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Configuration Language

note
OpenFGA is an open source Fine-Grained Authorization solution based on Google's Zanzibar. We welcome community contribution to this project.

The OpenFGA's Configuration Language is used to build a representation of a system's authorization model. It informs OpenFGA's API on what the object types in the system are and how they could relate to one another. It describes the relations possible on an object of a certain type and lists the conditions under which one is related to that object.

The DSL and the JSON syntax are two presentations of that configuration language. The JSON syntax is accepted by the API and closely matches the API described in the Zanzibar paper. The DSL is syntactic sugar on top of the JSON syntax and compiles down to it before being sent to OpenFGA's API. The DSL is meant to make modeling easier and more intuitive.

You'll encounter the JSON syntax when calling the API directly or through the SDKs, and the DSL when interacting with OpenFGA through the Playground. Throughout the documentation you can switch between the two presentations.

To understand this guide better, you should be familiar with some OpenFGA Concepts and How to get started on modeling.

What Does The Configuration Language Look Like?

Below is a sample authorization model. In the next sections we'll go over the building blocks that make the OpenFGA configuration language.

type domain
relations
define member as self
type folder
relations
define can_share as writer
define owner as self or owner from parent_folder
define parent_folder as self
define viewer as self or writer or viewer from parent_folder
define writer as self or owner or writer from parent_folder
type document
relations
define can_share as writer
define owner as self or owner from parent_folder
define parent_folder as self
define viewer as self or writer or viewer from parent_folder
define writer as self or owner or writer from parent_folder
info

The authorization model describes three types of objects: domain, folder and document.

The domain type definition has a single relation called member that only allows direct relationships.

The folder and document type definitions each have five relations: parent_folder, owner, editor, viewer and can_share.

The Direct Relationship Keyword

self, when used in the context of the relation definition allows direct relationships to the objects of this type. The absence of self disallows these direct relationships.

info

self in the OpenFGA DSL translates to this in the OpenFGA API syntax.

For example, let's take a closer look at the team type.

type team
relations
define member as self

This team type definition defines all the relations that users can have with an object of type team. In this case the relation is: member.

Due to the direct relationship keyword (self) being used, a user in the system can have a direct relationship with the team type as a member.

In the type definition snippet above, anne is a member of team:product if any one of the following relationship tuple sets exist:

  • [
    // Anne is directly related to the product team as a member
    {
    "user": "anne",
    "relation": "member",
    "object": "team:product",
    },
    ]
  • [
    // Everyone (`*`) is directly related to the product team as a member
    {
    "user": "*",
    "relation": "member",
    "object": "team:product",
    },
    ]
  • [
    // Members of the contoso team are members of the product team
    {
    "user": "team:contoso#member",
    "relation": "member",
    "object": "team:product",
    },
    // Anne is a member of the contoso team
    {
    "user": "anne",
    "relation": "member",
    "object": "team:contoso",
    },
    ]

For more examples, take look at Modeling Building Blocks: Direct Relationships.

Referencing Other Relations On The Same Object

You can also reference other relations on the same object. Let us look at a simplified document type definition.

type document
relations
define editor as self
define viewer as self or editor
define can_rename as editor

The above document type definition defines all the relations that users can have with an object of type document. In this case the relations are: editor, viewer and can_rename.

The viewer and can_rename relation definitions are both referencing editor, which is another relation on the same type.

info

Notice how can_rename does not reference the direct relationship keyword (self), indicating that a direct relationship is not possible (as in a user cannot be directly assigned this relation, it has to be inherited through an assignment of the editor relation). The viewer relation on the other hand allows both direct and indirect relationships using the Union Operator.

In the type definition snippet above, anne is a viewer of document:new-roadmap if any one of the following relationship tuple sets exists:

  • anne is an editor of document:new-roadmap

    [
    // Anne is an editor of the new-roadmap document
    {
    "user": "anne",
    "relation": "editor",
    "object": "document:new-roadmap",
    },
    ]
  • anne is a viewer of document:new-roadmap

    [
    // Anne is a viewer of the new-roadmap document
    {
    "user": "anne",
    "relation": "viewer",
    "object": "document:new-roadmap",
    },
    ]

anne has a can_rename relationship with document:new-roadmap only if anne has an editor relationship with the document:

  • anne is an editor of document:new-roadmap
    [
    // Anne is an editor of thew new-roadmap document
    {
    "user": "anne",
    "relation": "editor",
    "object": "document:new-roadmap",
    },
    ]

For more examples, take a look at Modeling Building Blocks: Concentric Relationships, Modeling: Roles and Permissions and Advanced Modeling: Google Drive.

Another form of indirect relationships is made possible by referencing relations on other objects.

The syntax is X from Y. It requires that:

  • the other object is related to the current object as Y
  • the user is related to another object as X

Take a look at the authorization model below.

type folder
relations
define viewer as self
type document
relations
define parent_folder as self
define viewer as self or viewer from parent_folder

The snippet below taken from the authorization model above is stating that viewers of a document are all users directly assigned the viewer relation and all users who can view the document's parent folder.

    define viewer as self or viewer from parent_folder

In the authorization model above, anne is a viewer of document:new-roadmap if any one of the following relationship tuple sets exists:

  • Anne is a viewer of the parent folder of the new-roadmap document
    [
    // planning folder is the parent folder of the new-roadmap document
    {
    "user": "folder:planning",
    "relation": "parent_folder",
    "object": "document:new-roadmap",
    },
    // anne is a viewer of the planning folder
    {
    "user": "anne",
    "relation": "viewer",
    "object": "folder:planning",
    },
    ]
  • Anne is a viewer of the new-roadmap document (direct relationship)
    [
    // anne is a viewer of the new-roadmap document
    {
    "user": "anne",
    "relation": "viewer",
    "object": "document:new-roadmap",
    },
    ]

This particular use of referencing relations on related objects is defining a transitive implied relationship. If user A is related to a certain object B as a viewer, and object B is related to object C as parent, then user A is related to object C as viewer.

This can be used to indicate that viewers of a folders are viewers of all documents in that folder.

For more examples, take look at Modeling: Parent-Child Objects, Advanced Modeling: Google Drive, Advanced Modeling: GitHub, and Advanced Modeling: Entitlements.

The Union Operator

The union operator (or in the DSL, union in the JSON syntax) is used to indicate that a relationship exists if the user is in any of the sets of users (union).

    define viewer as self or editor

In the type definition snippet above, anne is a viewer of document:new-roadmap if any of the following conditions are satisfied:

  • there exists a direct relationship with anne as editor of document:new-roadmap
    [
    {
    "user": "anne",
    "relation": "editor",
    "object": "document:new-roadmap",
    },
    ]
  • anne is a viewer of document:new-roadmap:
    [
    {
    "user": "anne",
    "relation": "viewer",
    "object": "document:new-roadmap",
    },
    ]
info

The above authorization model indicates that a user is related as a viewer if they are in any of:

  • the userset of all users related to the object as "viewer"; indicating that a user can be assigned a direct viewer relation
  • the userset of all users related to the object as "editor"; indicating that a user who is an editor is also implicitly a viewer

So if anne is in at least one of those usersets (is either an editor or a viewer), the check on {"user": "anne", "relation": "viewer", "object": "document:new-roadmap"} will return {"allowed": true}.

For more examples, take a look at Modeling Building Blocks: Concentric Relationships, Modeling Roles and Permissions and Advanced Modeling: Modeling for IoT.

The Intersection Operator

The intersection operator (and in the DSL, intersection in the JSON syntax) is used to indicate that a relationship exists if the user is in all the sets of users (intersection)

    define viewer as authorized_user and editor

In the type definition snippet above, anne is a viewer of document:new-roadmap if all of the following conditions are satisfied:

  • anne is an editor of document:new-roadmap
    [
    {
    "user": "anne",
    "relation": "editor",
    "object": "document:new-roadmap",
    },
    ]
    AND
  • anne is an authorized_user of document:new-roadmap:
    [
    {
    "user": "anne",
    "relation": "authorized_user",
    "object": "document:new-roadmap",
    },
    ]
info

The above authorization model indicates that a user is related as a viewer if they are in all of:

  • the userset of all users related to the object as "authorized_user"
  • the userset of all users related to the object as "editor"

So anne has to be in the intersection of the usersets (anne has to be both an editor AND an authorized_user), in order for the check on {"user": "anne", "relation": "viewer", "object": "document:new-roadmap"} to return {"allowed": true}.

anne is not a viewer for document:new-roadmap if either of the following is true:

  • anne is not an editor to document:new-roadmap: no relationship tuple of {"user": "anne", "relation": "editor", "object": "document:new-roadmap"}
  • anne is not an authorized_user on the document:new-roadmap: no relationship tuple of {"user": "anne", "relation": "authorized_user", "object": "document:new-roadmap"}

For more examples, take look at Modeling with Multiple Restrictions.

The Exclusion Operator

The exclusion operator (but not in the DSL, difference in the JSON syntax) is used to indicate that a relationship exists if the user is in the base userset, but not in the excluded userset. This is helpful in modeling exclusion or block lists.

    define viewer as self but not blocked

In the type definition snippet above, anne is a viewer of document:new-roadmap if:

  • anne is assigned a direct relationship as viewer to document:new-roadmap

    [
    {
    "user": "anne",
    "relation": "viewer",
    "object": "document:new-roadmap",
    },
    ]
    AND
  • anne is not blocked to document:new-roadmap. That is, the following relation tuple does not exists

    [
    {
    "user": "anne",
    "relation": "blocked",
    "object": "document:new-roadmap",
    },
    ]

For more information, see Modeling: Blocklists.

info

The above authorization model indicates that a user is related as a viewer if they are in:

  • the userset of all users related to the object as "viewer"

but not in:

  • the userset of all users related to the object as "blocked"

So anne has to be both a viewer AND NOT blocked, in order for the check on {"user": "anne", "relation": "viewer", "object": "document:new-roadmap"} to return {"allowed": true}.

anne is not a viewer for document:new-roadmap if either of the following is true:

  • anne is not assigned direct relationship as viewer to document:new-roadmap: no relationship tuple of {"user": "anne", "relation": "viewer", "object": "document:new-roadmap"}
  • anne is blocked on the document:new-roadmap {"user": "anne", "relation": "blocked", "object": "document:new-roadmap"}

Equivalent Zanzibar Concepts

The JSON syntax accepted by the OpenFGA API closely mirrors the syntax represented in the Zanzibar paper, with a bit of flattening and converting keys from snake_case to camelCase.

ZanzibarOpenFGA JSONOpenFGA DSL
thisthisself
unionunionor
intersectionintersectionand
exclusiondifferencebut not
tuple_to_usersettupleToUsersetx from y

In the Zanzibar paper, there's this example:

name: "doc"

relation { name: "owner" }

relation {
name: "editor"
userset_rewrite {
union {
child { _this {} }
child { computed_userset { relation: "owner" } }
}}}

relation {
name: "viewer"
userset_rewrite {
union {
child { _this {} }
child { computed_userset { relation: "editor" } }
child { tuple_to_userset {
tupleset { relation: "parent" }
computed_userset {
object: $TUPLE_USERSET_OBJECT # parent folder
relation: "viewer" }}}
}}}

In the OpenFGA DSL, it would become:

type doc
relations
define owner as self
define editor as self or owner
define viewer as self or editor or viewer from parent

And in the OpenFGA JSON, it would become:

{
"type_definitions": [
{
"type": "doc",
"relations": {
"owner": {
"this": {}
},
"editor": {
"union": {
"child": [
{
"this": {}
},
{
"computedUserset": {
"relation": "owner"
}
}
]
}
},
"viewer": {
"union": {
"child": [
{
"this": {}
},
{
"computedUserset": {
"relation": "editor"
}
},
{
"tupleToUserset": {
"tupleset": {
"relation": "parent"
},
"computedUserset": {
"relation": "viewer"
}
}
}
]
}
}
}
}
]
}

We believe this syntax is easier to read/write.

So the following:

    define viewer as self or editor or viewer from parent

Can be read as:

  • The users with a viewer relationship to a certain doc are any of:
    • the set of users who are directly related with this doc as viewer
    • the set of users who are related to this doc as editor
    • the set of users who are related to any object OBJ_1 as viewer, where object OBJ_1 is any object related to this doc as parent (e.g. viewers of this doc's parent folder, where the parent folder is OBJ_1)

Learn more about Zanzibar at the Zanzibar Academy.

OpenFGA Concepts

Learn about the OpenFGA Concepts.

Modeling: Getting Started

Learn about how to get started with modeling your permission system in OpenFGA.

Direct Access

Learn about modeling user access to an object.