2.0: Swagger UI broken for POST /dcim/cables/, possibly others

[glennmatthews]

Environment

• Nautobot version (Docker tag too if applicable): 2.0
• Python version:
• Database platform, version:
• Middleware(s):

Steps to Reproduce

1. Navigate to https://next.demo.nautobot.com/api/docs/ (you must be using the legacy UI or the page fails to load at all; this is probably a separate bug)
2. Click to expand the POST /dcim/cables/ subheading.

Expected Behavior

Section to expand and render information about how to POST to this endpoint - this works in demo.nautobot.com (1.5.7) by comparison:

Observed Behavior

Loading spinner appears indefinitely, eventually the browser may complain about a long-running script and offer to stop it for you:

Maybe related to #3500?

[glennmatthews]

Profiling in the browser shows that the size of the Swagger docs has increased by over an order of magnitude:

demo.nautobot.com: 295kB (and that includes a number of installed plugins, default size will be lower still)
next.demo.nautobot.com: 10.64MB

[gsnider2195]

I'm seeing similar schema sizes for demo and next:

https://demo.nautobot.com/api/swagger/?api_version=1.2

Allow: GET, HEAD, OPTIONS
Content-Disposition: inline; filename="API Documentation (1.2).json"
Content-Length: 12467165
Content-Type: application/json
Date: Tue, 20 Jun 2023 16:43:02 GMT
Referrer-Policy: same-origin
Vary: Accept, Cookie, Origin
X-Content-Type-Options: nosniff
X-Frame-Options: DENY

https://next.demo.nautobot.com/api/swagger/?api_version=2.0

Allow: GET, HEAD, OPTIONS
Content-Disposition: inline; filename="API Documentation (2.0).json"
Content-Length: 10640435
Content-Type: application/json
Date: Tue, 20 Jun 2023 16:44:52 GMT
Referrer-Policy: same-origin
Server: Caddy
Server: WSGIServer/0.2 CPython/3.9.16
Vary: Accept, Cookie, Origin
X-Content-Type-Options: nosniff
X-Frame-Options: DENY

$ wc -l *.json
  292742 1.2.json
  251157 2.0.json

$ sort 1.2.json | uniq -c | sort -n | tail -20
   2472                                                     },
   2617                                 "format": "uuid"
   2952                                 "type": "string",
   3049                                 },
   3552                                                         "type": "string",
   3578                         }
   3667                 ],
   4257                         "type": "string",
   4315                                 "type": "string"
   4723                     }
   7455                             "items": {
   7455                             "type": "array",
   7455                         "explode": true,
   7455                         "style": "form"
   9221                         "in": "query",
   9593                         },
   9948                         "schema": {
  10348                             }
  12735                     {
  18510                     },

$ sort 2.0.json | uniq -c | sort -n | tail -20
   1950                             "type": "string",
   2044                                 "schema": {
   2090                                 "type": "string",
   2268                                                         "type": "string",
   2791                                 }
   3508                         "type": "string",
   3570                 ],
   3679                         }
   3900                                 "type": "string"
   4269                     }
   6235                         "style": "form"
   6314                             "items": {
   6314                             "type": "array",
   6314                         "explode": true,
   8811                         },
   9015                             }
   9063                         "in": "query",
   9705                         "schema": {
  12240                     {
  15751                     },

[bryanculver]

Definition of Done: Ensure the Swagger UI loads, can expand different API endpoints, and is not stuck with a spinner like in the screenshot above. No hard line on file size.

[bryanculver]

Might want to look at "ENUM_GENERATE_CHOICE_DESCRIPTION": False to cut down on bloat. A feature introduced upstream in Swagger might be adding a lot of very verbose ENUM value choices.

[glennmatthews]

It looks like we now have a number of cyclic / infinitely recursive schema definitions. For example,

• Cable has termination_a of type CableTermination
• CableTermination is one of CircuitTermination, ConsolePort, etc.
• CircuitTermination has a cable_peer of type CableTermination.... 💀

Looks like the depth isn't being accurately reflected in the schema.

[lampwins]

Going guess this is a contributing factor to the size of the schema. Or at least, not helping.

[glennmatthews]

Fixed by #4000