chore: update linter

.github/workflows/validate.yaml

@@ -7,7 +7,7 @@ on:
 
 env:
   GO_VERSION: '1.22'
-  GOLANGCI_LINT_VERSION: v1.56.0
+  GOLANGCI_LINT_VERSION: v1.56.2
   MISSSPELL_VERSION: v0.4.1
 
 jobs:

.golangci.yml

@@ -225,7 +225,7 @@ issues:
     - 'SA1019: c.Providers.ConsulCatalog.Namespace is deprecated'
     - 'SA1019: c.Providers.Consul.Namespace is deprecated'
     - 'SA1019: c.Providers.Nomad.Namespace is deprecated'
-    - 'fmt.Sprintf can be replaced with string addition'
+    - 'fmt.Sprintf can be replaced with string'
   exclude-rules:
     - path: '(.+)_test.go'
       linters:

.semaphore/semaphore.yml

@@ -25,7 +25,7 @@ global_job_config:
       - export "PATH=${GOPATH}/bin:${PATH}"
       - mkdir -vp "${SEMAPHORE_GIT_DIR}" "${GOPATH}/bin"
       - export GOPROXY=https://proxy.golang.org,direct
-      - curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b "${GOPATH}/bin" v1.56.0
+      - curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b "${GOPATH}/bin" v1.56.2
       - curl -sSfL https://gist.githubusercontent.com/traefiker/6d7ac019c11d011e4f131bb2cca8900e/raw/goreleaser.sh | bash -s -- -b "${GOPATH}/bin"
       - checkout
       - cache restore traefik-$(checksum go.sum)

cmd/internal/gen/centrifuge.go

@@ -160,7 +160,7 @@ func (c Centrifuge) writeStruct(name string, obj *types.Struct, rootPkg string,
 	b := strings.Builder{}
 	b.WriteString(fmt.Sprintf("type %s struct {\n", name))
 
-	for i := 0; i < obj.NumFields(); i++ {
+	for i := range obj.NumFields() {
 		field := obj.Field(i)
 
 		if !field.Exported() {

integration/conf_throttling_test.go

@@ -67,7 +67,7 @@ func (s *ThrottlingSuite) TestThrottleConfReload() {
 
 	confChanges := 10
 
-	for i := 0; i < confChanges; i++ {
+	for i := range confChanges {
 		config.HTTP.Routers[fmt.Sprintf("routerHTTP%d", i)] = router
 		data, err := json.Marshal(config)
 		require.NoError(s.T(), err)

integration/healthcheck_test.go

@@ -312,7 +312,7 @@ func (s *HealthCheckSuite) TestPropagate() {
 
 	// Verify load-balancing on root still works, and that we're getting an alternation between wsp2, and wsp4.
 	reachedServers := make(map[string]int)
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		resp, err := client.Do(rootReq)
 		require.NoError(s.T(), err)
 
@@ -352,7 +352,7 @@ func (s *HealthCheckSuite) TestPropagate() {
 
 	// Verify load-balancing on foo still works, and that we're getting wsp2, wsp2, wsp2, wsp2, etc.
 	want := `IP: ` + s.whoami2IP
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		resp, err := client.Do(fooReq)
 		require.NoError(s.T(), err)
 
@@ -368,7 +368,7 @@ func (s *HealthCheckSuite) TestPropagate() {
 
 	// Verify load-balancing on bar still works, and that we're getting wsp2, wsp2, wsp2, wsp2, etc.
 	want = `IP: ` + s.whoami2IP
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		resp, err := client.Do(barReq)
 		require.NoError(s.T(), err)
 
@@ -390,7 +390,7 @@ func (s *HealthCheckSuite) TestPropagate() {
 	try.Sleep(time.Second)
 
 	// Verify that everything is down, and that we get 503s everywhere.
-	for i := 0; i < 2; i++ {
+	for range 2 {
 		resp, err := client.Do(rootReq)
 		require.NoError(s.T(), err)
 		assert.Equal(s.T(), http.StatusServiceUnavailable, resp.StatusCode)
@@ -417,7 +417,7 @@ func (s *HealthCheckSuite) TestPropagate() {
 
 	// Verify everything is up on root router.
 	reachedServers = make(map[string]int)
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		resp, err := client.Do(rootReq)
 		require.NoError(s.T(), err)
 
@@ -452,7 +452,7 @@ func (s *HealthCheckSuite) TestPropagate() {
 
 	// Verify everything is up on foo router.
 	reachedServers = make(map[string]int)
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		resp, err := client.Do(fooReq)
 		require.NoError(s.T(), err)
 
@@ -487,7 +487,7 @@ func (s *HealthCheckSuite) TestPropagate() {
 
 	// Verify everything is up on bar router.
 	reachedServers = make(map[string]int)
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		resp, err := client.Do(barReq)
 		require.NoError(s.T(), err)
 

integration/integration_test.go

@@ -239,7 +239,7 @@ func (s *BaseSuite) createComposeProject(name string) {
 		}
 
 		if containerConfig.Deploy.Replicas > 0 {
-			for i := 0; i < containerConfig.Deploy.Replicas; i++ {
+			for i := range containerConfig.Deploy.Replicas {
 				id = fmt.Sprintf("%s-%d", id, i+1)
 				con, err := s.createContainer(ctx, containerConfig, id, mounts)
 				require.NoError(s.T(), err)

integration/simple_test.go

@@ -307,7 +307,7 @@ func (s *SimpleSuite) TestMetricsPrometheusTwoRoutersOneService() {
 	require.NoError(s.T(), err)
 
 	// adding a loop to test if metrics are not deleted
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		request, err := http.NewRequest(http.MethodGet, "http://127.0.0.1:8080/metrics", nil)
 		require.NoError(s.T(), err)
 
@@ -771,7 +771,7 @@ func (s *SimpleSuite) TestWRR() {
 	require.NoError(s.T(), err)
 
 	repartition := map[string]int{}
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		req, err := http.NewRequest(http.MethodGet, "http://127.0.0.1:8000/whoami", nil)
 		require.NoError(s.T(), err)
 
@@ -817,7 +817,7 @@ func (s *SimpleSuite) TestWRRSticky() {
 	req, err := http.NewRequest(http.MethodGet, "http://127.0.0.1:8000/whoami", nil)
 	require.NoError(s.T(), err)
 
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		response, err := http.DefaultClient.Do(req)
 		require.NoError(s.T(), err)
 		assert.Equal(s.T(), http.StatusOK, response.StatusCode)
@@ -873,7 +873,7 @@ func (s *SimpleSuite) TestMirror() {
 
 	req, err := http.NewRequest(http.MethodGet, "http://127.0.0.1:8000/whoami", nil)
 	require.NoError(s.T(), err)
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		response, err := http.DefaultClient.Do(req)
 		require.NoError(s.T(), err)
 		assert.Equal(s.T(), http.StatusOK, response.StatusCode)
@@ -944,7 +944,7 @@ func (s *SimpleSuite) TestMirrorWithBody() {
 	req, err := http.NewRequest(http.MethodGet, "http://127.0.0.1:8000/whoami", bytes.NewBuffer(body20))
 	require.NoError(s.T(), err)
 	req.Header.Set("Size", "20")
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		response, err := http.DefaultClient.Do(req)
 		require.NoError(s.T(), err)
 		assert.Equal(s.T(), http.StatusOK, response.StatusCode)
@@ -965,7 +965,7 @@ func (s *SimpleSuite) TestMirrorWithBody() {
 	req, err = http.NewRequest(http.MethodGet, "http://127.0.0.1:8000/whoamiWithMaxBody", bytes.NewBuffer(body5))
 	require.NoError(s.T(), err)
 	req.Header.Set("Size", "5")
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		response, err := http.DefaultClient.Do(req)
 		require.NoError(s.T(), err)
 		assert.Equal(s.T(), http.StatusOK, response.StatusCode)
@@ -986,7 +986,7 @@ func (s *SimpleSuite) TestMirrorWithBody() {
 	req, err = http.NewRequest(http.MethodGet, "http://127.0.0.1:8000/whoamiWithMaxBody", bytes.NewBuffer(body20))
 	require.NoError(s.T(), err)
 	req.Header.Set("Size", "20")
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		response, err := http.DefaultClient.Do(req)
 		require.NoError(s.T(), err)
 		assert.Equal(s.T(), http.StatusOK, response.StatusCode)
@@ -1032,7 +1032,7 @@ func (s *SimpleSuite) TestMirrorCanceled() {
 	err := try.GetRequest("http://127.0.0.1:8080/api/http/services", 1000*time.Millisecond, try.BodyContains("mirror1", "mirror2", "service1"))
 	require.NoError(s.T(), err)
 
-	for i := 0; i < 5; i++ {
+	for range 5 {
 		req, err := http.NewRequest(http.MethodGet, "http://127.0.0.1:8000/whoami", nil)
 		require.NoError(s.T(), err)
 

integration/tcp_test.go

@@ -263,7 +263,7 @@ func (s *TCPSuite) TestWRR() {
 	require.NoError(s.T(), err)
 
 	call := map[string]int{}
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		// Traefik passes through, termination handled by whoami-b or whoami-bb
 		out, err := guessWhoTLSPassthrough("127.0.0.1:8093", "whoami-b.test")
 		require.NoError(s.T(), err)

integration/udp_test.go

@@ -82,7 +82,7 @@ func (s *UDPSuite) TestWRR() {
 	stop := make(chan struct{})
 	go func() {
 		call := map[string]int{}
-		for i := 0; i < 8; i++ {
+		for range 8 {
 			out, err := guessWhoUDP("127.0.0.1:8093")
 			require.NoError(s.T(), err)
 			switch {

internal/gendoc.go

@@ -223,7 +223,7 @@ func clean(element any) {
 	valueSvcRoot := valSvcs.MapIndex(key).Elem()
 
 	var svcFieldNames []string
-	for i := 0; i < valueSvcRoot.NumField(); i++ {
+	for i := range valueSvcRoot.NumField() {
 		svcFieldNames = append(svcFieldNames, valueSvcRoot.Type().Field(i).Name)
 	}
 

pkg/api/criterion.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/http"
 	"net/url"
+	"slices"
 	"strconv"
 	"strings"
 )
@@ -50,13 +51,9 @@ func (c *searchCriterion) searchIn(values ...string) bool {
 		return true
 	}
 
-	for _, v := range values {
-		if strings.Contains(strings.ToLower(v), strings.ToLower(c.Search)) {
-			return true
-		}
-	}
-
-	return false
+	return slices.ContainsFunc(values, func(v string) bool {
+		return strings.Contains(strings.ToLower(v), strings.ToLower(c.Search))
+	})
 }
 
 func pagination(request *http.Request, max int) (pageInfo, error) {

pkg/api/handler.go

@@ -149,7 +149,7 @@ func getProviderName(id string) string {
 
 func extractType(element interface{}) string {
 	v := reflect.ValueOf(element).Elem()
-	for i := 0; i < v.NumField(); i++ {
+	for i := range v.NumField() {
 		field := v.Field(i)
 
 		if field.Kind() == reflect.Map && field.Type().Elem() == reflect.TypeOf(dynamic.PluginConf{}) {

pkg/api/handler_entrypoint_test.go

@@ -256,7 +256,7 @@ func TestHandler_EntryPoints(t *testing.T) {
 
 func generateEntryPoints(nb int) map[string]*static.EntryPoint {
 	eps := make(map[string]*static.EntryPoint, nb)
-	for i := 0; i < nb; i++ {
+	for i := range nb {
 		eps[fmt.Sprintf("ep%2d", i)] = &static.EntryPoint{
 			Address: ":" + strconv.Itoa(i),
 		}

pkg/api/handler_http_test.go

@@ -972,7 +972,7 @@ func TestHandler_HTTP(t *testing.T) {
 
 func generateHTTPRouters(nbRouters int) map[string]*runtime.RouterInfo {
 	routers := make(map[string]*runtime.RouterInfo, nbRouters)
-	for i := 0; i < nbRouters; i++ {
+	for i := range nbRouters {
 		routers[fmt.Sprintf("bar%2d@myprovider", i)] = &runtime.RouterInfo{
 			Router: &dynamic.Router{
 				EntryPoints: []string{"web"},

pkg/api/handler_overview.go

@@ -226,7 +226,7 @@ func getProviders(conf static.Configuration) []string {
 	var providers []string
 
 	v := reflect.ValueOf(conf.Providers).Elem()
-	for i := 0; i < v.NumField(); i++ {
+	for i := range v.NumField() {
 		field := v.Field(i)
 		if field.Kind() == reflect.Ptr && field.Elem().Kind() == reflect.Struct {
 			if !field.IsNil() {
@@ -256,7 +256,7 @@ func getMetrics(conf static.Configuration) string {
 	}
 
 	v := reflect.ValueOf(conf.Metrics).Elem()
-	for i := 0; i < v.NumField(); i++ {
+	for i := range v.NumField() {
 		field := v.Field(i)
 		if field.Kind() == reflect.Ptr && field.Elem().Kind() == reflect.Struct {
 			if !field.IsNil() {
@@ -274,7 +274,7 @@ func getTracing(conf static.Configuration) string {
 	}
 
 	v := reflect.ValueOf(conf.Tracing).Elem()
-	for i := 0; i < v.NumField(); i++ {
+	for i := range v.NumField() {
 		field := v.Field(i)
 		if field.Kind() == reflect.Ptr && field.Elem().Kind() == reflect.Struct {
 			if !field.IsNil() {

pkg/collector/hydratation/hydration.go

@@ -93,7 +93,7 @@ func setTyped(field reflect.Value, i interface{}) {
 func setMap(field reflect.Value) error {
 	field.Set(reflect.MakeMap(field.Type()))
 
-	for i := 0; i < mapItemNumber; i++ {
+	for i := range mapItemNumber {
 		baseKeyName := makeKeyName(field.Type().Elem())
 		key := reflect.ValueOf(fmt.Sprintf("%s%d", baseKeyName, i))
 
@@ -125,7 +125,7 @@ func makeKeyName(typ reflect.Type) string {
 }
 
 func setStruct(field reflect.Value) error {
-	for i := 0; i < field.NumField(); i++ {
+	for i := range field.NumField() {
 		fld := field.Field(i)
 		stFld := field.Type().Field(i)
 
@@ -142,7 +142,7 @@ func setStruct(field reflect.Value) error {
 
 func setSlice(field reflect.Value) error {
 	field.Set(reflect.MakeSlice(field.Type(), sliceItemNumber, sliceItemNumber))
-	for j := 0; j < field.Len(); j++ {
+	for j := range field.Len() {
 		if err := fill(field.Index(j)); err != nil {
 			return err
 		}

pkg/config/kv/kv.go

@@ -55,7 +55,7 @@ func getFieldNames(rootName string, rootType reflect.Type) []string {
 		return nil
 	}
 
-	for i := 0; i < rootType.NumField(); i++ {
+	for i := range rootType.NumField() {
 		field := rootType.Field(i)
 
 		if !parser.IsExported(field) {

pkg/middlewares/accesslog/logger_test.go

@@ -74,7 +74,7 @@ func TestLogRotation(t *testing.T) {
 	halfDone := make(chan bool)
 	writeDone := make(chan bool)
 	go func() {
-		for i := 0; i < iterations; i++ {
+		for i := range iterations {
 			handler.ServeHTTP(recorder, req)
 			if i == iterations/2 {
 				halfDone <- true

pkg/middlewares/capture/capture_test.go

@@ -149,7 +149,7 @@ func BenchmarkCapture(b *testing.B) {
 			b.ReportAllocs()
 			b.SetBytes(int64(test.size))
 			b.ResetTimer()
-			for i := 0; i < b.N; i++ {
+			for range b.N {
 				runBenchmark(b, test.size, req, handlers)
 			}
 		})
@@ -170,7 +170,7 @@ func runBenchmark(b *testing.B, size int, req *http.Request, handler http.Handle
 
 func generateBytes(length int) []byte {
 	var value []byte
-	for i := 0; i < length; i++ {
+	for i := range length {
 		value = append(value, 0x61+byte(i%26))
 	}
 	return value

pkg/middlewares/compress/compress_test.go

@@ -499,7 +499,7 @@ func BenchmarkCompress(b *testing.B) {
 			}
 
 			b.ResetTimer()
-			for i := 0; i < b.N; i++ {
+			for range b.N {
 				runBenchmark(b, req, handler)
 			}
 		})
@@ -520,7 +520,7 @@ func runBenchmark(b *testing.B, req *http.Request, handler http.Handler) {
 
 func generateBytes(length int) []byte {
 	var value []byte
-	for i := 0; i < length; i++ {
+	for i := range length {
 		value = append(value, 0x61+byte(i))
 	}
 	return value

pkg/middlewares/emptybackendhandler/empty_backend_handler_test.go

@@ -58,7 +58,7 @@ func (lb *healthCheckLoadBalancer) ServeHTTP(w http.ResponseWriter, r *http.Requ
 
 func (lb *healthCheckLoadBalancer) Servers() []*url.URL {
 	servers := make([]*url.URL, lb.amountServer)
-	for i := 0; i < lb.amountServer; i++ {
+	for range lb.amountServer {
 		servers = append(servers, testhelpers.MustParseURL("http://localhost"))
 	}
 	return servers

pkg/middlewares/metrics/metrics.go

@@ -3,6 +3,7 @@ package metrics
 import (
 	"context"
 	"net/http"
+	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -175,12 +176,10 @@ func isSSERequest(req *http.Request) bool {
 
 func containsHeader(req *http.Request, name, value string) bool {
 	items := strings.Split(req.Header.Get(name), ",")
-	for _, item := range items {
-		if value == strings.ToLower(strings.TrimSpace(item)) {
-			return true
-		}
-	}
-	return false
+
+	return slices.ContainsFunc(items, func(item string) bool {
+		return value == strings.ToLower(strings.TrimSpace(item))
+	})
 }
 
 // getMethod returns the request's method.

pkg/middlewares/requestdecorator/hostresolver.go

@@ -49,7 +49,7 @@ func (hr *Resolver) CNAMEFlatten(ctx context.Context, host string) string {
 
 	logger := log.FromContext(ctx)
 	cacheDuration := 0 * time.Second
-	for depth := 0; depth < hr.ResolvDepth; depth++ {
+	for depth := range hr.ResolvDepth {
 		resolv, err := cnameResolve(ctx, request, hr.ResolvConfig)
 		if err != nil {
 			logger.Error(err)

pkg/middlewares/retry/retry_test.go

@@ -203,7 +203,7 @@ func TestMultipleRetriesShouldNotLooseHeaders(t *testing.T) {
 	}
 
 	// Validate that we don't have headers from previous attempts
-	for i := 0; i < attempt; i++ {
+	for i := range attempt {
 		headerName := fmt.Sprintf("X-Foo-Test-%d", i)
 		headerValue = responseRecorder.Header().Get("headerName")
 		if headerValue != "" {

pkg/muxer/http/mux.go

@@ -324,11 +324,7 @@ func addRuleOnRoute(route *mux.Route, rule *rules.Tree) error {
 
 // IsASCII checks if the given string contains only ASCII characters.
 func IsASCII(s string) bool {
-	for i := 0; i < len(s); i++ {
-		if s[i] >= utf8.RuneSelf {
-			return false
-		}
-	}
-
-	return true
+	return !strings.ContainsFunc(s, func(r rune) bool {
+		return r >= utf8.RuneSelf
+	})
 }

pkg/muxer/tcp/mux.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"net"
 	"regexp"
+	"slices"
 	"sort"
 	"strconv"
 	"strings"
@@ -301,15 +302,9 @@ func alpn(tree *matchersTree, protos ...string) error {
 	}
 
 	tree.matcher = func(meta ConnData) bool {
-		for _, proto := range meta.alpnProtos {
-			for _, filter := range protos {
-				if proto == filter {
-					return true
-				}
-			}
-		}
-
-		return false
+		return slices.ContainsFunc(meta.alpnProtos, func(proto string) bool {
+			return slices.Contains(protos, proto)
+		})
 	}
 
 	return nil
@@ -469,7 +464,7 @@ func varGroupName(idx int) string {
 func braceIndices(s string) ([]int, error) {
 	var level, idx int
 	var idxs []int
-	for i := 0; i < len(s); i++ {
+	for i := range len(s) {
 		switch s[i] {
 		case '{':
 			if level++; level == 1 {

pkg/provider/acme/challenge_tls.go

@@ -2,6 +2,7 @@ package acme
 
 import (
 	"fmt"
+	"slices"
 	"sync"
 	"time"
 
@@ -118,7 +119,7 @@ func (c *ChallengeTLSALPN) ListenConfiguration(conf dynamic.Configuration) {
 	c.muChans.Lock()
 
 	for _, certificate := range conf.TLS.Certificates {
-		if !containsACMETLS1(certificate.Stores) {
+		if !slices.Contains(certificate.Stores, tlsalpn01.ACMETLS1Protocol) {
 			continue
 		}
 
@@ -161,13 +162,3 @@ func createMessage(certs map[string]*Certificate) dynamic.Message {
 
 	return conf
 }
-
-func containsACMETLS1(stores []string) bool {
-	for _, store := range stores {
-		if store == tlsalpn01.ACMETLS1Protocol {
-			return true
-		}
-	}
-
-	return false
-}

pkg/provider/acme/provider.go

@@ -424,7 +424,7 @@ func (p *Provider) watchNewDomains(ctx context.Context) {
 
 						if len(route.TLS.Domains) > 0 {
 							domains := deleteUnnecessaryDomains(ctxRouter, route.TLS.Domains)
-							for i := 0; i < len(domains); i++ {
+							for i := range len(domains) {
 								domain := domains[i]
 								safe.Go(func() {
 									dom, cert, err := p.resolveCertificate(ctx, domain, traefiktls.DefaultTLSStoreName)
@@ -461,7 +461,7 @@ func (p *Provider) watchNewDomains(ctx context.Context) {
 
 						if len(route.TLS.Domains) > 0 {
 							domains := deleteUnnecessaryDomains(ctxRouter, route.TLS.Domains)
-							for i := 0; i < len(domains); i++ {
+							for i := range len(domains) {
 								domain := domains[i]
 								safe.Go(func() {
 									dom, cert, err := p.resolveCertificate(ctx, domain, traefiktls.DefaultTLSStoreName)

pkg/provider/constraints/constraints_tags.go

@@ -3,6 +3,7 @@ package constraints
 import (
 	"errors"
 	"regexp"
+	"slices"
 
 	"github.com/vulcand/predicate"
 )
@@ -47,12 +48,7 @@ func MatchTags(tags []string, expr string) (bool, error) {
 
 func tagFn(name string) constraintTagFunc {
 	return func(tags []string) bool {
-		for _, tag := range tags {
-			if tag == name {
-				return true
-			}
-		}
-		return false
+		return slices.Contains(tags, name)
 	}
 }
 
@@ -63,13 +59,9 @@ func tagRegexFn(expr string) constraintTagFunc {
 			return false
 		}
 
-		for _, tag := range tags {
-			if exp.MatchString(tag) {
-				return true
-			}
-		}
-
-		return false
+		return slices.ContainsFunc(tags, func(tag string) bool {
+			return exp.MatchString(tag)
+		})
 	}
 }
 

pkg/provider/consulcatalog/config_test.go

@@ -274,7 +274,7 @@ func TestDefaultRule(t *testing.T) {
 			err := p.Init()
 			require.NoError(t, err)
 
-			for i := 0; i < len(test.items); i++ {
+			for i := range len(test.items) {
 				var err error
 				test.items[i].ExtraConf, err = p.getExtraConf(test.items[i].Labels)
 				require.NoError(t, err)
@@ -2956,7 +2956,7 @@ func Test_buildConfiguration(t *testing.T) {
 			err := p.Init()
 			require.NoError(t, err)
 
-			for i := 0; i < len(test.items); i++ {
+			for i := range len(test.items) {
 				var err error
 				test.items[i].ExtraConf, err = p.getExtraConf(test.items[i].Labels)
 				require.NoError(t, err)

pkg/provider/docker/config_test.go

@@ -361,7 +361,7 @@ func TestDefaultRule(t *testing.T) {
 			err := p.Init()
 			require.NoError(t, err)
 
-			for i := 0; i < len(test.containers); i++ {
+			for i := range len(test.containers) {
 				var err error
 				test.containers[i].ExtraConf, err = p.getConfiguration(test.containers[i])
 				require.NoError(t, err)
@@ -3257,7 +3257,7 @@ func Test_buildConfiguration(t *testing.T) {
 			err := p.Init()
 			require.NoError(t, err)
 
-			for i := 0; i < len(test.containers); i++ {
+			for i := range len(test.containers) {
 				var err error
 				test.containers[i].ExtraConf, err = p.getConfiguration(test.containers[i])
 				require.NoError(t, err)

pkg/provider/ecs/config_test.go

@@ -333,7 +333,7 @@ func TestDefaultRule(t *testing.T) {
 			err := p.Init()
 			require.NoError(t, err)
 
-			for i := 0; i < len(test.instances); i++ {
+			for i := range len(test.instances) {
 				var err error
 				test.instances[i].ExtraConf, err = p.getConfiguration(test.instances[i])
 				require.NoError(t, err)
@@ -2863,7 +2863,7 @@ func Test_buildConfiguration(t *testing.T) {
 			err := p.Init()
 			require.NoError(t, err)
 
-			for i := 0; i < len(test.containers); i++ {
+			for i := range len(test.containers) {
 				var err error
 				test.containers[i].ExtraConf, err = p.getConfiguration(test.containers[i])
 				require.NoError(t, err)

pkg/provider/ecs/ecs.go

@@ -397,7 +397,7 @@ func (p *Provider) listInstances(ctx context.Context, client *awsClient) ([]ecsI
 }
 
 func (p *Provider) lookupMiInstances(ctx context.Context, client *awsClient, clusterName *string, ecsDatas map[string]*ecs.Task) (map[string]*ssm.InstanceInformation, error) {
-	instanceIds := make(map[string]string)
+	instanceIDs := make(map[string]string)
 	miInstances := make(map[string]*ssm.InstanceInformation)
 
 	var containerInstancesArns []*string
@@ -419,7 +419,7 @@ func (p *Provider) lookupMiInstances(ctx context.Context, client *awsClient, clu
 		}
 
 		for _, container := range resp.ContainerInstances {
-			instanceIds[aws.StringValue(container.Ec2InstanceId)] = aws.StringValue(container.ContainerInstanceArn)
+			instanceIDs[aws.StringValue(container.Ec2InstanceId)] = aws.StringValue(container.ContainerInstanceArn)
 
 			// Disallow EC2 Instance IDs
 			// This prevents considering EC2 instances in ECS
@@ -447,7 +447,7 @@ func (p *Provider) lookupMiInstances(ctx context.Context, client *awsClient, clu
 				if len(page.InstanceInformationList) > 0 {
 					for _, i := range page.InstanceInformationList {
 						if i.InstanceId != nil {
-							miInstances[instanceIds[aws.StringValue(i.InstanceId)]] = i
+							miInstances[instanceIDs[aws.StringValue(i.InstanceId)]] = i
 						}
 					}
 				}
@@ -463,7 +463,7 @@ func (p *Provider) lookupMiInstances(ctx context.Context, client *awsClient, clu
 }
 
 func (p *Provider) lookupEc2Instances(ctx context.Context, client *awsClient, clusterName *string, ecsDatas map[string]*ecs.Task) (map[string]*ec2.Instance, error) {
-	instanceIds := make(map[string]string)
+	instanceIDs := make(map[string]string)
 	ec2Instances := make(map[string]*ec2.Instance)
 
 	var containerInstancesArns []*string
@@ -485,7 +485,7 @@ func (p *Provider) lookupEc2Instances(ctx context.Context, client *awsClient, cl
 		}
 
 		for _, container := range resp.ContainerInstances {
-			instanceIds[aws.StringValue(container.Ec2InstanceId)] = aws.StringValue(container.ContainerInstanceArn)
+			instanceIDs[aws.StringValue(container.Ec2InstanceId)] = aws.StringValue(container.ContainerInstanceArn)
 			// Disallow Instance IDs of the form mi-*
 			// This prevents considering external instances in ECS Anywhere setups
 			// and getting InvalidInstanceID.Malformed error when calling the describe-instances endpoint.
@@ -508,7 +508,7 @@ func (p *Provider) lookupEc2Instances(ctx context.Context, client *awsClient, cl
 					for _, r := range page.Reservations {
 						for _, i := range r.Instances {
 							if i.InstanceId != nil {
-								ec2Instances[instanceIds[aws.StringValue(i.InstanceId)]] = i
+								ec2Instances[instanceIDs[aws.StringValue(i.InstanceId)]] = i
 							}
 						}
 					}

pkg/provider/ecs/ecs_test.go

@@ -73,7 +73,7 @@ func TestChunkIDs(t *testing.T) {
 			t.Parallel()
 
 			var IDs []*string
-			for v := 0; v < test.count; v++ {
+			for range test.count {
 				IDs = append(IDs, aws.String("a"))
 			}
 

pkg/provider/kubernetes/crd/client.go

@@ -6,6 +6,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"slices"
 	"time"
 
 	"github.com/traefik/traefik/v2/pkg/log"
@@ -452,12 +453,8 @@ func (c *clientWrapper) isWatchedNamespace(ns string) bool {
 	if c.isNamespaceAll {
 		return true
 	}
-	for _, watchedNamespace := range c.watchedNamespaces {
-		if watchedNamespace == ns {
-			return true
-		}
-	}
-	return false
+
+	return slices.Contains(c.watchedNamespaces, ns)
 }
 
 // translateNotFoundError will translate a "not found" error to a boolean return

pkg/provider/kubernetes/gateway/client.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"slices"
 	"time"
 
 	"github.com/traefik/traefik/v2/pkg/log"
@@ -548,10 +549,6 @@ func (c *clientWrapper) isWatchedNamespace(ns string) bool {
 	if c.isNamespaceAll {
 		return true
 	}
-	for _, watchedNamespace := range c.watchedNamespaces {
-		if watchedNamespace == ns {
-			return true
-		}
-	}
-	return false
+
+	return slices.Contains(c.watchedNamespaces, ns)
 }

pkg/provider/kubernetes/ingress/client.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"slices"
 	"time"
 
 	"github.com/hashicorp/go-version"
@@ -538,12 +539,8 @@ func (c *clientWrapper) isWatchedNamespace(ns string) bool {
 	if c.isNamespaceAll {
 		return true
 	}
-	for _, watchedNamespace := range c.watchedNamespaces {
-		if watchedNamespace == ns {
-			return true
-		}
-	}
-	return false
+
+	return slices.Contains(c.watchedNamespaces, ns)
 }
 
 // IngressClass objects are supported since Kubernetes v1.18.

pkg/provider/kubernetes/ingress/kubernetes.go

@@ -8,6 +8,7 @@ import (
 	"math"
 	"net"
 	"os"
+	"slices"
 	"sort"
 	"strconv"
 	"strings"
@@ -412,13 +413,9 @@ func (p *Provider) updateIngressStatus(ing *netv1.Ingress, k8sClient Client) err
 func (p *Provider) shouldProcessIngress(ingress *netv1.Ingress, ingressClasses []*netv1.IngressClass) bool {
 	// configuration through the new kubernetes ingressClass
 	if ingress.Spec.IngressClassName != nil {
-		for _, ic := range ingressClasses {
-			if *ingress.Spec.IngressClassName == ic.ObjectMeta.Name {
-				return true
-			}
-		}
-
-		return false
+		return slices.ContainsFunc(ingressClasses, func(ic *netv1.IngressClass) bool {
+			return *ingress.Spec.IngressClassName == ic.ObjectMeta.Name
+		})
 	}
 
 	return p.IngressClass == ingress.Annotations[annotationKubernetesIngressClass] ||

pkg/provider/rancher/config_test.go

@@ -1146,7 +1146,7 @@ func Test_buildConfiguration(t *testing.T) {
 			err := p.Init()
 			require.NoError(t, err)
 
-			for i := 0; i < len(test.containers); i++ {
+			for i := range len(test.containers) {
 				var err error
 				test.containers[i].ExtraConf, err = p.getConfiguration(test.containers[i])
 				require.NoError(t, err)

pkg/redactor/redactor.go

@@ -83,7 +83,7 @@ func doOnStruct(field reflect.Value, tag string, redactByDefault bool) error {
 			}
 		}
 	case reflect.Struct:
-		for i := 0; i < field.NumField(); i++ {
+		for i := range field.NumField() {
 			fld := field.Field(i)
 			stField := field.Type().Field(i)
 			if !isExported(stField) {
@@ -138,7 +138,7 @@ func doOnStruct(field reflect.Value, tag string, redactByDefault bool) error {
 			}
 		}
 	case reflect.Slice:
-		for j := 0; j < field.Len(); j++ {
+		for j := range field.Len() {
 			if err := doOnStruct(field.Index(j), tag, redactByDefault); err != nil {
 				return err
 			}
@@ -179,7 +179,7 @@ func reset(field reflect.Value, name string) error {
 			switch field.Type().Elem().Kind() {
 			case reflect.String:
 				slice := reflect.MakeSlice(field.Type(), field.Len(), field.Len())
-				for j := 0; j < field.Len(); j++ {
+				for j := range field.Len() {
 					slice.Index(j).SetString(maskShort)
 				}
 				field.Set(slice)

pkg/server/aggregator.go

@@ -1,6 +1,8 @@
 package server
 
 import (
+	"slices"
+
 	"github.com/go-acme/lego/v4/challenge/tlsalpn01"
 	"github.com/traefik/traefik/v2/pkg/config/dynamic"
 	"github.com/traefik/traefik/v2/pkg/log"
@@ -91,7 +93,7 @@ func mergeConfiguration(configurations dynamic.Configurations, defaultEntryPoint
 
 		if configuration.TLS != nil {
 			for _, cert := range configuration.TLS.Certificates {
-				if containsACMETLS1(cert.Stores) && pvd != "tlsalpn.acme" {
+				if slices.Contains(cert.Stores, tlsalpn01.ACMETLS1Protocol) && pvd != "tlsalpn.acme" {
 					continue
 				}
 
@@ -179,13 +181,3 @@ func applyModel(cfg dynamic.Configuration) dynamic.Configuration {
 
 	return cfg
 }
-
-func containsACMETLS1(stores []string) bool {
-	for _, store := range stores {
-		if store == tlsalpn01.ACMETLS1Protocol {
-			return true
-		}
-	}
-
-	return false
-}

pkg/server/configurationwatcher_test.go

@@ -305,7 +305,7 @@ func TestListenProvidersThrottleProviderConfigReload(t *testing.T) {
 		throttleDuration: 30 * time.Millisecond,
 	}
 
-	for i := 0; i < 5; i++ {
+	for i := range 5 {
 		pvd.messages = append(pvd.messages, dynamic.Message{
 			ProviderName: "mock",
 			Configuration: &dynamic.Configuration{

pkg/server/middleware/middlewares.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"net/http"
 	"reflect"
+	"slices"
 	"strings"
 
 	"github.com/containous/alice"
@@ -97,7 +98,7 @@ func checkRecursion(ctx context.Context, middlewareName string) (context.Context
 	if !ok {
 		currentStack = []string{}
 	}
-	if inSlice(middlewareName, currentStack) {
+	if slices.Contains(currentStack, middlewareName) {
 		return ctx, fmt.Errorf("could not instantiate middleware %s: recursion detected in %s", middlewareName, strings.Join(append(currentStack, middlewareName), "->"))
 	}
 	return context.WithValue(ctx, middlewareStackKey, append(currentStack, middlewareName)), nil
@@ -381,12 +382,3 @@ func (b *Builder) buildConstructor(ctx context.Context, middlewareName string) (
 
 	return tracing.Wrap(ctx, middleware), nil
 }
-
-func inSlice(element string, stack []string) bool {
-	for _, value := range stack {
-		if value == element {
-			return true
-		}
-	}
-	return false
-}

pkg/server/middleware/tcp/middlewares.go

@@ -3,6 +3,7 @@ package tcpmiddleware
 import (
 	"context"
 	"fmt"
+	"slices"
 	"strings"
 
 	"github.com/traefik/traefik/v2/pkg/config/runtime"
@@ -74,7 +75,7 @@ func checkRecursion(ctx context.Context, middlewareName string) (context.Context
 		currentStack = []string{}
 	}
 
-	if inSlice(middlewareName, currentStack) {
+	if slices.Contains(currentStack, middlewareName) {
 		return ctx, fmt.Errorf("could not instantiate middleware %s: recursion detected in %s", middlewareName, strings.Join(append(currentStack, middlewareName), "->"))
 	}
 
@@ -117,12 +118,3 @@ func (b *Builder) buildConstructor(ctx context.Context, middlewareName string) (
 
 	return middleware, nil
 }
-
-func inSlice(element string, stack []string) bool {
-	for _, value := range stack {
-		if value == element {
-			return true
-		}
-	}
-	return false
-}

pkg/server/router/router_test.go

@@ -945,7 +945,7 @@ func BenchmarkRouterServe(b *testing.B) {
 
 	reqHost := requestdecorator.New(nil)
 	b.ReportAllocs()
-	for i := 0; i < b.N; i++ {
+	for range b.N {
 		reqHost.ServeHTTP(w, req, handlers["web"].ServeHTTP)
 	}
 }
@@ -980,7 +980,7 @@ func BenchmarkService(b *testing.B) {
 
 	handler, _ := serviceManager.BuildHTTP(context.Background(), "foo-service")
 	b.ReportAllocs()
-	for i := 0; i < b.N; i++ {
+	for range b.N {
 		handler.ServeHTTP(w, req)
 	}
 }

pkg/server/server_entrypoint_tcp_test.go

@@ -112,7 +112,7 @@ func testShutdown(t *testing.T, router *tcprouter.Router) {
 	// but technically also as early as the Shutdown has closed the listener,
 	// i.e. during the shutdown and before the gracetime is over.
 	var testOk bool
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		loopConn, err := net.Dial("tcp", epAddr)
 		if err == nil {
 			loopConn.Close()
@@ -141,7 +141,7 @@ func startEntrypoint(entryPoint *TCPEntryPoint, router *tcprouter.Router) (net.C
 
 	entryPoint.SwitchRouter(router)
 
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		conn, err := net.Dial("tcp", entryPoint.listener.Addr().String())
 		if err != nil {
 			time.Sleep(100 * time.Millisecond)

pkg/server/service/loadbalancer/mirror/mirror_test.go

@@ -32,7 +32,7 @@ func TestMirroringOn100(t *testing.T) {
 	}), 50)
 	assert.NoError(t, err)
 
-	for i := 0; i < 100; i++ {
+	for range 100 {
 		mirror.ServeHTTP(httptest.NewRecorder(), httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 
@@ -61,7 +61,7 @@ func TestMirroringOn10(t *testing.T) {
 	}), 50)
 	assert.NoError(t, err)
 
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		mirror.ServeHTTP(httptest.NewRecorder(), httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 
@@ -156,7 +156,7 @@ func TestMirroringWithBody(t *testing.T) {
 
 	mirror := New(handler, pool, defaultMaxBodySize, nil)
 
-	for i := 0; i < numMirrors; i++ {
+	for range numMirrors {
 		err := mirror.AddMirror(http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
 			assert.NotNil(t, r.Body)
 			bb, err := io.ReadAll(r.Body)

pkg/server/service/loadbalancer/wrr/wrr_test.go

@@ -40,7 +40,7 @@ func TestBalancer(t *testing.T) {
 	}), Int(1))
 
 	recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
-	for i := 0; i < 4; i++ {
+	for range 4 {
 		balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 
@@ -68,7 +68,7 @@ func TestBalancerOneServerZeroWeight(t *testing.T) {
 	balancer.AddService("second", http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {}), Int(0))
 
 	recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
-	for i := 0; i < 3; i++ {
+	for range 3 {
 		balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 
@@ -113,7 +113,7 @@ func TestBalancerOneServerDown(t *testing.T) {
 	balancer.SetStatus(context.WithValue(context.Background(), serviceName, "parent"), "second", false)
 
 	recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
-	for i := 0; i < 3; i++ {
+	for range 3 {
 		balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 
@@ -135,14 +135,14 @@ func TestBalancerDownThenUp(t *testing.T) {
 	balancer.SetStatus(context.WithValue(context.Background(), serviceName, "parent"), "second", false)
 
 	recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
-	for i := 0; i < 3; i++ {
+	for range 3 {
 		balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 	assert.Equal(t, 3, recorder.save["first"])
 
 	balancer.SetStatus(context.WithValue(context.Background(), serviceName, "parent"), "second", true)
 	recorder = &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
-	for i := 0; i < 2; i++ {
+	for range 2 {
 		balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 	assert.Equal(t, 1, recorder.save["first"])
@@ -184,7 +184,7 @@ func TestBalancerPropagate(t *testing.T) {
 	})
 
 	recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
-	for i := 0; i < 8; i++ {
+	for range 8 {
 		topBalancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 	assert.Equal(t, 2, recorder.save["first"])
@@ -197,7 +197,7 @@ func TestBalancerPropagate(t *testing.T) {
 	// fourth gets downed, but balancer2 still up since third is still up.
 	balancer2.SetStatus(context.WithValue(context.Background(), serviceName, "top"), "fourth", false)
 	recorder = &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
-	for i := 0; i < 8; i++ {
+	for range 8 {
 		topBalancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 	assert.Equal(t, 2, recorder.save["first"])
@@ -211,7 +211,7 @@ func TestBalancerPropagate(t *testing.T) {
 	// down as well for topBalancer.
 	balancer2.SetStatus(context.WithValue(context.Background(), serviceName, "top"), "third", false)
 	recorder = &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
-	for i := 0; i < 8; i++ {
+	for range 8 {
 		topBalancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 	assert.Equal(t, 4, recorder.save["first"])
@@ -252,7 +252,7 @@ func TestSticky(t *testing.T) {
 	recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
 
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
-	for i := 0; i < 3; i++ {
+	for range 3 {
 		for _, cookie := range recorder.Result().Cookies() {
 			assert.NotContains(t, "test=first", cookie.Value)
 			assert.NotContains(t, "test=second", cookie.Value)
@@ -286,7 +286,7 @@ func TestSticky_FallBack(t *testing.T) {
 
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
 	req.AddCookie(&http.Cookie{Name: "test", Value: "second"})
-	for i := 0; i < 3; i++ {
+	for range 3 {
 		recorder.ResponseRecorder = httptest.NewRecorder()
 
 		balancer.ServeHTTP(recorder, req)
@@ -313,7 +313,7 @@ func TestBalancerBias(t *testing.T) {
 
 	recorder := &responseRecorder{ResponseRecorder: httptest.NewRecorder(), save: map[string]int{}}
 
-	for i := 0; i < 14; i++ {
+	for range 14 {
 		balancer.ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/", nil))
 	}
 

pkg/server/service/proxy_test.go

@@ -31,7 +31,7 @@ func BenchmarkProxy(b *testing.B) {
 	handler, _ := buildProxy(Bool(false), nil, &staticTransport{res}, pool)
 
 	b.ReportAllocs()
-	for i := 0; i < b.N; i++ {
+	for range b.N {
 		handler.ServeHTTP(w, req)
 	}
 }

pkg/server/service/roundtripper.go

@@ -9,6 +9,7 @@ import (
 	"net"
 	"net/http"
 	"reflect"
+	"slices"
 	"strings"
 	"sync"
 	"time"
@@ -210,12 +211,9 @@ func (k *KerberosRoundTripper) RoundTrip(request *http.Request) (*http.Response,
 }
 
 func containsNTLMorNegotiate(h []string) bool {
-	for _, s := range h {
-		if strings.HasPrefix(s, "NTLM") || strings.HasPrefix(s, "Negotiate") {
-			return true
-		}
-	}
-	return false
+	return slices.ContainsFunc(h, func(s string) bool {
+		return strings.HasPrefix(s, "NTLM") || strings.HasPrefix(s, "Negotiate")
+	})
 }
 
 func createRootCACertPool(rootCAs []traefiktls.FileOrContent) *x509.CertPool {

pkg/server/service/roundtripper_test.go

@@ -139,7 +139,7 @@ func TestKeepConnectionWhenSameConfiguration(t *testing.T) {
 		},
 	}
 
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		rtManager.Update(dynamicConf)
 
 		tr, err := rtManager.Get("test")

pkg/server/service/service.go

@@ -85,7 +85,7 @@ func (m *Manager) BuildHTTP(rootCtx context.Context, serviceName string) (http.H
 
 	value := reflect.ValueOf(*conf.Service)
 	var count int
-	for i := 0; i < value.NumField(); i++ {
+	for i := range value.NumField() {
 		if !value.Field(i).IsNil() {
 			count++
 		}

pkg/tcp/wrr_load_balancer_test.go

@@ -135,7 +135,7 @@ func TestLoadBalancing(t *testing.T) {
 			}
 
 			conn := &fakeConn{writeCall: make(map[string]int)}
-			for i := 0; i < test.totalCall; i++ {
+			for range test.totalCall {
 				balancer.ServeTCP(conn)
 			}
 

pkg/tls/tlsmanager.go

@@ -6,6 +6,7 @@ import (
 	"crypto/x509"
 	"errors"
 	"fmt"
+	"slices"
 	"strings"
 	"sync"
 
@@ -181,7 +182,7 @@ func (m *Manager) Get(storeName, configName string) (*tls.Config, error) {
 	tlsConfig.GetCertificate = func(clientHello *tls.ClientHelloInfo) (*tls.Certificate, error) {
 		domainToCheck := types.CanonicalDomain(clientHello.ServerName)
 
-		if isACMETLS(clientHello) {
+		if slices.Contains(clientHello.SupportedProtos, tlsalpn01.ACMETLS1Protocol) {
 			certificate := acmeTLSStore.GetBestCertificate(clientHello)
 			if certificate == nil {
 				log.WithoutContext().Debugf("TLS: no certificate for TLSALPN challenge: %s", domainToCheck)
@@ -419,13 +420,3 @@ func buildDefaultCertificate(defaultCertificate *Certificate) (*tls.Certificate,
 	}
 	return &cert, nil
 }
-
-func isACMETLS(clientHello *tls.ClientHelloInfo) bool {
-	for _, proto := range clientHello.SupportedProtos {
-		if proto == tlsalpn01.ACMETLS1Protocol {
-			return true
-		}
-	}
-
-	return false
-}

pkg/types/http_code_range.go

@@ -1,6 +1,7 @@
 package types
 
 import (
+	"slices"
 	"strconv"
 	"strings"
 )
@@ -34,10 +35,7 @@ func NewHTTPCodeRanges(strBlocks []string) (HTTPCodeRanges, error) {
 
 // Contains tests whether the passed status code is within one of its HTTP code ranges.
 func (h HTTPCodeRanges) Contains(statusCode int) bool {
-	for _, block := range h {
-		if statusCode >= block[0] && statusCode <= block[1] {
-			return true
-		}
-	}
-	return false
+	return slices.ContainsFunc(h, func(block [2]int) bool {
+		return statusCode >= block[0] && statusCode <= block[1]
+	})
 }

pkg/udp/conn_test.go

@@ -210,7 +210,7 @@ func testTimeout(t *testing.T, withRead bool) {
 		}
 	}()
 
-	for i := 0; i < 10; i++ {
+	for range 10 {
 		udpConn2, err := net.Dial("udp", ln.Addr().String())
 		require.NoError(t, err)