apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/controller/ClusterController.java/ClusterController/deleteCluster
class ClusterController:  @PreAuthorize(value = "@permissionValidator.isSuperAdmin()")
  @DeleteMapping(value = "apps/{appId}/envs/{env}/clusters/{clusterName:.+}")
  public ResponseEntity<Void> deleteCluster(@PathVariable String appId, @PathVariable String env,
                                            @PathVariable String clusterName){
    clusterService.deleteCluster(Env.valueOf(env), appId, clusterName);
    return ResponseEntity.ok().build();
  }