subprocess.Popenでgit ref: http://qiita.com/kazufusa/items/d3da5354be5d75926a5b

git_submodule_update.py

# vim: set fileencoding=utf-8 :
# Created:  2014-01-19
# Git submodule update within python subprocess
import os
import subprocess


GIT = "git"
SUBMODULE = "submodule"
FOREACH = "foreach"


class Git(object):
    def __init__(self):
        self._dir = ""
        pass

    @property
    def dir(self):
        return self._dir

    @dir.setter
    def dir(self, dir):
        self._dir = dir

    def submodule_update(self):
        pr = subprocess.Popen([GIT, SUBMODULE, FOREACH, 'git checkout master; git pull'],
                              cwd=os.path.dirname(self.dir),
                              stdout=subprocess.PIPE,
                              stderr=subprocess.PIPE,
                              shell=False)
        (out, error) = pr.communicate()
        return out, error

if __name__ == "__main__":
    APP_ROOT = os.path.dirname(os.path.abspath(__file__))
    dir = os.path.join(APP_ROOT, ".git")
    git = Git()
    git.dir = dir
    git.submodule_update()