Updates git hashes in requirements.txt files based on current state of adjacent repositories.

update-requirements-hashes.py

#!/usr/bin/env python2.6
"""Updates git hashes in requirements.txt files based on current state of adjacent repositories.

Expects to be run inside directory containing requirements.txt to be updated.

Be sure to commit regularly:  Performs an in-place update of requirements.txt.
"""

import re
import sys
import os
import subprocess


GIT_REQUIREMENT_RE = re.compile(r'^\-e git\+(?P<url>.+)@(?P<rev>\w*)\#egg=(?P<egg>[\w\._-]+)')
GIT_REQUIREMENT_FORMAT = '-e git+{url:}@{rev:}#egg={egg:}\n'

def find_git_revision(egg):
    egg_path = os.path.join(os.pardir, egg)
    git_path = os.path.join(egg_path, '.git')
    p = subprocess.Popen(['git', '--git-dir={0}'.format(git_path), 'rev-parse', 'HEAD'], stdout=subprocess.PIPE)
    stdout, stderr = p.communicate()
    return stdout.strip()

REQUIREMENT_FORMATS = (
    (GIT_REQUIREMENT_RE, GIT_REQUIREMENT_FORMAT, find_git_revision),
)


def read_requirements():
    with open('requirements.txt', 'rU') as f:
        return f.readlines()


def main(args):
    new_requirements = []
    for requirement in read_requirements():
        for req_re, req_fmt, find_revision in REQUIREMENT_FORMATS:
            match = req_re.match(requirement)
            if match is not None:
                d = match.groupdict()
                new_rev = find_revision(d['egg'])
                if new_rev:
                    d['rev'] = new_rev
                else:
                    # Keep the same revision.
                    pass
                requirement = req_fmt.format(**d)
                break
            else:
                continue
        new_requirements.append(requirement)
    with open('requirements.txt', 'wb') as f:
        f.writelines(new_requirements)
    os.system('git diff requirements.txt')
    return 0


if __name__ == '__main__':
    args = sys.argv[1:]
    sys.exit(main(args))