Will there be problems when writing to JSON from FLASK?

Question

Python

I am writing a small web project for the purpose of education.
There was such a question. Will I have problems if several users send the corresponding post request at the same time, which calls the function (it writes to the json file). After all, as I understand it, a new thread is allocated for each user and several threads will get access to the same file at once. Will some of the information be lost in this case?write_json(data['object'])

from flask import Flask, json, request

from config import secret,
from message_handler import write_json


app = Flask(__name__)


@app.route('/')
def hello_world():
    return 'Hello from Flask!'


@app.route('/', methods=['POST'])
def processing():
    data = json.loads(request.data)

    if data['secret'] == secret:
        write_json(data['object'])
        return 'ok'

Answer 1

Flask is single-threaded, requests are handled by a pool of processes. But in any case, some kind of lock is needed when accessing shared data.