New version

protocol_1.0/skysql_backend.c

@@ -1,29 +1,48 @@
 ////////////////////////////////////////
 // SKYSQL Backend
-// By Massimiliano Pinto 2012
+// By Massimiliano Pinto 2012/2013
 // SkySQL AB
 ////////////////////////////////////////
 
 #include "skysql_gw.h"
 
-#define SKYSQL_READ 0
-#define SKYSQL_WRITE 1
-
-int skysql_query_is_select(const char *query) {
-
-	return SKYSQL_READ;
-}
-
 int skysql_ext_file_ver(void) {
 	int ret = 13;
 	return ret;
 }
 
-int select_random_slave_server(int nslaves) {
-	int random_balancer = (int) ((nslaves) * (rand() / (RAND_MAX + 1.0)));
+//////////////////////////////////////////////////////////////
+// The function takes the server list, 
+// find the total server number
+// and return a random selection for slaves (from total -1)
+//////////////////////////////////////////////////////////////
+int select_random_slave_server(const char *server_list, int *num_slaves) {
+	int nslaves = 0;
+	int random_balancer = 0;
+	char *p = (char *)server_list;
+	while( (p = strchr(p, ',')) != NULL) {
+		p++;
+		nslaves++;
+	}
+
+	memcpy(num_slaves, &nslaves, sizeof(int));
+
+	if (nslaves == 1) {
+		return 1;
+	}
+
+	// random selection
+	random_balancer = (int) ((nslaves+1) * (rand() / (RAND_MAX + 1.0)));
+
 	return random_balancer;
 }
 
+///////////////////////////////////////////////////////////////
+// This takes a server from the list
+// index 0 is always the Master
+// the others refer to the salve,
+// the slave number comes from: select_random_slave_server()
+///////////////////////////////////////////////////////////////
 int get_server_from_list(char **selected_host, int *selected_port, char *server_list, int num, apr_pool_t *p) {
 	int ret = -1;
 	int curr_srv = 0;
@@ -42,6 +61,7 @@ int get_server_from_list(char **selected_host, int *selected_port, char *server_
 	next = server_list;
 
 	while (curr_srv < num) {
+
 		tmp = strchr(next, ',');
 		if (tmp != NULL) {
 			curr_srv++;
@@ -52,7 +72,10 @@ int get_server_from_list(char **selected_host, int *selected_port, char *server_
 	
 		if (curr_srv == num) {
 			port = atoi(strchr(next, ':') + 1);
+
 			memcpy(selected_port,  &port, sizeof(port));
+
+			// the host string must be allocated in the memory pool!
 			*selected_host = apr_pstrndup(p, next, strchr(next, ':') - next);
 			ret = 0;
 
@@ -62,3 +85,41 @@ int get_server_from_list(char **selected_host, int *selected_port, char *server_
 
 	return ret;
 }
+
+
+//////////////////////////////////////////////
+// This funcion take the master from the list
+// The index is always 0
+//////////////////////////////////////////////
+int get_master_from_list(char **selected_host, int *selected_port, char *server_list, apr_pool_t *p) {
+	int ret = -1;
+	int curr_srv = 0;
+	char *next = NULL;
+	char *tmp = NULL;
+	int port;
+
+	port = atoi(strchr(server_list, ':') + 1), sizeof(port);
+	memcpy(selected_port, &port, sizeof(int));
+
+	// the host string must be allocated in the memory pool!
+	*selected_host = apr_pstrndup(p, server_list, strchr(server_list, ':') - server_list);	
+
+	return 1;
+}
+
+///////////////////////////////////////
+// Query Routing basic implementation
+///////////////////////////////////////
+
+int query_routing(const char *server_list, const char *sql_command, int procotol_command, int current_slave) {
+
+	if (strstr(sql_command, "select ")) {
+		// to the slave
+		return SKYSQL_READ;
+	} else {
+		// to the master
+		return SKYSQL_WRITE;
+	}
+}
+
+//////////////////