Why Assertion `event_.ev_base != nullptr' failed?

[gateslu]

please help, when I run a demo, it always print these information, why?

proxygen_server: /work/code/proxygen-2019.07.01.00/proxygen/folly/folly/io/async/EventHandler.cpp:43: bool folly::EventHandler::registerImpl(uint16_t, bool): Assertionevent_.ev_base != nullptr' failed.
*** Aborted at 1562667593 (unix time) try "date -d @1562667593" if you are using GNU date ***
PC: @ 0x0 (unknown)
*** SIGABRT (@0x3e900000759) received by PID 1881 (TID 0x7fca99213700) from PID 1881; stack trace: ***
@ 0x7fca9c880390 (unknown)
@ 0x7fca9c4da428 gsignal
@ 0x7fca9c4dc02a abort
@ 0x7fca9c4d2bd7 (unknown)
@ 0x7fca9c4d2c82 __assert_fail
@ 0x7fca9e24bf4b folly::EventHandler::registerImpl()
@ 0x7fca9e23a927 folly::EventHandler::registerInternalHandler()
@ 0x7fca9e23c5c6 folly::NotificationQueue<>::Consumer::startConsumingInternal()
@ 0x7fca9e23809e folly::EventBase::initNotificationQueue()
@ 0x7fca9e233296 folly::EventBase::EventBase()
@ 0x7fca9e1bff27 folly::EventBase::EventBase()
@ 0x7fca9e24909a folly::EventBaseManager::EventBaseInfo::EventBaseInfo()
@ 0x7fca9e248e3d folly::EventBaseManager::getEventBase()
@ 0x7fca9e9d1cd1 proxygen::HTTPServer::start()
@ 0x431190 _ZZ4mainENKUlvE_clEv
@ 0x4329b2 _ZNSt12_Bind_simpleIFZ4mainEUlvE_vEE9_M_invokeIJEEEvSt12_Index_tupleIJXspT_EEE
@ 0x432908 _ZNSt12_Bind_simpleIFZ4mainEUlvE_vEEclEv
@ 0x432898 _ZNSt6thread5_ImplISt12_Bind_simpleIFZ4mainEUlvE_vEEE6_M_runEv
@ 0x7fca9cd5ac80 (unknown)
@ 0x7fca9c8766ba start_thread
@ 0x7fca9c5ac41d clone
@ 0x0 (unknown)
`

`
/*

• Copyright (c) 2015, Facebook, Inc.
• All rights reserved.
• This source code is licensed under the BSD-style license found in the
• LICENSE file in the root directory of this source tree. An additional grant
• of patent rights can be found in the PATENTS file in the same directory.

*/
#include <gflags/gflags.h>
#include <folly/Memory.h>
#include <folly/init/Init.h>
#include <folly/Portability.h>
#include <folly/io/async/EventBaseManager.h>
#include <proxygen/httpserver/HTTPServer.h>
#include <proxygen/httpserver/RequestHandlerFactory.h>
#include <unistd.h>

#include "DemoHandler.h"

using namespace DemoService;
using namespace proxygen;

using folly::EventBase;
using folly::EventBaseManager;
using folly::SocketAddress;

using Protocol = HTTPServer::Protocol;

DEFINE_int32(http_port, 10086, "Port to listen on with HTTP protocol");
DEFINE_string(ip, "localhost", "IP/Hostname to bind to");
DEFINE_int32(threads, 10, "Number of threads to listen on. Numbers <= 0 "
"will use the number of cores on this machine.");

class DemoHandlerFactory : public RequestHandlerFactory {
public:
void onServerStart(folly::EventBase* evb) noexcept override {
printf("on server start\n");
}

void onServerStop() noexcept override {
}

RequestHandler* onRequest(RequestHandler* handler, HTTPMessage* msg) noexcept override {
printf("%s\n", msg->getURL().c_str() );
return new DemoHandler();
}

private:
};

int main(int argc, char* argv[]) {
folly::init(&argc, &argv, true);

std::vectorHTTPServer::IPConfig IPs = {
{SocketAddress(FLAGS_ip, FLAGS_http_port, true), Protocol::HTTP},
};

if (FLAGS_threads <= 0) {
FLAGS_threads = sysconf(_SC_NPROCESSORS_ONLN);
CHECK(FLAGS_threads > 0);
}

HTTPServerOptions options;
options.threads = static_cast<size_t>(FLAGS_threads);
options.idleTimeout = std::chrono::milliseconds(60000);
options.shutdownOn = {SIGINT, SIGTERM};
options.enableContentCompression = true;
options.handlerFactories = RequestHandlerChain()
.addThen()
.build();

HTTPServer server(std::move(options));
server.bind(IPs);

// Start HTTPServer mainloop in a separate thread
std::thread t([&] () {
server.start();
});

t.join();
return 0;
}

`

[baranyaib90]

Seems like same issue as: facebook/folly#601

[xqq0629]

Seems like same issue as: facebook/folly#601

Hi, I also ran into this problem recently. I am wondering if this problem has been resolved now. If not, what should we do with it?

[baranyaib90]

Hi, use the work-around I wrote here: facebook/folly#601 (comment)
This problem should be resolved in libev library to separate libevent wrapper to a separate library. But as I see, it's not done yet.

[xqq0629]

Hi, use the work-around I wrote here: facebook/folly#601 (comment)
This problem should be resolved in libev library to separate libevent wrapper to a separate library. But as I see, it's not done yet.

Thanks, libevent was mixed and the problem has been resolved now.