cluster_metadata_ar.h

Go to the documentation of this file.

/*
  Copyright (c) 2019, 2025, Oracle and/or its affiliates.
 
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License, version 2.0,
  as published by the Free Software Foundation.
 
  This program is designed to work with certain software (including
  but not limited to OpenSSL) that is licensed under separate terms,
  as designated in a particular file or component or in included license
  documentation.  The authors of MySQL hereby grant you an additional
  permission to link the program and your derivative works with the
  separately licensed software that they have either included with
  the program or referenced in the documentation.
 
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  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
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/
 
#ifndef METADATA_CACHE_CLUSTER_METADATA_AR_INCLUDED
#define METADATA_CACHE_CLUSTER_METADATA_AR_INCLUDED
 
#include "mysqlrouter/metadata_cache_export.h"
 
#include "cluster_metadata.h"
#include "gr_notifications_listener.h"
 
/** @class ARClusterMetadata
 *
 * The `ARClusterMetadata` class encapsulates a connection to the ReplicaSet
 * Cluster metadata server.
 *
 */
class METADATA_CACHE_EXPORT ARClusterMetadata : public ClusterMetadata {
 public:
  /** @brief Constructor
   *
   * @param session_config Metadata MySQL session configuration
   * @param ssl_options SSL related options to use for MySQL connections
   * @param view_id last known view_id of the cluster metadata
   */
  ARClusterMetadata(
      const metadata_cache::MetadataCacheMySQLSessionConfig &session_config,
      const mysqlrouter::SSLOptions &ssl_options, uint64_t view_id)
      : ClusterMetadata(session_config, ssl_options), view_id_(view_id) {}
 
  explicit ARClusterMetadata(const ARClusterMetadata &) = delete;
  ARClusterMetadata &operator=(const ARClusterMetadata &) = delete;
 
  /** @brief Destructor
   *
   * Disconnect and release the connection to the metadata node.
   */
  ~ARClusterMetadata() override;
 
  /** @brief Returns cluster defined in the metadata given set of the
   *         metadata servers (cluster members)
   *
   * @param terminated flag indicating that the process is cterminating,
   * allowing the function to leave earlier if possible
   * @param [in,out] target_cluster object identifying the Cluster this
   * operation refers to
   * @param router_id id of the router in the cluster metadata
   * @param metadata_servers  set of the metadata servers to use to fetch the
   * metadata
   * @param needs_writable_node flag indicating if the caller needs us to query
   * for writable node
   * @param [out] instance_id id of the server the metadata was fetched from
   * @param routing_guidelines Routing Guidelines document
   * @return object containing cluster topology information in case of success,
   * or error code in case of failure
   * @throws metadata_cache::metadata_error If fetching metadata fails.
   */
  stdx::expected<metadata_cache::ClusterTopology, std::error_code>
  fetch_cluster_topology(
      const std::atomic<bool> &terminated,
      mysqlrouter::TargetCluster &target_cluster, const unsigned router_id,
      const metadata_cache::metadata_servers_list_t &metadata_servers,
      bool needs_writable_node, const std::string & /*clusterset_id*/,
      std::size_t &instance_id, std::string &routing_guidelines) override;
 
  /** @brief Returns cluster type this object is suppsed to handle
   */
  mysqlrouter::ClusterType get_cluster_type() override {
    return mysqlrouter::ClusterType::RS_V2;
  }
 
  void setup_notifications_listener(
      const metadata_cache::ClusterTopology & /*cluster_topology*/,
      const GRNotificationListener::NotificationClb & /*callback*/) override {}
 
  /** @brief Deinitializes the notifications listener thread
   */
  void shutdown_notifications_listener() override {}
 
 private:
  /** @brief Returns the current cluster topology according to the metadata of
   * the given metadata server.
   *
   * @param session active connection to the member that is checked for the
   * metadata
   * @param view_id last known view_id of the cluster metadata
   * @param cluster_id ID of the cluster this operation refers to
   * @return vector of the cluster members
   */
  metadata_cache::ClusterTopology fetch_topology_from_member(
      mysqlrouter::MySQLSession &session, unsigned view_id,
      const std::string &cluster_id = "");
 
  /** @brief Returns metadata view id the given member holds
   *
   * @param session active connection to the member that is checked for the view
   * id
   * @param cluster_id ID of the cluster this operation refers to
   * @param[out] result  member's metadata view_id
   * @retval true on success
   * @retval false otherwise.
   */
  bool get_member_view_id(mysqlrouter::MySQLSession &session,
                          const std::string &cluster_id, uint64_t &result);
 
  uint64_t view_id_;
};
 
#endif  // METADATA_CACHE_CLUSTER_METADATA_AR_INCLUDED