common.cpp

/* Copyright (c) 2018-2022 Marcelo Zimbres Silva (mzimbres@gmail.com)
 *
 * Distributed under the Boost Software License, Version 1.0. (See
 * accompanying file LICENSE.txt)
 */
 
#include "common.hpp"
 
#include <boost/asio.hpp>
#if defined(BOOST_ASIO_HAS_CO_AWAIT)
#include <boost/asio/experimental/awaitable_operators.hpp>
#include <iostream>
 
namespace net = boost::asio;
using namespace net::experimental::awaitable_operators;
using resolver = net::use_awaitable_t<>::as_default_on_t<net::ip::tcp::resolver>;
using timer_type = net::use_awaitable_t<>::as_default_on_t<net::steady_timer>;
using aedis::resp3::request;
using aedis::adapt;
using aedis::operation;
 
namespace
{
auto redir(boost::system::error_code& ec)
   { return net::redirect_error(net::use_awaitable, ec); }
}
 
auto healthy_checker(std::shared_ptr<connection> conn) -> net::awaitable<void>
{
   try {
      request req;
      req.push("PING");
 
      timer_type timer{co_await net::this_coro::executor};
 
      for (boost::system::error_code ec;;) {
         timer.expires_after(std::chrono::seconds{1});
         co_await (conn->async_exec(req, adapt()) || timer.async_wait(redir(ec)));
 
         if (!ec) {
            co_return;
         }
 
         // Waits some time before trying the next ping.
         timer.expires_after(std::chrono::seconds{1});
         co_await timer.async_wait();
      }
   } catch (...) {
   }
}
 
auto
connect(
   std::shared_ptr<connection> conn,
   std::string const& host,
   std::string const& port) -> net::awaitable<void>
{
   auto ex = co_await net::this_coro::executor;
   resolver resv{ex};
   timer_type timer{ex};
 
   boost::system::error_code ec;
   timer.expires_after(std::chrono::seconds{5});
   auto const addrs = co_await (resv.async_resolve(host, port) || timer.async_wait(redir(ec)));
   if (!ec)
      throw std::runtime_error("Resolve timeout");
 
   timer.expires_after(std::chrono::seconds{5});
   co_await (net::async_connect(conn->next_layer(), std::get<0>(addrs)) || timer.async_wait(redir(ec)));
   if (!ec)
      throw std::runtime_error("Connect timeout");
}
 
auto run(net::awaitable<void> op) -> int
{
   try {
      net::io_context ioc;
      net::co_spawn(ioc, std::move(op), [](std::exception_ptr p) {
         if (p)
            std::rethrow_exception(p);
      });
      ioc.run();
 
      return 0;
 
   } catch (std::exception const& e) {
      std::cerr << "Error: " << e.what() << std::endl;
   }
 
   return 1;
}
 
#endif // defined(BOOST_ASIO_HAS_CO_AWAIT)