whip.py

#!/usr/bin/env python3

import sys
import os
import os.path
import argparse

import subprocess

DEVNULL = open(os.devnull, 'wb')

class whip(object):
  def __init__(self, path, assign, revoke, verbose):
    self.verbose = verbose

    normalized_path = self._normalize_path(path)
    if not self._repo_initialized(normalized_path):
      self._create_repo(normalized_path)

    for user, perm in self._parse_perms(assign).items():
      self._grant_perms(normalized_path, user, perm)
    for user in revoke:
      self._grant_perms(normalized_path, user)

  def _normalize_path(self, path):
    return os.path.normpath(os.path.join(os.getcwd(), path))

  def _create_repo(self, path):
    os.chmod(path, 0o0700)
    try:
      self._silent_call('git init --bare {0}'.format(path))
    except subprocess.CalledProcessError:
      sys.stderr.write('error: could not initialize repository at {0}\n'.format(path))
    else:
      if self.verbose > 0:
        sys.stdout.write('> repository was initialized at {path}\n'.format(path=path))

  def _grant_perms(self, path, user, perm):
    try:
      self._silent_call('setfacl -R -m {user}:{perm} {repo}'.format(user=user, perm=perm, repo=path))
      self._silent_call('setfacl -d -R -m {user}:{perm} {repo}'.format(user=user, perm=perm, repo=path))
    except subprocess.CalledProcessError:
      sys.stderr.write('error: could not set permissions for user {user}\n'.format(user=user))
    else:
      if self.verbose > 0:
        sys.stdout.write('+ {user} gained {perm} permissions on {repo}\n').format(user=user, perm=perm, repo=path)

  def _revoke_perms(self, path, user):
    try:
      self._silent_call('setfacl -R -x {user} {repo}'.format(user=user, repo=path))
      self._silent_call('setfacl -d -R -x {user} {repo}'.format(user=user, repo=path))
    except subprocess.CalledProcessError:
      sys.stderr.write('error: could not revoke permissions for user {user}\n'.format(user=user))
    else:
      if self.verbose > 0:
        sys.stdout.write('- {user} lost all permissions to {repo}\n'.format(user=user, repo=path))

  def _parse_perms(self, assign):
    return dict(perm.split(':', 2) if ':' in perm else (perm, 'rwX') for perm in assign)

  def _repo_initialized(self, path):
    return os.path.exists(os.path.join(path, '.git/'))

  def _silent_call(self, command):
    subprocess.check_call(command, shell=True, stdout=DEVNULL, stderr=DEVNULL)

if __name__ == '__main__':
  parser = argparse.ArgumentParser(description='A tool for whipping up shared repositories.')
  parser.add_argument('path', default=os.getcwd(), nargs='?',
                      help='path to repository')
  parser.add_argument('-a', '--assign', nargs='*', default=[],
                      help='one or more permission strings separated by spaces')
  parser.add_argument('-r', '--revoke', nargs='*', default=[],
                      help='one or more user names separated by spaces')
  parser.add_argument('-v', '--verbose', action='count', default=0,
                      help='how chatty to be')

  args = parser.parse_args()
  whip(args.path, args.assign, args.revoke, args.verbose)