Question

I have a web app in python and there is a main file that is a router.

The router reads the path and should:

1. only now import the module needed for the request, or
2. call the method directly. (In this case all modules needed by the app are imported at the beginning of the file)

In the first case:

router(path, args):
    // now import the module needed and run it

In the second case the app would look like:

from services.a import a1
from services.a import a2
from services.a import a3
from services.a import a4
from services.a import a5
from services.a import a6
// and then in the router function

rooter(path, args):
   // based on the path will call a fn
   a1(args...)

What is better?

Answer 1

From PEP 8, “Style Guide for Python Code”:

Imports are always put at the top of the file, just after any module comments and docstrings, and before module globals and constants.

Unless you have a good reason to violate this, follow it.