How to set custom output handlers for argparse in Python?

Question

I have configured logger to print both onto terminal stdout and to a file so I can have an archive of logging messages that I can refer to.

Tha

Answer 1

Looking at the argparse.py source code there doesn't seem to be a way to configure this behaviour.

My suggestion(s) would be:

• File a bug report with a patch :)

Override/patch:

• print_* method(s)
• error method.

The print_* method(s) seem to take an optional file argument which defaults to _sys.stdout.

Update: Alternatively you could do something like this whereby you redirect sys.stdout temporarily while you parse arguments:

from contextlib import contextmanager

@contextmanager
def redirect_stdout_stderr(stream):
    old_stdout = sys.stdout
    old_stderr = sys.stderr
    sys.stdout = stream
    sys.stderr = stream
    try:
        yield
    finally:
        sys.stdout = old_stdout
        sys.stderr = old_stderr


with redirct_stdout_stderr(logstream):
    args = parser.parse_args()