Refresh Input Data

Dash Python
1

How to refresh my Dash app data with latest data set?

Problem Statement:

  1. I connect to a Database/csv (which changes with time)
  2. Plot the Data
  3. Refresh the data on every page reload (to accommodate new entries)
  4. To provide Live dashboards
2

Have you checked this?

https://plot.ly/dash/live-updates

1 Like
4

thanks raghunath, I have checked that part, here is my template

> import dash
> import dash_core_components as dcc
> import dash_html_components as html
> import pandas as pd
> import numpy as np
> from plotly import __version__
> from plotly.offline import download_plotlyjs, init_notebook_mode, plot, iplot
> import plotly.figure_factory as ff
> import plotly.graph_objs as go
> import urllib
> import urllib.parse
> import Levenshtein
> import datetime as dt
> from dateutil.relativedelta import *
> from pymongo import MongoClient
> import locale
> locale.setlocale(locale.LC_MONETARY, 'en_IN')
> 
> 
> app = dash.Dash()
> 
> 
> 
> client = MongoClient('xxxxx') #production
> db=client['yyyyyyy']
> data=pd.DataFrame()
> df=pd.DataFrame()
> pdf=pd.DataFrame()
> data2correct=pd.DataFrame()
> collection=db.lr
> 
> def data_in():
>     #data read and filling the global variables df,pdf,data and data2correct happens here
> 
> data_in()
> 
> def serve_layout():
>     data_in()
>     return html.Div([
>     html.Div([
>         html.H1('The time is: ' + str(dt.datetime.now())),
>         html.Label('Date Range'),
>         
>         html.Label('From'),
>         
>         html.Div([
>             dcc.Input(
>                 id='SD',
>                 type='Date',
>                 value=dt.date.today()-dt.timedelta(days=15)
>                 #SD=dt.date.today()-dt.timedelta(days=15)
>             )
>         ],
>         style={'width': '48%', 
>                'margin-right':'20%', 
>                'margin-top':'2%', 
>                'display': 'inline-block'}),
> 
>         html.Label('Till'),
>         
>         html.Div([
>             dcc.Input(
>                 id='ED',
>                 type='Date',
>                 value=dt.date.today()
>                 #ED=dt.date.today()
>             )
>         ],
>         style={'width': '48%', 
>                'margin-right':'20%', 
>                'margin-top':'2%', 
>                'display': 'inline-block'})
> 
>     ]),
>     
>     #html.Button('Click Me', id='my-button'),
> 
>     html.Hr(),
>     
>     html.Label('Summary'),
>     
>     dcc.Graph(id='fig1'),
>     #dcc.Graph(id='Tbl'),
>     dcc.Graph(id='fig2'),
>     dcc.Graph(id='fig3'),
> 
> 
> ])
> 
> app.layout = serve_layout
> app.css.append_css({"external_url": "https://codepen.io/chriddyp/pen/bWLwgP.css"})
>  
> @app.callback(
>     dash.dependencies.Output('fig1', 'figure'),
>     [dash.dependencies.Input('SD','value'),
>      dash.dependencies.Input('ED', 'value')])
> def update_graph(SD,ED):
>     metrics on df
> 
> @app.callback(
>     dash.dependencies.Output('fig2', 'figure'),
>     [dash.dependencies.Input('SD','value'),
>      dash.dependencies.Input('ED', 'value')])
> def update_graph(SD,ED):
>     metrics on pdf
> 
> 
> @app.callback(
>     dash.dependencies.Output('fig3', 'figure'),
>     [dash.dependencies.Input('SD','value'),
>      dash.dependencies.Input('ED', 'value')])
> def update_graph(SD,ED):
>     metrics on data2correct
> 
> 
> 
> 
> 
>     
> if __name__ == '__main__':
>     app.run_server(host='0.0.0.0',debug=True,use_reloader=False)

I’m calling the function data_in inside serve_layout so that it computes all the four global variables for every reload of the page and thus can be used inside in the call backs followed.

Or should I schedule a cron job to accommodate the in-time data

please suggest me what I should do to get it done

5

It is not safe to use global variables in dash. Instead, I recommend storing the df inside a hidden div inside the layout and using that hidden div as its own Input in the remaining callback functions.
For more information, see: