Error message "python-pylint 'C0103:Invalid constant name"

As explained by Kundor, PEP 8 states that:

Constants are usually defined on a module level and written in all capital letters with underscores separating words.

The point is that "constants" in Python don't really exist. Pylint, as per PEP 8, expects module level variables to be "constants."

That being said you've several options:

• you don't want this "constant" thing, then change Pylint's const-rgx regular expression to be the same as e.g. variable-rgx,

• you may deactivate those warnings for this file, or even locally in the file, using # pylint: disable=invalid-name,

• avoid module level variables, by wrapping them into a function.

In your case, I would go with the third option, by creating a build_app function or something similar. That would return the application (and maybe the 'db' object as well, but you have several choices there). Then you could add a salt of the second option to get something like:

app = build_app() # pylint: disable=invalid-name

The fact that PEP 8 considers only constants at the module level is probably the reason why many developers use a dedicated main() function.

So you could solve your problem like this:

def main():
    app = Flask(__name__)
    app.config['SECRET_KEY'] = 'hard to guess string'
    app.config['SQLALCHEMY_DATABASE_URI'] = 'mysql://root:@localhost:3306/test?'
    app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True
    app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True

    bootstrap = Bootstrap(app)
    moment = Moment(app)
    db = SQLAlchemy(app)
    db.create_all()
    app.run()

if __name__ == '__main__':
    main()

PEP 8 decrees that names of constants should be in all caps.

So, rename those variables to be all caps.

Tip: if you google 'C0103' it'll take you to the Pylint messages wiki entry for that message, with details on it.