How to clear cache using code?

Summary

I have a login/signup page. After logging in I store my user_name as session variable. When I want to logout, I click the log out button, and delete the session_variable (user_name). But now if I want to log back in, the same previous user is still logged in.

If I refresh the page, the session_variable get deleted and I can login with another user. I want to achieve this without reloading the page.

There is a CLI command to clear the cache streamlit cache clear but I have not had luck yet using os.system('streamlit cache clear') since it doesn’t appear to be pointing to the right cache location. I am playing around now to see if I can figure this out. Not sure if the new cache primitives being added into the mix changed how this command functions or if there is some other mismatch that happened over time.

In my local environment, it wants to clear cache from C:\Users\<username>\.streamlit\cache but I’m using an environment so I don’t think that’s right. When I run the command in Streamlit Cloud it tries to clear cache from /home/appuser/.streamlit/cache. In both cases it reports there is “nothing to clear” and indeed I don’t see anything cleared. I’ll update here if I find something that works.

Side note: if you only wish to empty out session state and not the actual cached function results, there is always manually removing keys from st.session_state as a low-tech option.

def clear_cache():
    keys = list(st.session_state.keys())
    for key in keys:
        st.session_state.pop(key)

st.button('Clear Cache', on_click=clear_cache)
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