Binlog Retrieval


This example shows how the binlog api can be used to retrieve the events from a mysql binlog.

First a drizzle_binlog_st is created by calling drizzle_binlog_init() with an already initialized drizzle_st connection. Two callbacks are specified; binlog_event, which is called every time a binlog event is retrieved and binlog_error which is called when an error occurs while parsing binlog-data. In addition it is possible to pass a user context to be used for the callback functions. When NULL is passed, as in this example, the context is unspecified. Calling drizzle_binlog_start() starts the parsing of the binlog. The second argument is the id of the server to connect to. It corresponds to the server_id variable defined in the MySQL config file. When 0 is passed as server_id the connection is disconnected automatically at the end of the last logfile.

In the callback function binlog_event several properties of the binlog event are retrieved from the drizzle_binlog_event_st object. E.g. the type of binlog event, cf. drizzle_binlog_event_types_t, is retrieved by calling drizzle_binlog_event_type().

The binlog api offers retrieval of information which is common for all binlog event types. To retrieve information specific to each type, please refer to the MySQL documentation

When all binlog events have been parsed, binlog_error is called with a return status DRIZZLE_RETURN_EOF indicating that end of the last binlog logfile has been reached.

To compile the example, save the code and run:

g++ binlog_example.cxx -ldrizzle-redux -lpthread -o binlog_example


#include <libdrizzle-redux/libdrizzle.h>
#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>

* @file binlog_example.cxx

void binlog_error(drizzle_return_t ret, drizzle_st *connection, void *context)
  (void) context;
  if (ret != DRIZZLE_RETURN_EOF)
    printf("Error retrieving binlog: %s\n", drizzle_error(connection));

void binlog_event(drizzle_binlog_event_st *event, void *context)
  (void) context;
  printf("Timestamp: %"PRIu32"\n", drizzle_binlog_event_timestamp(event));
  printf("Type: %"PRIu8"\n", drizzle_binlog_event_type(event));
  printf("Server-id: %"PRIu32"\n", drizzle_binlog_event_server_id(event));
  printf("Next-pos: %"PRIu32"\n", drizzle_binlog_event_next_pos(event));
  uint length= drizzle_binlog_event_length(event);
  printf("Length: %"PRIu32"\n", length);
  const unsigned char *data= drizzle_binlog_event_data(event);
  printf("Data: 0x");
  for (uint i=0; i<length; i++)
    printf("%02X ", data[i]);

int main(int argc, char *argv[])
  (void) argc;
  (void) argv;
  drizzle_st *con;
  drizzle_return_t ret;
  drizzle_binlog_st *binlog;

  // Should be changed to the specifics of the MySQL installation
  con = drizzle_create("localhost", 3306, "root", "", "", 0);
  if (con == NULL)
    printf("Drizzle connection object creation error\n");
    return EXIT_FAILURE;
  ret = drizzle_connect(con);
  if (ret != DRIZZLE_RETURN_OK)
    printf("Drizzle connection failure\n");
    return EXIT_FAILURE;

  binlog= drizzle_binlog_init(con, binlog_event, binlog_error, NULL, true);
  ret= drizzle_binlog_start(binlog, 0, "", 0);
  if (ret != DRIZZLE_RETURN_EOF)
    printf("Drizzle binlog start failure\n");
    return EXIT_FAILURE;

  return EXIT_SUCCESS;