Files
MaxScale/modules/monitor/mysql_mon.c
Mark Riddoch 02e60e215b Name change to MaxScale rather than gateway
Addition of code for dynamic reconfiguration by editign the cnf file and sendign a SIGHUP

Improvements to the make install rule
2013-07-17 13:32:04 +02:00

309 lines
6.9 KiB
C

/*
* This file is distributed as part of the SkySQL Gateway. It is free
* software: you can redistribute it and/or modify it under the terms of the
* GNU General Public License as published by the Free Software Foundation,
* version 2.
*
* 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Copyright SkySQL Ab 2013
*/
/**
* @file mysql_mon.c - A MySQL replication cluster monitor
*
* @verbatim
* Revision History
*
* Date Who Description
* 08/07/13 Mark Riddoch Initial implementation
* 11/07/13 Mark Riddoch Addition of code to check replication
* status
*
* @endverbatim
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <monitor.h>
#include <mysqlmon.h>
#include <thread.h>
#include <mysql.h>
#include <mysqld_error.h>
#include <skygw_utils.h>
#include <log_manager.h>
static void monitorMain(void *);
static char *version_str = "V1.0.0";
static void *startMonitor();
static void stopMonitor(void *);
static void registerServer(void *, SERVER *);
static void unregisterServer(void *, SERVER *);
static MONITOR_OBJECT MyObject = { startMonitor, stopMonitor, registerServer, unregisterServer };
/**
* Implementation of the mandatory version entry point
*
* @return version string of the module
*/
char *
version()
{
return version_str;
}
/**
* The module initialisation routine, called when the module
* is first loaded.
*/
void
ModuleInit()
{
fprintf(stderr, "Initialise the MySQL Monitor module.\n");
}
/**
* The module entry point routine. It is this routine that
* must populate the structure that is referred to as the
* "module object", this is a structure with the set of
* external entry points for this module.
*
* @return The module object
*/
MONITOR_OBJECT *
GetModuleObject()
{
return &MyObject;
}
/**
* Start the instance of the monitor, returning a handle on the monitor.
*
* This function creates a thread to execute the actual monitoring.
*
* @return A handle to use when interacting with the monitor
*/
static void *
startMonitor()
{
MYSQL_MONITOR *handle;
if ((handle = (MYSQL_MONITOR *)malloc(sizeof(MYSQL_MONITOR))) == NULL)
return NULL;
handle->databases = NULL;
handle->shutdown = 0;
spinlock_init(&handle->lock);
thread_start(monitorMain, handle);
return handle;
}
/**
* Stop a running monitor
*
* @param arg Handle on thr running monior
*/
static void
stopMonitor(void *arg)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
handle->shutdown = 1;
}
/**
* Register a server that must be added to the monitored servers for
* a monitoring module.
*
* @param arg A handle on the running monitor module
* @param server The server to add
*/
static void
registerServer(void *arg, SERVER *server)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
MONITOR_SERVERS *ptr, *db;
if ((db = (MONITOR_SERVERS *)malloc(sizeof(MONITOR_SERVERS))) == NULL)
return;
db->server = server;
db->con = NULL;
db->next = NULL;
spinlock_acquire(&handle->lock);
if (handle->databases == NULL)
handle->databases = db;
else
{
ptr = handle->databases;
while (ptr->next != NULL)
ptr = ptr->next;
ptr->next = db;
}
spinlock_release(&handle->lock);
}
/**
* Remove a server from those being monitored by a monitoring module
*
* @param arg A handle on the running monitor module
* @param server The server to remove
*/
static void
unregisterServer(void *arg, SERVER *server)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
MONITOR_SERVERS *ptr, *lptr;
spinlock_acquire(&handle->lock);
if (handle->databases == NULL)
{
spinlock_release(&handle->lock);
return;
}
if (handle->databases->server == server)
{
ptr = handle->databases;
handle->databases = handle->databases->next;
free(ptr);
}
else
{
ptr = handle->databases;
while (ptr->next != NULL && ptr->next->server != server)
ptr = ptr->next;
if (ptr->next)
{
lptr = ptr->next;
ptr->next = ptr->next->next;
free(lptr);
}
}
spinlock_release(&handle->lock);
}
/**
* Monitor an individual server
*
* @param database The database to probe
*/
static void
monitorDatabase(MONITOR_SERVERS *database)
{
MYSQL_ROW row;
MYSQL_RES *result;
int num_fields;
int ismaster = 0, isslave = 0;
if (database->con == NULL || mysql_ping(database->con) != 0)
{
database->con = mysql_init(NULL);
if (mysql_real_connect(database->con, database->server->name,
database->server->monuser, database->server->monpw,
NULL, database->server->port, NULL, 0) == NULL)
{
server_clear_status(database->server, SERVER_RUNNING);
return;
}
}
/* If we get this far then we have a working connection */
server_set_status(database->server, SERVER_RUNNING);
/* Check SHOW SLAVE HOSTS - if we get rows then we are a master */
if (mysql_query(database->con, "SHOW SLAVE HOSTS"))
{
if (mysql_errno(database->con) == ER_SPECIFIC_ACCESS_DENIED_ERROR)
{
/* Log lack of permission */
}
}
else if ((result = mysql_store_result(database->con)) != NULL)
{
num_fields = mysql_num_fields(result);
while ((row = mysql_fetch_row(result)))
{
ismaster = 1;
}
mysql_free_result(result);
}
/* Check if the Slave_SQL_Running and Slave_IO_Running status is
* set to Yes
*/
if (mysql_query(database->con, "SHOW SLAVE STATUS") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
num_fields = mysql_num_fields(result);
while ((row = mysql_fetch_row(result)))
{
if (strncmp(row[10], "Yes", 3) == 0
&& strncmp(row[11], "Yes", 3) == 0)
isslave = 1;
}
mysql_free_result(result);
}
if (ismaster)
{
server_set_status(database->server, SERVER_MASTER);
server_clear_status(database->server, SERVER_SLAVE);
}
else if (isslave)
{
server_set_status(database->server, SERVER_SLAVE);
server_clear_status(database->server, SERVER_MASTER);
}
if (ismaster == 0 && isslave == 0)
{
server_clear_status(database->server, SERVER_SLAVE);
server_clear_status(database->server, SERVER_MASTER);
}
}
/**
* The entry point for the monitoring module thread
*
* @param arg The handle of the monitor
*/
static void
monitorMain(void *arg)
{
MYSQL_MONITOR *handle = (MYSQL_MONITOR *)arg;
MONITOR_SERVERS *ptr;
if (mysql_thread_init())
{
skygw_log_write_flush(NULL,
LOGFILE_ERROR,
"Fatal : mysql_init_thread failed in monitor "
"module. Exiting.\n");
return;
}
while (1)
{
if (handle->shutdown)
{
mysql_thread_end();
return;
}
ptr = handle->databases;
while (ptr)
{
monitorDatabase(ptr);
ptr = ptr->next;
}
thread_millisleep(10000);
}
}