Clarification on OPL usage & namespaces in Keto

[jjhwan-h]

Hello,
I’m a new user who just started exploring Keto.
While following the cat-videos-example, I came across some questions:

1. In this example, policy evaluation works without using OPL. What is the actual role of OPL in this case?
   Is it simply because the policy here is very simple, so there was no need to define OPL explicitly?

2. Looking at the config schema, I noticed there are both namespace and namespaces.
   If I understand correctly, namespaces points to an OPL file, and if we don’t want to use OPL, we can just configure a simple namespace instead. Is that correct?

"namespace": {
  "type": "object",
  "properties": {
    "$schema": {
      "$ref": "#/definitions/$schema"
    },
    "name": {
      "type": "string",
      "title": "The name of the namespace.",
      "examples": ["videos", "groups", "files"]
    },
    "id": {
      "type": "integer",
      "title": "The unique ID of the namespace. Can not be changed once set.",
      "minimum": 0,
      "maximum": 2147483647
    },
    "config": {
      "type": "object",
      "title": "The configuration of the namespace.",
      "description": "To be defined."
    }
  },
  "additionalProperties": false,
  "required": ["name"]
},
...
"namespaces": {
  "description": "Namespace configuration or its location.",
  "default": "file://./keto_namespaces",
  "oneOf": [
    {
      "title": "Legacy namespace Repo URI",
      "description": "A URI that points to a directory of namespace files, a single file with all namespaces, or a websocket connection that provides former via `github.com/ory/x/watcherx.WatchAndServeWS`",
      "type": "string",
      "format": "uri"
    },
    {
      "type": "array",
      "title": "Legacy namespace configuration",
      "items": {
        "$ref": "#/definitions/namespace"
      }
    }
  ]
}

Sorry if my question is a bit unclear.

[vinckr]

Hello @jjhwan-h

You're correct: the cat-videos example is a bit older and doesn't use OPL at all. It uses tuple-based authorization (Zanzibar model), which is Ory Keto's core feature. The example is simple enough that defining relationships like videos:cat-video#view@users:user1 suffices.

namespace vs namespaces Confusion

• namespaces (plural): Legacy configuration pointing to namespace definitions. Can be a file path, URI, or inline array of namespace objects.
• namespace (singular): The schema definition for a single namespace object within that configuration.