a service layer use flask local stack

__init__.py

from functools import partial

from flask import Flask
from flask import current_app
from werkzeug.local import LocalProxy
from werkzeug.local import LocalStack

from .boto import Boto3Service
from .cognito import CognitoService

_thread_ctx = LocalStack()


def _lookup_thread_ctx_stack(cls, *deps):
    ctx = _thread_ctx.top

    if ctx is None:
        _thread_ctx.push(ctx := {})

    if cls not in ctx:
        ctx[cls.__name__] = cls(current_app, *deps)

    return ctx[cls.__name__]


def thread_context(cls, *deps):
    return LocalProxy(partial(_lookup_thread_ctx_stack, cls, *deps))


def setup(app: Flask):
    @app.teardown_appcontext
    def teardown(*_):
        ctx = _thread_ctx.top
        if ctx is None:
            return

        for name, value in ctx.items():
            if hasattr(value, "__teardown__"):
                value.__teardown__()


boto3: BotoService = thread_context(Boto3Service)  # type: ignore
cognito: CognitoContext = thread_context(CognitoService, boto3)  # type: ignore