How do I get Flask to run on port 80?

Question

I have a Flask server running through port 5000, and it's fine. I can access it at http://example.com:5000

But is it possible to simply access it at http://example.com? I'm assuming that means I have to change the port from 5000 to 80. But when I try that on Flask, I get this error message when I run it.

Traceback (most recent call last):   File "xxxxxx.py", line 31, in <module> app.run(host="0.0.0.0", port=int("80"), debug=True)    File "/usr/local/lib/python2.6/dist-packages/flask/app.py", line 772, in run run_simple(host, port, self, **options)   File "/usr/local/lib/python2.6/dist-packages/werkzeug/serving.py", line 706, in run_simple     test_socket.bind((hostname, port))   File "<string>", line 1, in bind socket.error: [Errno 98] Address already in use 

Running lsof -i :80 returns

COMMAND   PID     USER   FD   TYPE   DEVICE SIZE/OFF NODE NAME apache2   467     root    3u  IPv4 92108840      0t0  TCP *:www (LISTEN) apache2  4413 www-data    3u  IPv4 92108840      0t0  TCP *:www (LISTEN) apache2 14346 www-data    3u  IPv4 92108840      0t0  TCP *:www (LISTEN) apache2 14570 www-data    3u  IPv4 92108840      0t0  TCP *:www (LISTEN) apache2 14571 www-data    3u  IPv4 92108840      0t0  TCP *:www (LISTEN) apache2 14573 www-data    3u  IPv4 92108840      0t0  TCP *:www (LISTEN) 

Do I need to kill these processes first? Is that safe? Or is there another way to keep Flask running on port 5000 but have the main website domain redirect somehow?

Answer 1

1- Stop other applications that are using port 80. 2- run application with port 80 :

if __name__ == '__main__':       app.run(host='0.0.0.0', port=80) 

Answer 2

For externally visible server, where you don't use apache or other web server you just type

flask run --host=0.0.0.0 --port=80