librelist archives

init_app was not enough for flask-sqlalchemy

From:

Italo Maia

Date:

2011-10-01 @ 03:10

Folks, I had a very weird problem with my tests in flask.


As flask-script Manager class requires a Flask instance to be instanciated,
I was creating a simple Flask instance with *Dev* configuration, then, in my
tests create_app, I was creating the Flask instance with *Test* configuration.
Test and Dev configurations used different databases. I noticed that, when
calling db.create_all, if I had not set db.app = (new flask instance with
test config) before db.init_app(app), my test database would never be
created.

Does that make sense to you guys? I have a feeling that db.init_db should be
enough. Anyway, this fix, db.app = app, i saw looking around flask code.

-- 
"A arrogância é a arma dos fracos."

===========================
Italo Moreira Campelo Maia
Bacharel em Ciência da Computação - UECE
Desenvolvedor WEB e Desktop (Java, Python, Lua)
Coordenador do Pug-CE
-----------------------------------------------------
http://www.italomaia.com/
http://twitter.com/italomaia/
http://eusouolobomau.blogspot.com/
-----------------------------------------------------
Turtle Linux  9.10 - http://tiny.cc/blogturtle910
Turtle Linux 10.10 - http://bit.ly/cEw4ET
===========================

On Oct 1, 2011, at 6:10 AM, Italo Maia wrote:

> Folks, I had a very weird problem with my tests in flask. 
> 
> 
> As flask-script Manager class requires a Flask instance to be 
instanciated, I was creating a simple Flask instance with Dev 
configuration, then, in my tests create_app, I was creating the Flask 
instance with Test configuration. Test and Dev configurations used 
different databases. I noticed that, when calling db.create_all, if I had 
not set db.app = (new flask instance with test config) before 
db.init_app(app), my test database would never be created.
> 
> Does that make sense to you guys? I have a feeling that db.init_db 
should be enough. Anyway, this fix, db.app = app, i saw looking around 
flask code. 

I think I had the same problem, and the solution was to call db.create_all
in the context of the application. This code is run in the application 
factory, so it creates tables for either test or dev (or production) 
database.

    with app.test_request_context():
        db.create_all()

Cheers,
-- Alex