Create a background scheduled task which will update the cache and auto update UI

Using Streamlit
,
1

Description

I want to create an app. When user clicks button, the app will create a background task. After a specific time interval, the task is completed. The task will change something and I want this change to auto appear in the UI. Here is a simple example code below.

import streamlit as st
import threading
from streamlit.runtime.scriptrunner import add_script_run_ctx


def task():
    st.session_state.counter += 1
    # want to auto update the website UI
    st.rerun()

if __name__ == "__main__":

    st.session_state.counter = 0

    if st.button("Click me."):
        # do not block the main thread
        interval = 3
        timer = threading.Timer(3, task)
        add_script_run_ctx(timer)
        timer.daemon = True
        timer.start()

    # you can do other things here
    st.write("Counter: ", st.session_state.counter)

Question

The code st.rerun() does not work as expected. I still need to manually rerun in the website.
I want the counter to update automatically while the main thread remains unblocked.

Can anyone help me?

2

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