zmq_server.cpp

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// Copyright (c) 2016-2019, The Monero Project
// 
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//    conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright notice, this list
//    of conditions and the following disclaimer in the documentation and/or other
//    materials provided with the distribution.
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#include "zmq_server.h"
 
#include <chrono>
#include <cstdint>
#include <system_error>
 
namespace cryptonote
{
 
namespace
{
    constexpr const int num_zmq_threads = 1;
    constexpr const std::int64_t max_message_size = 10 * 1024 * 1024; // 10 MiB
    constexpr const std::chrono::seconds linger_timeout{2}; // wait period for pending out messages
}
 
namespace rpc
{
 
ZmqServer::ZmqServer(RpcHandler& h) :
    handler(h),
    context(zmq_init(num_zmq_threads))
{
  if (!context)
    ELECTRONEUM_ZMQ_THROW("Unable to create ZMQ context");
}
 
ZmqServer::~ZmqServer()
{
}
 
void ZmqServer::serve()
{
  try
  {
    // socket must close before `zmq_term` will exit.
    const net::zmq::socket socket = std::move(rep_socket);
    if (!socket)
    {
      MERROR("ZMQ RPC server reply socket is null");
      return;
    }
 
    while (1)
    {
      const std::string message = ELECTRONEUM_UNWRAP(net::zmq::receive(socket.get()));
      MDEBUG("Received RPC request: \"" << message << "\"");
      const std::string& response = handler.handle(message);
 
      ELECTRONEUM_UNWRAP(net::zmq::send(epee::strspan<std::uint8_t>(response), socket.get()));
      MDEBUG("Sent RPC reply: \"" << response << "\"");
    }
  }
  catch (const std::system_error& e)
  {
    if (e.code() != net::zmq::make_error_code(ETERM))
      MERROR("ZMQ RPC Server Error: " << e.what());
  }
  catch (const std::exception& e)
  {
    MERROR("ZMQ RPC Server Error: " << e.what());
  }
  catch (...)
  {
    MERROR("Unknown error in ZMQ RPC server");
  }
}
 
bool ZmqServer::addIPCSocket(const boost::string_ref address, const boost::string_ref port)
{
  MERROR("ZmqServer::addIPCSocket not yet implemented!");
  return false;
}
 
bool ZmqServer::addTCPSocket(boost::string_ref address, boost::string_ref port)
{
  if (!context)
  {
    MERROR("ZMQ RPC Server already shutdown");
    return false;
  }
 
  rep_socket.reset(zmq_socket(context.get(), ZMQ_REP));
  if (!rep_socket)
  {
    ELECTRONEUM_LOG_ZMQ_ERROR("ZMQ RPC Server socket create failed");
    return false;
  }
 
  if (zmq_setsockopt(rep_socket.get(), ZMQ_MAXMSGSIZE, std::addressof(max_message_size), sizeof(max_message_size)) != 0)
  {
    ELECTRONEUM_LOG_ZMQ_ERROR("Failed to set maximum incoming message size");
    return false;
  }
 
  static constexpr const int linger_value = std::chrono::milliseconds{linger_timeout}.count();
  if (zmq_setsockopt(rep_socket.get(), ZMQ_LINGER, std::addressof(linger_value), sizeof(linger_value)) != 0)
  {
    ELECTRONEUM_LOG_ZMQ_ERROR("Failed to set linger timeout");
    return false;
  }
 
  if (address.empty())
    address = "*";
  if (port.empty())
    port = "*";
 
  std::string bind_address = "tcp://";
  bind_address.append(address.data(), address.size());
  bind_address += ":";
  bind_address.append(port.data(), port.size());
 
  if (zmq_bind(rep_socket.get(), bind_address.c_str()) < 0)
  {
    ELECTRONEUM_LOG_ZMQ_ERROR("ZMQ RPC Server bind failed");
    return false;
  }
  return true;
}
 
void ZmqServer::run()
{
  run_thread = boost::thread(boost::bind(&ZmqServer::serve, this));
}
 
void ZmqServer::stop()
{
  if (!run_thread.joinable())
    return;
 
  context.reset(); // destroying context terminates all calls
  run_thread.join();
}
 
 
}  // namespace cryptonote
 
}  // namespace rpc