group_replication_message_service.h

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/* Copyright (c) 2019, 2025, Oracle and/or its affiliates.
 
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   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
#ifndef GROUP_REPLICATION_MESSAGE_SERVICE_H
#define GROUP_REPLICATION_MESSAGE_SERVICE_H
 
#include <mysql/components/service.h>
#include <stddef.h>
 
/**
  @ingroup group_components_services_inventory
 
  A service that sends content agnostic messages from a member to the group.
 
  This only works if the component is on a server with group replication
  running and the member state is ONLINE. If server isn't ONLINE message won't
  be deliver.
 
  After message sent to all members of the group, all components that have
  registered group_replication_message_service_recv service will be notified.
 
  @code
  SERVICE_TYPE(registry) *plugin_registry = mysql_plugin_registry_acquire();
  my_service<SERVICE_TYPE(group_replication_message_service_send)> svc(
      "group_replication_message_service_send", plugin_registry);
 
  if (svc.is_valid()) {
    bool error = svc->send("tag", "payload", sizeof("payload"));
  }
  @endcode
*/
BEGIN_SERVICE_DEFINITION(group_replication_message_service_send)
 
/**
  This function SHALL be called whenever the caller wants to
  send an agnostic messages to the group replication stream.
 
  @param[in] tag              tag identifies message
  @param[in] payload          data to be deliver
  @param[in] payload_length   size of data
 
  @return false success, true on failure. Failure can happen if Group
  Replication status isn't ONLINE or RECOVERING  or a communication failure
  occurs.
*/
DECLARE_BOOL_METHOD(send, (const char *tag, const unsigned char *payload,
                           const size_t payload_length));
 
END_SERVICE_DEFINITION(group_replication_message_service_send)
 
/**
  A service that gets called whenever an agnostic message
  from the group replication stream is to be delivered by
  the group replication receiver thread.
 
  The implementation MUST NOT block the caller.
 
  This only works if the component is on a server with group replication
  running and the member state is ONLINE. If server isn't ONLINE message won't
  be notified about messages received.
 
  @code
DEFINE_BOOL_METHOD(recv, (const char *tag, const unsigned char *data,
                          size_t data_length)) {
 
  // If tag is of interest do something with data
  return false;
}
 
BEGIN_SERVICE_IMPLEMENTATION(listener_example,
                             group_replication_message_service_recv)
recv, END_SERVICE_IMPLEMENTATION();
 
bool register_listener() {
  SERVICE_TYPE(registry) *plugin_registry = mysql_plugin_registry_acquire();
  my_service<SERVICE_TYPE(registry_registration)> reg("registry_registration",
                                                      plugin_registry);
  using group_replication_message_service_recv_t =
      SERVICE_TYPE_NO_CONST(group_replication_message_service_recv);
  bool result = reg->register_service(
      "group_replication_message_service_recv.listener_example",
      reinterpret_cast<my_h_service>(
          const_cast<group_replication_message_service_recv_t *>(
              &SERVICE_IMPLEMENTATION(
                  listener_example,
                  group_replication_message_service_recv))));
  @endcode
*/
BEGIN_SERVICE_DEFINITION(group_replication_message_service_recv)
 
/**
  This function of every service implementation SHALL be called by group
  replication whenever the group replication receive a service message sent to
  the group.
 
  @param[out] tag              tag identifies message
  @param[out] payload          data to be deliver
  @param[out] payload_length   size of data
 
  @return false success, true on failure.
*/
DECLARE_BOOL_METHOD(recv, (const char *tag, const unsigned char *payload,
                           const size_t payload_length));
 
END_SERVICE_DEFINITION(group_replication_message_service_recv)
 
#endif /* GROUP_REPLICATION_MESSAGE_SERVICE_H */