py.test import error "- 'config' not found."

Question

While trying to add py.test functionality to a Flask API I ran into the following error message when calling py.test on my source directory

E               ImportStringError: import_string() failed for 'config'. Possible reasons are:
E               
E               - missing __init__.py in a package;
E               - package or module path not included in sys.path;
E               - duplicated package or module name taking precedence in sys.path;
E               - missing module, class, function or variable;
E               
E               Debugged import:
E               
E               - 'config' not found.
E               
E               Original exception:
E               
E               ImportError: No module named config

The issue seems to stem after I have instantiated my Flask app and try to import the config from config.py (line 5).

from flask import Flask

# Setup app
app = Flask(__name__)
app.config.from_object('config')

# Import views
from views import *

if __name__ == '__main__':
    app.run()

Everything seems to work accordingly if I manually set the config variables instead of importing them. Has anyone encountered anything like this? I wasn't able to find anything helpful in the documentation.

Answer 1

Although this is an old post and very essential problem of Flask, which I happen to have this these days. In case that anyone also have the same problem, you should check the path of config.py file. At first, I created config.py inside app dir. Then I moved outside the app, it works. Like this:

-app---
   |
   |----__init__.py
   |----config.py

Change to:

-app---
   |
   |----__init__.py
-config.py

Answer 2

Changing app.config.from_object(config) to app.config.from_pyfile('config.py') solved.

Answer 3

I suppose these ones are the most probable

E           - package or module path not included in sys.path;
E           - duplicated package or module name taking precedence in sys.path;

So the first thing I'd try is to rename config file to something like config_default.py.

Then you can try to use the real object instead of string eg. importing config yourself:

from flask import Flask
import config

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

But most likely you'll face the same error: ImportError: No module named config

Also you can use app.config.from_pyfile() and specify full path to your config file:

app.config.from_pyfile('config.py')

from_pyfile() uses a different technique to create the object (it uses [exc](https://github.com/mitsuhiko/flask/blob/master/flask/config.py#L129)).

I myself prefer to use from_envvar() and specify which config file to use in launcher (supervisord nowadays).

Answer 4

Twil makes good points and alternatives to app.config.from_object. However, I stumbled upon this question while having trouble with the following Flask Tutorial and I wanted to follow the guide and use from_object.

The way I corrected my issue was that I had originally put the config.py file in my 'app' package. It should reside outside of my app in that same folder from which I had my run.py script.

I hope this answer saves someone a bit of time.