WSGI middleware storing request env. in the thread, it will work with Django, Flask, Fast API

middleware.py

# A middlware that stores the envrionement dict inside the current
# thread, implement a get_request_id method for easy retrieval

from threading import local

_threadlocals = local()
_threadvariables = set()


def set_thread_variable(key, val):
    _threadvariables.add(key)
    setattr(_threadlocals, key, val)


def get_thread_variable(key, default=None):
    return getattr(_threadlocals, key, default)


def get_request_id():
    environ = get_thread_variable('environ')
    return environ.get('HTTP_X_REQUEST_ID', '-')


class thread_environ():
    '''
    WSGI middleware that saves the environnement variable
    on the thread
    '''
    def __init__(self, app):
        self.app = app

    def __call__(self, environ, start_response):
        set_thread_variable('environ', environ)
        
        return self.app(environ, start_response)
    
    
##### later on in the Flask application setup

import requests
import time
from flask import Flask, request
import logging
import sys
from middleware import thread_environ, get_request_id, get_thread_variable


app = Flask(__name__)

# SETUP the WSGI middlware here
app.wsgi_app = thread_environ(app.wsgi_app)


@app.route("/")
def hello():
    print(get_request_id())
    print(get_thread_variable('environ').get('HTTP_CACHE_CONTROL'))
    time.sleep(1)
    return "<h1 style='color:blue'>Hello There!</h1>"