Deploy Flask app in Heroku

In a flask app,database let us consider postgresql

Now we have to deploy Flask app in heroku which is success in local host.First,

In our app,database connection is  like this

con = psycopg2.connect(database='firstdb') 
cur = con.cursor()

Instead of this,use....

urlparse.uses_netloc.append("postgres")
url = urlparse.urlparse(os.environ["DATABASE_URL"])
con=psycopg2.connect(database=url.path[1:],user=url.username,password=url.password,host=url.hostname,port=url.port)

also import some modules

import os
import psycopg2
import urlparse

wherever database to connect,we should connect like above in each function..

Next in routes.py or the routing python program.our app includes

app.run(debug=True)

Instead of this...

if __name__ == "__main__":
    port = int(os.environ.get("PORT", 5000))
    app.run(host='0.0.0.0', port=port)


Then also add

app.config.from_object(__name__)

in the below of app = Flask(__name__)..so it should be like this..

app = Flask(__name__)
app.config.from_object(__name__)


Then,

Create account on heroku.com
open terminal and enter

Heroku login     #to enter username and password
cd appfloder      #appfolder includes route.py,templates etc...
heroku create websitename   #should like www.websitename.herokuapp.com
heroku addons:add heroku-postgresql:dev   #creating database
heroku config:set HEROKU=1
virtualenv venv --distribute   #virtual environment for flask
source venv/bin/activate
pip freeze > requirements.txt

requirements.txt should be like this

Flask==0.10.1
Jinja2==2.7.1
MarkupSafe==0.18
Werkzeug==0.9.4
argparse==1.2.1
distribute==0.6.34
gunicorn==18.0
itsdangerous==0.23
psycopg2==2.5.1
wsgiref==0.1.2

then,

pip install -r requirements.txt
git init

Create a Procfile using vi Procfile ('P' is capital) and add following line in it

web: python routeprogam.py #here route program is yours

Also add a .gitignore file using vi .gitignore and add following 3 lines in it.This is for avoiding the virtual env files to deploy.

venv
*.pyc
*.py~

Then,


git add .
git commit -m "hosting"
git push heroku master 

After launching it,

heroku pg:promote HEROKU_POSTGRESQL_PINK   #PINK is here only your's can be find using

heroku config | grep HEROKU_POSTGRESQL

Then,'

heroku ps:scale web=1
heroku restart --app websitename

heroku open

Then you can see it is working......!!!!!!

heroku logs #for further info

If u have any doubts just clone my simple microblog app using,

heroku git:clone -a latheefmicroblog

and verify the codes and structure of Flask app