Locally (through anaconda) this app runs fine and all the returns work but when I put my app on a webfaction flask server the “Years for Payback” callback doesn’t return a value (but prints one in the log) I’ve been looking at this for days and my other resources came up empty, additionally there’s nothing in the log showing an error. What’s the deal?
I’ve hardcoded inputs for ease of use for anyone helping, all you have to do is type in say, 400, in the Cost of Retrofit box.
the callback at issue is:
@app.callback(Output(‘payback’,‘value’), [Input(‘savings’,‘value’),Input(‘cost’,‘value’)])
def payback(savings,cost):
if savings is None or cost is None:
return None
else:
payback = float(cost) / float(savings)
payback = np.round(payback,2)
print(payback)
return payback
full code below:
import dash
import dash_core_components as dcc
import dash_html_components as html
import pandas as pd
import numpy as np
from textwrap import dedent
import os
from dash.dependencies import Input, Output, State
app = dash.Dash(__name__)
server = app.server #this is the underlying flask app
this_dir = os.path.dirname(os.path.realpath(__file__))
data_dir = os.path.join(this_dir, 'static')
app.css.append_css({
'external_url': 'http://windowreplacementpaybackcalc.cchrc.org/static/style.css',
})
# Overriding the index template allows you to change the title of the
# application and load external resources.
app.index_string = '''
<!DOCTYPE html>
<html>
<head>
{%metas%}
<title>Window Replacement Payback Calculator</title>
{%favicon%}
<link rel="icon" href="/assets/favicon.ico">
{%css%}
<link rel="stylesheet" href="/static/style.css">
<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans|Roboto">
</head>
<body>
{%app_entry%}
<footer>
{%config%}
{%scripts%}
</footer>
</body>
</html>
'''
#declarations
hrs = 24
oilbtu = 140000 #in one gallon of fuel
natgasbtu = 100000 #in one ccf of natgas
# -- layout -- #
app.layout = html.Div([
html.Div([
html.H1('Location Information'),
html.Label('Select your location'),
dcc.Dropdown(
id='city',
options=[
{'label': 'Anchorage', 'value': 'home'},
{'label': 'Annette', 'value': 'base'},
{'label': 'Bethel', 'value': '13098'},
{'label': 'Bettles', 'value': '15689'},
{'label': 'Big Delta', 'value': '13535'},
{'label': 'Cold Bay', 'value': '9733'},
{'label': 'Fairbanks', 'value': '13940'},
{'label': 'Gulkana', 'value': '13807'},
{'label': 'Homer', 'value': '10054'},
{'label': 'Juneau', 'value': '8897'},
{'label': 'King Salmon', 'value': '11456'},
{'label': 'Kodiak', 'value': '8817'},
{'label': 'Kotzebue', 'value': '15812'},
{'label': 'Mcgrath', 'value': '14396'},
{'label': 'Nome', 'value': '14129'},
{'label': 'St. Paul Island', 'value': '11031'},
{'label': 'Talkeetna', 'value': '11606'},
{'label': 'Unalakleet', 'value': '13795'},
{'label': 'Utqiagvik', 'value': '20226'},
{'label': 'Valdez', 'value': '9953'},
{'label': 'Yakutat', 'value': '9485'}
],
value = '13940',
),
html.Br(),
html.Label('Heating Degree Days'),
html.Br(),
dcc.Input(id='hdd', type='text',value='13940'),
html.Br(),
html.Label('Fuel Type'),
dcc.RadioItems(id='fuel_type',
options=[
{'label': 'heating fuel', 'value': 'fuel'},
{'label': 'natural gas', 'value': 'natgas'},
],
value='fuel',
),
html.Br(),
html.Label('Solar Heat Gain Coefficient (%)'),
html.Br(),
dcc.Input(id='shgc', type='number',value='0.7'),
html.Br(),
html.Label('Fuel Cost ($)'),
html.Br(),
dcc.Input(id='fuelprice', type='number',value='3.0'),html.Abbr(" ", title="please enter the price per unit (gal for oil or ccf for natural gas)"),
html.Br(),
html.Label('Heating AFUE (%)'),
html.Br(),
dcc.Input(id='afue', type='number',value='0.87'),html.Abbr(" ", title="also known as Annualized Fuel Use/Utilization Efficiency, this information is on a sticker or in the manual for your heating system"),
html.Br(),
html.Label('Heating Cost Multiplier ($)'),
html.Br(),
dcc.Input(id='hcmlt',type='number'),
],id='location'),
html.Div([
html.H1('Existing Windows'),
html.Label('Area of existing window'),
html.Br(),
dcc.Input(id='ex_area', type='number',value='16'),
html.Br(),
html.Label('Window U Value'),
html.Br(),
dcc.Input(id='ex_uval', type='number',value='1.8'),
html.Br(),
html.Label('BTU Heat Factor'),
html.Br(),
dcc.Input(id='ex_btuhf', type='text'),
html.Br(),
html.Label('Annual Heating Cost '),
html.Br(),
dcc.Input(id='ex_ahc',type='number'),html.Abbr(" ", title="heating cost through the window"),
], id='existing'),
html.Div([
html.H1('New Windows'),
html.Label('Area of new window'),
html.Br(),
dcc.Input(id='nw_area', type='number',value='16'),
html.Br(),
html.Label('New Window U Value'),
html.Br(),
dcc.Input(id='nw_uval', type='number',value='0.2'),
html.Br(),
html.Label('New Window BTU Heat Factor'),
html.Br(),
dcc.Input(id='nw_btuhf', type='text'),
html.Br(),
html.Label('Annual Heating Cost'),
html.Br(),
dcc.Input(id='nw_ahc',type='number'),html.Abbr(" ", title="heating cost through the window"),
], id='new'),
html.Div([
html.H1('Cost Savings & Payback'),
html.Label('Cost of Retrofit'),
html.Br(),
dcc.Input(id='cost',type='number'),
html.Br(),
html.Label('Annual Savings'),
html.Br(),
dcc.Input(id='savings',type='number'),
html.Br(),
html.Label('Years for Payback'),
html.Br(),
dcc.Input(id='payback',type='number'),
], id='costs'),
html.Div([
dcc.Input(id='sub1',type='number'),
dcc.Input(id='sub2',type='number'),
], id='hidden'),
], id='main')
# -- callbacks -- #
#step 1 look up AFI
@app.callback(Output('hdd', 'value'), [Input('city','value')])
def findhdd(value):
hdd = '{}'.format(value)
return hdd
#subcalc1 hdd * hrs * shgc * fuel cost
@app.callback(Output('sub1', 'value'), [Input('hdd','value'),Input('shgc','value'),Input('fuelprice','value')])
def sub1(hdd,shgc,fuelprice):
if hdd is None or shgc is None or fuelprice is None:
return None
else:
sub1 = int(hdd) * hrs * float(shgc) * float(fuelprice)
sub1 = np.round(sub1,0)
return sub1
#subcalc2 btu * afue
@app.callback(Output('sub2','value'), [Input('fuel_type','value'),Input('afue','value')])
def sub2(fuel_type,afue):
if fuel_type is None or afue is None:
return None
else:
if fuel_type == 'fuel':
sub2 = int(oilbtu) * float(afue)
sub2 = np.round(sub2)
elif fuel_type == 'natgas':
sub2 = int(natgasbtu) * float(afue)
sub2 = np.round(sub2)
return sub2
#heatcostmultiplier
@app.callback(Output('hcmlt','value'), [Input('sub1','value'), Input('sub2','value')])
def hcmlt(sub1,sub2):
if sub1 is None or sub2 is None:
return None
else:
hcmlt = int(sub1) / int(sub2)
hcmlt = np.round(hcmlt,2)
return hcmlt
#oldbtuheatfactor
@app.callback(Output('ex_btuhf','value'), [Input('ex_area','value'),Input('ex_uval','value')])
def ex_btuhf(ex_area,ex_uval):
if ex_area is None or ex_uval is None:
return None
else:
ex_btuhf = int(ex_area) * float(ex_uval)
ex_btuhf = np.round(ex_btuhf,6)
return ex_btuhf
#annlheatingcost existing
@app.callback(Output('ex_ahc','value'), [Input('ex_btuhf','value'), Input('hcmlt','value')])
def ex_ahc(ex_btuhf,hcmlt):
if ex_btuhf is None or hcmlt is None:
return None
else:
ex_ahc = float(ex_btuhf) * float(hcmlt)
ex_ahc = np.round(ex_ahc,2)
return ex_ahc
#newbtuheatfactor
@app.callback(Output('nw_btuhf','value'), [Input('nw_area','value'),Input('nw_uval','value')])
def nw_btuhf(nw_area,nw_uval):
if nw_area is None or nw_uval is None:
return None
else:
nw_btuhf = int(nw_area) * float(nw_uval)
nw_btuhf = np.round(nw_btuhf,6)
return nw_btuhf
#annlheatingcost new
@app.callback(Output('nw_ahc','value'), [Input('nw_btuhf','value'), Input('hcmlt','value')])
def ex_ahc(nw_btuhf,hcmlt):
if nw_btuhf is None or hcmlt is None:
return None
else:
nw_ahc = float(nw_btuhf) * float(hcmlt)
nw_ahc = np.round(nw_ahc,2)
return nw_ahc
#annl savings
@app.callback(Output('savings','value'), [Input('ex_ahc','value'),Input('nw_ahc','value')])
def savings(ex_ahc,nw_ahc):
if ex_ahc is None or nw_ahc is None:
return None
else:
savings = float(ex_ahc) - float(nw_ahc)
savings = float(np.round(savings,2))
return savings
@app.callback(Output('payback','value'), [Input('savings','value'),Input('cost','value')])
def payback(savings,cost):
if savings is None or cost is None:
return None
else:
payback = float(cost) / float(savings)
payback = np.round(payback,2)
print(payback)
return payback
if __name__ == '__main__':
app.run_server(host="0.0.0.0",debug=True)
