Exception while calling 'pip.main(...)' from a Flask-Restful application

• Pip version: 9.0.1
• Python version: 2.7.10
• Operating system: Macos (Darwin Kernel Version 16.5.0)

Description:

I’m running an application using Flask-Restful (0.3.5), which exposes several APIs. I’m trying to uninstall a module using pip.main(['uninstall', '-y', '--log', 'pip.log','foobar']). This function returns 2, and the following exception is logged

Uninstalling foobar:
Exception:
Traceback (most recent call last):
  File "/Users/jmdacruz/workspace/App/build/virtualenv/lib/python2.7/site-packages/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/Users/jmdacruz/workspace/App/build/virtualenv/lib/python2.7/site-packages/pip/commands/uninstall.py", line 76, in run
    requirement_set.uninstall(auto_confirm=options.yes)
  File "/Users/jmdacruz/workspace/App/build/virtualenv/lib/python2.7/site-packages/pip/req/req_set.py", line 346, in uninstall
    req.uninstall(auto_confirm=auto_confirm)
  File "/Users/jmdacruz/workspace/App/build/virtualenv/lib/python2.7/site-packages/pip/req/req_install.py", line 754, in uninstall
    paths_to_remove.remove(auto_confirm)
  File "/Users/jmdacruz/workspace/App/build/virtualenv/lib/python2.7/site-packages/pip/req/req_uninstall.py", line 95, in remove
    with indent_log():
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/contextlib.py", line 17, in __enter__
    return self.gen.next()
  File "/Users/jmdacruz/workspace/App/build/virtualenv/lib/python2.7/site-packages/pip/utils/logging.py", line 34, in indent_log
    _log_state.indentation += num
AttributeError: 'thread._local' object has no attribute 'indentation'

What I’ve run:

pip.main(['uninstall', '-y', 'foobar'])
pip.main(['uninstall', '-y', '--log', 'pip.log','foobar'])
...

The command above returns 2 (which I think is UNKNOWN). I also tried replacing pip’s logger in memory instead of using the --log parameter to pip.main(...), but the result was the same. It seems that this could be solved with a failsafe here and here when the attribute indentation is not set on _log_state

[pfmoore]

Using pip’s internal functions from within another application is not supported, sorry. I suggest trying to run pip in a subprocess.

But please note that the behaviour of a running Python program if a module it’s using is uninstalled is not well defined. It’s quite possible that even if you run pip in a subprocess, your application may not behave as expected after the uninstall.

[xavfernandez]

Should we close this issue if using the internal functions is not supported?

Yup 🙂