apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/controller/PermissionController.java/PermissionController/getNamespaceEnvRoles
class PermissionController:  @GetMapping("/apps/{appId}/envs/{env}/namespaces/{namespaceName}/role_users")
  public NamespaceEnvRolesAssignedUsers getNamespaceEnvRoles(@PathVariable String appId, @PathVariable String env, @PathVariable String namespaceName) {

    // validate env parameter
    if (Env.UNKNOWN == Env.transformEnv(env)) {
      throw new BadRequestException("env is illegal");
    }

    NamespaceEnvRolesAssignedUsers assignedUsers = new NamespaceEnvRolesAssignedUsers();
    assignedUsers.setNamespaceName(namespaceName);
    assignedUsers.setAppId(appId);
    assignedUsers.setEnv(Env.valueOf(env));

    Set<UserInfo> releaseNamespaceUsers =
        rolePermissionService.queryUsersWithRole(RoleUtils.buildReleaseNamespaceRoleName(appId, namespaceName, env));
    assignedUsers.setReleaseRoleUsers(releaseNamespaceUsers);

    Set<UserInfo> modifyNamespaceUsers =
        rolePermissionService.queryUsersWithRole(RoleUtils.buildModifyNamespaceRoleName(appId, namespaceName, env));
    assignedUsers.setModifyRoleUsers(modifyNamespaceUsers);

    return assignedUsers;
  }