Error installing scikits.audiolab when using pytho

Question

I am trying to install scikits.audiolab with using the pip tool. Pip appears to run the command python setup.py egg_info from within the scikits.audiolab source directory. When it does so, I get this error:

Andrews-MacBook-Pro-2:scikits.audiolab-0.11.0 andrewhannigan$ pip install scikits.audiolab
Collecting scikits.audiolab
  Using cached scikits.audiolab-0.11.0.tar.gz
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 20, in <module>
      File "/private/var/folders/xb/qwlsm44s1wxfr82kytrgjtl80000gn/T/pip-build-vSZaU8/scikits.audiolab/setup.py", line 32, in <module>
        from numpy.distutils.core import setup
    ImportError: No module named numpy.distutils.core

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/xb/qwlsm44s1wxfr82kytrgjtl80000gn/T/pip-build-vSZaU8/scikits.audiolab

The issue is clearly that it can't import numpy.distutils.core. Looking at the setup.py script, this import happens early on (at the bottom of the snippet below):

#! /usr/bin/env python
# Last Change: Fri Mar 27 05:00 PM 2009 J

# Copyright (C) 2006-2007 Cournapeau David <[e-mail]>
#
# This library is free software; you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option) any
# later version.
#
# This library is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
# PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with this library; if not, write to the Free Software Foundation, Inc., 51
# Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

# TODO:
#   - check how to handle cmd line build options with distutils and use
#   it in the building process

from os.path import join
import os
import sys

# The following is more or less random copy/paste from numpy.distutils ...
import setuptools

from distutils.errors import DistutilsError
from numpy.distutils.core import setup

The odd part is that if I just run the above snippet of the setup.py script via python setup.py, I don't get the import error. How does the egg_info command line argument affect the way setup.py runs and why does it suddenly make python unable to import from numpy.distutils.core?

Answer 1

There's a problem in scikits.audiolab's setup.py file. Take a look at https://github.com/cournape/audiolab/blob/master/setup.py:

import os

# The following is more or less random copy/paste from numpy.distutils ...
import setuptools

from numpy.distutils.core import setup

The very first thing it does is import from numpy. If numpy is not installed, this is guaranteed to fail with the import error you shared.

I suspect that between your failed installation attempt and your successful installation, you installed numpy manually with pip install numpy. It's unlikely that egg_info had anything to do with it.

Here's a demonstration of how to work around this problem, taken from the scipy project's setup.py:

def setup_package():
    ...
    build_requires = []
    try:
        import numpy
    except:
        build_requires = ['numpy']

    metadata = dict(
        ...
        setup_requires = build_requires,
        install_requires = build_requires,
    )