/
replica.go
317 lines (281 loc) · 7.72 KB
/
replica.go
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package replica
import (
"database/sql"
"errors"
"fmt"
"strconv"
"strings"
"github.com/Songmu/prompter"
"github.com/jmoiron/sqlx"
_ "github.com/go-sql-driver/mysql"
)
type (
ReplicaNode struct {
AutoPosition bool `db:"Auto_Position"`
ChannelName string `db:"Channel_Name"`
ExecutedGtidSet string `db:"Executed_Gtid_Set"`
GtidExecuted string // @@gtid_executed
Info MySQLServerInfo
Level int
Source *ReplicaNode
MasterHost string `db:"Master_Host"`
MasterPort int `db:"Master_Port"`
MasterUUID string `db:"Master_UUID"`
ReplicaIORunning string `db:"Slave_IO_Running"`
ReplicaSQLRunning string `db:"Slave_SQL_Running"`
}
MySQLDB struct {
dbh *sql.DB
executedGtidSet string
monitorUser string
monitorPass string
replicaNodes map[string]ReplicaNode
serverUuid string
}
MySQLServerInfo struct {
ServerId int `db:"Server_id"`
Host string `db:"Host"`
ServerUuid string `db:"Slave_UUID"`
}
)
const (
resetMasterQuery = `RESET MASTER`
resetReplicaQuery = `RESET SLAVE`
// see https://dev.mysql.com/doc/refman/5.7/en/gtid-functions.html
getErrantGTIDsQuery = `SELECT GTID_SUBTRACT('%s', '%s')`
getGTIDExecutedQuery = `SELECT @@global.gtid_executed`
getServerUuidQuery = `SELECT @@server_uuid`
setGtidPurgedQuery = `SET GLOBAL gtid_purged='%s'`
showReplicaHostQuery = `SHOW SLAVE HOSTS`
showReplicaStatusQuery = `SHOW SLAVE STATUS`
startReplicaQuery = `START SLAVE`
stopReplicaQuery = `STOP SLAVE`
)
func NewMySQLDB(db *sql.DB, monitorUser string, monitorPass string) (*MySQLDB, error) {
var serverUuid string
if err := db.QueryRow(getServerUuidQuery).Scan(&serverUuid); err != nil {
return nil, err
}
return &MySQLDB{
db,
"",
monitorUser,
monitorPass,
map[string]ReplicaNode{},
serverUuid,
}, nil
}
func (node ReplicaNode) searchNode(db *MySQLDB) error {
var sqlxDb *sqlx.DB
if node.Level == 0 {
sqlxDb = sqlx.NewDb(db.dbh, "mysql")
} else {
sqlxDb, err := node.DB(db.monitorUser, db.monitorPass)
if err != nil {
return err
}
defer sqlxDb.Close()
}
rows, err := sqlxDb.Unsafe().Queryx(showReplicaStatusQuery)
if err != nil {
return err
}
// if the node is treetop
if !rows.NextResultSet() {
n := db.replicaNodes[node.MasterUUID]
n.updateSelfInfo()
return nil
}
// if the node is not treetop
newNode := ReplicaNode{}
rows, err = sqlxDb.Unsafe().Queryx(showReplicaStatusQuery)
if err != nil {
return err
}
for rows.Next() {
if err = rows.StructScan(&newNode); err != nil {
return err
}
newNode.Level = node.Level + 1
newNode.Source = &node
db.replicaNodes[newNode.MasterUUID] = newNode
if err := newNode.updateDownstreamInfo(db); err != nil {
return err
}
// recursive search
if err := newNode.searchNode(db); err != nil {
return err
}
}
return nil
}
func (node ReplicaNode) updateSelfInfo() error {
return nil
}
func (node ReplicaNode) DB(monitorUser string, monitorPass string) (*sqlx.DB, error) {
dsn := monitorUser + ":" + monitorPass + "@(" + node.MasterHost + ":" + strconv.Itoa(node.MasterPort) + ")/"
return sqlx.Open("mysql", dsn)
}
func (node ReplicaNode) updateDownstreamInfo(db *MySQLDB) error {
// collect replication node info
sqlxDb, err := node.DB(db.monitorUser, db.monitorPass)
if err != nil {
return err
}
defer sqlxDb.Close()
rows, err := sqlxDb.Unsafe().Queryx(showReplicaHostQuery)
if err != nil {
return err
}
server := MySQLServerInfo{}
for rows.Next() {
if err = rows.StructScan(&server); err != nil {
return err
}
if val, ok := db.replicaNodes[server.ServerUuid]; ok {
val.Info = server
} else {
node := ReplicaNode{}
node.Info = server
db.replicaNodes[server.ServerUuid] = node
}
}
return nil
}
// gatherReplicaNodeses update replStatus of MySQLDB
func (db *MySQLDB) gatherReplicaStatus() error {
node := ReplicaNode{}
if _, ok := db.replicaNodes[db.serverUuid]; !ok {
node.Level = 0
node.MasterUUID = db.serverUuid
if err := node.updateSelfInfo(); err != nil {
return err
}
db.replicaNodes[db.serverUuid] = node
}
if err := node.searchNode(db); err != nil {
return err
}
for _, node := range db.replicaNodes {
if node.Level == 1 {
db.executedGtidSet = node.ExecutedGtidSet
break
}
}
return nil
}
// function autoPosition check whether auto position is enabled for all the channel
func (db *MySQLDB) autoPosition() bool {
for _, node := range db.replicaNodes {
if node.Level == 2 && !node.AutoPosition {
return false
}
}
return true
}
func (db *MySQLDB) stopReplica() error {
fmt.Println("stopping replica")
if _, err := db.dbh.Exec(stopReplicaQuery); err != nil {
return err
}
return nil
}
func (db *MySQLDB) resumeReplica() error {
fmt.Println("resuming replica")
if _, err := db.dbh.Exec(startReplicaQuery); err != nil {
return err
}
return nil
}
func (db *MySQLDB) errantTransaction() (string, error) {
fmt.Println("errant transaction pre-check: ")
var errantGtidSets string
var executedGtidSets []string
for _, node := range db.replicaNodes {
if node.Level == 1 {
fmt.Printf("checking %s\n", node.MasterHost)
sqlxDb, err := node.DB(db.monitorUser, db.monitorPass)
if err != nil {
return "", err
}
defer sqlxDb.Close()
// gtid_executed
if err := sqlxDb.QueryRowx(getGTIDExecutedQuery).Scan(&node.GtidExecuted); err != nil {
return "", err
}
executedGtidSets = append(executedGtidSets, node.GtidExecuted)
}
}
replicaGtidSets := strings.Replace(db.executedGtidSet, "\n", "", -1)
masterGtidSets := strings.Join(executedGtidSets, ",")
sqlxDb := sqlx.NewDb(db.dbh, "mysql")
if err := sqlxDb.QueryRowx(fmt.Sprintf(getErrantGTIDsQuery, replicaGtidSets, masterGtidSets)).Scan(&errantGtidSets); err != nil {
return errantGtidSets, err
}
if errantGtidSets != "" {
for _, errant := range strings.Split(errantGtidSets, ",") {
errant = strings.Replace(errant, "\n", "", -1)
node := db.replicaNodes[strings.Split(errant, ":")[0]]
fmt.Printf(" errant_gtid %s: server_id: %d, host %s\n", errant, node.Info.ServerId, node.Info.Host)
}
}
fmt.Println("")
return errantGtidSets, nil
}
func (db *MySQLDB) FixErrantGTID(forceOption bool) error {
if err := db.gatherReplicaStatus(); err != nil {
return err
}
if !db.autoPosition() {
return errors.New("auto position must be enabled for all the channel")
}
errantGtidSets, err := db.errantTransaction()
if err != nil {
return err
}
if errantGtidSets == "" {
fmt.Println("errant GTID not found")
return nil
}
if err := db.stopReplica(); err != nil {
return err
}
defer db.resumeReplica()
if err := db.gatherReplicaStatus(); err != nil {
return err
}
// print original state just in case
executedGtidSet := db.executedGtidSet
fmt.Printf("original gtid_executed: \n%s\n", executedGtidSet)
gtidSet := strings.Split(executedGtidSet, ",")
var gtidPurged []string
for _, gtid := range gtidSet {
gtid = strings.Replace(gtid, "\n", "", -1)
errantFound := false
for _, errant := range strings.Split(errantGtidSets, ",") {
if strings.HasPrefix(gtid, strings.Split(errant, ":")[0]) {
errantFound = true
}
}
if !errantFound {
gtidPurged = append(gtidPurged, gtid)
}
}
if !forceOption && !prompter.YN("\nWould you continue to reset?", false) {
fmt.Println("do nothing")
return nil
}
fmt.Println(resetReplicaQuery)
if _, err := db.dbh.Exec(resetReplicaQuery); err != nil {
return err
}
fmt.Println(resetMasterQuery)
if _, err := db.dbh.Exec(resetMasterQuery); err != nil {
return err
}
fmt.Println(fmt.Sprintf(setGtidPurgedQuery, strings.Join(gtidPurged, ",")))
if _, err := db.dbh.Exec(fmt.Sprintf(setGtidPurgedQuery, strings.Join(gtidPurged, ","))); err != nil {
return err
}
return nil
}