Sample Git update hook that deploys the changed files to the web root.

update.py

#!/usr/bin/python

import logging
import git
import sys
import os

def main():
    """
    Update all files according to a diff.
    """
    # Configure logging.
    logger = logging.getLogger()
    logger.setLevel(logging.INFO)
    formatter = logging.Formatter('%(levelname)s: %(message)s')
    ch = logging.StreamHandler(sys.stdout)
    ch.setFormatter(formatter)
    logger.addHandler(ch)

    # Start.
    logging.info('Starting update hook.')
    repo = git.Repo()

    # Check arguments.
    logging.debug('Arguments: %s', sys.argv)
    assert len(sys.argv) == 4
    if sys.argv[2] == '0000000000000000000000000000000000000000':
        sys.argv[2] = repo.git.hash_object('-w', '-t', 'tree', os.devnull)
    if sys.argv[3] == '0000000000000000000000000000000000000000':
        sys.argv[3] = repo.git.hash_object('-w', '-t', 'tree', os.devnull)

    # Iterate over the diff.
    assert repo.bare == True
    diff = repo.git.diff('--name-status', sys.argv[2], sys.argv[3])
    tree = repo.commit(sys.argv[3]).tree
    for line in diff.split("\n"):
        if not line: continue

    status, file = line.split("\t", 1)
    assert status in ['A', 'D', 'M']
    target = get_target(file)
    logging.debug('%s %s -> %s', status, file, target)

    if target:
        if status == 'D':
            # Unlink file.
            os.unlink(target)
            logging.info('Deleted %s', target)
            # Remove parent dirs.
            try:
                os.removedirs(os.path.dirname(target))
                logging.info('Cleaned away parent of %s', target)
            except OSError:
                logging.debug('Did not clean away parent of %s', target)
      else:
          # Create directories.
          node = tree[file]
          assert isinstance(node, git.Blob)
          if status == 'A':
              try:
                  os.makedirs(os.path.dirname(target))
                  logging.info('Created directory for %s', target)
              except OSError:
                  logging.debug('Did not create directory for %s', target)
          # Write blob.
          node.stream_data(open(target, 'w'))
          logging.info('Wrote %s', target)
    else:
        logging.info('Ignored %s', target)

    # Done.
    logging.info('update hook finished.')

def get_target(file):
    """
    Returns the target by a given filename.
    """
    splitpath = file.split(os.sep)
    if splitpath[0] in ['www', 'local', 'tools', 'data']:
        return os.path.join('/var', file)
    else:
        return False

if __name__ == "__main__":
    main()