I used to Python logging, it works fine. The logging.basicConfig(...) set in one module (a some.py file), then we can use logging every where. Obviously, logging is global.

The question is how logging find it's settings, when we not call the module where basicConfig(...) appeared (in some.py file )? Is logging scan all the packages?

Even the logging.basicConfig(...) put into an any.py and the module (any.py) never get imported, or not used anywhere, the logging setting take effect!

• python
• logging

To understand logging you have dive into Python's standard library sources.

Here is the trick:

#/usr/lib/python3.2/logging/__init__.py
...
root = RootLogger(WARNING)
Logger.root = root
Logger.manager = Manager(Logger.root)
...

# and 
def basicConfig(**kwargs):
    ...
        hdlr = StreamHandler(stream)
        fs = kwargs.get("format", BASIC_FORMAT)
        dfs = kwargs.get("datefmt", None)
        style = kwargs.get("style", '%')
        fmt = Formatter(fs, dfs, style)
        hdlr.setFormatter(fmt)
        root.addHandler(hdlr)

So, when you call basicconfig() with certain parameters, root logger is set. Finally getLogger:

def getLogger(name=None):
    """
    Return a logger with the specified name, creating it if necessary.

    If no name is specified, return the root logger.
    """
    if name:
        return Logger.manager.getLogger(name)
    else:
        return root

I think there is no magic scanning here.

• Try to test it this way in a separate test directory:

  
  test/main.py:
      import logging
      logging.info('test')
  
  
  test/any.py:
      import logging
      logging.basicConfig(filename='test.log', level=logging.INFO)
  
  python main.py
  

  Result: NO test.log file.

• Now let's update the test:

  
  test/main.py:
      import logging
      import any
      logging.info('test')
  
  
  python main.py
  

  Result: new test.log file with INFO:root:test string inside.

• So I guess that any.py in your case is imported somehow, despite your expectations.

  You may find the way any.py is imported easily, just add few lines there:

  
  test/any.py:
      from traceback import print_stack
      print_stack()
      ...
  
  
  python main.py
  

  Result:

  
  File "main.py", line 2, in 
      import any
  File "any.py", line 2, in 
      print_stack()
  

  This stack shows that any.py is imported from main.py.

  I hope you will find where it is imported from in your case.