MERC XX: Unify Roles and Groups

MERC:XX
Author:Michael Price
Status:Draft
Type:Feature
Created:2018-02-27
Last-Modified:2018-02-27

Abstract

This MERC proposes the merging of the Roles and Group models.

Rationale

Mayan EDMS uses Groups as units of users that are meant to mirror an organization’s actual user hierarchy. Roles are used as permission units.

Separation of concerns is a concept Mayan EDMS executes very successfully but when it comes to the Roles/Groups relationship that execution causes overheads without providing advantages in the day to day operations.

In reality there is almost a 1 to 1 correlation between Roles and Groups. Other permissions systems already use Groups as permission units without disadvantages. An example of this is LDAP and its commercial counterpart Active Directory.

Motivation

Merging the Role and Group model will reduce some complexity when initially setting up Mayan EDMS. The merge allows removing a Mayan EDMS model in favor of using a native Django model for the same task.

Merging the Role and Group models will also provide a speed boost in every permission check and queryset filtering. These checks are nested in nature. Since the access checks are performed for every view and for every link in the view the performance gain should be substantial.

Backwards Compatibility

To avoid loss of role configuration a data migration will be needed to convert existing roles to groups.

Specification

Changes needed:

  1. Data migration to convert existing roles to groups.
  2. Prepend or append an identifier to the migrated roles.
  3. Intermediate model to map permissions to a group. This will substitute the Role model’s permissions many to many field.
  4. Update the AccessControlList models roles field to point to the group models.
  5. Update the role checks in the check_access and filter_by_access AccessControlList model manager methods.