Wrong response from previous request using future or eventbase

[kapcino]

I created a server using Proxygen based on EchoServer, since it is most based on folly, I post here for help.

The basic procedure to receive a request from a client, and then I create a thread to fetch data from db. After the data is fetched, send the response back to the client.

onEOM() {
    auto eventBase = folly::EventBaseManager::get()->getEventBase();
    thread t([&, eventBase]() {

        auto d = fetch(); // call function to fetch data from db

        eventBase->runInEventBaseThread([&]() {
            sendResponse(d);
          });
});

 t.detach();
}

It works well for slow requests, but when I want to use wrk for benchmark, I found a problem.

Say the service is like ip2location, I use wrk to benchmark, like this:

wrk -t1 -c100 -d2m  'http://127.0.0.1:80/test?q=8.8.8.8'

Before it finishes, interrupt with Ctrl+C, and then do manual request with curl, like this:

curl -sv 'http://127.0.0.1:80/test?q=4.4.4.4'

The expected result for curl is for 4.4.4.4, but the actual result is for 8.8.8.8.

After several retry, it some times return the correct info, but most times are incorrect.

I tried to use Future and then pattern, but it has the same problem.

Future<string> getData(const string& ip) {
  Promise<string> promise;
  auto f = promise.getFuture();
  auto ev = EventBaseManager::get()->getEventBase();
      ev->runInLoop([promise = std::move(promise), &]() mutable {
      auto d = fetch();
      promise.setValue(d);
  });
  return f;
}

I also tried to set the idleTimeout to 100ms, and it still exists!

options.idleTimeout = std::chrono::milliseconds(100);

I tried to add flag in onError function, but it seems never called when I sends Ctrl+C.

I also tried to use folly::async to get a Future, and use the then pattern, but it only works with one CPUExecutor, if I set more than one, there will be crash saying runInEventBaseThread not the request one.

Please help to resolve this problem, thanks.

[kapcino]

Just found the bug in my own code, thanks!