A friend and I wrote a Python app to plot the number of Covid-19 cases by country on a world map.
Here is our code:
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Sun Mar 15 17:01:50 2020
@author: sheldon
"""
import os
import pandas as pd
import folium
from folium import plugins
import rasterio as rio
from rasterio.warp import calculate_default_transform, reproject, Resampling
import earthpy as et
import pdb
import flask
from flask import Flask
class CovidDF:
def __init__(self, url):
self.url = url
self.raw = None
self.aggregated = None
def reload(self, date):
self.raw = pd.read_csv(self.url)
self.group_by_regions(date)
def group_by_regions(self,date):
df=self.raw[['Province/State','Country/Region','Lat','Long',date]]
self.aggregated=df.groupby(['Country/Region']).agg({'Lat':'mean',
'Long':'mean',
date: 'sum'})
self.aggregated.at['France','Lat']=46.2276
self.aggregated.at['France','Long']=2.2137
class CovidData(object):
def __init__(self):
self.confirmed_cases = CovidDF('https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_19-covid-Confirmed.csv')
self.deaths = CovidDF('https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_19-covid-Deaths.csv')
self.recoveries = CovidDF('https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_19-covid-Recovered.csv')
self.loaded = False
self.map = folium.Map(location=[0,0],
tiles = 'Stamen Terrain',
zoom_start=2)
def populate(self, date):
if not self.loaded:
self.confirmed_cases.reload(date)
self.deaths.reload(date)
self.recoveries.reload(date)
self.loaded=True
def plot_number_of_cases(self,df,date,custom_color):
dc=df.iloc[df[date].to_numpy().nonzero()]
latitude = dc.Lat.values.astype('float')
longitude = dc.Long.values.astype('float')
radius = dc[date].values.astype('float')
for la,lo,ra in zip(latitude,longitude,radius):
folium.Circle(
location=[la,lo],
radius=ra*10,
fill=True,
color=custom_color,
fill_color=custom_color,
fill_opacity=0.5
).add_to(self.map)
def plot_number_of_cases_for_all_dataframes(self,date):
self.plot_number_of_cases(self.confirmed_cases.aggregated,date,'blue')
self.plot_number_of_cases(self.deaths.aggregated,date,'red')
self.plot_number_of_cases(self.recoveries.aggregated,date,'green')
my_date='3/14/20'
covid_data=CovidData()
covid_data.populate(my_date)
covid_data.plot_number_of_cases_for_all_dataframes(my_date)
#covid_data.map.save("./mytest.html")
app = Flask(__name__)
@app.route("/")
def display_map():
return covid_data.map._repr_html_()
The app builds fine on Heroku, but we are getting an application error when trying to open it. Checking the logs yields the following error messages:
2020-03-16T10:37:49.600873+00:00 heroku[web.1]: Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 60 seconds of launch
2020-03-16T10:37:49.600972+00:00 heroku[web.1]: Stopping process with SIGKILL
2020-03-16T10:37:49.697252+00:00 heroku[web.1]: Process exited with status 137
2020-03-16T10:41:33.514461+00:00 heroku[router]: at=error code=H10 desc="App crashed" method=GET path="/" host=covid19-viz.herokuapp.com request_id=2e0727f9-d3eb-4966-8252-92a871deaa41 fwd="77.150.72.89" dyno= connect= service= status=503 bytes= protocol=https
I have checked this other post and understand that the error is related to a port specification issue but I do not know how to fix it. Any help will be appreciated!
Solution 1:
When running the app via python app.py add to your app.py:
if __name__ == "__main__":
app.run(host='0.0.0.0', port=os.environ.get('PORT', 80))
Solution 2:
When running the app via flask run adjust Procfile to:
web: flask run --host=0.0.0.0 --port=$PORT
Solution 3:
With Gunicorn adjust Procfile to:
web: gunicorn app:app
Add gunicorn to requirements.txt. Gunicorn automatically binds to $PORT.
When hosting on Heroku you need to bind to $PORT which is given to you as an environment variable by Heroku.