python - Azure Flask Deployment - WSGI Interface

Question

I'm currently working through the book Flask Web Development, Developing Web Applications with Python and am currently having some issues determining where I should place the WSGI interface so that I can deploy it to an Azure Web Service. For reference I'm currently at Chapter 7 and a copy of this code that I'm currently working through can be found at https://github.com/miguelgrinberg/flasky/tree/7a

To try and work out where the problem is I've created a test Azure Cloud Service with Flask in Visual Studio which runs perfectly in the Azure Emulator. The following code is a copy of the app.py file.

"""
This script runs the application using a development server.
It contains the definition of routes and views for the application.
"""

from flask import Flask
app = Flask(__name__)

# Make the WSGI interface available at the top level so wfastcgi can get it.
wsgi_app = app.wsgi_app

@app.route('/')
def hello():
    """Renders a sample page."""
    return "Hello World!"

if __name__ == '__main__':
    import os
    HOST = os.environ.get('SERVER_HOST', 'localhost')
    try:
        PORT = int(os.environ.get('SERVER_PORT', '5555'))
    except ValueError:
        PORT = 5555
    app.run(HOST, PORT)

The key line here is the declaration of the wsgi_app attribute which is picked up by wfastcgi. However when I try to insert this into the following code (manage.py for reference) and change it slightly to run with the test project settings

#!/usr/bin/env python
import os
from app import create_app, db
from app.models import User, Role
from flask.ext.script import Manager, Shell
from flask.ext.migrate import Migrate, MigrateCommand

app = create_app(os.getenv('FLASK_CONFIG') or 'default')
manager = Manager(app)
migrate = Migrate(app, db)


def make_shell_context():
    return dict(app=app, db=db, User=User, Role=Role)
manager.add_command("shell", Shell(make_context=make_shell_context))
manager.add_command('db', MigrateCommand)


@manager.command
def test():
    """Run the unit tests."""
    import unittest
    tests = unittest.TestLoader().discover('tests')
    unittest.TextTestRunner(verbosity=2).run(tests)

# Make the WSGI interface available at the top level so wfastcgi can get it.
wsgi_app = app.wsgi_app

if __name__ == '__main__':
    HOST = os.environ.get('SERVER_HOST', 'localhost')
    try:
        PORT = int(os.environ.get('SERVER_PORT', '5555'))
    except ValueError:
        PORT = 5555
    app.run(HOST, PORT)

I receive the following error when I try to run it inside of an Azure Emulator.

AttributeError: 'module' object has no attribute 'wsgi_app'

I suspect that I'm not putting the wsgi_app variable in the correct location but I can't figure out exactly where I should put it.

Any help would be greatly appreciative.

Answer 1

Have you considered using a web app to get Flask up and running? Here is a comprehensive guide about how to deploy Flask on a web app: https://azure.microsoft.com/en-us/documentation/articles/web-sites-python-create-deploy-flask-app/

It will automatically set you up with a site and handle the web.config and fast cgi scripts.