apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/controller/NamespaceBranchController.java/NamespaceBranchController/getBranchGrayRules
class NamespaceBranchController:  @GetMapping(value = "/apps/{appId}/envs/{env}/clusters/{clusterName}/namespaces/{namespaceName}/branches/{branchName}/rules")
  public GrayReleaseRuleDTO getBranchGrayRules(@PathVariable String appId, @PathVariable String env,
                                                     @PathVariable String clusterName,
                                                     @PathVariable String namespaceName,
                                                     @PathVariable String branchName) {

    return namespaceBranchService.findBranchGrayRules(appId, Env.valueOf(env), clusterName, namespaceName, branchName);
  }