Usersets

What is a userset?

A userset represents a set or collection of users.

Usersets can be used to indicate that a group of users in the system have a certain relation with an object. This can be used to assign permissions to groups of users rather than specific ones, allowing us to represent the permissions in our system using less tuples and granting us flexibility in granting or denying access in bulk.

In OpenFGA, usersets are represented via this notation: object#relation, where object is made up of a type and an object identifier. For example:

• company:xyz#employee represents all users that are related to company:xyz as employee
• tweet:12345#viewer represents all users that are related to tweet:12345 as viewer

How do check requests work with usersets?

Imagine the following authorization model:

DSL

model
  schema 1.1

type user

type org
  relations
    define member: [user]

type document
  relations
    define reader: [user, org#member]

JSON

{
  "schema_version": "1.1",
  "type_definitions": [
    {
      "type": "user"
    },
    {
      "type": "org",
      "relations": {
        "member": {
          "this": {}
        }
      },
      "metadata": {
        "relations": {
          "member": {
            "directly_related_user_types": [
              {
                "type": "user"
              }
            ]
          }
        }
      }
    },
    {
      "type": "document",
      "relations": {
        "reader": {
          "this": {}
        }
      },
      "metadata": {
        "relations": {
          "reader": {
            "directly_related_user_types": [
              {
                "type": "user"
              },
              {
                "type": "org",
                "relation": "member"
              }
            ]
          }
        }
      }
    }
  ]
}

Now let us assume that the store has the following tuples:

[// Userset "Members of the xyz org" can read the budget document
  {
  "_description": "Userset \"Members of the xyz org\" can read the budget document",
  "user": "org:xyz#member",
  "relation": "reader",
  "object": "document:budget"
}// Anne is part of the userset "Members of the xyz org"
  {
  "_description": "Anne is part of the userset \"Members of the xyz org\"",
  "user": "user:anne",
  "relation": "member",
  "object": "org:xyz"
}]

If we call the check API to see if user anne has a reader relationship with document:budget, OpenFGA will check whether anne is part of the userset that does have a reader relationship. Because she is part of that userset, the request will return true:

Node.js

Initialize the SDK

// ApiTokenIssuer, ApiAudience, ClientId and ClientSecret are optional.
// import the SDK
const { OpenFgaClient } = require('@openfga/sdk');

// Initialize the SDK with no auth - see "How to setup SDK client" for more options
const fgaClient = new OpenFgaClient({
  apiUrl: process.env.FGA_API_URL, // required, e.g. https://api.fga.example
  storeId: process.env.FGA_STORE_ID,
  authorizationModelId: process.env.FGA_MODEL_ID, // Optional, can be overridden per request
});

// Run a check
const { allowed } = await fgaClient.check({
    user: 'user:anne',
    relation: 'reader',
    object: 'document:budget',
  }, {
  authorization_model_id: '01HVMMBCMGZNT3SED4Z17ECXCA',
});

// allowed = true

Go

Initialize the SDK

// ApiTokenIssuer, ApiAudience, ClientId and ClientSecret are optional.
import (
    "os"

    . "github.com/openfga/go-sdk"
    . "github.com/openfga/go-sdk/client"
)

func main() {
    // Initialize the SDK with no auth - see "How to setup SDK client" for more options
    fgaClient, err := NewSdkClient(&ClientConfiguration{
        ApiUrl:               os.Getenv("FGA_API_URL"), // required, e.g. https://api.fga.example
        StoreId:              os.Getenv("FGA_STORE_ID"), // optional, not needed for `CreateStore` and `ListStores`, required before calling for all other methods
        AuthorizationModelId: os.Getenv("FGA_MODEL_ID"),  // Optional, can be overridden per request
    })

    if err != nil {
    // .. Handle error
    }
}

options := ClientCheckOptions{
    AuthorizationModelId: PtrString("01HVMMBCMGZNT3SED4Z17ECXCA"),
}

body := ClientCheckRequest{
    User:     "user:anne",
    Relation: "reader",
    Object:   "document:budget",
}

data, err := fgaClient.Check(context.Background()).
    Body(body).
    Options(options).
    Execute()

// data = { allowed: true }

.NET

Initialize the SDK

// ApiTokenIssuer, ApiAudience, ClientId and ClientSecret are optional.
// import the SDK
using OpenFga.Sdk.Client;
using OpenFga.Sdk.Client.Model;
using OpenFga.Sdk.Model;
using Environment = System.Environment;

namespace Example;

class Example {
    public static async Task Main() {
        // Initialize the SDK with no auth - see "How to setup SDK client" for more options
        var configuration = new ClientConfiguration() {
          ApiUrl = Environment.GetEnvironmentVariable("FGA_API_URL"), ?? "http://localhost:8080", // required, e.g. https://api.fga.example
          StoreId = Environment.GetEnvironmentVariable("FGA_STORE_ID"), // optional, not needed for `CreateStore` and `ListStores`, required before calling for all other methods
          AuthorizationModelId = Environment.GetEnvironmentVariable("FGA_MODEL_ID"), // Optional, can be overridden per request
        };
        var fgaClient = new OpenFgaClient(configuration);
    }
}

var options = new ClientCheckOptions {
    AuthorizationModelId = "01HVMMBCMGZNT3SED4Z17ECXCA",
};
var body = new ClientCheckRequest {
    User = "user:anne",
    Relation = "reader",
    Object = "document:budget",
    
};
var response = await fgaClient.Check(body, options);

// response.Allowed = true

Python

Initialize the SDK

# ApiTokenIssuer, ApiAudience, ClientId and ClientSecret are optional.

import asyncio
import os
import json
from openfga_sdk.client import ClientConfiguration, OpenFgaClient

async def main():
    configuration = ClientConfiguration(
        api_url = os.environ.get('FGA_API_URL'), # required, e.g. https://api.fga.example
        store_id = os.environ.get('FGA_STORE_ID'), # optional, not needed for `CreateStore` and `ListStores`, required before calling for all other methods
        authorization_model_id = os.environ.get('FGA_MODEL_ID'), # Optional, can be overridden per request
    )

    # Enter a context with an instance of the OpenFgaClient
    async with OpenFgaClient(configuration) as fga_client:
        api_response = await fga_client.read_authorization_models()
        await fga_client.close()

asyncio.run(main())

options = {
    "authorization_model_id": "01HVMMBCMGZNT3SED4Z17ECXCA"
}
body = ClientCheckRequest(
    user="user:anne",
    relation="reader",
    object="document:budget",
)

response = await fga_client.check(body, options)

# response.allowed = true

Java

Initialize the SDK

// ApiTokenIssuer, ApiAudience, ClientId and ClientSecret are optional.

import dev.openfga.sdk.api.client.OpenFgaClient;
import dev.openfga.sdk.api.configuration.ClientConfiguration;

public class Example {
  public static void main(String[] args) throws Exception {
      var config = new ClientConfiguration()
              .apiUrl(System.getenv("FGA_API_URL")) // If not specified, will default to "https://localhost:8080"
              .storeId(System.getenv("FGA_STORE_ID")) // Not required when calling createStore() or listStores()
              .authorizationModelId(System.getenv("FGA_AUTHORIZATION_MODEL_ID")); // Optional, can be overridden per request

      var fgaClient = new OpenFgaClient(config);
  }
}

var options = new ClientCheckOptions()
        .authorizationModelId("01HVMMBCMGZNT3SED4Z17ECXCA");

var body = new ClientCheckRequest()
        .user("user:anne")
        .relation("reader")
        ._object("document:budget");

var response = fgaClient.check(body, options).get();

// response.getAllowed() = true 

CLI

Set FGA_API_URL according to the service you are using (e.g. https://api.fga.example)

Set FGA_API_URL according to the service you are using (e.g. https://api.fga.example)

fga query check --store-id=$FGA_STORE_ID --model-id=01HVMMBCMGZNT3SED4Z17ECXCA user:anne reader document:budget

# Response: {"allowed":true}

curl

Set FGA_API_URL according to the service you are using (e.g. https://api.fga.example)

Set FGA_API_URL according to the service you are using (e.g. https://api.fga.example)

curl -X POST $FGA_API_URL/stores/$FGA_STORE_ID/check \
  -H "Authorization: Bearer $FGA_API_TOKEN" \ # Not needed if service does not require authorization
  -H "content-type: application/json" \
  -d '{"authorization_model_id": "01HVMMBCMGZNT3SED4Z17ECXCA", "tuple_key":{"user":"user:anne","relation":"reader","object":"document:budget"}}'

# Response: {"allowed":true}

Pseudocode

check(
  user = "user:anne", // check if the user `user:anne`
  relation = "reader", // has an `reader` relation
  object = "document:budget", // with the object `document:budget`
   authorization_id = "01HVMMBCMGZNT3SED4Z17ECXCA"
);

Reply: true

How do expand requests work with usersets?

Imagine the following authorization model:

DSL

model
  schema 1.1

type user

type document
  relations
    define writer: [user, org#member]
    define reader: [user, org#member] or writer

JSON

{
  "schema_version": "1.1",
  "type_definitions": [
    {
      "type": "user"
    },
    {
      "type": "document",
      "relations": {
        "writer": {
          "this": {}
        },
        "reader": {
          "union": {
            "child": [
              {
                "this": {}
              },
              {
                "computedUserset": {
                  "relation": "writer"
                }
              }
            ]
          }
        }
      },
      "metadata": {
        "relations": {
          "reader": {
            "directly_related_user_types": [
              {
                "type": "user"
              },
              {
                "type": "org",
                "relation": "member"
              }
            ]
          },
          "writer": {
            "directly_related_user_types": [
              {
                "type": "user"
              },
              {
                "type": "org",
                "relation": "member"
              }
            ]
          }
        }
      }
    }
  ]
}

If we wanted to see which users and usersets have a reader relationship with document:budget, we can call the Expand API. The response will contain a userset tree where the leaf nodes are specific user IDs and usersets. For example:

{
  "tree": {
    "root": {
      "type": "document:budget#reader",
      "union": {
        "nodes": [
          {
            "type": "document:budget#reader",
            "leaf": {
              "users": {
                "users": ["user:bob"]
              }
            }
          },
          {
            "type": "document:budget#reader",
            "leaf": {
              "computed": {
                "userset": "document:budget#writer"
              }
            }
          }
        ]
      }
    }
  }
}

As you can see from the response above, with usersets we can express unions of user groups. We can also express intersections and exclusions.

Internals

Using the type definitions in the authorization model, some of the situations we can represent are:

• that a user is not in a set of users having a certain relation to an object, even if a relationship tuple exists in the system. See Disabling Direct Relationships
• that a user has a certain relationship with an object if they are in the union, intersection or exclusion of usersets.
• that a user being in a set of users having a certain relation to an object can result in them having another relation to the object. See Concentric Relationships
• that the user being in a set of users having a certain relation to an object and that object is in a set of users having a certain relation to another object, can imply that the original user has a certain relationship to the final object. See Object-to-Object Relationships

When executing the Check API of the form check(user, relation, object), OpenFGA will perform the following steps:

1. In the authorization model, look up type and its relation. Start building a tree where the root node will be the definition of that relation, which can be a union, exclusion, or intersection of usersets, or it can be direct users.
2. Expand all the usersets involved into new nodes in the tree. This means recursively finding all the users that are members of the usersets. If there are direct relationships with users, create leaf nodes.
3. Check whether user is a leaf node in the tree. If the API finds one match, it will return immediately and will not expand the remaining nodes.

Related Sections

See the following sections for more information:

Managing Group Membership

How to add users to a userset

• More

Managing Group Access

How to add permissions to a userset

• More