Support UniFi Controller

[AlekSi]

What should be done?

• [ ] #3929
• [ ] Something else?

[vifino]

Hey. I run the Unifi Controller semi-successfully on FerretDB with SQLite.

It exhibits strange behaviour, some pages don't load on the web ui, at least not on the first try. I believe #3792 is necessary as I get a bunch of "$group accumulator \"$first\" is not implemented yet" error messages.

Because I use it with sqlite, I needed to tweak the Mongo URI in system.properties of the unifi controller to drop the user/pass. Other than that, it seems to function enough to provision APs, though not with much joy.

[vs49688]

Things are definitely moving along - I'm running Unifi 7.5 w/ Mongo 4.4. With Ferret 1.21.0, it works, but:

• There's a bunch of these errors during the mongorestore

  {
   "FlagBits": "[]",
   "Checksum": int64(0),
   "Sections": [
     {
       "Kind": 0,
       "Document": {
         "ok": 0.0,
         "errmsg": "Index option \"ns\" is unknown",
         "code": 2,
         "codeName": "BadValue",
       },
     },
   ],
  }

• It uses way, way too much CPU - this is just from browsing the Web UI and responding to /inform requests from the APs.