// ScanInstanceRow executes a read-a-single-row query on a given MySQL topology instance
func ScanInstanceRow(instanceKey *InstanceKey, query string, dest ...interface{}) error {
db, err := db.OpenTopology(instanceKey.Hostname, instanceKey.Port)
if err != nil {
return err
}
err = db.QueryRow(query).Scan(dest...)
return err
}
// ExecInstance executes a given query on the given MySQL topology instance
func ExecInstance(instanceKey *InstanceKey, query string, args ...interface{}) (sql.Result, error) {
db, err := db.OpenTopology(instanceKey.Hostname, instanceKey.Port)
if err != nil {
return nil, err
}
res, err := sqlutils.Exec(db, query, args...)
return res, err
}
// ReadTopologyInstance connects to a topology MySQL instance and reads its configuration and
// replication status. It writes read info into orchestrator's backend.
func ReadTopologyInstance(instanceKey *InstanceKey) (*Instance, error) {
defer func() {
if err := recover(); err != nil {
log.Errorf("Unexpected error: %+v", err)
}
}()
instance := NewInstance()
instanceFound := false
foundBySlaveHosts := false
db, err := db.OpenTopology(instanceKey.Hostname, instanceKey.Port)
if err != nil {
goto Cleanup
}
instance.Key = *instanceKey
err = db.QueryRow("select @@global.server_id, @@global.version, @@global.binlog_format, @@global.log_bin, @@global.log_slave_updates").Scan(
&instance.ServerID, &instance.Version, &instance.Binlog_format, &instance.LogBinEnabled, &instance.LogSlaveUpdatesEnabled)
if err != nil {
goto Cleanup
}
instanceFound = true
err = sqlutils.QueryRowsMap(db, "show slave status", func(m sqlutils.RowMap) error {
instance.Slave_IO_Running = (m.GetString("Slave_IO_Running") == "Yes")
instance.Slave_SQL_Running = (m.GetString("Slave_SQL_Running") == "Yes")
instance.ReadBinlogCoordinates.LogFile = m.GetString("Master_Log_File")
instance.ReadBinlogCoordinates.LogPos = m.GetInt64("Read_Master_Log_Pos")
instance.ExecBinlogCoordinates.LogFile = m.GetString("Relay_Master_Log_File")
instance.ExecBinlogCoordinates.LogPos = m.GetInt64("Exec_Master_Log_Pos")
masterKey, err := NewInstanceKeyFromStrings(m.GetString("Master_Host"), m.GetString("Master_Port"))
if err != nil {
log.Errore(err)
}
instance.MasterKey = *masterKey
instance.SecondsBehindMaster = m.GetNullInt64("Seconds_Behind_Master")
if config.Config.SlaveLagQuery == "" {
instance.SlaveLagSeconds = instance.SecondsBehindMaster
}
// Not breaking the flow even on error
return nil
})
if err != nil {
goto Cleanup
}
if config.Config.SlaveLagQuery != "" {
err = db.QueryRow(config.Config.SlaveLagQuery).Scan(&instance.SlaveLagSeconds)
if err != nil {
goto Cleanup
}
}
err = sqlutils.QueryRowsMap(db, "show master status", func(m sqlutils.RowMap) error {
var err error
instance.SelfBinlogCoordinates.LogFile = m.GetString("File")
instance.SelfBinlogCoordinates.LogPos = m.GetInt64("Position")
return err
})
if err != nil {
goto Cleanup
}
// Get slaves, either by SHOW SLAVE HOSTS or via PROCESSLIST
if config.Config.DiscoverByShowSlaveHosts {
err = sqlutils.QueryRowsMap(db, `show slave hosts`,
func(m sqlutils.RowMap) error {
slaveKey, err := NewInstanceKeyFromStrings(m.GetString("Host"), m.GetString("Port"))
if err == nil {
instance.AddSlaveKey(slaveKey)
foundBySlaveHosts = true
}
return err
})
if err != nil {
goto Cleanup
}
}
if !foundBySlaveHosts {
// Either not configured to read SHOW SLAVE HOSTS or nothing was there.
// Discover by processlist
err = sqlutils.QueryRowsMap(db, `
select
substring_index(host, ':', 1) as slave_hostname
from
information_schema.processlist
where
command='Binlog Dump'`,
func(m sqlutils.RowMap) error {
cname, err := GetCNAME(m.GetString("slave_hostname"))
if err != nil {
return err
}
slaveKey := InstanceKey{Hostname: cname, Port: instance.Key.Port}
instance.AddSlaveKey(&slaveKey)
return err
})
if err != nil {
goto Cleanup
}
}
if err != nil {
goto Cleanup
}
instance.ClusterName, err = ReadClusterNameByMaster(&instance.Key, &instance.MasterKey)
if err != nil {
goto Cleanup
}
Cleanup:
if instanceFound {
_ = WriteInstance(instance, err)
} else {
_ = UpdateInstanceLastChecked(instanceKey)
}
if err != nil {
log.Errore(err)
}
return instance, err
}
