Dash app is successfully deployed to azure web app but application is not displayed

Dash Python
1

Good afternoon,
I am having issues displaying my dash app to azure web applications. I have the code deployed but when I click on the link it says the app is up and running but there is no code…Even though I have code. Here is the website
Is there something I am missing?
Here is my dash_app code:

""" Import Dash modules"""
from dash import Dash
from Callbacks import add_callbacks
from Layout import dash_layout

external_stylesheets = ["https://codepen.io/chriddyp/pen/bWLwgP.css"]
dash_app: Dash = Dash(__name__, external_stylesheets=external_stylesheets)
app = dash_app.server
add_callbacks(dash_app)
dash_app.layout = dash_layout

if __name__ == "__main__":
    dash_app.run_server(debug=True)

callbacks and layout are in different modules. its a lot of code so it all cannot be in this file. Also this runs perfectly on my local machine.

2

Hi @MauriD,

It’s difficult to say, but I suspect you aren’t forwarding ports properly. When you run dash_app.run_server(debug=True), the development server is run on port 8050 on the server. To remedy this, you could try setting in-bound rules for traffic such that in-bound traffic from port 80 (or 443 for HTTPS), is redirected to port 8050. Another option is to directly set the port argument in run_server. In any care, both of these suggestions are not best practice.

If you actually intend to use the application for production, I would use a production server like gunicorn on your Azure server, and avoid using run_server at all.

3

Hello @MauriD,

Id start with a basic app like the one I posted and go from there.

Make sure you also have your requirements set up to import all the dependencies for the Azure environment.

4

It looks like the app is up now, for information sake what was the issue @MauriD ?

5

the issue was the port that the correct port was not exposed. I actually didn’t figure it out my colleague did. This is what he did via azure CLI:

az webapp config appsettings set --resource-group <group-name> --name <app-name> --settings WEBSITES_PORT=8050

you can find more info here: Configure a custom container - Azure App Service | Microsoft Learn

6

The default port for gunicorn is 8000, the default for dash is 8050 and the default for Flask is 5000.

At least from my understanding this is the case.

2 Likes
7

Ah, yup can’t tell you the amount of times i’ve gone down the same path wondering why my app isn’t working only to find i didn’t open the security group ports. Good find!

8

Well I just noticed I am having some issues with the application. I think maybe it has to to with using a development port instead of production. the dropdown for ADF files is not populating when a file is uploaded…What do you think I can do to fix this? what port is used for a production environment?

9

I think I use all the same ports (my app doesn’t need that much security to change them) so i think its set to 8050 regardless of environment.