Support Redis unix socket

[kommserv]

Presently, NetBox is limited to communicating with Redis TCP port, with no support for Redis unix socket.
This limitation feels unnecessary, and for someone familiar with settings.py it should be fairly easy to add support for socket.

For a quick-and-dirty hack, I can force NetBox to use socket instead of port by changing this line:

'LOCATION': f'{CACHING_REDIS_PROTO}://{CACHING_REDIS_HOST}:{CACHING_REDIS_PORT}/{CACHING_REDIS_DATABASE}',

to

'LOCATION': f'unix://@{CACHING_REDIS_HOST}?db={CACHING_REDIS_DATABASE}',

This works, but is of course horrible as it breaks existing support for TCP. (The syntax was easily gleaned from comments in the other Python scripts).

A much neater approach has been suggested before, namely in issue #4377, which seems to have been closed without any action taken. I think the outlined syntax in configuration.py is good, but the suggested changes to settings.py have of course become outdated.

And so I hope this post might inspire you, dear maintainer/developer, to bring Redis socket support to NetBox! :-)

[minijackson]

Hello, I'm also interested in supporting Redis through Unix sockets, and I'm willing to provide a patch. We already have one in the Nixpkgs distribution, which has worked without any issues.

This defines a new REDIS['tasks']['URL'] and REDIS['caching']['URL'] which take priority if defined by the user. The user can then set this config if they want to use Unix sockets:

REDIS = {
    "tasks": {"URL": "unix:///run/redis-netbox/redis.sock?db=0", "SSL": False},
    "caching": {"URL": "unix:///run/redis-netbox/redis.sock?db=1", "SSL": False},
}

What do you all think? Would this be accepted?

[jeremystretch]

@minijackson could you comment with your proposed implementation on #15962? That would be the best place to discuss.

[minijackson]

Done! Thanks for pointing me there