Make Flask use Postgres on Heroku - postgresql

Question

i have been following the Flask book by Miguel Ginberg and I am thinking about how to deploy my app and use the PostgresDB.
In my local production config I have to manually go in and run Role.insert_roles() before any roles can be assigned.
How do I do this in Heroku with postgres? In fact, how do you connect to the postgres db? It is not really clear where in the code postgres takes over using the environment variable:
https://github.com/miguelgrinberg/flasky/blob/master/config.py
I have a feeling my app is just running sqlite and the book isn't really clear on how to switch over.
SOLUTION:
if you have deployed to heroku and you have not changed the environment variables:
DATABASE_URI to SQLALCHEMY_DATABASE_URI
FLASK_CONFIG = heroku
FLASKY_ADMIN = your email
then ran in your shell:
heroku run python manage.py shell
db.create_all()
db.commit()
Role.insert_roles()
then you are probably running the development config from the SQLite database!

Answer 1

If you want to connect manually, you could use the http://initd.org/psycopg/ libarary directly. Flask-SQLAlchemy provides uses psycopg underneath the hood itself, see here - in your example it may be easier to continue using SQLAlchemy. More information here.

Answer 2

I had the same problem and solved like the follow:
1. provisioning a db
$:heroku addons:create heroku-postgresql bobby-dev
......
add database_url:
$:hero config -s |grep HEROKU-PSOTGRESQL
( then show HEROKU_POSTGRESQL_RED_URL=..... )
$:heroku pg:promote HEROKU-POSTGRESQL-RED
install this extention:psycopg2
3.change the config.py:
config = {
.....
'default' : ProductionConfig
}