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@arrieta
Last active September 1, 2023 03:49
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Dirt Simple Heart Beat Server in C++
#include <cerrno>
#include <cstdio>
#include <cstring>
#include <sstream>
#include <chrono>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <unistd.h>
#ifndef HEARTBEAT_BUILD_ID
#define HEARTBEAT_BUILD_ID <undefined>
#endif
#define STRINGIFY_DETAIL(x) #x
#define STRINGIFY(x) STRINGIFY_DETAIL(x)
using namespace std::chrono;
class HeartBeatServer {
public:
explicit HeartBeatServer(int port)
: m_tbeg { system_clock::now() },
m_fd{::socket(AF_INET, SOCK_STREAM, 0) }
{
if (m_fd < 0) {
throw std::runtime_error("cannot create socket");
}
struct sockaddr_in server;
server.sin_family = AF_INET;
server.sin_port = htons(port);
server.sin_addr.s_addr = htonl(INADDR_ANY);
int opt = 1;
::setsockopt(m_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
if (auto err = ::bind(m_fd, (struct sockaddr*)(&server), sizeof(server));
err < 0) {
throw std::runtime_error("cannot bind socket");
}
if (auto err = ::listen(m_fd, 64); err < 0) {
throw std::runtime_error("cannot start listening");
}
}
void serve() {
while (true) {
struct sockaddr_in client;
socklen_t client_len = sizeof(client);
const auto cfd = ::accept(m_fd, (struct sockaddr*)(&client), &client_len);
if (cfd < 0) {
throw std::runtime_error("cannot create new client connection");
}
const auto response = status();
if (auto status = ::send(cfd, response.c_str(), response.size(), 0);
status < 0) {
throw std::runtime_error("cannot send response to client");
}
::shutdown(cfd, SHUT_RDWR);
::close(cfd);
}
}
private:
std::string status() const {
const auto uptime = system_clock::now() - m_tbeg;
std::ostringstream oss;
oss << "{\"status\":\"ok\",\"uptime\":"
<< duration_cast<seconds>(uptime).count()
<< ",\"build\":\"" << STRINGIFY(HEARTBEAT_BUILD_ID) << "\"}";
return oss.str();
}
private:
const system_clock::time_point m_tbeg;
const int m_fd;
};
int main() {
HeartBeatServer server(8081);
server.serve();
}
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