Update variable value in variables Python file

Question

I have a variables.py file with a key TOKEN= 123456. I need to update that value dynamically when ever it required.

The file Constants.py reads:

#!/usr/bin/env python
# encoding: utf-8
"""
variables.py
"""

TOKEN= 50

And refresh_tok.py

#!/usr/bin/env python
# encoding: utf-8
"""
refresh_tok.py
"""
import variables

def refresh_token():
    print(variables.TOKEN) // previous value 50
    change_constant(variables.TOKEN, 100)
    print(variables.TOKEN) // value I am expecting is 100 but it says 50


def change_constant(match_string, replace_string):
    read_file = open("variables.py", "rt")
    read_data = read_file.read()
    read_data = read_data.replace(match_string, replace_string)
    read_file.close()
    
    write_file = open("variables.py", "wt")
    write_file.write(read_data)
    write_file.close()

Value that I am expecting in 2nd print statement in refresh_tok.py is 100 but it is still on previous value and print 50 rather then 100.

I would suggest going through the inspect module: docs.python.org/3/library/inspect.html maybe you'll find it helpful :) — Novus Edge
– Novus Edge, Commented Dec 23, 2020 at 6:35
Python source code is not the right place to store dynamic data. Use a JSON file or similar! — Klaus D.
– Klaus D., Commented Dec 23, 2020 at 6:38

juanpa.arrivillaga · Accepted Answer · 2020-12-23 06:39:19Z

1

You seem to have a fundamental misunderstanding about the nature of computer programs.

Your change_constant function reads the source code from a file as a string, creates a new string which changes that source code, then writes that new string to the same file. This will never affect the module that you've loaded. This is very important to understand.

Instead, all you need to do is:

variables.TOKEN = new_value

Of course, this only affects the running process. If you need to persist these changes, then you need to choose some sort of persistence strategy, e.g. writing to a file. It is generally not a good practice to use python source code for this, instead, use some suitable serialization format, e.g. JSON, pickle, INI-like config files, YAML, etc etc (or even if it is very simple just a text file).

answered Dec 23, 2020 at 6:39

juanpa.arrivillaga

97.6k14 gold badges141 silver badges190 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Update variable value in variables Python file

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related