如何检查导入python模块的原因？

Question

我有一个庞大的python模块库.有时,在导入模块时,我看到正在导入意外模块.为此,我一直在使用python -v,以查看正在导入哪些模块.从联机帮助页:

-v     Print  a  message  each  time a module is initialized, showing the place
       (filename or built-in module) from which it is loaded.  When given twice,
       print a message for each file that is checked for when searching for a
       module.  Also provides information on module cleanup at exit.

嗯,这不是真的.例如:

import portalmq # directory /home/blahblah/python_modules/portalmq
# /home/blahblah/python_modules/portalmq/__init__.pyc matches /home/blahblah/python_modules/portalmq/__init__.py
import portalmq # precompiled from /home/blahblah/python_modules/portalmq/__init__.pyc

如您所见,该-v标志只是向我提供有关导入哪些模块的信息,而不是关于哪个import语句,哪个文件/行触发导入.使用-vv不会改变任何东西(显示已尝试模块的列表,但没有关于为什么首先尝试导入)

但我需要确切地知道:哪个import语句,哪个文件/行触发那些导入.我怎样才能获得这些信息？

Answer 1

导入钩子!只需将此代码添加到主脚本入口点,即可在sys.meta_path.append执行后跟踪每个导入.

import traceback

class TracingFinder:
    def find_module(self, fullname, path=None):
        print 'loading module', fullname
        traceback.print_stack()

import sys
sys.meta_path.append(TracingFinder())

测试:

def foo():
    import test
    import this

foo()

输出:

loading module test
  File "moo.py", line 15, in <module>
    foo()
  File "moo.py", line 12, in foo
    import test
  File "moo.py", line 6, in find_module
    traceback.print_stack()
loading module this
  File "moo.py", line 15, in <module>
    foo()
  File "moo.py", line 13, in foo
    import this
  File "moo.py", line 6, in find_module
    traceback.print_stack()