group_action_message.h

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/* Copyright (c) 2018, 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.
 
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   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
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   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, version 2.0, 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 GROUP_ACTION_MESSAGE_INCLUDED
#define GROUP_ACTION_MESSAGE_INCLUDED
 
#include <string>
 
#include "my_inttypes.h"
#include "plugin/group_replication/include/gcs_plugin_messages.h"
#include "plugin/group_replication/libmysqlgcs/include/mysql/gcs/gcs_types.h"
 
class Group_action_message : public Plugin_gcs_message {
 public:
  enum enum_payload_item_type {
    // This type should not be used anywhere.
    PIT_UNKNOWN = 0,
    // Length of the payload item: 2 bytes
    PIT_ACTION_TYPE = 1,
    // Length of the payload item: 2 bytes
    PIT_ACTION_PHASE = 2,
    // Length of the payload item: 4 bytes
    PIT_ACTION_RETURN_VALUE = 3,
    // The uuid field
    PIT_ACTION_PRIMARY_ELECTION_UUID = 4,
    // The GCS protocol field: 2 bytes
    PIT_ACTION_SET_COMMUNICATION_PROTOCOL_VERSION = 5,
    // The running_transactions_timeout field: 4 bytes
    PIT_ACTION_TRANSACTION_MONITOR_TIMEOUT = 6,
    // The action initiator information: 4 bytes
    PIT_ACTION_INITIATOR = 7,
    // Length of the payload item: 8 bytes
    PIT_SENT_TIMESTAMP = 8,
    // No valid type codes can appear after this one.
    PIT_MAX = 9
  };
 
  /** Enum for the types of message / actions */
  enum enum_action_message_type {
    // This type should not be used
    ACTION_UNKNOWN_MESSAGE = 0,
    // Change to multi primary
    ACTION_MULTI_PRIMARY_MESSAGE = 1,
    // Elect/Change mode to primary member
    ACTION_PRIMARY_ELECTION_MESSAGE = 2,
    // Change GCS protocol version
    ACTION_SET_COMMUNICATION_PROTOCOL_MESSAGE = 3,
    // The end of the enum
    ACTION_MESSAGE_END = 4
  };
  /** Enum for the phase of the action in the message */
  enum enum_action_message_phase {
    ACTION_UNKNOWN_PHASE = 0,  // This type should not be used
    ACTION_START_PHASE = 1,    // Start a new action
    ACTION_END_PHASE = 2,      // The action was ended
    ACTION_ABORT_PHASE = 3,    // The action was aborted
    ACTION_PHASE_END = 4,      // The enum end
  };
 
  /** Enum to identify initiator and action. */
  enum enum_action_initiator_and_action {
    // This type should not be used
    ACTION_INITIATOR_UNKNOWN = 0,  // to match with ACTION_UNKNOWN_MESSAGE
    // Change to multi primary
    ACTION_UDF_SWITCH_TO_MULTI_PRIMARY_MODE = 1,
    // Change primary
    ACTION_UDF_SET_PRIMARY = 2,
    // Change to single primary
    ACTION_UDF_SWITCH_TO_SINGLE_PRIMARY_MODE = 3,
    // Change to single primary with UUID
    ACTION_UDF_SWITCH_TO_SINGLE_PRIMARY_MODE_UUID = 4,
    // Change GCS protocol version
    ACTION_UDF_COMMUNICATION_PROTOCOL_MESSAGE = 5,
    // The end of the enum
    ACTION_INITIATOR_END = 6
  };
 
  /**
    Message constructor
  */
  Group_action_message();
 
  /**
    Message constructor
 
    @param[in] type         the action message type
  */
  Group_action_message(enum_action_message_type type);
 
  /**
    Message constructor for ACTION_PRIMARY_ELECTION_MESSAGE action type
 
    @param[in] primary_uuid   the primary uuid to elect
    @param[in] transaction_monitor_timeout_arg The number of seconds to wait
    before setting the kill flag for the transactions that did not reach commit
    stage
  */
  Group_action_message(std::string &primary_uuid,
                       int32 &transaction_monitor_timeout_arg);
 
  /**
    Message constructor for ACTION_SET_COMMUNICATION_PROTOCOL_MESSAGE action
    type
 
    @param[in] gcs_protocol   the GCS protocol to change to
   */
  explicit Group_action_message(Gcs_protocol_version gcs_protocol);
 
  /**
    Message destructor
   */
  ~Group_action_message() override;
 
  /**
    Message constructor for raw data
 
    @param[in] buf raw data
    @param[in] len raw length
  */
  Group_action_message(const uchar *buf, size_t len);
 
  /** Returns this group action message type */
  enum_action_message_type get_group_action_message_type() {
    return group_action_type;
  }
 
  /** Returns this group action message phase */
  enum_action_message_phase get_group_action_message_phase() {
    return group_action_phase;
  }
 
  void set_group_action_message_phase(enum_action_message_phase phase) {
    group_action_phase = phase;
  }
 
  /**
    Set the return value for this message
    @param return_value_arg the value to set
  */
  void set_return_value(int return_value_arg) {
    return_value = return_value_arg;
  }
 
  /**
    Set the action initiator.
    @param initiator Identifier for Group action initiator
  */
  void set_action_initiator(const enum_action_initiator_and_action initiator) {
    m_action_initiator = initiator;
  }
 
  /**
    @return Identifier for Group action initiator
  */
  const enum_action_initiator_and_action &get_action_initiator() {
    return m_action_initiator;
  }
 
  /**
    @return The return value associated to this message.
  */
  int32 get_return_value() { return return_value; }
 
  /**
    Check what is the action that this message encodes from a buffer
    @param buf the raw data buffer
    @return If the message is a primary election action or other
  */
  static enum_action_message_type get_action_type(const uchar *buf);
 
  /**
    Returns this group action primary to be elected uuid.
 
    @return the primary to be elected uuid, which can be empty
  */
  const std::string &get_primary_to_elect_uuid();
 
  /**
    Returns the GCS protocol this group action wants the group to change to.
 
    @return the GCS protocol version
   */
  Gcs_protocol_version const &get_gcs_protocol();
 
  /**
    Returns the running_transactions_timeout.
 
    @return the running_transactions_timeout value
   */
  int32 get_transaction_monitor_timeout();
 
  /**
    Return the time at which the message contained in the buffer was sent.
    @see Metrics_handler::get_current_time()
 
    @param[in] buffer            the buffer to decode from.
    @param[in] length            the buffer length
 
    @return the time on which the message was sent.
  */
  static uint64_t get_sent_timestamp(const unsigned char *buffer,
                                     size_t length);
 
 protected:
  /**
    Encodes the message contents for transmission.
 
    @param[out] buffer   the message buffer to be written
  */
  void encode_payload(std::vector<unsigned char> *buffer) const override;
 
  /**
    Message decoding method
 
    @param[in] buffer the received data
    @param[in] end    the end of the buffer.
  */
  void decode_payload(const unsigned char *buffer,
                      const unsigned char *end) override;
 
 private:
  /** The action type for this message */
  enum_action_message_type group_action_type;
 
  /** If it is a start, stop or other message */
  enum_action_message_phase group_action_phase;
 
  /** Is there any return value associated to this action */
  int32 return_value;
 
  /* Option Values */
 
  /** The uuid for election, can be empty if not defined */
  std::string primary_election_uuid;
 
  /** The GCS protocol version to change to */
  Gcs_protocol_version gcs_protocol;
  /**
    The number of seconds to wait before setting the kill flag for the
    transactions that did not reach commit stage.
  */
  int32 m_transaction_monitor_timeout{-1};
  /** Group action identifier */
  enum_action_initiator_and_action m_action_initiator;
};
 
#endif /* GROUP_ACTION_MESSAGE_INCLUDED */