Hi, I write an app which uses the ECMWF Magics (https://anaconda.org/conda-forge/magics) to produce weather analysis maps in streamlit. When one user accesses the app, it’s OK. But several users access the app at the same time, I always get the error: “Segmentation fault (core dumped)”. I think the ECMWF Magics doesn’t support multiple threadings. So I want to lock the threading when one user makes some pictures with Magics. I use the following code:
from threading import Lock
import streamlit as st
lock = Lock()
with lock:
# call the Magics functions.
image = draw_weather_analysis()
st.image(image, use_column_width=True)
But this does not worked. The “Segmentation fault (core dumped)” error still display, and I found the ‘lock’ can not lock the streamlit thread. So how can I do? Thanks very much.
As the code is run in different threads (one per user session), in your example you are just creating two different locks in each session. What you want instead is a lock shared with every session.
To do that, you could try to use @thiago’s GlobalState.
Another option is to instead make a small webapp around magics so that becomes a single threaded API. Then your streamlit app just calls out to that, no locking and hacking needed.
Hi, Synode:
Thanks for your reply very much. With the global state of “st_state_patch”, I can lock the threading and the Magics functions run correctly.
from threading import Lock
import streamlit as st
import st_state_patch
s = st.GlobalState(key="mySate")
if not s:
s.lock = Lock()
with s.lock:
# call the Magics functions.
image = draw_weather_analysis()
st.image(image, use_column_width=True)
Sorry for warming up that thread again, but is there still a global state implementation available? I would need it also for locking (in that case matplotlib).