using argparse to start flask server

Question

I have created a flask application and want to run the server($ python run.py ) but before that want to do some basic db tasks on running $ python run.py --init

Code (run.py):

def init():
    do_dbstuff()
    start_server()

def do_dbstuff():
    # doing db stuff

def start_server():
    app.run(host='127.0.0.1', port=8080, debug=True)

parser = argparse.ArgumentParser(description="Welcome to my server", prog="Simpleserver")

parser.add_argument('--init', dest='run_init', action='store_true', help="does db stuff and starts the server")
parser.add_argument('--dbstuff', dest='run_do_dbstuff', action='store_true', help="does db stuff")

args = parser.parse_args()

if args.run_init:
    init()
elif args.run_do_db_stuff:
    do_dbstuff()
else:
    start_server()

Above code works, but the problem is when the server gets started init() function is called again( want it to run only once).

Why is that happening?

Thanks

For debugging I'd do a `print args` right after parsing. If that is correct, and doesn't repeat, it rules out any `argparse` issues. — hpaulj, Nov 03 '15 at 10:36
When you run Flask with the reloader, [it runs twice](http://stackoverflow.com/questions/25504149/why-does-running-the-flask-dev-server-run-itself-twice). — dirn, Nov 03 '15 at 12:11

score 2 · Answer 1 · answered Nov 03 '15 at 10:36

2

Isn't your script lacking something like this:

if __name__ == "__main__":
    args = parser.parse_args()
    if args.run_init:
        init()
    elif args.run_do_db_stuff:
        do_dbstuff()
    else:
        start_server()

IMHO you have another python file that is importing "run.py" and this is why your function is run twice. Remember that python code is executed when imported as a module.

answered Nov 03 '15 at 10:36

Morreski

302
1
5

you are right about using `if __name__...` line but i am not importing run.py anywhere, i mentioned in the ques, and i don't see any reason why would this be a reason for function being called twice. Also, i checked, it doesn't solve my problem. – Deepak Nov 03 '15 at 10:47
It could have been that because as it is said in this thread: That's how python works: http://stackoverflow.com/questions/6523791/why-is-python-running-my-module-when-i-import-it-and-how-do-i-stop-it – Morreski Nov 03 '15 at 11:05

using argparse to start flask server

1 Answers1