Importing variable names into class namespace

Question

Is it possible to import global variables into an object's instance namespace?

In a structure like this:

./mypackage/module1.py
./config.py
./script1.py

If config.py has:

#config
MYSETTING=1

and script1.py has:

#SCRIPT1
from config import *
from mypackage.mymodule import MyClass as MC

obj=MC()

module1.py:

#Myclass
class MyClass(object):
    def test(self):
        print MYSETTING

will give error NameError: global name "MYSETTING" is not defined

Is there some way I can import variables from config.py into MyClass namespace as globals without doing enumerated "global x" on each of them?

@juanpa.arrivillaga But is it normal practice to import from parent directory? Can I do in module1.py `from ..config import *` then? — Gnudiff, Jan 24 '18 at 08:31
sure. I would instead opt for `import config` and then use the `config.MYSETTING` instead of a starred import. — juanpa.arrivillaga, Jan 24 '18 at 08:32
@juanpa.arrivillaga I get `ValueError: Attempted relative import beyond toplevel package` — Gnudiff, Jan 24 '18 at 08:32
@juanpa.arrivillaga No, the config.py is in parent directory. If I do single point it gives `ImportError: No module named config` — Gnudiff, Jan 24 '18 at 08:36
Basically, what I want is to refer to certain global settings throughout all of my code as globals, no matter whether I refer to them from inside module or from script using that module. — Gnudiff, Jan 24 '18 at 08:38
then add the directory that contains `config.py` to your PATH, or cut the Gordian knot and pass the settings to your class/method. — juanpa.arrivillaga, Jan 24 '18 at 08:39

score 0 · Answer 1 · answered Jan 24 '18 at 08:35

This problem is a little confusing. There are three parts.

config: contains variables you want.

script: contains your logical code and variables imported from config.

module: contains functions' definition.

When you call MC.test, it will find MYSETTING in module's namespace, but what you want is to find in script's namespace. So in test function, what you real want is to access parent frame's global namespace.

In this case, you need to use inspect built-in module.

import inspect

print(inspect.current_frame().f_back.f_globals["MYSETTING"])

inspect.current_frame() will return current frame, and f_back refers to parent frame which is the frame calling this function, then f_globals refers to frame's globals()

Importing variable names into class namespace

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