sys.pathat the entry points; e.g. you could target just your module's __init__.pyfiles.
如果 SingleNegationElimination 的解决方案不起作用，请注意您不需要替换导入的所有 33 个实例；您只需要sys.path在入口点进行修改；例如，您可以只针对您的模块__init__.py文件。
There you would insert e.g.
在那里你会插入例如
import sys
sys.path.insert(0, DIR)
