WL#15535 Allow components to register and use session scope system variables

Currently the component_sys_variable_register/component_sys_variable_unregister
services support registering only GLOBAL system variables.

Extend these to also support session level (SET SESSION) system variables.

Change-Id: I0901b7cf59bf878a846253c49094f3c83b866726

Author: V S Murthy Sidagam

components/libminchassis/gunit_harness/include/mock/component_sys_variable_all_empty.cc

@@ -22,9 +22,11 @@ along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
 #include <stdio.h>
+#include "my_compiler.h"
 #include "mysql/components/component_implementation.h"
 #include "mysql/components/service_implementation.h"
 #include "mysql/components/services/component_sys_var_service.h"
+#include "mysql/components/services/mysql_system_variable.h"
 
 namespace mysql_service_simple_error_log_spc {
 
@@ -44,18 +46,33 @@ static DEFINE_BOOL_METHOD(get_variable, (const char * /*component_name*/,
   return false;
 }
 
+static DEFINE_BOOL_METHOD(get, (MYSQL_THD /*thd handle*/,
+                                const char * /*variable type*/,
+                                const char * /*component_name*/,
+                                const char * /*name*/, void ** /*val*/,
+                                size_t * /*out_length_of_val*/)) {
+  return false;
+}
+
 static DEFINE_BOOL_METHOD(unregister_variable, (const char * /*component_name*/,
                                                 const char * /*name*/)) {
   return false;
 }
 
 }  // namespace mysql_service_simple_error_log_spc
 
+MY_COMPILER_DIAGNOSTIC_PUSH()
+MY_COMPILER_CLANG_DIAGNOSTIC_IGNORE("-Wdeprecated-declarations")
 BEGIN_SERVICE_IMPLEMENTATION(HARNESS_COMPONENT_NAME,
                              component_sys_variable_register)
 mysql_service_simple_error_log_spc::register_variable,
     mysql_service_simple_error_log_spc::get_variable,
     END_SERVICE_IMPLEMENTATION();
+MY_COMPILER_DIAGNOSTIC_POP()
+
+BEGIN_SERVICE_IMPLEMENTATION(HARNESS_COMPONENT_NAME,
+                             mysql_system_variable_reader)
+mysql_service_simple_error_log_spc::get, END_SERVICE_IMPLEMENTATION();
 
 BEGIN_SERVICE_IMPLEMENTATION(HARNESS_COMPONENT_NAME,
                              component_sys_variable_unregister)

components/logging/log_filter_dragnet.cc

@@ -80,12 +80,14 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 
 #include <mysql/components/services/component_status_var_service.h>
 #include <mysql/components/services/component_sys_var_service.h>
+#include <mysql/components/services/mysql_system_variable.h>
 #include <mysql/plugin.h>
 
 #include "../sql/set_var.h"
 
 REQUIRES_SERVICE_PLACEHOLDER(component_sys_variable_register);
 REQUIRES_SERVICE_PLACEHOLDER(component_sys_variable_unregister);
+REQUIRES_SERVICE_PLACEHOLDER(mysql_system_variable_reader);
 REQUIRES_SERVICE_PLACEHOLDER(status_variable_registration);
 
 STR_CHECK_ARG(rules) values_filter_rules;  ///< limits and default for sysvar
@@ -1690,9 +1692,9 @@ mysql_service_status_t log_filter_init() {
           (void *)&values_filter_rules, (void *)&log_error_filter_rules) ||
       mysql_service_status_variable_registration->register_variable(
           (SHOW_VAR *)&show_var_filter_rules_decompile) ||
-      mysql_service_component_sys_variable_register->get_variable(
-          LOG_FILTER_LANGUAGE_NAME, LOG_FILTER_SYSVAR_NAME, (void **)&var_value,
-          &var_len) ||
+      mysql_service_mysql_system_variable_reader->get(
+          nullptr, "GLOBAL", LOG_FILTER_LANGUAGE_NAME, LOG_FILTER_SYSVAR_NAME,
+          (void **)&var_value, &var_len) ||
       ((rr = log_filter_dragnet_set(log_filter_dragnet_rules, var_value,
                                     &state)) != 0)) {
     /*
@@ -1757,6 +1759,7 @@ PROVIDES_SERVICE(log_filter_dragnet, log_service), END_COMPONENT_PROVIDES();
 BEGIN_COMPONENT_REQUIRES(log_filter_dragnet)
 REQUIRES_SERVICE(component_sys_variable_register),
     REQUIRES_SERVICE(component_sys_variable_unregister),
+    REQUIRES_SERVICE(mysql_system_variable_reader),
     REQUIRES_SERVICE(status_variable_registration),
     REQUIRES_SERVICE(log_builtins), REQUIRES_SERVICE(log_builtins_string),
     REQUIRES_SERVICE(log_builtins_filter), REQUIRES_SERVICE(log_builtins_tmp),

components/logging/log_sink_syseventlog.cc

@@ -34,6 +34,7 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 #include <mysql/components/service_implementation.h>
 
 #include <mysql/components/services/component_sys_var_service.h>
+#include <mysql/components/services/mysql_system_variable.h>
 #include <mysql/plugin.h>
 
 #include "../sql/set_var.h"
@@ -96,6 +97,7 @@ static bool inited = false; /**< component initialized */
 // components we'll be using
 REQUIRES_SERVICE_PLACEHOLDER(component_sys_variable_register);
 REQUIRES_SERVICE_PLACEHOLDER(component_sys_variable_unregister);
+REQUIRES_SERVICE_PLACEHOLDER(mysql_system_variable_reader);
 
 REQUIRES_SERVICE_PLACEHOLDER(log_builtins);
 REQUIRES_SERVICE_PLACEHOLDER(log_builtins_string);
@@ -491,8 +493,8 @@ static int sysvar_install_tag(void) {
           "default ident of '" PREFIX "', connected by a hyphen.",
           sysvar_check_tag, sysvar_update_tag, (void *)&values_tag,
           (void *)&buffer_tag) ||
-      mysql_service_component_sys_variable_register->get_variable(
-          MY_NAME, OPT_TAG, (void **)&var_value, &var_len))
+      mysql_service_mysql_system_variable_reader->get(
+          nullptr, "GLOBAL", MY_NAME, OPT_TAG, (void **)&var_value, &var_len))
     goto done; /* purecov: inspected */
 
   /*
@@ -620,8 +622,8 @@ static int sysvar_install_fac(void) {
           "identify as a facility of the given type (to aid in log filtering).",
           sysvar_check_fac, sysvar_update_fac, (void *)&values_fac,
           (void *)&buffer_fac) ||
-      mysql_service_component_sys_variable_register->get_variable(
-          MY_NAME, OPT_FAC, (void **)&var_value, &var_len))
+      mysql_service_mysql_system_variable_reader->get(
+          nullptr, "GLOBAL", MY_NAME, OPT_FAC, (void **)&var_value, &var_len))
     goto done; /* purecov: inspected */
 
   /*
@@ -710,8 +712,8 @@ static int sysvar_install_pid(void) {
           (void *)&log_syslog_include_pid) ||
 
       // get variable in case it was PERSISTed
-      mysql_service_component_sys_variable_register->get_variable(
-          MY_NAME, OPT_PID, (void **)&var_value, &var_len))
+      mysql_service_mysql_system_variable_reader->get(
+          nullptr, "GLOBAL", MY_NAME, OPT_PID, (void **)&var_value, &var_len))
     goto done; /* purecov: inspected */
 
   // set the (possibly PERSISTed) value we received from the server
@@ -959,6 +961,7 @@ PROVIDES_SERVICE(log_sink_syseventlog, log_service), END_COMPONENT_PROVIDES();
 BEGIN_COMPONENT_REQUIRES(log_sink_syseventlog)
 REQUIRES_SERVICE(component_sys_variable_register),
     REQUIRES_SERVICE(component_sys_variable_unregister),
+    REQUIRES_SERVICE(mysql_system_variable_reader),
     REQUIRES_SERVICE(log_builtins), REQUIRES_SERVICE(log_builtins_string),
     REQUIRES_SERVICE(log_builtins_syseventlog),
 #ifdef _WIN32

components/mysqlbackup/backup_page_tracker.cc

@@ -387,8 +387,8 @@ long long Backup_page_tracker::page_track_get_changed_pages(UDF_INIT *,
   void *p = &mysqlbackup_backupdir;
   size_t var_len = 1023;
 
-  mysql_service_component_sys_variable_register->get_variable(
-      "mysql_server", "datadir", (void **)&p, &var_len);
+  mysql_service_mysql_system_variable_reader->get(
+      nullptr, "GLOBAL", "mysql_server", "datadir", (void **)&p, &var_len);
   if (var_len == 0) return 2;
 
   std::string changed_pages_file_dir =

components/mysqlbackup/mysqlbackup.cc

@@ -386,6 +386,7 @@ REQUIRES_SERVICE_PLACEHOLDER(log_builtins);
 REQUIRES_SERVICE_PLACEHOLDER(log_builtins_string);
 REQUIRES_SERVICE_PLACEHOLDER(component_sys_variable_register);
 REQUIRES_SERVICE_PLACEHOLDER(component_sys_variable_unregister);
+REQUIRES_SERVICE_PLACEHOLDER(mysql_system_variable_reader);
 REQUIRES_SERVICE_PLACEHOLDER(status_variable_registration);
 REQUIRES_SERVICE_PLACEHOLDER(udf_registration);
 REQUIRES_SERVICE_PLACEHOLDER(mysql_thd_security_context);
@@ -405,6 +406,7 @@ BEGIN_COMPONENT_REQUIRES(mysqlbackup)
 REQUIRES_SERVICE(registry), REQUIRES_SERVICE(log_builtins),
     REQUIRES_SERVICE(log_builtins_string),
     REQUIRES_SERVICE(component_sys_variable_register),
+    REQUIRES_SERVICE(mysql_system_variable_reader),
     REQUIRES_SERVICE(component_sys_variable_unregister),
     REQUIRES_SERVICE(status_variable_registration),
     REQUIRES_SERVICE(udf_registration),

components/mysqlbackup/mysqlbackup.h

@@ -31,6 +31,7 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */
 #include <mysql/components/services/dynamic_privilege.h>
 #include <mysql/components/services/log_builtins.h>
 #include <mysql/components/services/mysql_current_thread_reader.h>
+#include <mysql/components/services/mysql_system_variable.h>
 #include <mysql/components/services/psi_memory_service.h>
 #include <mysql/components/services/security_context.h>
 #include <mysql/components/services/udf_registration.h>
@@ -44,6 +45,7 @@ extern REQUIRES_SERVICE_PLACEHOLDER(registry);
 extern REQUIRES_SERVICE_PLACEHOLDER(log_builtins);
 extern REQUIRES_SERVICE_PLACEHOLDER(log_builtins_string);
 extern REQUIRES_SERVICE_PLACEHOLDER(component_sys_variable_register);
+extern REQUIRES_SERVICE_PLACEHOLDER(mysql_system_variable_reader);
 extern REQUIRES_SERVICE_PLACEHOLDER(component_sys_variable_unregister);
 extern REQUIRES_SERVICE_PLACEHOLDER(status_variable_registration);
 extern REQUIRES_SERVICE_PLACEHOLDER(udf_registration);

components/test/CMakeLists.txt

@@ -186,4 +186,8 @@ MYSQL_ADD_COMPONENT(test_mysql_signal_handler
   MODULE_ONLY
   TEST_ONLY
   )
-
+MYSQL_ADD_COMPONENT(test_session_var_service
+  test_session_var_service.cc
+  MODULE_ONLY
+  TEST_ONLY
+  )