As well as WSGI, Django also supports deploying on ASGI, the emerging Python standard for asynchronous web servers and applications.
Django’s startproject management command sets up a default ASGI
configuration for you, which you can tweak as needed for your project, and
direct any ASGI-compliant application server to use.
Django includes getting-started documentation for the following ASGI servers:
application object¶Like WSGI, ASGI has you supply an application callable which
the application server uses to communicate with your code. It’s commonly
provided as an object named application in a Python module accessible to
the server.
The startproject command creates a file
<project_name>/asgi.py that contains such an application callable.
It’s not used by the development server (runserver), but can be used by
any ASGI server either in development or in production.
ASGI servers usually take the path to the application callable as a string;
for most Django projects, this will look like myproject.asgi:application.
Warning
While Django’s default ASGI handler will run all your code in a synchronous thread, if you choose to run your own async handler you must be aware of async-safety.
Do not call blocking synchronous functions or libraries in any async code. Django prevents you from doing this with the parts of Django that are not async-safe, but the same may not be true of third-party apps or Python libraries.
When the ASGI server loads your application, Django needs to import the settings module — that’s where your entire application is defined.
Django uses the DJANGO_SETTINGS_MODULE environment variable to locate
the appropriate settings module. It must contain the dotted path to the
settings module. You can use a different value for development and production;
it all depends on how you organize your settings.
If this variable isn’t set, the default asgi.py sets it to
mysite.settings, where mysite is the name of your project.
To apply ASGI middleware, or to embed Django in another ASGI application, you
can wrap Django’s application object in the asgi.py file. For example:
from some_asgi_library import AmazingMiddleware
application = AmazingMiddleware(application)
Jan 24, 2024