Flask-socketio: Cannot connect to development server after adding flask-socketio

Created on 19 Sep 2018 · 2Comments · Source: miguelgrinberg/Flask-SocketIO

When I add flask_socketio into my __init__.py I don't get any errors running flask run but suddenly the debugger PIN is missing and the development server no longer serves requests at http://127.0.0.1:5000. Everything just fails silently.

My FLASK_APP variable is set to the name of my package and FLASK_ENV is set to development.

requirements.txt

click==6.7
Flask==1.0.2
Flask-SocketIO==3.0.2
itsdangerous==0.24
Jinja2==2.10
MarkupSafe==1.0
pkg-resources==0.0.0
python-engineio==2.2.0
python-socketio==2.0.0
six==1.11.0
Werkzeug==0.14.1

__init__.py

import os

from flask import Flask
from flask_socketio import SocketIO

socketio = SocketIO()

def create_app(test_config=None):
    # create and configure the app
    app = Flask(__name__, instance_relative_config=True)
    app.config.from_mapping(
        SECRET_KEY='dev',
        DATABASE=os.path.join(app.instance_path, 'garden.sqlite'),
    )

    if test_config is None:
        # load the instance config, if it exists, when not testing
        app.config.from_pyfile('config.py', silent=True)
    else:
        # load the test config if passed in
        app.config.from_mapping(test_config)

    # ensure the instance folder exists
    try:
        os.makedirs(app.instance_path)
    except OSError:
        pass

    from . import db
    db.init_app(app)

    from . import auth
    app.register_blueprint(auth.bp)

    socketio.init_app(app)
    return app

console output missing debugger PIN

 * Serving Flask-SocketIO app "garden"
 * Forcing debug mode on
 * Restarting with stat
WebSocket transport not available. Install eventlet or gevent and gevent-websocket for improved performance.

question

Source

owalerys

Most helpful comment

Installing eventlet via pip install eventlet fixed the issue, and suddenly the development server launches perfectly fine. If I'm not mistaken, the docs mentioned that the development server could run without eventlet and the last console message seems to indicate the same: WebSocket transport not available. Install eventlet or gevent and gevent-websocket for improved performance.

owalerys on 19 Sep 2018

👍2