GRPC：客户端超时

Question

我正在尝试让客户端使用超时。为此，我修改了 async_greeter_server.cpp 和 async_greeter_client.cpp 文件来测试这个概念。

我在客户端（在客户端上下文）设置了一个截止日期，如果有超时，我会等到我收到来自服务器的实际（延迟）响应。以下是更改（在 Finish() 调用之后）。

同样，服务器端在延迟一段时间后发送响应以在客户端产生超时。

由于 CallData cq_.Next() 循环“GPR_ASSERT(ok)”中的断言，服务器端崩溃。

客户端在添加的超时代码中一直等待实际响应。

知道这个程序有什么问题吗？

greeter_async_client.cc

std::string SayHello(const std::string& user) 
{
    // Data we are sending to the server.
    HelloRequest request;
    request.set_name(user);

    HelloReply reply;
    ClientContext context;
    CompletionQueue cq;
    Status status;

    std::chrono::system_clock::time_point deadline = std::chrono::system_clock::now() + std::chrono::seconds(10);
    context.set_deadline(deadline);

    std::unique_ptr<ClientAsyncResponseReader<HelloReply> > rpc(stub_->AsyncSayHello(&context, request, &cq));

    rpc->Finish(&reply, &status, (void*)1);
    void* got_tag;
    bool ok = false;

    GPR_ASSERT(cq.Next(&got_tag, &ok));
    GPR_ASSERT(got_tag == (void*)1);
    GPR_ASSERT(ok);

    // -------------- HANDLE TIMEOUT ------------------------------------------
    // If timeout error wait for the actual reply
    if (status.error_code() == grpc::StatusCode::DEADLINE_EXCEEDED)
    {
      std::cout << "Timeout exceeded .., waiting for the next event "<< status.error_message() << std::endl;

      GPR_ASSERT(cq.Next(&got_tag, &ok));
      GPR_ASSERT(got_tag == (void *) 1);
      GPR_ASSERT(ok);
    }
    // Act upon the status of the actual RPC.
    if (status.ok()) 
    {
      return reply.message();
    } 
    else 
    {
      return "RPC failed";
    }
}

greeter_async_server.cc

void Proceed() 
{
  if (status_ == CREATE) 
  {
    status_ = PROCESS;
    service_->RequestSayHello(&ctx_, &request_, &responder_, cq_, cq_,this);
  } 
  else if (status_ == PROCESS) 
  {
    new CallData(service_, cq_);

    std::string prefix("Hello ");
    reply_.set_message(prefix + request_.name());

    std::cout << "Sleeping for 20 seconds .... \n";
    std::this_thread::sleep_for(std::chrono::seconds(20));
    std::cout << "Out of sleep ..... \n";

    status_ = FINISH;
    responder_.Finish(reply_, Status::OK, this);
    std::cout <<" Reply sent - Finish ....... \n";
  } 
  else 
  {
    GPR_ASSERT(status_ == FINISH);
    // Once in the FINISH state, deallocate ourselves (CallData).
    delete this;
  }
}

Answer 1

在您的客户端，收到deadline_exceeded错误后，您不应该再次尝试获取标签1...标签只会从cq中出来一次。