Transparently open a file with open or gzip.open depending on file extension

open_file.py

import gzip
import logging

from contextlib import contextmanager


@contextmanager
def open_file(filename, *args, **kwargs):
    """
    Detect if a file is gzipped and use the appropriate open method.
    """
    if filename.endswith('.gz') or filename.endswith('.gzip'):
        logging.debug("Opening gzipped file {}".format(filename))
        open_func = gzip.open
    else:
        logging.debug("Opening plain file {}".format(filename))
        open_func = open

    with open_func(filename, *args, **kwargs) as f:
        yield f