python - 为什么 twistd 不能从当前工作目录中导入模块？

Question

请考虑以下测试用例。

项目目录结构如下:

foo
├── foo
│   ├── __init__.py
│   └── bar.py
└── test.tac

bar.py包含一个简单的类定义:

# bar.py
class Bar:
    pass

test.tac ，Twisted 应用程序配置文件，包含一个导入语句:

#test.tac
from foo.bar import Bar

运行时twistd -ny test.tac ，我收到以下错误:

$ twistd -ny test.tac
Unhandled Error
Traceback (most recent call last):
  File "/Users/lthibault/.pyenv/versions/3.6.2/lib/python3.6/site-packages/twisted/application/app.py", line 674, in run
    runApp(config)
  File "/Users/lthibault/.pyenv/versions/3.6.2/lib/python3.6/site-packages/twisted/scripts/twistd.py", line 25, in runApp
    runner.run()
  File "/Users/lthibault/.pyenv/versions/3.6.2/lib/python3.6/site-packages/twisted/application/app.py", line 381, in run
    self.application = self.createOrGetApplication()
  File "/Users/lthibault/.pyenv/versions/3.6.2/lib/python3.6/site-packages/twisted/application/app.py", line 453, in createOrGetApplication
    application = getApplication(self.config, passphrase)
--- <exception caught here> ---
  File "/Users/lthibault/.pyenv/versions/3.6.2/lib/python3.6/site-packages/twisted/application/app.py", line 464, in getApplication
    application = service.loadApplication(filename, style, passphrase)
  File "/Users/lthibault/.pyenv/versions/3.6.2/lib/python3.6/site-packages/twisted/application/service.py", line 416, in loadApplication
    application = sob.loadValueFromFile(filename, 'application')
  File "/Users/lthibault/.pyenv/versions/3.6.2/lib/python3.6/site-packages/twisted/persisted/sob.py", line 177, in loadValueFromFile
    eval(codeObj, d, d)
  File "test.tac", line 1, in <module>
    from foo.bar import Bar
builtins.ModuleNotFoundError: No module named 'foo'


Failed to load application: No module named 'foo'

这非常令人惊讶，因为 python test.tac不会产生错误。为了进一步调试，我修改了test.tac如下:

from sys import path
print(path)
from foo.bar import Bar

这表明正在运行 python <filename>在运行 twistd <filename> 时将当前工作目录添加到路径中没有。

我的问题有两个:

1. 这是一个错误，还是有充分的理由 twistd以这种方式行事？
2. 在 twistd 中推荐的修复此问题的方法是什么？ .我可以设置某种选项还是需要手动完成？

Answer 1

此代码段会将包含 tac 文件的目录添加到 python 路径

import os
import sys

sys.path.append(os.path.abspath(os.path.dirname(__file__)))

from foo.bar import Bar