Minimal dash app for testing PID

dash_pid.py

#!/usr/bin/env python

import base64, io
import dash
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output
from dash_table import DataTable
from dash.exceptions import PreventUpdate
import plotly.graph_objects as go
from os.path import isfile, isdir, abspath, join as pjoin, dirname
from os import makedirs
from subprocess import check_call

import pandas as pd
import numpy as np
import os

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']
app = dash.Dash(__name__, external_stylesheets=external_stylesheets, suppress_callback_exceptions=True)


app.layout= html.Div([
    html.H1('Input'),
    html.Div(id='page-content'),
    dcc.Input(id='var1'),
])

@app.callback(Output('page-content','children'),
             [Input('var1','value')])
def dummy(value):
    print(value)
    return str(os.getpid())

if __name__=='__main__':
    app.run_server(debug=True, port=8050, host='localhost')