Access Flask config outside of application factory

Question

I'm currently using the Flask Application Factory pattern with Blueprints. The issue that I'm having is how do I access the app.config object outside of the application factory?

I don't need all the configuration options from the Flask app. I just need 6 keys. So the current way I do this is when the create_app(application factory) is called, I basically create a global_config dictionary object and I just set the global_config dictionary to have the 6 keys that I need.

Then, the other modules that need those configuration options, they just import global_config dictionary.

I'm thinking, there has to be a better way to do this right?

So, on to the code

My current init.py file:

def set_global_config(app_config):
    global_config['CUPS_SAFETY'] = app_config['CUPS_SAFETY']
    global_config['CUPS_SERVERS'] = app_config['CUPS_SERVERS']
    global_config['API_SAFE_MODE'] = app_config['API_SAFE_MODE']
    global_config['XSS_SAFETY'] = app_config['XSS_SAFETY']
    global_config['ALLOWED_HOSTS'] = app_config['ALLOWED_HOSTS']
    global_config['SQLALCHEMY_DATABASE_URI'] = app_config['SQLALCHEMY_DATABASE_URI']


def create_app(config_file):
    app = Flask(__name__, instance_relative_config=True)

    try:
        app.config.from_pyfile(config_file)
    except IOError:
        app.config.from_pyfile('default.py')
        cel.conf.update(app.config)
        set_global_config(app.config)
    else:
        cel.conf.update(app.config)
        set_global_config(app.config)

    CORS(app, resources=r'/*')
    Compress(app)

    # Initialize app with SQLAlchemy
    db.init_app(app)
    with app.app_context():
        db.Model.metadata.reflect(db.engine)
        db.create_all()

    from authenication.auth import auth
    from club.view import club
    from tms.view import tms
    from reports.view import reports
    from conveyor.view import conveyor

    # Register blueprints
    app.register_blueprint(auth)
    app.register_blueprint(club)
    app.register_blueprint(tms)
    app.register_blueprint(reports)
    app.register_blueprint(conveyor)
    return app

An example of a module that needs access to those global_config options:

from package import global_config as config

club = Blueprint('club', __name__)

@club.route('/get_printers', methods=['GET', 'POST'])
def getListOfPrinters():
    dict = {}

    for eachPrinter in config['CUPS_SERVERS']:
        dict[eachPrinter] = {
            'code': eachPrinter,
            'name': eachPrinter
        }
    outDict = {'printers': dict, 'success': True}
    return jsonify(outDict)

There has to be a better way then passing a global dictionary around the application correct?

in set_global_config why not just doing global_config.update(app_config) as you seem to want to copy all the keys / values as is ? or even simpler: global_config = app_config.copy(). This is not an answer, just a simple remark. — DevLounge
Hmmm that does make sense and I'll make that change right now. Thanks. Do you see any issue with storing these configuration details and passing them? — Jimmy

davidism davidism · Accepted Answer · 2016-04-05T22:19:59

There is no need to use global names here, that defeats the purpose of using an app factory in the first place.

Within views, such as in your example, current_app is bound to the app handling the current app/request context.

from flask import current_app

@bp.route('/')
def example():
    servers = current_app.config['CUPS_SERVERS']
    ...

If you need access to the app while setting up a blueprint, the record decorator marks functions that are called with the state the blueprint is being registered with.

@bp.record
def setup(state):
    servers = state.app.config['CUPS_SERVERS']
    ...

Access Flask config outside of application factory

1 Answers