Channels

Strapper real-time deployment log

by Archie To, 18 April 2023

This real-time deployment log feature was implemented by following a tutorial on Django Channels.

All of the code below can be found in the Strapper GitLab repository

Setup

Install daphne and channels:

$ pip install -U daphne channels["daphne"]

In app_starter/app_starter/settings.py:

INSTALLED_APPS = [
    "daphne",
    ...,
]

ASGI_APPLICATION = "app_starter.asgi.application"

Configure ASGI app

Since wsgi doesn’t support long-lived connections, we will have to serve our app as an asgi app. In app_starter/app_starter/asgi.py:

"""
ASGI config for app_starter project.

It exposes the ASGI callable as a module-level variable named ``application``.

For more information on this file, see
https://docs.djangoproject.com/en/4.1/howto/deployment/asgi/
"""

import os

from channels.auth import AuthMiddlewareStack
from channels.routing import ProtocolTypeRouter, URLRouter
from channels.security.websocket import AllowedHostsOriginValidator
from django.core.asgi import get_asgi_application

from normal_users.routing import websocket_urlpatterns

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'app_starter.settings')
# Initialize Django ASGI application early to ensure the AppRegistry
# is populated before importing code that may import ORM models.
django_asgi_app = get_asgi_application()

application = ProtocolTypeRouter({
    "http": django_asgi_app,
    "websocket": AllowedHostsOriginValidator(
        AuthMiddlewareStack(URLRouter(websocket_urlpatterns))
    ),
})

Here we are using ProtocolTypeRouter as the root application, which defines what asgi application to serve depending on the protocol type: