feat(feat-set-binlogsyncer-maxreconnectattempts): feat-set-binlogsyncer-maxreconnectattempts (#1279)

Co-authored-by: shaohoukun <shaohoukun@meituan.com>

.github/dependabot.yml

@@ -1,7 +0,0 @@
----
-version: 2
-updates:
-- package-ecosystem: github-actions
-  directory: "/"
-  schedule:
-    interval: daily

doc/command-line-flags.md

@@ -61,6 +61,9 @@ It is not reliable to parse the `ALTER` statement to determine if it is instant
 
 `gh-ost` will automatically fallback to the normal DDL process if the attempt to use instant DDL is unsuccessful.
 
+### binlogsyncer-max-reconnect-attempts
+`--binlogsyncer-max-reconnect-attempts=0`, the maximum number of attempts to re-establish a broken inspector connection for sync binlog. `0` or `negative number` means infinite retry, default `0`
+
 ### conf
 
 `--conf=/path/to/my.cnf`: file where credentials are specified. Should be in (or contain) the following format:

go/base/context.go

@@ -232,6 +232,8 @@ type MigrationContext struct {
 
 	recentBinlogCoordinates mysql.BinlogCoordinates
 
+	BinlogSyncerMaxReconnectAttempts int
+
 	Log Logger
 }
 

go/binlog/gomysql_reader.go

@@ -44,6 +44,7 @@ func NewGoMySQLReader(migrationContext *base.MigrationContext) *GoMySQLReader {
 			Password:             connectionConfig.Password,
 			TLSConfig:            connectionConfig.TLSConfig(),
 			UseDecimal:           true,
+			MaxReconnectAttempts: migrationContext.BinlogSyncerMaxReconnectAttempts,
 		}),
 	}
 }

go/cmd/gh-ost/main.go

@@ -134,6 +134,7 @@ func main() {
 	flag.Int64Var(&migrationContext.HooksStatusIntervalSec, "hooks-status-interval", 60, "how many seconds to wait between calling onStatus hook")
 
 	flag.UintVar(&migrationContext.ReplicaServerId, "replica-server-id", 99999, "server id used by gh-ost process. Default: 99999")
+	flag.IntVar(&migrationContext.BinlogSyncerMaxReconnectAttempts, "binlogsyncer-max-reconnect-attempts", 0, "when master node fails, the maximum number of binlog synchronization attempts to reconnect. 0 is unlimited")
 
 	maxLoad := flag.String("max-load", "", "Comma delimited status-name=threshold. e.g: 'Threads_running=100,Threads_connected=500'. When status exceeds threshold, app throttles writes")
 	criticalLoad := flag.String("critical-load", "", "Comma delimited status-name=threshold, same format as --max-load. When status exceeds threshold, app panics and quits")

go/logic/applier.go

@@ -9,7 +9,6 @@ import (
 	gosql "database/sql"
 	"fmt"
 	"strings"
-	"sync"
 	"sync/atomic"
 	"time"
 
@@ -935,7 +934,7 @@ func (this *Applier) CreateAtomicCutOverSentryTable() error {
 }
 
 // AtomicCutOverMagicLock
-func (this *Applier) AtomicCutOverMagicLock(sessionIdChan chan int64, tableLocked chan<- error, okToUnlockTable <-chan bool, tableUnlocked chan<- error, dropCutOverSentryTableOnce *sync.Once) error {
+func (this *Applier) AtomicCutOverMagicLock(sessionIdChan chan int64, tableLocked chan<- error, okToUnlockTable <-chan bool, tableUnlocked chan<- error) error {
 	tx, err := this.db.Begin()
 	if err != nil {
 		tableLocked <- err
@@ -946,6 +945,7 @@ func (this *Applier) AtomicCutOverMagicLock(sessionIdChan chan int64, tableLocke
 		tableLocked <- fmt.Errorf("Unexpected error in AtomicCutOverMagicLock(), injected to release blocking channel reads")
 		tableUnlocked <- fmt.Errorf("Unexpected error in AtomicCutOverMagicLock(), injected to release blocking channel reads")
 		tx.Rollback()
+		this.DropAtomicCutOverSentryTableIfExists()
 	}()
 
 	var sessionId int64
@@ -1014,12 +1014,10 @@ func (this *Applier) AtomicCutOverMagicLock(sessionIdChan chan int64, tableLocke
 		sql.EscapeName(this.migrationContext.GetOldTableName()),
 	)
 
-	dropCutOverSentryTableOnce.Do(func() {
 	if _, err := tx.Exec(query); err != nil {
 		this.migrationContext.Log.Errore(err)
 		// We DO NOT return here because we must `UNLOCK TABLES`!
 	}
-	})
 
 	// Tables still locked
 	this.migrationContext.Log.Infof("Releasing lock from %s.%s, %s.%s",

go/logic/migrator.go

@@ -13,7 +13,6 @@ import (
 	"math"
 	"os"
 	"strings"
-	"sync"
 	"sync/atomic"
 	"time"
 
@@ -639,12 +638,8 @@ func (this *Migrator) atomicCutOver() (err error) {
 	defer atomic.StoreInt64(&this.migrationContext.InCutOverCriticalSectionFlag, 0)
 
 	okToUnlockTable := make(chan bool, 4)
-	var dropCutOverSentryTableOnce sync.Once
 	defer func() {
 		okToUnlockTable <- true
-		dropCutOverSentryTableOnce.Do(func() {
-			this.applier.DropAtomicCutOverSentryTableIfExists()
-		})
 	}()
 
 	atomic.StoreInt64(&this.migrationContext.AllEventsUpToLockProcessedInjectedFlag, 0)
@@ -653,7 +648,7 @@ func (this *Migrator) atomicCutOver() (err error) {
 	tableLocked := make(chan error, 2)
 	tableUnlocked := make(chan error, 2)
 	go func() {
-		if err := this.applier.AtomicCutOverMagicLock(lockOriginalSessionIdChan, tableLocked, okToUnlockTable, tableUnlocked, &dropCutOverSentryTableOnce); err != nil {
+		if err := this.applier.AtomicCutOverMagicLock(lockOriginalSessionIdChan, tableLocked, okToUnlockTable, tableUnlocked); err != nil {
 			this.migrationContext.Log.Errore(err)
 		}
 	}()