How Can I Share Global Variables Between Python Modules Without Causing Circular Imports?

Global Variable Visibility in Imported Modules

Issue:

Importing modules can cause visibility issues when accessing global variables. When a global variable is defined in an auxiliary module but referred to in the main module, an error may occur indicating that the variable is not defined.

Requirement:

A Python program connecting to a MySQL database seeks to maintain a shared variable (a database cursor object) that is accessible to both the main module and imported modules containing utility functions.

Proposed Solution:

The proposed solution suggests importing the global variable from the main module into the imported utility module. However, this approach can result in circular imports and crashes.

Actual Solution:

There are multiple solutions to this issue:

Avoid Global Variables:

Consider converting the utility functions into instance methods of a class. This eliminates the need for a shared global variable.

Set the Global Variable in the Imported Module:

Define the global variable within the imported module using import instead of from. This allows the imported module to modify the variable if necessary.

Utilize an External Module for Shared Variables:

If the global variable is shared by multiple modules, place it in a separate module and have all the other modules import it. This ensures consistent access to the variable.

Add the Variable to the Builtin Module (Not Recommended):

For true global access, add the variable to the builtins module. However, this approach should be used with caution to avoid conflicts with existing builtins.

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