Modernize

components/cluster/command/start.go

@@ -114,7 +114,6 @@ func initPassword(clusterName string) (string, error) {
 
 	var lastErr error
 	for _, spec := range metadata.Topology.TiDBServers {
-		spec := spec
 		endpoint := utils.JoinHostPort(spec.Host, spec.Port)
 		if tcpProxy != nil {
 			closeC := tcpProxy.Run([]string{endpoint})

components/cluster/command/test.go

@@ -77,7 +77,6 @@ func data(topo *spec.Specification, tcpProxy *proxy.TCPProxy) error {
 	errg, _ := errgroup.WithContext(context.Background())
 
 	for _, spec := range topo.TiDBServers {
-		spec := spec
 		endpoint := utils.JoinHostPort(spec.Host, spec.Port)
 		errg.Go(func() error {
 			if tcpProxy != nil {
@@ -112,7 +111,6 @@ func writable(topo *spec.Specification, tcpProxy *proxy.TCPProxy) error {
 	errg, _ := errgroup.WithContext(context.Background())
 
 	for _, spec := range topo.TiDBServers {
-		spec := spec
 		endpoint := utils.JoinHostPort(spec.Host, spec.Port)
 		errg.Go(func() error {
 			if tcpProxy != nil {

components/dm/command/prune.go

@@ -99,15 +99,13 @@ func clearOutDatedEtcdInfo(clusterName string, metadata *spec.Metadata, opt oper
 	var wg sync.WaitGroup
 
 	for _, master := range mastersToDelete {
-		master := master
 		wg.Add(1)
 		go func() {
 			errCh <- dmMasterClient.OfflineMaster(master, nil)
 			wg.Done()
 		}()
 	}
 	for _, worker := range workersToDelete {
-		worker := worker
 		wg.Add(1)
 		go func() {
 			errCh <- dmMasterClient.OfflineWorker(worker, nil)

components/dm/spec/logic.go

@@ -91,7 +91,6 @@ func (c *DMMasterComponent) SetVersion(version string) {
 func (c *DMMasterComponent) Instances() []Instance {
 	ins := make([]Instance, 0)
 	for _, s := range c.Topology.Masters {
-		s := s
 		ins = append(ins, &MasterInstance{
 			Name: s.Name,
 			BaseInstance: spec.BaseInstance{
@@ -315,7 +314,6 @@ func (c *DMWorkerComponent) SetVersion(version string) {
 func (c *DMWorkerComponent) Instances() []Instance {
 	ins := make([]Instance, 0)
 	for _, s := range c.Topology.Workers {
-		s := s
 		ins = append(ins, &WorkerInstance{
 			Name: s.Name,
 			BaseInstance: spec.BaseInstance{

components/playground/instance/tiflash.go

@@ -165,7 +165,7 @@ func isKeyPresentInMap(m map[string]any, key string) bool {
 	keys := strings.Split(key, ".")
 	currentMap := m
 
-	for i := 0; i < len(keys); i++ {
+	for i := range keys {
 		if _, ok := currentMap[keys[i]]; !ok {
 			return false
 		}

components/playground/main.go

@@ -430,7 +430,7 @@ func tryConnect(addr string, timeoutSec int) error {
 // checkDB check if the addr is connectable by getting a connection from sql.DB. timeout <=0 means no timeout
 func checkDB(dbAddr string, timeout int) bool {
 	if timeout > 0 {
-		for i := 0; i < timeout; i++ {
+		for range timeout {
 			if tryConnect(dbAddr, timeout) == nil {
 				return true
 			}
@@ -449,7 +449,7 @@ func checkDB(dbAddr string, timeout int) bool {
 // checkStoreStatus uses pd client to check whether a store is up. timeout <= 0 means no timeout
 func checkStoreStatus(pdClient *api.PDClient, storeAddr string, timeout int) bool {
 	if timeout > 0 {
-		for i := 0; i < timeout; i++ {
+		for range timeout {
 			if up, err := pdClient.IsUp(storeAddr); err == nil && up {
 				return true
 			}
@@ -467,7 +467,7 @@ func checkStoreStatus(pdClient *api.PDClient, storeAddr string, timeout int) boo
 
 func checkDMMasterStatus(dmMasterClient *api.DMMasterClient, dmMasterAddr string, timeout int) bool {
 	if timeout > 0 {
-		for i := 0; i < timeout; i++ {
+		for range timeout {
 			if _, isActive, _, err := dmMasterClient.GetMaster(dmMasterAddr); err == nil && isActive {
 				return true
 			}

pkg/cluster/ansible/service.go

@@ -61,9 +61,9 @@ func parseDirs(ctx context.Context, user string, ins spec.InstanceSpec, sshTimeo
 	case spec.ComponentTiDB:
 		// parse dirs
 		newIns := ins.(*spec.TiDBSpec)
-		for _, line := range strings.Split(stdout, "\n") {
-			if strings.HasPrefix(line, "DEPLOY_DIR=") {
-				newIns.DeployDir = strings.TrimPrefix(line, "DEPLOY_DIR=")
+		for line := range strings.SplitSeq(stdout, "\n") {
+			if after, ok := strings.CutPrefix(line, "DEPLOY_DIR="); ok {
+				newIns.DeployDir = after
 				continue
 			}
 			if strings.Contains(line, "--log-file=") {
@@ -78,7 +78,7 @@ func parseDirs(ctx context.Context, user string, ins spec.InstanceSpec, sshTimeo
 	case spec.ComponentTiKV:
 		// parse dirs
 		newIns := ins.(*spec.TiKVSpec)
-		for _, line := range strings.Split(stdout, "\n") {
+		for line := range strings.SplitSeq(stdout, "\n") {
 			if strings.HasPrefix(line, "cd \"") {
 				newIns.DeployDir = strings.Trim(strings.Split(line, " ")[1], "\"")
 				continue
@@ -100,9 +100,9 @@ func parseDirs(ctx context.Context, user string, ins spec.InstanceSpec, sshTimeo
 	case spec.ComponentPD:
 		// parse dirs
 		newIns := ins.(*spec.PDSpec)
-		for _, line := range strings.Split(stdout, "\n") {
-			if strings.HasPrefix(line, "DEPLOY_DIR=") {
-				newIns.DeployDir = strings.TrimPrefix(line, "DEPLOY_DIR=")
+		for line := range strings.SplitSeq(stdout, "\n") {
+			if after, ok := strings.CutPrefix(line, "DEPLOY_DIR="); ok {
+				newIns.DeployDir = after
 				continue
 			}
 			if strings.Contains(line, "--name") {
@@ -129,7 +129,7 @@ func parseDirs(ctx context.Context, user string, ins spec.InstanceSpec, sshTimeo
 	case spec.ComponentTiFlash:
 		// parse dirs
 		newIns := ins.(*spec.TiFlashSpec)
-		for _, line := range strings.Split(stdout, "\n") {
+		for line := range strings.SplitSeq(stdout, "\n") {
 			if strings.HasPrefix(line, "cd \"") {
 				newIns.DeployDir = strings.Trim(strings.Split(line, " ")[1], "\"")
 				continue
@@ -154,9 +154,9 @@ func parseDirs(ctx context.Context, user string, ins spec.InstanceSpec, sshTimeo
 	case spec.ComponentPump:
 		// parse dirs
 		newIns := ins.(*spec.PumpSpec)
-		for _, line := range strings.Split(stdout, "\n") {
-			if strings.HasPrefix(line, "DEPLOY_DIR=") {
-				newIns.DeployDir = strings.TrimPrefix(line, "DEPLOY_DIR=")
+		for line := range strings.SplitSeq(stdout, "\n") {
+			if after, ok := strings.CutPrefix(line, "DEPLOY_DIR="); ok {
+				newIns.DeployDir = after
 				continue
 			}
 			if strings.Contains(line, "--data-dir") {
@@ -177,9 +177,9 @@ func parseDirs(ctx context.Context, user string, ins spec.InstanceSpec, sshTimeo
 	case spec.ComponentDrainer:
 		// parse dirs
 		newIns := ins.(*spec.DrainerSpec)
-		for _, line := range strings.Split(stdout, "\n") {
-			if strings.HasPrefix(line, "DEPLOY_DIR=") {
-				newIns.DeployDir = strings.TrimPrefix(line, "DEPLOY_DIR=")
+		for line := range strings.SplitSeq(stdout, "\n") {
+			if after, ok := strings.CutPrefix(line, "DEPLOY_DIR="); ok {
+				newIns.DeployDir = after
 				continue
 			}
 			if strings.Contains(line, "--data-dir") {
@@ -206,9 +206,9 @@ func parseDirs(ctx context.Context, user string, ins spec.InstanceSpec, sshTimeo
 	case spec.ComponentPrometheus:
 		// parse dirs
 		newIns := ins.(*spec.PrometheusSpec)
-		for _, line := range strings.Split(stdout, "\n") {
-			if strings.HasPrefix(line, "DEPLOY_DIR=") {
-				newIns.DeployDir = strings.TrimPrefix(line, "DEPLOY_DIR=")
+		for line := range strings.SplitSeq(stdout, "\n") {
+			if after, ok := strings.CutPrefix(line, "DEPLOY_DIR="); ok {
+				newIns.DeployDir = after
 				continue
 			}
 			if strings.Contains(line, "exec > >(tee -i -a") {
@@ -229,9 +229,9 @@ func parseDirs(ctx context.Context, user string, ins spec.InstanceSpec, sshTimeo
 	case spec.ComponentAlertmanager:
 		// parse dirs
 		newIns := ins.(*spec.AlertmanagerSpec)
-		for _, line := range strings.Split(stdout, "\n") {
-			if strings.HasPrefix(line, "DEPLOY_DIR=") {
-				newIns.DeployDir = strings.TrimPrefix(line, "DEPLOY_DIR=")
+		for line := range strings.SplitSeq(stdout, "\n") {
+			if after, ok := strings.CutPrefix(line, "DEPLOY_DIR="); ok {
+				newIns.DeployDir = after
 				continue
 			}
 			if strings.Contains(line, "exec > >(tee -i -a") {
@@ -252,9 +252,9 @@ func parseDirs(ctx context.Context, user string, ins spec.InstanceSpec, sshTimeo
 	case spec.ComponentGrafana:
 		// parse dirs
 		newIns := ins.(*spec.GrafanaSpec)
-		for _, line := range strings.Split(stdout, "\n") {
-			if strings.HasPrefix(line, "DEPLOY_DIR=") {
-				newIns.DeployDir = strings.TrimPrefix(line, "DEPLOY_DIR=")
+		for line := range strings.SplitSeq(stdout, "\n") {
+			if after, ok := strings.CutPrefix(line, "DEPLOY_DIR="); ok {
+				newIns.DeployDir = after
 				continue
 			}
 		}

pkg/cluster/api/types.go

@@ -126,7 +126,7 @@ type RegionInfo struct {
 	RegionEpoch *metapb.RegionEpoch `json:"epoch,omitempty"`
 	Peers       []MetaPeer          `json:"peers,omitempty"`
 
-	Leader          MetaPeer      `json:"leader,omitempty"`
+	Leader          MetaPeer      `json:"leader"`
 	DownPeers       []PDPeerStats `json:"down_peers,omitempty"`
 	PendingPeers    []MetaPeer    `json:"pending_peers,omitempty"`
 	WrittenBytes    uint64        `json:"written_bytes"`

pkg/cluster/audit/audit_test.go

@@ -54,7 +54,7 @@ func TestOutputAuditLog(t *testing.T) {
 	resetDir()
 
 	var g errgroup.Group
-	for i := 0; i < 20; i++ {
+	for range 20 {
 		g.Go(func() error { return OutputAuditLog(dir, "", []byte("audit log")) })
 	}
 	err := g.Wait()

pkg/cluster/executor/executor.go

@@ -173,7 +173,7 @@ func FindSSHAuthorizedKeysFile(ctx context.Context, exec ctxt.Executor) string {
 	sshAuthorizedKeys := defaultSSHAuthorizedKeys
 	cmd := "grep -Ev '^\\s*#|^\\s*$' /etc/ssh/sshd_config"
 	stdout, _, _ := exec.Execute(ctx, cmd, true) // error ignored as we have default value
-	for _, line := range strings.Split(string(stdout), "\n") {
+	for line := range strings.SplitSeq(string(stdout), "\n") {
 		if !strings.Contains(line, "AuthorizedKeysFile") {
 			continue
 		}

pkg/cluster/manager/builder.go

@@ -135,7 +135,7 @@ func buildScaleOutTask(
 		var dirs []string
 		globalOptions := metadata.GetTopology().BaseTopo().GlobalOptions
 		for _, dir := range []string{globalOptions.DeployDir, globalOptions.DataDir, globalOptions.LogDir} {
-			for _, dirname := range strings.Split(dir, ",") {
+			for dirname := range strings.SplitSeq(dir, ",") {
 				if dirname == "" {
 					continue
 				}

pkg/cluster/manager/cleanup.go

@@ -218,13 +218,13 @@ func (c *cleanupFiles) instanceCleanupFiles(topo spec.Topology) {
 			tlsPath := set.NewStringSet()
 
 			if c.cleanupData && len(ins.DataDir()) > 0 {
-				for _, dataDir := range strings.Split(ins.DataDir(), ",") {
+				for dataDir := range strings.SplitSeq(ins.DataDir(), ",") {
 					dataPaths.Insert(path.Join(dataDir, "*"))
 				}
 			}
 
 			if c.cleanupLog && len(ins.LogDir()) > 0 {
-				for _, logDir := range strings.Split(ins.LogDir(), ",") {
+				for logDir := range strings.SplitSeq(ins.LogDir(), ",") {
 					// need to judge the audit log of tidb server
 					if ins.ComponentName() == spec.ComponentTiDB {
 						logPaths.Insert(path.Join(logDir, "tidb?[!audit]*.log"))
@@ -236,7 +236,7 @@ func (c *cleanupFiles) instanceCleanupFiles(topo spec.Topology) {
 			}
 
 			if c.cleanupAuditLog && ins.ComponentName() == spec.ComponentTiDB {
-				for _, logDir := range strings.Split(ins.LogDir(), ",") {
+				for logDir := range strings.SplitSeq(ins.LogDir(), ",") {
 					logPaths.Insert(path.Join(logDir, "tidb-audit*.log"))
 				}
 			}

pkg/cluster/manager/transfer.go

@@ -132,7 +132,7 @@ func renderInstanceSpec(t string, inst spec.Instance) ([]string, error) {
 	result := make([]string, 0)
 	switch inst.ComponentName() {
 	case spec.ComponentTiFlash:
-		for _, d := range strings.Split(inst.DataDir(), ",") {
+		for d := range strings.SplitSeq(inst.DataDir(), ",") {
 			tfs, ok := inst.(*spec.TiFlashInstance).InstanceSpec.(*spec.TiFlashSpec)
 			if !ok {
 				return result, perrs.Errorf("instance type mismatch for %v", inst)

pkg/cluster/operation/action.go

@@ -315,7 +315,6 @@ func systemctlMonitor(ctx context.Context, hosts []string, noAgentHosts set.Stri
 
 		errg, _ := errgroup.WithContext(ctx)
 		for _, host := range hosts {
-			host := host
 			if noAgentHosts.Exist(host) {
 				logger.Debugf("Ignored %s component %s for %s", action, comp, host)
 				continue
@@ -460,8 +459,6 @@ func EnableComponent(ctx context.Context, instances []spec.Instance, noAgentHost
 	errg, _ := errgroup.WithContext(ctx)
 
 	for _, ins := range instances {
-		ins := ins
-
 		// skip certain instances
 		switch name {
 		case spec.ComponentNodeExporter,
@@ -514,7 +511,6 @@ func StartComponent(ctx context.Context, instances []spec.Instance, noAgentHosts
 	errg, _ := errgroup.WithContext(ctx)
 
 	for _, ins := range instances {
-		ins := ins
 		switch name {
 		case spec.ComponentNodeExporter,
 			spec.ComponentBlackboxExporter:
@@ -586,7 +582,6 @@ func StopComponent(ctx context.Context,
 	errg, _ := errgroup.WithContext(ctx)
 
 	for _, ins := range instances {
-		ins := ins
 		switch name {
 		case spec.ComponentNodeExporter,
 			spec.ComponentBlackboxExporter:

pkg/cluster/operation/check.go

@@ -386,7 +386,7 @@ func CheckSysLimits(opt *CheckOptions, user string, l []byte) []*CheckResult {
 		nofileHard int
 	)
 
-	for _, line := range strings.Split(string(l), "\n") {
+	for line := range strings.SplitSeq(string(l), "\n") {
 		line = strings.TrimSpace(line)
 		if strings.HasPrefix(line, "#") {
 			continue
@@ -447,7 +447,7 @@ func CheckSysLimits(opt *CheckOptions, user string, l []byte) []*CheckResult {
 func CheckKernelParameters(opt *CheckOptions, p []byte) []*CheckResult {
 	var results []*CheckResult
 
-	for _, line := range strings.Split(string(p), "\n") {
+	for line := range strings.SplitSeq(string(p), "\n") {
 		line = strings.TrimSpace(line)
 		fields := strings.Fields(line)
 		if len(fields) < 3 {
@@ -615,7 +615,7 @@ func CheckListeningPort(opt *CheckOptions, host string, topo *spec.Specification
 	})
 
 	for p := range ports {
-		for _, line := range strings.Split(string(rawData), "\n") {
+		for line := range strings.SplitSeq(string(rawData), "\n") {
 			fields := strings.Fields(line)
 			if len(fields) < 5 || fields[0] != "LISTEN" {
 				continue
@@ -859,7 +859,7 @@ func CheckTHP(ctx context.Context, e ctxt.Executor, sudo bool) *CheckResult {
 		return result
 	}
 
-	for _, line := range strings.Split(strings.Trim(string(stdout), "\n"), "\n") {
+	for line := range strings.SplitSeq(strings.Trim(string(stdout), "\n"), "\n") {
 		if len(line) > 0 && !strings.Contains(line, "[never]") {
 			result.Err = fmt.Errorf("THP is enabled, please disable it for best performance")
 			return result

pkg/cluster/operation/scale_in.go

@@ -437,7 +437,6 @@ func scaleInCDC(
 	if len(instances) == len(cluster.CDCServers) {
 		g, _ := errgroup.WithContext(ctx)
 		for _, ins := range instances {
-			ins := ins
 			instCount[ins.GetManageHost()]++
 			destroyNode := instCount[ins.GetManageHost()] == 0
 			g.Go(func() error {

pkg/cluster/operation/systemd.go

@@ -47,8 +47,8 @@ func GetServiceStatus(ctx context.Context, e ctxt.Executor, name string, scope s
 	// ignore error since stopped service returns exit code 3
 	stdout, _, _ := systemd.Execute(ctx, e)
 
-	lines := strings.Split(string(stdout), "\n")
-	for _, line := range lines {
+	lines := strings.SplitSeq(string(stdout), "\n")
+	for line := range lines {
 		words := strings.Split(strings.TrimSpace(line), " ")
 		if len(words) >= 2 {
 			switch words[0] {

pkg/cluster/spec/alertmanager.go

@@ -127,7 +127,6 @@ func (c *AlertManagerComponent) Instances() []Instance {
 	ins := make([]Instance, 0, len(alertmanagers))
 
 	for _, s := range alertmanagers {
-		s := s
 		ins = append(ins, &AlertManagerInstance{
 			BaseInstance: BaseInstance{
 				InstanceSpec: s,

pkg/cluster/spec/cdc.go

@@ -132,7 +132,6 @@ func (c *CDCComponent) SetVersion(version string) {
 func (c *CDCComponent) Instances() []Instance {
 	ins := make([]Instance, 0, len(c.Topology.CDCServers))
 	for _, s := range c.Topology.CDCServers {
-		s := s
 		instance := &CDCInstance{BaseInstance{
 			InstanceSpec: s,
 			Name:         c.Name(),

pkg/cluster/spec/dashboard.go

@@ -134,7 +134,6 @@ func (c *DashboardComponent) SetVersion(version string) {
 func (c *DashboardComponent) Instances() []Instance {
 	ins := make([]Instance, 0, len(c.Topology.Drainers))
 	for _, s := range c.Topology.DashboardServers {
-		s := s
 		ins = append(ins, &DashboardInstance{BaseInstance{
 			InstanceSpec: s,
 			Name:         c.Name(),

pkg/cluster/spec/drainer.go

@@ -153,7 +153,6 @@ func (c *DrainerComponent) SetVersion(version string) {
 func (c *DrainerComponent) Instances() []Instance {
 	ins := make([]Instance, 0, len(c.Topology.Drainers))
 	for _, s := range c.Topology.Drainers {
-		s := s
 		ins = append(ins, &DrainerInstance{BaseInstance{
 			InstanceSpec: s,
 			Name:         c.Name(),

pkg/cluster/spec/grafana.go

@@ -139,7 +139,6 @@ func (c *GrafanaComponent) Instances() []Instance {
 	ins := make([]Instance, 0, len(servers))
 
 	for _, s := range servers {
-		s := s
 		ins = append(ins, &GrafanaInstance{
 			BaseInstance: BaseInstance{
 				InstanceSpec: s,