Dash app Pages not shown when running gunicorn

Dash Python
1

Hi,

I’m facing a strange issue for which I couldn’t find any solution. I have a dash app with the structure

  | -- src
         - __init__.py
         - app.py
         - index.py
         | -- pages
                - home.py
                - contact.py
                | -- home_input
                       - __init__.py
                       - input_components.py
                       - input_layout.py
                 | -- home_results
                       - __init__.py
                       - results_components.py
                       - results_layout.py
                 | -- home_settings
                       - __init__.py
                       - settings_components.py
                       - settings_layout.py
                | -- rmsd
                       - __init__.py
                       - rmsd_components.py
                       - layout.py
         | -- assets
         | -- components
                - __init__.py
                - footer
                - navbar
                - login
         | -- data
         | -- utils
                - __init__.py
                -  common_functions.py
                -  settings.py

In app.py I have:

app = Dash(__name__, external_stylesheets=[dbc.themes.LUX], suppress_callback_exceptions=True, title="CoDi", use_pages=True, assets_folder=script_path + 'assets',  
           pages_folder="src/pages",
           meta_tags=[
               {  
                   'name': 'viewport',
                   'content': 'width=device-width, initial-scale=1'
               }
           ])
server = app.server

my index.py:

from src.app import app

# CALLBACKS
from src.pages.home_input.input_components import *
from src.pages.home_results.results_components import *
from src.pages.home_settings.settings_components import *
from src.pages.home_settings.background_components import *
from src.pages.rmsd.rmsd_components import *

app.layout = html.Div([
    html.Div([navbar.navbar]),
    page_container,
    dcc.Store(id='subunit_figure', storage_type='session'),),
    dcc.Store(id='single_data_names', storage_type='session'),
    dcc.Store(id='protein_data_names', storage_type='session'),
    html.Div([footer.footer]),
], className="dash-bootstrap")

register_callbacks(app)
register_callbacks1(app)
register_callbacks2(app)
register_long_callbacks1(app)
register_callbacks_rmsd(app)

if __name__ == '__main__':
    # app.run(debug=False, use_reloader=False)
    app.run_server(debug=False, port=8022, use_reloader=False, host='127.0.0.1')

When I run it locally everything works fine, but when I run it via gunicorn “gunicorn app:server --workers 4” I just get the main page but without navbar, footer and especially the page_container is not displayed. The same problem I have when I want to put it onrender or on pythonanywhere.
I tried a lot of different stuff and sometimes I managed to get the navbar and footer into it, but the page_container is never shown.

I also tried to add requests_pathname_prefix=‘/myapp/’, routes_pathname_prefix=‘/myapp/’. It didn’t help.

Any suggestion on what I can do? Is it the paths to the pages that are not managed with gunicorn ?

Thank you so much for the help!

Best,
Filip

2

Shouldn’t your navbar and footer be imported?

It doesn’t look like they are in the index file.

If you change the url do the pages load properly?

1 Like
3

It was strange, but I found out what the issue was. Index.py and App.py have to be above the src folder. This resolved all the issues