I cannot initialize Flask SocketIO with app.from_object parameter - flask-socketio

Question

I have an app.py file where I initialize my app. I have another file (run.py) where I run Flask server from. Everything works with a standard flask app. However I am trying to integrate flask-socketio and it keeps failing with different errors depending on how I try to initialize the app.
I have tried the following ways to initialize flask-socketio:
socketio = SocketIO(app.config.from_object(app_config[env_name]))
socketio = SocketIO(app, **app.config[env_name])
socketio = SocketIO(**app.config[env_name])
Here is the relevant code from my app.py file.
def create_app(env_name):
"""
Create app
"""
# app initiliazation
app = Flask(__name__)
app.config.from_object(app_config[env_name])
async_mode = None
# initializing bcrypt and db
bcrypt.init_app(app)
db.init_app(app)
socketio = SocketIO(app.config.from_object(app_config[env_name]))
return socketio
My run.py file looks like this:
rom src.app import create_app
load_dotenv(find_dotenv())
env_name = os.getenv('FLASK_ENV')
app = create_app(env_name)
if __name__ == '__main__':
port = os.getenv('PORT')
# run app
app.run(app, host='0.0.0.0', port=port)
You will notice I am importing from a config.py file. That is where my environment variables are being for (dev, test, prod). Each environment is it's own class. For example:
class Development(object):
"""
Development environment configuration
"""
DEBUG = True
TESTING = False
SQLALCHEMY_TRACK_MODIFICATIONS=False
JWT_SECRET_KEY = os.getenv('JWT_SECRET_KEY')
SQLALCHEMY_DATABASE_URI = os.getenv('DATABASE_URL')
ALLOWED_EXTENSIONS = set(['png', 'jpg', 'jpeg', 'gif'])
UPLOADED_FILES_DEST = os.getenv('UPLOADED_FILES_DEST')
As you can see, most of those values are set in an environment variable since it is bad practice to put such sensitive information into a repo.
I would like to be able to initialize flask-socketio so I can setup rooms where users can share location based information.
Thanks in advance.

Answer 1

The Flask-SocketIO extensions takes the application instance as an argument. You should configure the application and then initialize it. For example:
app.config.from_object(app_config[env_name])
socketio = SocketIO(app)

Answer 2

I found the issue. I cannot instantiate SocketIO in my app.py file. I have to export app from my app.py file and instantiate SocketIO in my run.py file. My final code looks like this:
app.py
def create_app(env_name):
"""
Create app
"""
# app initiliazation
app = Flask(__name__)
app.config.from_object(app_config[env_name])
# initializing bcrypt and db
bcrypt.init_app(app)
db.init_app(app)
return app
Finally, my run.py file looks like this.
import os
import logging
from dotenv import load_dotenv, find_dotenv
from flask_socketio import SocketIO, join_room, emit
from src.app import create_app
load_dotenv(find_dotenv())
env_name = os.getenv('FLASK_ENV')
app = create_app(env_name)
socketio = SocketIO(app)
if __name__ == '__main__':
port = os.getenv('PORT')
# run app
socketio.run(app, host='0.0.0.0', port=port)