flask-jitsu, used backslashes, 'cause gist won't let me use proper ones

app.py

# Other Stuff
from lib import auth


app = Flask(__name__)
auth.init_app(app)


with app.app_context():
    auth.send_request('whatever')  # Same instance as below, but different context.


@app.route('/')
def index():
    return auth.send_request('nothing')  # Works always on the same instance of `auth`.
    
# Other Stuff

lib\__init__.py

from auth import Auth

auth = Auth()

lib\auth.py

from random import randint
from flask import current_app


class Auth(object):
    def __init__(self):
        self.i = randint(0, 666)
        
    def init_app(self, app):
        self.api_key = app.config['API_PUBLIC']
        self.pri_key = app.config['API_PRIVATE']
        
    def send_request(self, *args, **kwargs):
        # DO STUFF
        print(self.i, current_app.app_context())
        
        
################## OR


class Auth(object):
    def __init__(self):
        self.i = randint(0, 666)
        
    def send_request(self, *args, **kwargs):
        app = current_app
        api_key = app.config['API_PUBLIC']
        pri_key = app.config['API_PRIVATE']
        # DO STUFF
        print(self.i, current_app.app_context())

views\product.py

# Some Stuff

from lib import auth


@product_view.route('/products', methods=['GET'])
def prods_get():
    # Same instance of `auth` as in app.py, but different context.
    auth.send_request('sth')

Could also be solved by shaping directories structure like this: https://github.com/miguelgrinberg/microblog/tree/version-0.4.

But when you're stuck, you're stuck.