git: configures git to filter / clear the output of ipython notebooks

add_filter.py

#!/usr/bin/python
# coding: utf-8
"""
    configures git to filter / clear the output of ipython notebooks by
    patching the .git/config and .gitattributes and adding 'filter_notebook' as filter
"""
import os
import sys
import warnings
import distutils.spawn


__author__ = 'Henning Dickten'


def add_filter(repopath=os.path.curdir):
    "main routine"
    # check if filter_notebook is in PATH
    if distutils.spawn.find_executable('filter_notebook', path=None) is None:
        warnings.warn('filter_notebook not in PATH')
        sys.exit(os.errno.ENOPKG)

    # check for git
    if not os.path.exists(os.path.join(repopath, '.git')):
        warnings.warn('.git directory not found! EXIT.')
        sys.exit(os.errno.ENOENT)

    # patch .git/config
    with open(os.path.join(repopath, '.git', 'config'), 'r') as fobj:
        config = [line.rstrip('\r\n') for line in fobj.readlines()]

    line = '[filter "filter_notebook"]'

    if line not in config:
        with open(os.path.join(repopath, '.git', 'config'), 'w') as fobj:
            print('patching %s ...' % fobj.name)
            config.append(line)
            config.append('\tclean = "./filter_notebook"')
            fobj.writelines([line + '\n' for line in config])

    # add .gitattributes
    with open(os.path.join(repopath, '.gitattributes'), 'a+') as fobj:
        attributes = [line.rstrip('\r\n') for line in fobj.readlines()]

    line = '*.ipynb filter=filter_notebook'

    if line not in attributes:
        with open(os.path.join(repopath, '.gitattributes'), 'w') as fobj:
            print('patching %s ...' % fobj.name)
            attributes.append(line)
            fobj.writelines([line + '\n' for line in attributes])

    print('done!\n')


if __name__ == '__main__':
    if len(sys.argv) == 2:
        add_filter(sys.argv[1])
    elif len(sys.argv) == 1:
        add_filter()
    else:
        print("usage: %s [path to repository]\n" % sys.argv[0])