streamlit-caching-multithreading

#!/usr/bin/env python3
import numpy as np
import requests
import streamlit as st
from concurrent.futures import ThreadPoolExecutor

@st.cache(suppress_st_warning=True, allow_output_mutation=True)
def make_image(id, opacity, column_index):
    print('requesting image from api')
    print(f'id:{id} oppacity:{opacity}, column:{column_index}')
    # image get request, normally we would load the image from disk
    img = requests.get(url='https://picsum.photos/100/100')
    return img.content


# standard caching without specifiying the hash func gives: UnhashableTypeError: Cannot hash object of type streamlit.delta_generator.DeltaGenerator, found in the arguments of show_image().
# @st.cache(suppress_st_warning=True,allow_output_mutation=True)
def show_image(id, column, column_index):
    print('showing image')
    with column:
        category = st.selectbox('category', ['base', 'ground truth', 'prediction'], key=str(column_index)+ 'cat' + str(id))

        print(f'cat: {category}')

        oppacity = st.select_slider(
            "Oppacity",
            [round(i, 2) for i in np.linspace(0, 1, 21).tolist()],  # dat_filtered["x1"].tolist()
            value=0.5,
            key=str(column_index) + 'op' + str(id)
        )

        st.image(
            make_image(id=id, opacity=oppacity, column_index=column_index),
            # make_caption(d),
            use_column_width=False,
            output_format="PNG",
            channels="RGB",
        )


def show_image_threadpool_test(id, column, column_index):
    print(f'threadpool: id: {id}, column: {column}, column_index: {column_index}')

######################################
######################################
st.beta_set_page_config(layout="wide")

column1, column2 = st.beta_columns(2)

#Regular FOR loop
for i in range(0, 200):
    show_image(i, column1, column_index=0)
    show_image(i, column2, column_index=1)

#ThreadPoolExecutor
#with ThreadPoolExecutor(max_workers=20) as exec:
#    for i in range(0, 200):
#        #this needs some work to sync both images, so they display next to each other
#        #as completed could help
#        exec.submit(show_image_threadpool_test, i, column1, 0)
#        exec.submit(show_image_threadpool_test, i, column2, 1)