Run a dash request from a flask app gives 404 error while the other flask routes ran well

Question

I am trying to integrate my Dashboard built with dash into a flask app that does other things. I wanted it to display the dashboard on http://127.0.0.1:5000/Dashboard . I have gone through a lot of resources and still not clear. The URL keeps giving me a 404 Not found error but the URL to all other flask routes work.

app.py

from flask import Flask, render_template, request, redirect
import flask
from dashboard import *

app = Flask(__name__)
@app.route('/Recalculate', methods = ['GET','POST'])
def calculate():
    return render_template('recalculate.html', tables=[final_merged_data.to_html(classes='data', index=False)], titles=round_data.columns.values)

@app.route('/Dashboard')
def render_dashboard():
    return redirect("/pathname/")


if __name__ == '__main__':
    app.run(debug=True)

dashboard.py

    import dash
    import flask
    from flask import Flask
    import dash_table
    import numpy
    import dash_core_components as dcc
    import dash_html_components as html

    external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']


    server = flask.Flask(__name__)
    app_dash = dash.Dash(__name__,server=server, routes_pathname_prefix="/pathname/", external_stylesheets=external_stylesheets)
    
    
    colors = {
        'background': '#111111',
        'text': '#7FDBFF'

    }
    # assume you have a "long-form" data frame
    # see https://plotly.com/python/px-arguments/ for more options

   
    data = [trace1, trace2]
    layout = go.Layout(barmode = 'group',xaxis_title="Day of the month", yaxis_title="Power Generated in MW")
    fig = go.Figure(data = data, layout = layout)

    fig.update_layout(
        plot_bgcolor=colors['background'],
        paper_bgcolor=colors['background'],
        font_color=colors['text']
    )
    
    app_dash.layout = html.Div(style={'backgroundColor': colors['background']}, children=[
        html.H1(
    

children='Hello George',
    style={
        'textAlign': 'center',
        'color': colors['text']
    }
),

html.Div(children='Predicted output from your wind and solar plants', style={
    'textAlign': 'center',
    'color': colors['text']
})

    if __name__ == '__main__':
        app_dash.run_server(debug=True)

Answer 1

I am not an expert, but I understand that for doing that you have to declare the dash app as a function in your code, let's say:

def init_dash(server):
    dash_app = dash.Dash(
        server=server, ...

You can have a look to this web for more professional details.

Cheers