apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/controller/PermissionController.java/PermissionController/getAppRoles
class PermissionController:  @GetMapping("/apps/{appId}/role_users")
  public AppRolesAssignedUsers getAppRoles(@PathVariable String appId) {
    AppRolesAssignedUsers users = new AppRolesAssignedUsers();
    users.setAppId(appId);

    Set<UserInfo> masterUsers = rolePermissionService.queryUsersWithRole(RoleUtils.buildAppMasterRoleName(appId));
    users.setMasterUsers(masterUsers);

    return users;
  }