//
// Lazy Pirate client
// Use zmq_poll to do a safe request-reply
// To run, start piserver and then randomly kill/restart it
//
#include "zhelpers.hpp"
#include <sstream>
#define REQUEST_TIMEOUT 2500 // msecs, (> 1000!)
#define REQUEST_RETRIES 3 // Before we abandon
// Helper function that returns a new configured socket
// connected to the Hello World server
//
static zmq::socket_t * s_client_socket (zmq::context_t & context) {
std::cout << "I: connecting to server…" << std::endl;
zmq::socket_t * client = new zmq::socket_t (context, ZMQ_REQ);
client->connect ("tcp://localhost:5555");
// Configure socket to not wait at close time
int linger = 0;
client->setsockopt (ZMQ_LINGER, &linger, sizeof (linger));
return client;
}
int main () {
zmq::context_t context (1);
zmq::socket_t * client = s_client_socket (context);
int sequence = 0;
int retries_left = REQUEST_RETRIES;
while (retries_left) {
std::stringstream request;
request << ++sequence;
s_send (*client, request.str());
sleep (1);
bool expect_reply = true;
while (expect_reply) {
// Poll socket for a reply, with timeout
zmq::pollitem_t items[] = { { *client, 0, ZMQ_POLLIN, 0 } };
zmq::poll (&items[0], 1, REQUEST_TIMEOUT * 1000);
// If we got a reply, process it
if (items[0].revents & ZMQ_POLLIN) {
// We got a reply from the server, must match sequence
std::string reply = s_recv (*client);
if (atoi (reply.c_str ()) == sequence) {
std::cout << "I: server replied OK (" << reply << ")" << std::endl;
retries_left = REQUEST_RETRIES;
expect_reply = false;
}
else {
std::cout << "E: malformed reply from server: " << reply << std::endl;
}
}
else
if (--retries_left == 0) {
std::cout << "E: server seems to be offline, abandoning" << std::endl;
expect_reply = false;
break;
}
else {
std::cout << "W: no response from server, retrying…" << std::endl;
// Old socket will be confused; close it and open a new one
delete client;
client = s_client_socket (context);
// Send request again, on new socket
s_send (*client, request.str());
}
}
}
delete client;
return 0;
}
