How to know if the singleton function has been called before

šŸŽˆ Using Streamlit
1

I want to have a heavy object shared between all connected users. The singleton does this for me:

@st.experimental_singleton
def get_big_database(url):
   ...

but additionally Iā€™d like to have this behaviour: if youā€™re the first user opening the app, i.e. no one has given the database url and therefore get_big_database() hasnā€™t been called before, then display a bunch of widgets like text input for entering database URL and a button that is connected to get_big_database(). Otherwise I want to display something like ā€œDatabase already loaded: {URL}ā€.

Is there an easy way to do this? i.e. Iā€™m looking for something like a global_state instead of session_state

2

Hi @milad, we actually have something like global_state on the roadmap! The next frontier for Streamlit For now, the best alternative, if youā€™re running your app on Streamlit Cloud you could use a lightweight third-party database for keeping track of something like this ā€“ here are some options to consider Connect to data sources - Streamlit Docs

If youā€™re working locally, or on a permanent machine that you control, you could do something as simple as saving a little file to your disk that keeps track of whether the database has been loaded.

Hope thatā€™s helpful