Quart

To run apps built with the Quart web framework using Unit:

Install Unit with a Python 3.5+ language module.

Create a virtual environment to install Quart`s PIP package, for instance:

$ cd /path/to/app/  # Path to the application directory; use a real path in your configuration
$ python --version  # Make sure your virtual environment version matches the module version
      Python X.Y.Z  # Major version, minor version, and revision number
$ python -m venv venv  # Arbitrary name of the virtual environment
$ source venv/bin/activate  # Name of the virtual environment from the previous command
$ pip install quart
$ deactivate

Warning:
Create your virtual environment with a Python version that matches the language module from Step 1 up to the minor number (X.Y in this example). Also, the app type in Step 5 must resolve to a similarly matching version; Unit doesn’t infer it from the environment.

Let’s try a WebSocket-enabled version of a tutorial app, saving it as /path/to/app/asgi.py:

from quart import Quart, websocket

app = Quart(__name__)

@app.route('/')
async def hello():
    return '<body><h1>Hello, World!</h1></body>'

# Let's add WebSocket support to the app as well
@app.websocket('/ws')
async def ws():
    while True:
        await websocket.send('Hello, World!')

Change ownership:

Run the following command (as root) so Unit can access the application directory (If the application uses several directories, run the command for each one):
```
# chown -R unit:unit /path/to/app/  # User and group that Unit's router runs as by default
   
```
Note:
The unit:unit user-group pair is available only with official packages , Docker images, and some third-party repos. Otherwise, account names may differ; run the ps aux | grep unitd command to be sure.

For further details, including permissions, see the security checklist.

Next, prepare the Quart configuration for Unit (use real values for type, home, and path):

{
   "listeners": {
      "*:80": {
         "pass": "applications/quart"
      }
   },
   "applications": {
      "quart": {
         "type": "python 3.Y",
         "type_comment": "Must match language module version and virtual environment version",
         "path": "/path/to/app/",
         "path_comment": "Path to the ASGI module",
         "home": "/path/to/app/venv/",
         "home_comment": "Path to the virtual environment, if any",
         "module": "asgi",
         "module_comment": "ASGI module filename with extension omitted",
         "callable": "app",
         "callable_comment": "Name of the callable in the module to run"
      }
   }
}

Upload the updated configuration.

Assuming the JSON above was added to config.json. Run the following command as root:

# curl -X PUT --data-binary @config.json --unix-socket \
      /path/to/control.unit.sock \  # Path to Unit's control socket in your installation
      http://localhost/config/      # Path to the config section in Unit's control API

Note:
The control socket path may vary; run unitd -h or see Startup and shutdown for details.

After a successful update, your app should be available on the listener’s IP address and port:

$ curl http://localhost

      <body><h1>Hello, World!</h1></body>

$ wscat -c ws://localhost/ws

      < Hello, World!
      < Hello, World!
      < Hello, World!
      ...

Last modified February 6, 2025