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Clean up scheduled event handling

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Removes some duplicated code.
This commit is contained in:
Esa Korhonen 2019-06-10 11:25:35 +03:00
parent d03e025046
commit 6ee9736803
2 changed files with 63 additions and 73 deletions
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123
server/modules/monitor/mariadbmon/mariadbserver.cc
View File

@ -1231,76 +1231,49 @@ const SlaveStatus* MariaDBServer::slave_connection_status_host_port(const MariaD
bool MariaDBServer::enable_events(BinlogMode binlog_mode, const EventNameSet& event_names, json_t** error_out)
{
int found_disabled_events = 0;
int events_enabled = 0;
// Helper function which enables a disabled event if that event name is found in the events-set.
ManipulatorFunc enabler = [this, event_names, &found_disabled_events, &events_enabled](
const EventInfo& event, json_t** error_out) {
if (event_names.count(event.name) > 0
&& (event.status == "SLAVESIDE_DISABLED" || event.status == "DISABLED"))
{
found_disabled_events++;
if (alter_event(event, "ENABLE", error_out))
{
events_enabled++;
}
}
};
string error_msg;
if (binlog_mode == BinlogMode::BINLOG_OFF)
{
if (!execute_cmd("SET @@session.sql_log_bin=0;", &error_msg))
EventStatusMapper mapper = [&event_names](const EventInfo& event) {
string rval;
if (event_names.count(event.name) > 0
&& (event.status == "SLAVESIDE_DISABLED" || event.status == "DISABLED"))
{
const char FMT[] = "Could not disable session binlog on '%s': %s Server events not enabled.";
PRINT_MXS_JSON_ERROR(error_out, FMT, name(), error_msg.c_str());
return false;
rval = "ENABLE";
}
}
return rval;
};
return alter_events(binlog_mode, mapper, error_out);
bool rval = false;
if (events_foreach(enabler, error_out))
{
if (found_disabled_events > 0)
{
warn_event_scheduler();
}
if (found_disabled_events == events_enabled)
{
rval = true;
}
}
if (binlog_mode == BinlogMode::BINLOG_OFF)
{
// Failure in re-enabling the session binlog doesn't really matter because we don't want the monitor
// generating binlog events anyway.
execute_cmd("SET @@session.sql_log_bin=1;");
}
return rval;
}
bool MariaDBServer::disable_events(BinlogMode binlog_mode, json_t** error_out)
{
int found_enabled_events = 0;
int events_disabled = 0;
// Helper function which disables an enabled event.
ManipulatorFunc disabler = [this, &found_enabled_events, &events_disabled](const EventInfo& event,
json_t** error_out) {
if (event.status == "ENABLED")
{
found_enabled_events++;
if (alter_event(event, "DISABLE ON SLAVE", error_out))
{
events_disabled++;
}
}
};
EventStatusMapper mapper = [](const EventInfo& event) {
string rval;
if (event.status == "ENABLED")
{
rval = "DISABLE ON SLAVE";
}
return rval;
};
return alter_events(binlog_mode, mapper, error_out);
}
/**
* Alter scheduled server events.
*
* @param binlog_mode Should binary logging be disabled while performing this task.
* @param mapper A function which takes an event and returns the requested event state. If empty is returned,
* event is not altered.
* @param error_out Error output
* @return True if all requested alterations succeeded.
*/
bool
MariaDBServer::alter_events(BinlogMode binlog_mode, const EventStatusMapper& mapper, json_t** error_out)
{
// If the server is rejoining the cluster, no events may be added to binlog. The ALTER EVENT query
// itself adds events. To prevent this, disable the binlog for this method.
string error_msg;
if (binlog_mode == BinlogMode::BINLOG_OFF)
const bool disable_binlog = (binlog_mode == BinlogMode::BINLOG_OFF);
if (disable_binlog)
{
if (!execute_cmd("SET @@session.sql_log_bin=0;", &error_msg))
{
@ -1310,28 +1283,44 @@ bool MariaDBServer::disable_events(BinlogMode binlog_mode, json_t** error_out)
}
}
int target_events = 0;
int events_altered = 0;
// Helper function which alters an event depending on the mapper-function.
EventManipulator alterer = [this, &target_events, &events_altered, &mapper](const EventInfo& event,
json_t** error_out) {
string target_state = mapper(event);
if (!target_state.empty())
{
target_events++;
if (alter_event(event, target_state, error_out))
{
events_altered++;
}
}
};
bool rval = false;
if (events_foreach(disabler, error_out))
// TODO: For better error handling, this function should try to re-enable any disabled events if a later
// disable fails.
if (events_foreach(alterer, error_out))
{
if (found_enabled_events > 0)
if (target_events > 0)
{
warn_event_scheduler();
}
if (found_enabled_events == events_disabled)
if (target_events == events_altered)
{
rval = true;
}
}
if (binlog_mode == BinlogMode::BINLOG_OFF)
if (disable_binlog)
{
// Failure in re-enabling the session binlog doesn't really matter because we don't want the monitor
// generating binlog events anyway.
execute_cmd("SET @@session.sql_log_bin=1;");
}
return rval;
// TODO: For better error handling, this function should try to re-enable any disabled events if a later
// disable fails.
}
/**
@ -1365,7 +1354,7 @@ void MariaDBServer::warn_event_scheduler()
* @return True if event information could be read from information_schema.EVENTS. The return value does not
* depend on the manipulator function.
*/
bool MariaDBServer::events_foreach(ManipulatorFunc& func, json_t** error_out)
bool MariaDBServer::events_foreach(EventManipulator& func, json_t** error_out)
{
string error_msg;
// Get info about all scheduled events on the server.
@ -2343,4 +2332,4 @@ bool MariaDBServer::kick_out_super_users(GeneralOpData& op)
}
}
return !error;
}
}

13
server/modules/monitor/mariadbmon/mariadbserver.hh
View File

@ -543,7 +543,8 @@ public:
void set_status(uint64_t bits);
private:
typedef std::function<void (const EventInfo&, json_t** error_out)> ManipulatorFunc;
using EventManipulator = std::function<void (const EventInfo& event, json_t** error_out)>;
using EventStatusMapper = std::function<std::string (const EventInfo& event)>;
enum class StopMode
{
@ -572,11 +573,6 @@ private:
bool sstatus_array_topology_equal(const SlaveStatusArray& new_slave_status);
const SlaveStatus* sstatus_find_previous_row(const SlaveStatus& new_row, size_t guess);
void warn_event_scheduler();
bool events_foreach(ManipulatorFunc& func, json_t** error_out);
bool alter_event(const EventInfo& event, const std::string& target_status,
json_t** error_out);
bool stop_slave_conn(const std::string& conn_name, StopMode mode, maxbase::Duration time_limit,
json_t** error_out);
@ -592,4 +588,9 @@ private:
std::string generate_change_master_cmd(GeneralOpData& op, const SlaveStatus& slave_conn);
bool update_enabled_events();
bool alter_events(BinlogMode binlog_mode, const EventStatusMapper& mapper, json_t** error_out);
void warn_event_scheduler();
bool events_foreach(EventManipulator& func, json_t** error_out);
bool alter_event(const EventInfo& event, const std::string& target_status, json_t** error_out);
};