Oso

actor User { }
 
resource Organization {
    roles = ["admin", "member"];
    permissions = ["create_repository"];
 
    "member" if "admin";
}
 
 
resource Plan { 
    roles = ["subscriber"];
    relations = { subscribed_organization: Organization };
    
    "subscriber" if role on "subscribed_organization";
}
 
resource Feature {
    relations = { plan: Plan };
}
 
declare plan_quota(Plan, Feature, Integer);
declare quota_used(Organization, Feature, Integer);
 
plan_quota(Plan{"pro"}, Feature{"repository"}, 10);
plan_quota(Plan{"basic"}, Feature{"repository"}, 0);
 
has_quota_remaining(org: Organization, feature: Feature) if
    has_quota(org, feature, quota) and
    quota_used(org, feature, used) and
    used < quota;
 
has_quota(org: Organization, feature: Feature, quota: Integer) if
    plan matches Plan and
    has_relation(plan, "subscribed", org) and
    plan_quota(plan, feature, quota);
 
 
has_permission(user: User, "create_repository", org: Organization) if
    has_role(user, "member", org) and
    has_quota_remaining(org, Feature{"repository"});
 
 
 
test "members can create repositorys if they have quota" {
    setup {
        quota_used(Organization{"apple"}, Feature{"repository"}, 5);
        quota_used(Organization{"netflix"}, Feature{"repository"}, 10);
        quota_used(Organization{"amazon"}, Feature{"repository"}, 0);
        has_relation(Plan{"pro"}, "subscribed", Organization{"apple"});
        has_relation(Plan{"pro"}, "subscribed", Organization{"netflix"});
        has_relation(Plan{"basic"}, "subscribed", Organization{"amazon"});
        has_role(User{"alice"}, "member", Organization{"apple"});
        has_role(User{"bob"}, "member", Organization{"netflix"});
        has_role(User{"charlie"}, "member", Organization{"amazon"});
    }
    assert has_quota_remaining(Organization{"apple"}, Feature{"repository"});
    # Apple has quota remaining, so all good
    assert allow(User{"alice"}, "create_repository", Organization{"apple"});
    # Netflix has used all quota 
    assert_not allow(User{"bob"}, "create_repository", Organization{"netflix"});
    # Amazon doesn't have any quota left
    assert_not allow(User{"charlie"}, "create_repository", Organization{"amazon"});
}