> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fga.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Modeling GitHub permissions with Auth0 FGA

> Modeling GitHub permissions

This tutorial explains how to model GitHub's Organization permission model using [Auth0 FGA](/fga). [This article](https://docs.github.com/en/free-pro-team@latest/github/setting-up-and-managing-organizations-and-teams/managing-access-to-your-organizations-repositories) from the GitHub docs has links to all other articles we are going to be exploring in this document.

**What you will learn**

* Indicate [relationships](/fga-concepts#what-is-a-relationship) between a group of **[users](/fga-concepts#what-is-a-user)** and an **[object](/fga-concepts#what-is-an-object)**. See [Modeling User Groups](/modeling/basics/user-groups) for more details.\

  Used here to indicate that all members of an organization are repository admins on the organization.
* Modeling **concentric relationship** to have a certain [relation](/fga-concepts#what-is-a-relation) on an object imply another relation on the same object. See [Modeling Concepts: Concentric Relationships](/modeling/concepts/concentric-relationships) for more.\

  Used here to indicate that maintainers of a repository are also writers of that repository.
* Using [**the union operator**](/modeling/configuration-language#the-union-operator) condition to indicate that a user might have a certain relation with an object if they match any of the criteria indicated.\

  Used here to indicate that a user can be a reader on a repository, or can have the reader relationship implied through triager.
* Model [**parent-child objects**](/modeling/basics/parent-child) to indicate that a user having a relationship with a certain object implies having a relationship with another object in Auth0 FGA.\

  Used here to indicate that a repository admin on a GitHub organization, is an admin on all repositories that organization owns.

[GitHub
Explore the GitHub sample on the Auth0 FGA Playground](https://play.fga.dev/sandbox/?store=github)

## Before you start

In order to understand this guide correctly you must be familiar with some Auth0 Fine-Grained Authorization (FGA) concepts and know how to develop the things that we will list below.

<details>
  <summary>
    ### Auth0 FGA concepts

    It would be helpful to have an understanding of some concepts of Auth0 FGA before you start.
  </summary>

  #### Modeling concentric relationships

  You need to know how to update the authorization model to allow having nested relations such as all writers are readers. [Learn more →](/modeling/concepts/concentric-relationships)

  #### Modeling object-to-object relationships

  You need to know how to create relationships between objects and how that might affect a user's relationships to those objects. [Learn more →](/modeling/concepts/object-to-object-relationships)

  Used here to indicate that users who have repo admin access on an organization, have admin access to all repositories owned by that organization.

  #### Concepts & configuration language

  * Some [Auth0 FGA Concepts](/fga-concepts)
  * [Configuration Language](/modeling/configuration-language)
</details>

## What you will be modeling

GitHub is a system to develop and collaborate on code.

In this tutorial, you will build a subset of the GitHub permission model (detailed below) in Auth0 Fine-Grained Authorization (FGA), using some scenarios to validate the model.

> Note: For brevity, this tutorial will not model all of GitHub's permissions. Instead, it will focus on modeling for the scenarios outlined below

### Requirements

GitHub's permission model is represented in [their documentation](https://docs.github.com/en/organizations/managing-access-to-your-organizations-repositories/repository-roles-for-an-organization#repository-roles-for-organizations).

In this tutorial, you will be focusing on a subset of these permissions.

Requirements:

* Users can be admins, maintainers, writers, triagers or readers of repositories (each level inherits all access of the level lower than it. e.g. admins inherit maintainer access and so forth)
* Teams can have members
* Organizations can have members
* Organizations can own repositories
* Users can have repository admin access on organizations, and thus have admin access to all repositories owned by that organization

### Defined scenarios

There will be the following users:

* Anne
* Beth
* Charles, a member of the contoso/engineering team
* Diane, a member of the contoso/protocols team
* Erik, a member of the contoso org

And these requirements:

* members of the contoso/protocols team are members of the contoso/engineering team
* members of the contoso org are repo\_admins on the org
* repo admins on the org are admins on all the repos the org owns

There will be a:

* contoso/tooling repository, owned by the contoso org and of which Beth is a writer and Anne is a reader and members of the contoso/engineering team are admins

## Modeling GitHub's permissions

### 01. Permissions For Individuals In An Org

GitHub has [5 different permission levels for repositories](https://docs.github.com/en/free-pro-team@latest/github/setting-up-and-managing-organizations-and-teams/repository-permission-levels-for-an-organization):

![Image showing github permission levels](https://mintlify.s3.us-west-1.amazonaws.com/auth0-fga/images/fga/docs/content/modeling/advanced/assets/github-permission-level.svg)

At the end of this section we want to end up with the following permissions represented:

![Image showing permissions](https://mintlify.s3.us-west-1.amazonaws.com/auth0-fga/images/fga/docs/content/modeling/advanced/assets/github-01.svg)

To represent permissions in Auth0 Fine-Grained Authorization (FGA) we use [relations](/fga-concepts#what-is-a-relation). For repository permissions we need to create the following [authorization model](/fga-concepts#what-is-an-authorization-model):

The Auth0 FGA service determines if a [user](/fga-concepts#what-is-a-user) has access to an [object](/fga-concepts#what-is-an-object) by [checking](/fga-concepts#what-is-a-check-request) if the user has a relation to that object. Let us examine one of those relations in detail:

> [!NOTE]
>
> Objects of type "repo" have users related to them as "reader" if those users belong to the userset of all users related to the repo as "reader"

If we want to say `anne` is a reader of repository **repo:contoso/tooling** we create this [relationship tuple](/fga-concepts#what-is-a-relationship-tuple):

We can now [ask](/fga-concepts#what-is-a-check-request) Auth0 FGA "is `anne` a reader of repository **repo:contoso/tooling**?"

We could also say that `beth` is a writer of the same repository:

And ask some questions to Auth0 FGA:

The first reply makes sense but the second one does not. Intuitively, if `beth` was writer, she was also be a reader. In fact, GitHub explains this in [their documentation](https://docs.github.com/en/free-pro-team@latest/github/setting-up-and-managing-organizations-and-teams/repository-permission-levels-for-an-organization#repository-access-for-each-permission-level)

![Showing various GitHub repo access level](https://mintlify.s3.us-west-1.amazonaws.com/auth0-fga/images/fga/docs/content/modeling/advanced/assets/github-repo-access-level.svg)

To make Auth0 FGA aware of this "concentric" permission model we need to update our definitions:

Let us examine one of those relations in detail:

> [!NOTE]
>
> The users with a reader relationship to a certain object of type "repo" are any of:
>
> * the "readers": the set of users who are [directly related](/fga-concepts#what-are-direct-and-implied-relationships) to the repo as a "reader"
> * the "triagers": the set of users who are related to the object as "triager"

With this simple update our model now supports nested definitions and now:

### 02. Permissions for teams in an org

GitHub also supports [creating teams in an organization](https://docs.github.com/en/free-pro-team@latest/github/setting-up-and-managing-organizations-and-teams/creating-a-team), [adding members to a team](https://docs.github.com/en/free-pro-team@latest/github/setting-up-and-managing-organizations-and-teams/adding-organization-members-to-a-team) and [granting teams permissions, rather than individuals](https://docs.github.com/en/free-pro-team@latest/github/setting-up-and-managing-organizations-and-teams/managing-team-access-to-an-organization-repository).

At the end of this section we want to end up with the following permissions represented:

![Image showing permissions](https://mintlify.s3.us-west-1.amazonaws.com/auth0-fga/images/fga/docs/content/modeling/advanced/assets/github-02.svg)

To add support for teams and memberships all we need to do is add this object to the Auth0 FGA [authorization model](/fga-concepts#what-is-an-authorization-model):

In addition, the repo's relations should have team member as a directly related user types.

Let us now create a team, add a member to it and make it an admin of **repo:contoso/tooling** by adding the following [relationship tuples](/fga-concepts#what-is-a-relationship-tuple):

The last relationship tuple introduces a new **Auth0 FGA** concept. A **[userset](/fga-concepts#what-is-a-user)**. When the value of a user is formatted like this **type:objectId#relation**, Auth0 FGA will automatically expand the userset into all its individual user identifiers:

### 03. Permissions for child teams in an org

GitHub also supports team nesting, [known as "child teams"](https://docs.github.com/en/free-pro-team@latest/github/setting-up-and-managing-organizations-and-teams/requesting-to-add-a-child-team). **Child teams inherit the access permissions of the parent team.**
Let's say we have a **protocols** team that is part of the **engineering**. The simplest way to achieve the aforementioned requirement is just adding this [relationship tuple](/fga-concepts#what-is-a-relationship-tuple):

which says that members of protocols are members of engineering.

> **Note:** this is enough and valid for our current requirements, and for other read cases allows determining members of the direct team vs sub teams as the latter come from **team:contoso/protocols#member**. If the #member relation should not be followed for use cases a different approach could be taken.

We can now add a member to the protocols team and check that they are admins of the tooling repository.

At the end of this section ended with the following permissions represented:

![Image showing permissions](https://mintlify.s3.us-west-1.amazonaws.com/auth0-fga/images/fga/docs/content/modeling/advanced/assets/github-03.svg)

### 04. Base permissions for org members

In GitHub, ["you can set base permissions that apply to all members of an organization when accessing any of the organization's repositories"](https://docs.github.com/en/free-pro-team@latest/github/setting-up-and-managing-organizations-and-teams/setting-base-permissions-for-an-organization). For our purposes this means that if:

* User `erik` is a member of an organization `contoso`
* *and* `contoso` has a repository `tooling`
* *and* `contoso` has configured base permission to be "write"

then `erik` has write permissions to tooling.

Let us model that!

At the end of this section we want to end up with the following permissions represented:

![](https://mintlify.s3.us-west-1.amazonaws.com/auth0-fga/images/fga/docs/content/modeling/advanced/assets/github-04.svg)

We need to introduce the notion of organization as a type, user organization membership and repository ownership as a relation. - It is worth calling that before this addition we were able to represent almost the entire GitHub repo permissions without adding the notion of organization to Auth0 FGA. Identifiers for users, repositories and teams were all that was necessary.
Let us add support for organizations and membership. Hopefully this feels familiar by now:

And support for repositories having owners:

> [!NOTE]
>
> Note the added "owner" relation, indicating that organizations can own repositories.

We can now make Erik a member of contoso and make contoso own **contoso/tooling**:

What we still lack is the ability to create "default permissions" for the organization and have those be considered when determining if a user has a particular relation to a repository. Let's start with the simplest case **admin**. We want to say that a user is an admin of a repo if either:

* \[done] they have a repo admin relation (directly or through team membership)
* \[pending] their organization is configured with **repo\_admin** as the base permission

We need a way to consider the organization members, not just direct relations to the repo when getting a check for:

More details on this technique can be found in the section [Modeling Parent-Child Objects](/modeling/basics/parent-child).

We express it like this:

> [!NOTE]
>
> The users with an admin relationship to a certain object of type "repo" are any of:
>
> * the "admins": the set of users who are [directly related](/fga-concepts#what-are-direct-and-implied-relationships) to the repo as an "admin"
> * the "repository admins of the org that owns the repo": from the objects who are related to the doc as owner, return the sets of users who are related to those objects as "repo\_admin"
>
> What the added section is doing is:
>
> 1. read all relationship tuples related to repo:contoso/tooling as owner which returns:
>
> `[{ "object": "repo:contoso/tooling", "relation": "owner", "user": "organization:contoso" }]`
>
> 2. for each relationship tuple read, return all usersets that match the following, returning tuples of shape:
>
> `{ "object": "organization:contoso", "relation": "repo_admin", "user": ??? }`

What should the **users** in those relationship tuples with **???** be?

* Well:
  * If the base permission for org contoso is repo\_admin then it should be **organization:contoso#member**.
  * If the base permission for org contoso is NOT repo\_admin, then it should be empty (no relationship tuple).
* Whenever the value of this dropdown changes:

  ![Selecting new permission level from base permissions drop-down](https://mintlify.s3.us-west-1.amazonaws.com/auth0-fga/images/fga/docs/content/modeling/advanced/assets/github-org-base-permissions-drop-down.png)
  * Delete the previous relationship tuple and create a new one:

The updated authorization model looks like this:

## Summary

GitHub has a number of other permissions. You have [organization billing managers, users that can manage specific apps, etc](https://docs.github.com/en/free-pro-team@latest/github/setting-up-and-managing-organizations-and-teams/permission-levels-for-an-organization). We might explore those in the future, but hopefully this blog post has shown you how you could represent those cases using Auth0 Fine-Grained Authorization (FGA).

[GitHub
Explore the GitHub sample on the Auth0 FGA Playground](https://play.fga.dev/sandbox/?store=github)