classic_connect.h

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/*
  Copyright (c) 2022, 2024, Oracle and/or its affiliates.
 
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  it under the terms of the GNU General Public License, version 2.0,
  as published by the Free Software Foundation.
 
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  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
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  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
 
#ifndef ROUTING_CLASSIC_CONNECT_INCLUDED
#define ROUTING_CLASSIC_CONNECT_INCLUDED
 
#include <chrono>
#include "classic_connection_base.h"
#include "destination.h"  // RouteDestination
#include "mysql/harness/net_ts/io_context.h"
#include "mysql/harness/net_ts/timer.h"
#include "mysqlrouter/destination.h"
#include "processor.h"
 
class ConnectProcessor : public Processor {
 public:
  ConnectProcessor(
      MysqlRoutingClassicConnectionBase *conn,
      std::function<void(const classic_protocol::message::server::Error &err)>
          on_error)
      : Processor(conn),
        io_ctx_{conn->socket_splicer()->client_conn().connection()->io_ctx()},
        destinations_{conn->current_destinations()},
        destinations_it_{destinations_.begin()},
        on_error_(std::move(on_error)) {}
 
  using server_protocol_type = net::ip::tcp;
 
  enum class Stage {
    InitDestination,
    Resolve,
    InitEndpoint,
    NextEndpoint,
    NextDestination,
    InitConnect,
    FromPool,
    Connect,
    ConnectFinish,
    Connected,
 
    Error,
    Done,
  };
 
  stdx::expected<Processor::Result, std::error_code> process() override;
 
  void stage(Stage stage) { stage_ = stage; }
  [[nodiscard]] Stage stage() const { return stage_; }
 
  bool is_destination_good(const std::string &hostname, uint16_t port) const;
 
 private:
  stdx::expected<Processor::Result, std::error_code> init_destination();
  stdx::expected<Processor::Result, std::error_code> resolve();
  stdx::expected<Processor::Result, std::error_code> init_endpoint();
  stdx::expected<Processor::Result, std::error_code> next_endpoint();
  stdx::expected<Processor::Result, std::error_code> next_destination();
  stdx::expected<Processor::Result, std::error_code> init_connect();
  stdx::expected<Processor::Result, std::error_code> from_pool();
  stdx::expected<Processor::Result, std::error_code> connect();
  stdx::expected<Processor::Result, std::error_code> connect_finish();
  stdx::expected<Processor::Result, std::error_code> connected();
  stdx::expected<Processor::Result, std::error_code> error();
 
  Stage stage_{Stage::InitDestination};
 
  net::io_context &io_ctx_;
 
  net::ip::tcp::resolver resolver_{io_ctx_};
  server_protocol_type::endpoint server_endpoint_;
 
  Destinations &destinations_;
  Destinations::iterator destinations_it_;
  net::ip::tcp::resolver::results_type endpoints_;
  net::ip::tcp::resolver::results_type::iterator endpoints_it_;
 
  bool all_quarantined_{false};
  std::error_code destination_ec_;
 
  // stack of errors.
  std::vector<std::pair<std::string, std::error_code>> connect_errors_;
 
  std::function<void(const classic_protocol::message::server::Error &err)>
      on_error_;
 
  std::chrono::steady_clock::time_point connect_started_;
};
 
#endif