Files
MaxScale/modules/routing/readwritesplit/router.c

237 lines
6.4 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
*/
#include <stdio.h>
#include <router.h>
#if defined(SS_DEBUG)
# include <stdlib.h>
# include <mysql.h>
# include <skygw_utils.h>
# include <log_manager.h>
# include <query_classifier.h>
#endif /* SS_DEBUG */
/**
* @file router.c The entry points for the read/write query splitting
* router module.
*
* This file contains the entry points that comprise the API to the read write
* query splitting router.
*
*/
static char *version_str = "V1.0.0";
static ROUTER *createInstance(SERVICE *service, char **options);
static void *newSession(ROUTER *instance, SESSION *session);
static void closeSession(ROUTER *instance, void *session);
static int routeQuery(ROUTER *instance, void *session, GWBUF *queue);
static void diagnostic(ROUTER *instance, DCB *dcb);
static ROUTER_OBJECT MyObject = { createInstance, newSession, closeSession, routeQuery, diagnostic };
#if defined(SS_DEBUG)
static char* server_options[] = {
"raatikka",
"--datadir=/home/raatikka/data/skygw_parse/",
"--skip-innodb",
"--default-storage-engine=myisam",
NULL
};
const int num_elements = (sizeof(server_options) / sizeof(char *)) - 1;
static char* server_groups[] = {
"embedded",
"server",
"server",
"server",
NULL
};
static void vilhos_test_for_query_classifier(void)
{
bool failp;
MYSQL* mysql = NULL;
/**
* Init libmysqld.
*/
failp = mysql_library_init(num_elements, server_options, server_groups);
if (failp) {
MYSQL* mysql = mysql_init(NULL);
ss_dassert(mysql != NULL);
fprintf(stderr,
"mysql_init failed, %d : %s\n",
mysql_errno(mysql),
mysql_error(mysql));
goto return_without_server;
}
char* str = (char *)calloc(1,
sizeof("Query type is ")+
sizeof("QUERY_TYPE_SESSION_WRITE"));
/**
* Call query classifier.
*/
sprintf(str,
"Query type is %s\n",
STRQTYPE(
skygw_query_classifier_get_type(
"SELECT user from mysql.user", 0)));
/**
* generate some log
*/
skygw_log_write(NULL, LOGFILE_MESSAGE,str);
mysql_close(mysql);
mysql_thread_end();
mysql_library_end();
return_without_server:
ss_dfprintf(stderr, "\n<< testmain\n");
fflush(stderr);
}
#endif /* SS_DEBUG */
/**
* 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()
{
#if defined(SS_DEBUG)
vilhos_test_for_query_classifier();
#endif
fprintf(stderr, "Initialse read/writer splitting query router 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
*/
ROUTER_OBJECT *
GetModuleObject()
{
fprintf(stderr, "Returing test router module object.\n");
return &MyObject;
}
/**
* Create an instance of the router for a particular service
* within the gateway.
*
* The job of ths entry point is to create the service wide data needed
* for the query router. This is information needed to route queries that
* is not related to any individual client session, exmaples of data that
* might be stored in the ROUTER object for a particular query router are
* connections counts, last used connection etc so that balancing may
* take place.
*
* @param service The service this router is being create for
* @param options The options for this query router
*
* @return The instance data for this new instance
*/
static ROUTER *
createInstance(SERVICE *service, char **options)
{
return NULL;
}
/**
* Associate a new session with this instance of the router.
*
* The session is used to store all the data required for a particular
* client connection.
*
* @param instance The router instance data
* @param session The session itself
* @return Session specific data for this session
*/
static void *
newSession(ROUTER *instance, SESSION *session)
{
return NULL;
}
/**
* Close a session with the router, this is the mechanism
* by which a router may cleanup data structure etc.
*
* @param instance The router instance data
* @param session The session being closed
*/
static void
closeSession(ROUTER *instance, void *session)
{
}
/**
* The main routing entry, this is called with every packet that is
* received and has to be forwarded to the backend database.
*
* The routeQuery will make the routing decision based on the contents
* of the instance, session and the query itself in the queue. The
* data in the queue may not represent a complete query, it represents
* the data that has been received. The query router itself is responsible
* for buffering the partial query, a later call to the query router will
* contain the remainder, or part thereof of the query.
*
* @param instance The query router instance
* @param session The session assoicated with the client
* @param queue Gateway buffer queue with the packets received
*
* @return The number of queries forwarded
*/
static int
routeQuery(ROUTER *instance, void *session, GWBUF *queue)
{
return 0;
}
/**
* Diagnostics routine
*
* Print query router statistics to the DCB passed in
*
* @param instance The router instance
* @param dcb The DCB for diagnostic output
*/
static void
diagnostic(ROUTER *instance, DCB *dcb)
{
}