Deploy docs for nginx unclear

[Helveg]

The deploy documentation for nginx contains the following config:

     upstream app_server {
        # fail_timeout=0 means we always retry an upstream even if it failed
       # to return a good HTTP response

       # for UNIX domain socket setups
       server unix:/tmp/gunicorn.sock fail_timeout=0;

       # for a TCP configuration
       # server 192.168.0.7:8000 fail_timeout=0;
     }

    location @proxy_to_app {
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header X-Forwarded-Proto $scheme;
      proxy_set_header Host $http_host;
      # we don't want nginx trying to do something clever with
      # redirects, we set the Host: header above already.
      proxy_redirect off;
      proxy_pass http://app_server;
    }

But it does not continue to provide steps to make gunicorn listen to http://app_server or unix:/tmp/gunicorn.sock. As the main recommended deployment option I think it's important to ensure that a minimal working example can be obtained from the docs without any blanks.

Combining this with the default command for Django gunicorn my_app.wsgi seems to make gunicorn listen on port 8000:

(venv) robin@Physio_NAS:~/ndsv# gunicorn vault.wsgi
[2020-10-12 18:36:13 +0200] [5237] [INFO] Starting gunicorn 20.0.4
[2020-10-12 18:36:13 +0200] [5237] [INFO] Listening at: http://127.0.0.1:8000 (5237)
[2020-10-12 18:36:13 +0200] [5237] [INFO] Using worker: sync
[2020-10-12 18:36:13 +0200] [5240] [INFO] Booting worker with pid: 5240

Meaning that the documentation for the recommended deployment for Python's largest web framework is not optimal.

Shouldn't we change:

       # for UNIX domain socket setups
       server unix:/tmp/gunicorn.sock fail_timeout=0;

       # for a TCP configuration
       # server 192.168.0.7:8000 fail_timeout=0;

to

       # for UNIX domain socket setups
       # server unix:/tmp/gunicorn.sock fail_timeout=0;

       # for a TCP configuration
       server 127.0.0.1:8000 fail_timeout=0;

and explain that you still have to run have gunicorn running on 127.0.0.1:8000 behind this (and not that it somehow gets invoked like someone coming from Apache+mod_wsgi might expect) and a simple command to test this like gunicorn -w 3 <your_wsgi_module> followed by a note that there are other better ways to ensure gunicorn is always running and then link to the monitoring part of the docs?

[benoitc]

unix socket is a good default.