Refactor the code and remove the global variable of

support-aliyun-rds branch.

go/base/context.go

@@ -215,8 +215,6 @@ type ContextConfig struct {
 	}
 }
 
-var Context *MigrationContext
-
 func NewMigrationContext() *MigrationContext {
 	return &MigrationContext{
 		Uuid:                                uuid.NewV4().String(),

go/base/utils.go

@@ -64,7 +64,7 @@ func StringContainsAll(s string, substrings ...string) bool {
 	return nonEmptyStringsFound
 }
 
-func ValidateConnection(db *gosql.DB, connectionConfig *mysql.ConnectionConfig) (string, error) {
+func ValidateConnection(db *gosql.DB, connectionConfig *mysql.ConnectionConfig, migrationContext *MigrationContext) (string, error) {
 	versionQuery := `select @@global.version`
 	var port, extraPort int
 	var version string
@@ -76,7 +76,7 @@ func ValidateConnection(db *gosql.DB, connectionConfig *mysql.ConnectionConfig)
 		// swallow this error. not all servers support extra_port
 	}
 	// AliyunRDS set users port to "NULL", replace it by gh-ost param
-	if Context.AliyunRDS {
+	if migrationContext.AliyunRDS {
 		port = connectionConfig.Key.Port
 	} else {
 		portQuery := `select @@global.port`

go/cmd/gh-ost/main.go

@@ -44,8 +44,6 @@ func acceptSignals(migrationContext *base.MigrationContext) {
 // main is the application's entry point. It will either spawn a CLI or HTTP interfaces.
 func main() {
 	migrationContext := base.NewMigrationContext()
-	base.Context = migrationContext
-
 	flag.StringVar(&migrationContext.InspectorConnectionConfig.Key.Hostname, "host", "127.0.0.1", "MySQL hostname (preferably a replica, not the master)")
 	flag.StringVar(&migrationContext.AssumeMasterHostname, "assume-master-host", "", "(optional) explicitly tell gh-ost the identity of the master. Format: some.host.com[:port] This is useful in master-master setups where you wish to pick an explicit master, or in a tungsten-replicator where gh-ost is unable to determine the master")
 	flag.IntVar(&migrationContext.InspectorConnectionConfig.Key.Port, "port", 3306, "MySQL port (preferably a replica, not the master)")

go/logic/applier.go

@@ -78,21 +78,21 @@ func (this *Applier) InitDBConnections() (err error) {
 		return err
 	}
 	this.singletonDB.SetMaxOpenConns(1)
-	version, err := base.ValidateConnection(this.db, this.connectionConfig)
+	version, err := base.ValidateConnection(this.db, this.connectionConfig, this.migrationContext)
 	if err != nil {
 		return err
 	}
-	if _, err := base.ValidateConnection(this.singletonDB, this.connectionConfig); err != nil {
+	if _, err := base.ValidateConnection(this.singletonDB, this.connectionConfig, this.migrationContext); err != nil {
 		return err
 	}
 	this.migrationContext.ApplierMySQLVersion = version
 	if err := this.validateAndReadTimeZone(); err != nil {
 		return err
 	}
-	if impliedKey, err := mysql.GetInstanceKey(this.db, this.migrationContext.AliyunRDS); err != nil {
+	if !this.migrationContext.AliyunRDS {
-		return err
+		if impliedKey, err := mysql.GetInstanceKey(this.db); err != nil {
-	} else {
+			return err
-		if this.migrationContext.AliyunRDS != true {
+		} else {
 			this.connectionConfig.ImpliedKey = impliedKey
 		}
 	}

go/logic/inspect.go

@@ -53,10 +53,10 @@ func (this *Inspector) InitDBConnections() (err error) {
 	if err := this.validateConnection(); err != nil {
 		return err
 	}
-	if impliedKey, err := mysql.GetInstanceKey(this.db, this.migrationContext.AliyunRDS); err != nil {
+	if !this.migrationContext.AliyunRDS {
-		return err
+		if impliedKey, err := mysql.GetInstanceKey(this.db); err != nil {
-	} else {
+			return err
-		if this.migrationContext.AliyunRDS != true {
+		} else {
 			this.connectionConfig.ImpliedKey = impliedKey
 		}
 	}
@@ -205,7 +205,7 @@ func (this *Inspector) validateConnection() error {
 		return fmt.Errorf("MySQL replication length limited to 32 characters. See https://dev.mysql.com/doc/refman/5.7/en/assigning-passwords.html")
 	}
 
-	version, err := base.ValidateConnection(this.db, this.connectionConfig)
+	version, err := base.ValidateConnection(this.db, this.connectionConfig, this.migrationContext)
 	this.migrationContext.InspectorMySQLVersion = version
 	return err
 }

go/logic/streamer.go

@@ -107,7 +107,7 @@ func (this *EventsStreamer) InitDBConnections() (err error) {
 	if this.db, _, err = mysql.GetDB(this.migrationContext.Uuid, EventsStreamerUri); err != nil {
 		return err
 	}
-	if _, err := base.ValidateConnection(this.db, this.connectionConfig); err != nil {
+	if _, err := base.ValidateConnection(this.db, this.connectionConfig, this.migrationContext); err != nil {
 		return err
 	}
 	if err := this.readCurrentBinlogCoordinates(); err != nil {

go/mysql/utils.go

@@ -171,11 +171,9 @@ func GetSelfBinlogCoordinates(db *gosql.DB) (selfBinlogCoordinates *BinlogCoordi
 }
 
 // GetInstanceKey reads hostname and port on given DB
-func GetInstanceKey(db *gosql.DB, isAliyunRDS bool) (instanceKey *InstanceKey, err error) {
+func GetInstanceKey(db *gosql.DB) (instanceKey *InstanceKey, err error) {
 	instanceKey = &InstanceKey{}
-	if isAliyunRDS != true {
+	err = db.QueryRow(`select @@global.hostname, @@global.port`).Scan(&instanceKey.Hostname, &instanceKey.Port)
-		err = db.QueryRow(`select @@global.hostname, @@global.port`).Scan(&instanceKey.Hostname, &instanceKey.Port)
-	}
 	return instanceKey, err
 }