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/* 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 <boost/redis/connection.hpp>
#include <boost/asio/consign.hpp>
#include <boost/asio/detached.hpp>
#include <boost/asio/redirect_error.hpp>
#include <boost/asio/use_awaitable.hpp>
#include <iostream>
#if defined(BOOST_ASIO_HAS_CO_AWAIT)
namespace asio = boost::asio;
using endpoints = asio::ip::tcp::resolver::results_type;
using boost::redis::request;
using boost::redis::response;
using boost::redis::ignore_t;
using boost::redis::config;
using boost::redis::address;
using boost::redis::connection;
auto redir(boost::system::error_code& ec) { return asio::redirect_error(asio::use_awaitable, ec); }
// For more info see
// - https://redis.io/docs/manual/sentinel.
// - https://redis.io/docs/reference/sentinel-clients.
auto resolve_master_address(std::vector<address> const& addresses) -> asio::awaitable<address>
{
request req;
req.push("SENTINEL", "get-master-addr-by-name", "mymaster");
req.push("QUIT");
auto conn = std::make_shared<connection>(co_await asio::this_coro::executor);
response<std::optional<std::array<std::string, 2>>, ignore_t> resp;
for (auto addr : addresses) {
boost::system::error_code ec;
config cfg;
cfg.addr = addr;
// TODO: async_run and async_exec should be lauched in
// parallel here so we can wait for async_run completion
// before eventually calling it again.
conn->async_run(cfg, asio::consign(asio::detached, conn));
co_await conn->async_exec(req, resp, redir(ec));
conn->cancel();
if (!ec && std::get<0>(resp))
co_return address{
std::get<0>(resp).value().value().at(0),
std::get<0>(resp).value().value().at(1)};
}
co_return address{};
}
auto co_main(config cfg) -> asio::awaitable<void>
{
// A list of sentinel addresses from which only one is responsive.
// This simulates sentinels that are down.
std::vector<address> const addresses{
address{"foo", "26379"},
address{"bar", "26379"},
cfg.addr
};
auto const ep = co_await resolve_master_address(addresses);
std::clog << "Host: " << ep.host << "\n"
<< "Port: " << ep.port << "\n"
<< std::flush;
}
#endif // defined(BOOST_ASIO_HAS_CO_AWAIT)
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