Write file with specific permissions in Python

Question

I\'m trying to create a file that is only user-readable and -writable (0600).

Is the only way to do so by using os.open() as follows?

Answer 1

I'd do differently.

from contextlib import contextmanager

@contextmanager
def umask_helper(desired_umask):
    """ A little helper to safely set and restore umask(2). """
    try:
        prev_umask = os.umask(desired_umask)
        yield
    finally:
        os.umask(prev_umask)

# ---------------------------------- […] ---------------------------------- #

        […]

        with umask_helper(0o077):
            os.mkdir(os.path.dirname(MY_FILE))
            with open(MY_FILE, 'wt') as f:
                […]

File-manipulating code tends to be already try-except-heavy; making it even worse with os.umask's finally isn't going to bring your eyes any more joy. Meanwhile, rolling your own context manager is that easy, and results in somewhat neater indentation nesting.