api/permission.go
func removeRole(w http.ResponseWriter, r *http.Request, t auth.Token) (err error) {
	if !permission.Check(t, permission.PermRoleDelete) {
		return permission.ErrUnauthorized
	}
	roleName := r.URL.Query().Get(":name")
	evt, err := event.New(&event.Opts{
		Target:     event.Target{Type: event.TargetTypeRole, Value: roleName},
		Kind:       permission.PermRoleDelete,
		Owner:      t,
		CustomData: event.FormToCustomData(InputFields(r)),
		Allowed:    event.Allowed(permission.PermRoleReadEvents),
	})
	if err != nil {
		return err
	}
	defer func() { evt.Done(err) }()
	usersWithRole, err := auth.ListUsersWithRole(roleName)
	if err != nil {
		return err
	}
	if len(usersWithRole) != 0 {
		return &errors.HTTP{Code: http.StatusPreconditionFailed, Message: permTypes.ErrRemoveRoleWithUsers.Error()}
	}
	err = permission.DestroyRole(roleName)
	if err == permTypes.ErrRoleNotFound {
		return &errors.HTTP{Code: http.StatusNotFound, Message: err.Error()}
	}
	return err
}
func removeRole(w http.ResponseWriter, r *http.Request, t auth.Token) (err error) {
	if !permission.Check(t, permission.PermRoleDelete) {
		return permission.ErrUnauthorized
	}
	roleName := r.URL.Query().Get(":name")
	evt, err := event.New(&event.Opts{
		Target:     event.Target{Type: event.TargetTypeRole, Value: roleName},
		Kind:       permission.PermRoleDelete,
		Owner:      t,
		CustomData: event.FormToCustomData(InputFields(r)),
		Allowed:    event.Allowed(permission.PermRoleReadEvents),
	})
	if err != nil {
		return err
	}
	defer func() { evt.Done(err) }()
	usersWithRole, err := auth.ListUsersWithRole(roleName)
	if err != nil {
		return err
	}
	if len(usersWithRole) != 0 {
		return &errors.HTTP{Code: http.StatusPreconditionFailed, Message: permTypes.ErrRemoveRoleWithUsers.Error()}
	}
	err = permission.DestroyRole(roleName)
	if err == permTypes.ErrRoleNotFound {
		return &errors.HTTP{Code: http.StatusNotFound, Message: err.Error()}
	}
	return err
}
// title: remove role
// path: /roles/{name}
// method: DELETE
// responses:
//   200: Role removed
//   401: Unauthorized
//   404: Role not found
//   412: Role with users