updated vendor

2026-06-16 08:02:19 +02:00
parent 2f7f99d3f0
commit 77299d0c64
1283 changed files with 67302 additions and 208958 deletions
@@ -48,8 +48,6 @@ How to use klog
 - For more logging conventions (See [Logging Conventions](https://github.com/kubernetes/community/blob/master/contributors/devel/sig-instrumentation/logging.md))
 - See our documentation on [pkg.go.dev/k8s.io](https://pkg.go.dev/k8s.io/klog).

-**NOTE**: please use the newer go versions that support semantic import versioning in modules, ideally go 1.11.4 or greater.
-
 ### Coexisting with klog/v2

 See [this example](examples/coexist_klog_v1_and_v2/) to see how to coexist with both klog/v1 and klog/v2.
@@ -20,7 +20,9 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"slices"
 	"strconv"
+	"strings"

 	"github.com/go-logr/logr"
 )
@@ -51,139 +53,157 @@ func WithValues(oldKV, newKV []interface{}) []interface{} {
 	return kv
 }

-// MergeKVs deduplicates elements provided in two key/value slices.
-//
-// Keys in each slice are expected to be unique, so duplicates can only occur
-// when the first and second slice contain the same key. When that happens, the
-// key/value pair from the second slice is used. The first slice must be well-formed
-// (= even key/value pairs). The second one may have a missing value, in which
-// case the special "missing value" is added to the result.
-func MergeKVs(first, second []interface{}) []interface{} {
-	maxLength := len(first) + (len(second)+1)/2*2
-	if maxLength == 0 {
-		// Nothing to do at all.
-		return nil
-	}
-
-	if len(first) == 0 && len(second)%2 == 0 {
-		// Nothing to be overridden, second slice is well-formed
-		// and can be used directly.
-		return second
-	}
-
-	// Determine which keys are in the second slice so that we can skip
-	// them when iterating over the first one. The code intentionally
-	// favors performance over completeness: we assume that keys are string
-	// constants and thus compare equal when the string values are equal. A
-	// string constant being overridden by, for example, a fmt.Stringer is
-	// not handled.
-	overrides := map[interface{}]bool{}
-	for i := 0; i < len(second); i += 2 {
-		overrides[second[i]] = true
-	}
-	merged := make([]interface{}, 0, maxLength)
-	for i := 0; i+1 < len(first); i += 2 {
-		key := first[i]
-		if overrides[key] {
-			continue
-		}
-		merged = append(merged, key, first[i+1])
-	}
-	merged = append(merged, second...)
-	if len(merged)%2 != 0 {
-		merged = append(merged, missingValue)
-	}
-	return merged
-}
-
 type Formatter struct {
 	AnyToStringHook AnyToStringFunc
 }

 type AnyToStringFunc func(v interface{}) string

-// MergeKVsInto is a variant of MergeKVs which directly formats the key/value
-// pairs into a buffer.
-func (f Formatter) MergeAndFormatKVs(b *bytes.Buffer, first, second []interface{}) {
-	if len(first) == 0 && len(second) == 0 {
-		// Nothing to do at all.
-		return
-	}
-
-	if len(first) == 0 && len(second)%2 == 0 {
-		// Nothing to be overridden, second slice is well-formed
-		// and can be used directly.
-		for i := 0; i < len(second); i += 2 {
-			f.KVFormat(b, second[i], second[i+1])
-		}
-		return
-	}
-
-	// Determine which keys are in the second slice so that we can skip
-	// them when iterating over the first one. The code intentionally
-	// favors performance over completeness: we assume that keys are string
-	// constants and thus compare equal when the string values are equal. A
-	// string constant being overridden by, for example, a fmt.Stringer is
-	// not handled.
-	overrides := map[interface{}]bool{}
-	for i := 0; i < len(second); i += 2 {
-		overrides[second[i]] = true
-	}
-	for i := 0; i < len(first); i += 2 {
-		key := first[i]
-		if overrides[key] {
-			continue
-		}
-		f.KVFormat(b, key, first[i+1])
-	}
-	// Round down.
-	l := len(second)
-	l = l / 2 * 2
-	for i := 1; i < l; i += 2 {
-		f.KVFormat(b, second[i-1], second[i])
-	}
-	if len(second)%2 == 1 {
-		f.KVFormat(b, second[len(second)-1], missingValue)
-	}
-}
-
-func MergeAndFormatKVs(b *bytes.Buffer, first, second []interface{}) {
-	Formatter{}.MergeAndFormatKVs(b, first, second)
-}
-
 const missingValue = "(MISSING)"

-// KVListFormat serializes all key/value pairs into the provided buffer.
-// A space gets inserted before the first pair and between each pair.
-func (f Formatter) KVListFormat(b *bytes.Buffer, keysAndValues ...interface{}) {
-	for i := 0; i < len(keysAndValues); i += 2 {
-		var v interface{}
-		k := keysAndValues[i]
-		if i+1 < len(keysAndValues) {
-			v = keysAndValues[i+1]
-		} else {
-			v = missingValue
+func FormatKVs(b *bytes.Buffer, kvs ...[]interface{}) {
+	Formatter{}.FormatKVs(b, kvs...)
+}
+
+// FormatKVs formats all key/value pairs such that the output contains no
+// duplicates ("last one wins").
+func (f Formatter) FormatKVs(b *bytes.Buffer, kvs ...[]interface{}) {
+	// De-duplication is done by optimistically formatting all key value
+	// pairs and then cutting out the output of those key/value pairs which
+	// got overwritten later.
+	//
+	// In the common case of no duplicates, the only overhead is tracking
+	// previous keys. This uses a slice with a simple linear search because
+	// the number of entries is typically so low that allocating a map or
+	// keeping a sorted slice with binary search aren't justified.
+	//
+	// Using a fixed size here makes the Go compiler use the stack as
+	// initial backing store for the slice, which is crucial for
+	// performance.
+	existing := make([]obsoleteKV, 0, 32)
+	obsolete := make([]interval, 0, 32) // Sorted by start index.
+	for _, keysAndValues := range kvs {
+		for i := 0; i < len(keysAndValues); i += 2 {
+			var v interface{}
+			k := keysAndValues[i]
+			if i+1 < len(keysAndValues) {
+				v = keysAndValues[i+1]
+			} else {
+				v = missingValue
+			}
+			var e obsoleteKV
+			e.start = b.Len()
+			e.key = f.KVFormat(b, k, v)
+			e.end = b.Len()
+			i := findObsoleteEntry(existing, e.key)
+			if i >= 0 {
+				data := b.Bytes()
+				if bytes.Compare(data[existing[i].start:existing[i].end], data[e.start:e.end]) == 0 {
+					// The new entry gets obsoleted because it's identical.
+					// This has the advantage that key/value pairs from
+					// a WithValues call always come first, even if the same
+					// pair gets added again later. This makes different log
+					// entries more consistent.
+					//
+					// The new entry has a higher start index and thus can be appended.
+					obsolete = append(obsolete, e.interval)
+				} else {
+					// The old entry gets obsoleted because it's value is different.
+					//
+					// Sort order is not guaranteed, we have to insert at the right place.
+					index, _ := slices.BinarySearchFunc(obsolete, existing[i].interval, func(a, b interval) int { return a.start - b.start })
+					obsolete = slices.Insert(obsolete, index, existing[i].interval)
+					existing[i].interval = e.interval
+				}
+			} else {
+				// Instead of appending at the end and doing a
+				// linear search in findEntry, we could keep
+				// the slice sorted by key and do a binary search.
+				//
+				// Above:
+				//    i, ok := slices.BinarySearchFunc(existing, e, func(a, b entry) int { return strings.Compare(a.key, b.key) })
+				// Here:
+				//    existing = slices.Insert(existing, i, e)
+				//
+				// But that adds a dependency on the slices package
+				// and made performance slightly worse, presumably
+				// because the cost of shifting entries around
+				// did not pay of with faster lookups.
+				existing = append(existing, e)
+			}
 		}
-		f.KVFormat(b, k, v)
+	}
+
+	// If we need to remove some obsolete key/value pairs then move the memory.
+	if len(obsolete) > 0 {
+		// Potentially the next remaining output (might itself be obsolete).
+		from := obsolete[0].end
+		// Next obsolete entry.
+		nextObsolete := 1
+		// This is the source buffer, before truncation.
+		all := b.Bytes()
+		b.Truncate(obsolete[0].start)
+
+		for nextObsolete < len(obsolete) {
+			if from == obsolete[nextObsolete].start {
+				// Skip also the next obsolete key/value.
+				from = obsolete[nextObsolete].end
+				nextObsolete++
+				continue
+			}
+
+			// Preserve some output. Write uses copy, which
+			// explicitly allows source and destination to overlap.
+			// That could happen here.
+			valid := all[from:obsolete[nextObsolete].start]
+			b.Write(valid)
+			from = obsolete[nextObsolete].end
+			nextObsolete++
+		}
+		// Copy end of buffer.
+		valid := all[from:]
+		b.Write(valid)
 	}
 }

-func KVListFormat(b *bytes.Buffer, keysAndValues ...interface{}) {
-	Formatter{}.KVListFormat(b, keysAndValues...)
+type obsoleteKV struct {
+	key string
+	interval
 }

-func KVFormat(b *bytes.Buffer, k, v interface{}) {
-	Formatter{}.KVFormat(b, k, v)
+// interval includes the start and excludes the end.
+type interval struct {
+	start int
+	end   int
+}
+
+func findObsoleteEntry(entries []obsoleteKV, key string) int {
+	for i, entry := range entries {
+		if entry.key == key {
+			return i
+		}
+	}
+	return -1
 }

 // formatAny is the fallback formatter for a value. It supports a hook (for
 // example, for YAML encoding) and itself uses JSON encoding.
 func (f Formatter) formatAny(b *bytes.Buffer, v interface{}) {
-	b.WriteRune('=')
 	if f.AnyToStringHook != nil {
-		b.WriteString(f.AnyToStringHook(v))
+		str := f.AnyToStringHook(v)
+		if strings.Contains(str, "\n") {
+			// If it's multi-line, then pass it through writeStringValue to get start/end delimiters,
+			// which separates it better from any following key/value pair.
+			writeStringValue(b, str)
+			return
+		}
+		// Otherwise put it directly after the separator, on the same lime,
+		// The assumption is that the hook returns something where start/end are obvious.
+		b.WriteRune('=')
+		b.WriteString(str)
 		return
 	}
+	b.WriteRune('=')
 	formatAsJSON(b, v)
 }

@@ -28,7 +28,7 @@ import (

 // KVFormat serializes one key/value pair into the provided buffer.
 // A space gets inserted before the pair.
-func (f Formatter) KVFormat(b *bytes.Buffer, k, v interface{}) {
+func (f Formatter) KVFormat(b *bytes.Buffer, k, v interface{}) string {
 	// This is the version without slog support. Must be kept in sync with
 	// the version in keyvalues_slog.go.

@@ -37,13 +37,15 @@ func (f Formatter) KVFormat(b *bytes.Buffer, k, v interface{}) {
 	// https://github.com/kubernetes/community/blob/master/contributors/devel/sig-instrumentation/migration-to-structured-logging.md#name-arguments
 	// for the sake of performance. Keys with spaces,
 	// special characters, etc. will break parsing.
+	var key string
 	if sK, ok := k.(string); ok {
 		// Avoid one allocation when the key is a string, which
 		// normally it should be.
-		b.WriteString(sK)
+		key = sK
 	} else {
-		b.WriteString(fmt.Sprintf("%s", k))
+		key = fmt.Sprintf("%s", k)
 	}
+	b.WriteString(key)

 	// The type checks are sorted so that more frequently used ones
 	// come first because that is then faster in the common
@@ -94,4 +96,6 @@ func (f Formatter) KVFormat(b *bytes.Buffer, k, v interface{}) {
 	default:
 		f.formatAny(b, v)
 	}
+
+	return key
 }
@@ -29,8 +29,8 @@ import (
 )

 // KVFormat serializes one key/value pair into the provided buffer.
-// A space gets inserted before the pair.
-func (f Formatter) KVFormat(b *bytes.Buffer, k, v interface{}) {
+// A space gets inserted before the pair. It returns the key.
+func (f Formatter) KVFormat(b *bytes.Buffer, k, v interface{}) string {
 	// This is the version without slog support. Must be kept in sync with
 	// the version in keyvalues_slog.go.

@@ -39,13 +39,15 @@ func (f Formatter) KVFormat(b *bytes.Buffer, k, v interface{}) {
 	// https://github.com/kubernetes/community/blob/master/contributors/devel/sig-instrumentation/migration-to-structured-logging.md#name-arguments
 	// for the sake of performance. Keys with spaces,
 	// special characters, etc. will break parsing.
+	var key string
 	if sK, ok := k.(string); ok {
 		// Avoid one allocation when the key is a string, which
 		// normally it should be.
-		b.WriteString(sK)
+		key = sK
 	} else {
-		b.WriteString(fmt.Sprintf("%s", k))
+		key = fmt.Sprintf("%s", k)
 	}
+	b.WriteString(key)

 	// The type checks are sorted so that more frequently used ones
 	// come first because that is then faster in the common
@@ -112,6 +114,8 @@ func (f Formatter) KVFormat(b *bytes.Buffer, k, v interface{}) {
 	default:
 		f.formatAny(b, v)
 	}
+
+	return key
 }

 // generateJSON has the same preference for plain strings as KVFormat.
@@ -0,0 +1,303 @@
+/*
+Copyright 2013 Google Inc. All Rights Reserved.
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package verbosity
+
+import (
+	"bytes"
+	"errors"
+	"flag"
+	"fmt"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"sync/atomic"
+)
+
+// New returns a struct that implements -v and -vmodule support. Changing and
+// checking these settings is thread-safe, with all concurrency issues handled
+// internally.
+func New() *VState {
+	vs := new(VState)
+
+	// The two fields must have a pointer to the overal struct for their
+	// implementation of Set.
+	vs.vmodule.vs = vs
+	vs.verbosity.vs = vs
+
+	return vs
+}
+
+// Value is an extension that makes it possible to use the values in pflag.
+type Value interface {
+	flag.Value
+	Type() string
+}
+
+func (vs *VState) V() Value {
+	return &vs.verbosity
+}
+
+func (vs *VState) VModule() Value {
+	return &vs.vmodule
+}
+
+// VState contains settings and state. Some of its fields can be accessed
+// through atomic read/writes, in other cases a mutex must be held.
+type VState struct {
+	mu sync.Mutex
+
+	// These flags are modified only under lock, although verbosity may be fetched
+	// safely using atomic.LoadInt32.
+	vmodule   moduleSpec // The state of the -vmodule flag.
+	verbosity levelSpec  // V logging level, the value of the -v flag/
+
+	// pcs is used in V to avoid an allocation when computing the caller's PC.
+	pcs [1]uintptr
+	// vmap is a cache of the V Level for each V() call site, identified by PC.
+	// It is wiped whenever the vmodule flag changes state.
+	vmap map[uintptr]Level
+	// filterLength stores the length of the vmodule filter chain. If greater
+	// than zero, it means vmodule is enabled. It may be read safely
+	// using sync.LoadInt32, but is only modified under mu.
+	filterLength int32
+}
+
+// Level must be an int32 to support atomic read/writes.
+type Level int32
+
+type levelSpec struct {
+	vs *VState
+	l  Level
+}
+
+// get returns the value of the level.
+func (l *levelSpec) get() Level {
+	return Level(atomic.LoadInt32((*int32)(&l.l)))
+}
+
+// set sets the value of the level.
+func (l *levelSpec) set(val Level) {
+	atomic.StoreInt32((*int32)(&l.l), int32(val))
+}
+
+// String is part of the flag.Value interface.
+func (l *levelSpec) String() string {
+	return strconv.FormatInt(int64(l.l), 10)
+}
+
+// Get is part of the flag.Getter interface. It returns the
+// verbosity level as int32.
+func (l *levelSpec) Get() interface{} {
+	return int32(l.l)
+}
+
+// Type is part of pflag.Value.
+func (l *levelSpec) Type() string {
+	return "Level"
+}
+
+// Set is part of the flag.Value interface.
+func (l *levelSpec) Set(value string) error {
+	v, err := strconv.ParseInt(value, 10, 32)
+	if err != nil {
+		return err
+	}
+	l.vs.mu.Lock()
+	defer l.vs.mu.Unlock()
+	l.vs.set(Level(v), l.vs.vmodule.filter, false)
+	return nil
+}
+
+// moduleSpec represents the setting of the -vmodule flag.
+type moduleSpec struct {
+	vs     *VState
+	filter []modulePat
+}
+
+// modulePat contains a filter for the -vmodule flag.
+// It holds a verbosity level and a file pattern to match.
+type modulePat struct {
+	pattern string
+	literal bool // The pattern is a literal string
+	level   Level
+}
+
+// match reports whether the file matches the pattern. It uses a string
+// comparison if the pattern contains no metacharacters.
+func (m *modulePat) match(file string) bool {
+	if m.literal {
+		return file == m.pattern
+	}
+	match, _ := filepath.Match(m.pattern, file)
+	return match
+}
+
+func (m *moduleSpec) String() string {
+	// Lock because the type is not atomic. TODO: clean this up.
+	// Empty instances don't have and don't need a lock (can
+	// happen when flag uses introspection).
+	if m.vs != nil {
+		m.vs.mu.Lock()
+		defer m.vs.mu.Unlock()
+	}
+	var b bytes.Buffer
+	for i, f := range m.filter {
+		if i > 0 {
+			b.WriteRune(',')
+		}
+		fmt.Fprintf(&b, "%s=%d", f.pattern, f.level)
+	}
+	return b.String()
+}
+
+// Get is part of the (Go 1.2)  flag.Getter interface. It always returns nil for this flag type since the
+// struct is not exported.
+func (m *moduleSpec) Get() interface{} {
+	return nil
+}
+
+// Type is part of pflag.Value
+func (m *moduleSpec) Type() string {
+	return "pattern=N,..."
+}
+
+var errVmoduleSyntax = errors.New("syntax error: expect comma-separated list of filename=N")
+
+// Set will sets module value
+// Syntax: -vmodule=recordio=2,file=1,gfs*=3
+func (m *moduleSpec) Set(value string) error {
+	var filter []modulePat
+	for _, pat := range strings.Split(value, ",") {
+		if len(pat) == 0 {
+			// Empty strings such as from a trailing comma can be ignored.
+			continue
+		}
+		patLev := strings.Split(pat, "=")
+		if len(patLev) != 2 || len(patLev[0]) == 0 || len(patLev[1]) == 0 {
+			return errVmoduleSyntax
+		}
+		pattern := patLev[0]
+		v, err := strconv.ParseInt(patLev[1], 10, 32)
+		if err != nil {
+			return errors.New("syntax error: expect comma-separated list of filename=N")
+		}
+		if v < 0 {
+			return errors.New("negative value for vmodule level")
+		}
+		if v == 0 {
+			continue // Ignore. It's harmless but no point in paying the overhead.
+		}
+		// TODO: check syntax of filter?
+		filter = append(filter, modulePat{pattern, isLiteral(pattern), Level(v)})
+	}
+	m.vs.mu.Lock()
+	defer m.vs.mu.Unlock()
+	m.vs.set(m.vs.verbosity.l, filter, true)
+	return nil
+}
+
+// isLiteral reports whether the pattern is a literal string, that is, has no metacharacters
+// that require filepath.Match to be called to match the pattern.
+func isLiteral(pattern string) bool {
+	return !strings.ContainsAny(pattern, `\*?[]`)
+}
+
+// set sets a consistent state for V logging.
+// The mutex must be held.
+func (vs *VState) set(l Level, filter []modulePat, setFilter bool) {
+	// Turn verbosity off so V will not fire while we are in transition.
+	vs.verbosity.set(0)
+	// Ditto for filter length.
+	atomic.StoreInt32(&vs.filterLength, 0)
+
+	// Set the new filters and wipe the pc->Level map if the filter has changed.
+	if setFilter {
+		vs.vmodule.filter = filter
+		vs.vmap = make(map[uintptr]Level)
+	}
+
+	// Things are consistent now, so enable filtering and verbosity.
+	// They are enabled in order opposite to that in V.
+	atomic.StoreInt32(&vs.filterLength, int32(len(filter)))
+	vs.verbosity.set(l)
+}
+
+// Enabled checks whether logging is enabled at the given level. This must be
+// called with depth=0 when the caller of enabled will do the logging and
+// higher values when more stack levels need to be skipped.
+//
+// The mutex will be locked only if needed.
+func (vs *VState) Enabled(level Level, depth int) bool {
+	// This function tries hard to be cheap unless there's work to do.
+	// The fast path is two atomic loads and compares.
+
+	// Here is a cheap but safe test to see if V logging is enabled globally.
+	if vs.verbosity.get() >= level {
+		return true
+	}
+
+	// It's off globally but vmodule may still be set.
+	// Here is another cheap but safe test to see if vmodule is enabled.
+	if atomic.LoadInt32(&vs.filterLength) > 0 {
+		// Now we need a proper lock to use the logging structure. The pcs field
+		// is shared so we must lock before accessing it. This is fairly expensive,
+		// but if V logging is enabled we're slow anyway.
+		vs.mu.Lock()
+		defer vs.mu.Unlock()
+		if runtime.Callers(depth+2, vs.pcs[:]) == 0 {
+			return false
+		}
+		// runtime.Callers returns "return PCs", but we want
+		// to look up the symbolic information for the call,
+		// so subtract 1 from the PC. runtime.CallersFrames
+		// would be cleaner, but allocates.
+		pc := vs.pcs[0] - 1
+		v, ok := vs.vmap[pc]
+		if !ok {
+			v = vs.setV(pc)
+		}
+		return v >= level
+	}
+	return false
+}
+
+// setV computes and remembers the V level for a given PC
+// when vmodule is enabled.
+// File pattern matching takes the basename of the file, stripped
+// of its .go suffix, and uses filepath.Match, which is a little more
+// general than the *? matching used in C++.
+// Mutex is held.
+func (vs *VState) setV(pc uintptr) Level {
+	fn := runtime.FuncForPC(pc)
+	file, _ := fn.FileLine(pc)
+	// The file is something like /a/b/c/d.go. We want just the d.
+	file = strings.TrimSuffix(file, ".go")
+	if slash := strings.LastIndex(file, "/"); slash >= 0 {
+		file = file[slash+1:]
+	}
+	for _, filter := range vs.vmodule.filter {
+		if filter.match(file) {
+			vs.vmap[pc] = filter.level
+			return filter.level
+		}
+	}
+	vs.vmap[pc] = 0
+	return 0
+}
@@ -58,15 +58,30 @@
 //
 //		-logtostderr=true
 //			Logs are written to standard error instead of to files.
-//	             This shortcuts most of the usual output routing:
-//	             -alsologtostderr, -stderrthreshold and -log_dir have no
-//	             effect and output redirection at runtime with SetOutput is
-//	             ignored.
+//	             By default, all logs are written regardless of severity
+//	             (legacy behavior). To filter logs by severity when
+//	             -logtostderr=true, set -legacy_stderr_threshold_behavior=false
+//	             and use -stderrthreshold.
+//              With -legacy_stderr_threshold_behavior=true,
+//              -stderrthreshold has no effect.
+//
+//	             The following flags always have no effect:
+//	             -alsologtostderr, -alsologtostderrthreshold, and -log_dir.
+//	             Output redirection at runtime with SetOutput is also ignored.
 //		-alsologtostderr=false
 //			Logs are written to standard error as well as to files.
+//		-alsologtostderrthreshold=INFO
+//			Log events at or above this severity are logged to standard
+//			error when -alsologtostderr=true (no effect when -logtostderr=true).
+//			Default is INFO to maintain backward compatibility.
 //		-stderrthreshold=ERROR
 //			Log events at or above this severity are logged to standard
-//			error as well as to files.
+//			error as well as to files. When -logtostderr=true, this flag
+//			has no effect unless -legacy_stderr_threshold_behavior=false.
+//		-legacy_stderr_threshold_behavior=true
+//			If true, -stderrthreshold is ignored when -logtostderr=true
+//			(legacy behavior). If false, -stderrthreshold is honored even
+//			when -logtostderr=true, allowing severity-based filtering.
 //		-log_dir=""
 //			Log files will be written to this directory instead of the
 //			default temporary directory.
@@ -156,7 +171,7 @@ func (s *severityValue) Set(value string) error {
 		}
 		threshold = severity.Severity(v)
 	}
-	logging.stderrThreshold.set(threshold)
+	s.set(threshold)
 	return nil
 }

@@ -409,6 +424,15 @@ var commandLine flag.FlagSet

 // init sets up the defaults and creates command line flags.
 func init() {
+	// Initialize severity thresholds
+	logging.stderrThreshold = severityValue{
+		Severity: severity.ErrorLog, // Default stderrThreshold is ERROR.
+	}
+	logging.alsologtostderrthreshold = severityValue{
+		Severity: severity.InfoLog, // Default alsologtostderrthreshold is INFO (to maintain backward compatibility).
+	}
+	logging.setVState(0, nil, false)
+
 	commandLine.StringVar(&logging.logDir, "log_dir", "", "If non-empty, write log files in this directory (no effect when -logtostderr=true)")
 	commandLine.StringVar(&logging.logFile, "log_file", "", "If non-empty, use this log file (no effect when -logtostderr=true)")
 	commandLine.Uint64Var(&logging.logFileMaxSizeMB, "log_file_max_size", 1800,
@@ -416,16 +440,14 @@ func init() {
 			"If the value is 0, the maximum file size is unlimited.")
 	commandLine.BoolVar(&logging.toStderr, "logtostderr", true, "log to standard error instead of files")
 	commandLine.BoolVar(&logging.alsoToStderr, "alsologtostderr", false, "log to standard error as well as files (no effect when -logtostderr=true)")
-	logging.setVState(0, nil, false)
+	commandLine.BoolVar(&logging.legacyStderrThresholdBehavior, "legacy_stderr_threshold_behavior", true, "If true, stderrthreshold is ignored when logtostderr=true (legacy behavior). If false, stderrthreshold is honored even when logtostderr=true")
 	commandLine.Var(&logging.verbosity, "v", "number for the log level verbosity")
 	commandLine.BoolVar(&logging.addDirHeader, "add_dir_header", false, "If true, adds the file directory to the header of the log messages")
 	commandLine.BoolVar(&logging.skipHeaders, "skip_headers", false, "If true, avoid header prefixes in the log messages")
 	commandLine.BoolVar(&logging.oneOutput, "one_output", false, "If true, only write logs to their native severity level (vs also writing to each lower severity level; no effect when -logtostderr=true)")
 	commandLine.BoolVar(&logging.skipLogHeaders, "skip_log_headers", false, "If true, avoid headers when opening log files (no effect when -logtostderr=true)")
-	logging.stderrThreshold = severityValue{
-		Severity: severity.ErrorLog, // Default stderrThreshold is ERROR.
-	}
-	commandLine.Var(&logging.stderrThreshold, "stderrthreshold", "logs at or above this threshold go to stderr when writing to files and stderr (no effect when -logtostderr=true or -alsologtostderr=true)")
+	commandLine.Var(&logging.stderrThreshold, "stderrthreshold", "logs at or above this threshold go to stderr when writing to files and stderr (no effect when -logtostderr=true or -alsologtostderr=true unless -legacy_stderr_threshold_behavior=false)")
+	commandLine.Var(&logging.alsologtostderrthreshold, "alsologtostderrthreshold", "logs at or above this threshold go to stderr when -alsologtostderr=true (no effect when -logtostderr=true)")
 	commandLine.Var(&logging.vmodule, "vmodule", "comma-separated list of pattern=N settings for file-filtered logging")
 	commandLine.Var(&logging.traceLocation, "log_backtrace_at", "when logging hits line file:N, emit a stack trace")

@@ -470,11 +492,13 @@ type settings struct {
 	// Boolean flags. Not handled atomically because the flag.Value interface
 	// does not let us avoid the =true, and that shorthand is necessary for
 	// compatibility. TODO: does this matter enough to fix? Seems unlikely.
-	toStderr     bool // The -logtostderr flag.
-	alsoToStderr bool // The -alsologtostderr flag.
+	toStderr                      bool // The -logtostderr flag.
+	alsoToStderr                  bool // The -alsologtostderr flag.
+	legacyStderrThresholdBehavior bool // The -legacy_stderr_threshold_behavior flag.

 	// Level flag. Handled atomically.
-	stderrThreshold severityValue // The -stderrthreshold flag.
+	stderrThreshold          severityValue // The -stderrthreshold flag.
+	alsologtostderrthreshold severityValue // The -alsologtostderrthreshold flag.

 	// Access to all of the following fields must be protected via a mutex.

@@ -809,16 +833,21 @@ func (l *loggingT) infoS(logger *logWriter, filter LogFilter, depth int, msg str
 // printS is called from infoS and errorS if logger is not specified.
 // set log severity by s
 func (l *loggingT) printS(err error, s severity.Severity, depth int, msg string, keysAndValues ...interface{}) {
-	// Only create a new buffer if we don't have one cached.
-	b := buffer.GetBuffer()
 	// The message is always quoted, even if it contains line breaks.
 	// If developers want multi-line output, they should use a small, fixed
 	// message and put the multi-line output into a value.
-	b.WriteString(strconv.Quote(msg))
+	qMsg := make([]byte, 0, 1024)
+	qMsg = strconv.AppendQuote(qMsg, msg)
+
+	// Only create a new buffer if we don't have one cached.
+	b := buffer.GetBuffer()
+	b.Write(qMsg)
+
+	var errKV []interface{}
 	if err != nil {
-		serialize.KVListFormat(&b.Buffer, "err", err)
+		errKV = []interface{}{"err", err}
 	}
-	serialize.KVListFormat(&b.Buffer, keysAndValues...)
+	serialize.FormatKVs(&b.Buffer, errKV, keysAndValues)
 	l.printDepth(s, nil, nil, depth+1, &b.Buffer)
 	// Make the buffer available for reuse.
 	buffer.PutBuffer(b)
@@ -885,9 +914,25 @@ func (l *loggingT) output(s severity.Severity, logger *logWriter, buf *buffer.Bu
 			}
 		}
 	} else if l.toStderr {
-		os.Stderr.Write(data)
+		// When logging to stderr only, check if we should filter by severity.
+		// This is controlled by the legacy_stderr_threshold_behavior flag.
+		if l.legacyStderrThresholdBehavior {
+			// Legacy behavior: always write to stderr, ignore stderrthreshold
+			os.Stderr.Write(data)
+		} else {
+			// New behavior: honor stderrthreshold even when logtostderr=true
+			if s >= l.stderrThreshold.get() {
+				os.Stderr.Write(data)
+			}
+		}
 	} else {
-		if alsoToStderr || l.alsoToStderr || s >= l.stderrThreshold.get() {
+		// Write to stderr if any of these conditions are met:
+		// - alsoToStderr is set (legacy behavior)
+		// - alsologtostderr is set and severity meets alsologtostderrthreshold
+		// - alsologtostderr is not set and severity meets stderrThreshold
+		if alsoToStderr ||
+			(l.alsoToStderr && s >= l.alsologtostderrthreshold.get()) ||
+			(!l.alsoToStderr && s >= l.stderrThreshold.get()) {
 			os.Stderr.Write(data)
 		}

@@ -53,7 +53,7 @@ func (l *klogger) Init(info logr.RuntimeInfo) {
 }

 func (l *klogger) Info(level int, msg string, kvList ...interface{}) {
-	merged := serialize.MergeKVs(l.values, kvList)
+	merged := serialize.WithValues(l.values, kvList)
 	// Skip this function.
 	VDepth(l.callDepth+1, Level(level)).InfoSDepth(l.callDepth+1, msg, merged...)
 }
@@ -63,7 +63,7 @@ func (l *klogger) Enabled(level int) bool {
 }

 func (l *klogger) Error(err error, msg string, kvList ...interface{}) {
-	merged := serialize.MergeKVs(l.values, kvList)
+	merged := serialize.WithValues(l.values, kvList)
 	ErrorSDepth(l.callDepth+1, err, msg, merged...)
 }

@@ -63,12 +63,17 @@ func slogOutput(file string, line int, now time.Time, err error, s severity.Seve
 	}

 	// See printS.
+	qMsg := make([]byte, 0, 1024)
+	qMsg = strconv.AppendQuote(qMsg, msg)
+
 	b := buffer.GetBuffer()
-	b.WriteString(strconv.Quote(msg))
+	b.Write(qMsg)
+
+	var errKV []interface{}
 	if err != nil {
-		serialize.KVListFormat(&b.Buffer, "err", err)
+		errKV = []interface{}{"err", err}
 	}
-	serialize.KVListFormat(&b.Buffer, kvList...)
+	serialize.FormatKVs(&b.Buffer, errKV, kvList)

 	// See print + header.
 	buf := logging.formatHeader(s, file, line, now)
@@ -0,0 +1,172 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package textlogger
+
+import (
+	"flag"
+	"io"
+	"os"
+	"strconv"
+	"time"
+
+	"k8s.io/klog/v2/internal/verbosity"
+)
+
+// Config influences logging in a text logger. To make this configurable via
+// command line flags, instantiate this once per program and use AddFlags to
+// bind command line flags to the instance before passing it to NewTestContext.
+//
+// Must be constructed with NewConfig.
+type Config struct {
+	vstate *verbosity.VState
+	co     configOptions
+}
+
+// Verbosity returns a value instance that can be used to query (via String) or
+// modify (via Set) the verbosity threshold. This is thread-safe and can be
+// done at runtime.
+func (c *Config) Verbosity() flag.Value {
+	return c.vstate.V()
+}
+
+// VModule returns a value instance that can be used to query (via String) or
+// modify (via Set) the vmodule settings. This is thread-safe and can be done
+// at runtime.
+func (c *Config) VModule() flag.Value {
+	return c.vstate.VModule()
+}
+
+// ConfigOption implements functional parameters for NewConfig.
+type ConfigOption func(co *configOptions)
+
+type configOptions struct {
+	verbosityFlagName string
+	vmoduleFlagName   string
+	verbosityDefault  int
+	fixedTime         *time.Time
+	unwind            func(int) (string, int)
+	withHeader        bool
+	output            io.Writer
+}
+
+// VerbosityFlagName overrides the default -v for the verbosity level.
+func VerbosityFlagName(name string) ConfigOption {
+	return func(co *configOptions) {
+
+		co.verbosityFlagName = name
+	}
+}
+
+// VModulFlagName overrides the default -vmodule for the per-module
+// verbosity levels.
+func VModuleFlagName(name string) ConfigOption {
+	return func(co *configOptions) {
+		co.vmoduleFlagName = name
+	}
+}
+
+// Verbosity overrides the default verbosity level of 0.
+// See https://github.com/kubernetes/community/blob/9406b4352fe2d5810cb21cc3cb059ce5886de157/contributors/devel/sig-instrumentation/logging.md#logging-conventions
+// for log level conventions in Kubernetes.
+func Verbosity(level int) ConfigOption {
+	return func(co *configOptions) {
+		co.verbosityDefault = level
+	}
+}
+
+// Output overrides stderr as the output stream.
+func Output(output io.Writer) ConfigOption {
+	return func(co *configOptions) {
+		co.output = output
+	}
+}
+
+// FixedTime overrides the actual time with a fixed time. Useful only for testing.
+//
+// # Experimental
+//
+// Notice: This function is EXPERIMENTAL and may be changed or removed in a
+// later release.
+func FixedTime(ts time.Time) ConfigOption {
+	return func(co *configOptions) {
+		co.fixedTime = &ts
+	}
+}
+
+// WithHeader controls whether the header (time, source code location, etc.)
+// is included in the output. The default is to include it.
+//
+// This can be useful in combination with redirection to a buffer to
+// turn structured log parameters into a string (see example).
+//
+// # Experimental
+//
+// Notice: This function is EXPERIMENTAL and may be changed or removed in a
+// later release.
+func WithHeader(enabled bool) ConfigOption {
+	return func(co *configOptions) {
+		co.withHeader = enabled
+	}
+}
+
+// Backtrace overrides the default mechanism for determining the call site.
+// The callback is invoked with the number of function calls between itself
+// and the call site. It must return the file name and line number. An empty
+// file name indicates that the information is unknown.
+//
+// # Experimental
+//
+// Notice: This function is EXPERIMENTAL and may be changed or removed in a
+// later release.
+func Backtrace(unwind func(skip int) (filename string, line int)) ConfigOption {
+	return func(co *configOptions) {
+		co.unwind = unwind
+	}
+}
+
+// NewConfig returns a configuration with recommended defaults and optional
+// modifications. Command line flags are not bound to any FlagSet yet.
+func NewConfig(opts ...ConfigOption) *Config {
+	c := &Config{
+		vstate: verbosity.New(),
+		co: configOptions{
+			verbosityFlagName: "v",
+			vmoduleFlagName:   "vmodule",
+			verbosityDefault:  0,
+			unwind:            runtimeBacktrace,
+			withHeader:        true,
+			output:            os.Stderr,
+		},
+	}
+	for _, opt := range opts {
+		opt(&c.co)
+	}
+
+	// Cannot fail for this input.
+	_ = c.Verbosity().Set(strconv.FormatInt(int64(c.co.verbosityDefault), 10))
+	return c
+}
+
+// AddFlags registers the command line flags that control the configuration.
+//
+// The default flag names are the same as in klog, so unless those defaults
+// are changed, either klog.InitFlags or Config.AddFlags can be used for the
+// same flag set, but not both.
+func (c *Config) AddFlags(fs *flag.FlagSet) {
+	fs.Var(c.Verbosity(), c.co.verbosityFlagName, "number for the log level verbosity of the testing logger")
+	fs.Var(c.VModule(), c.co.vmoduleFlagName, "comma-separated list of pattern=N log level settings for files matching the patterns")
+}
@@ -0,0 +1,200 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+Copyright 2020 Intel Corporation.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package textlogger contains an implementation of the logr interface which is
+// producing the exact same output as klog. It does not route output through
+// klog (i.e. ignores [k8s.io/klog/v2.InitFlags]). Instead, all settings must be
+// configured through its own [NewConfig] and [Config.AddFlags].
+package textlogger
+
+import (
+	"runtime"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/go-logr/logr"
+
+	"k8s.io/klog/v2/internal/buffer"
+	"k8s.io/klog/v2/internal/serialize"
+	"k8s.io/klog/v2/internal/severity"
+	"k8s.io/klog/v2/internal/verbosity"
+)
+
+var (
+	// TimeNow is used to retrieve the current time. May be changed for testing.
+	TimeNow = time.Now
+)
+
+const (
+	// nameKey is used to log the `WithName` values as an additional attribute.
+	nameKey = "logger"
+)
+
+// NewLogger constructs a new logger.
+//
+// Verbosity can be modified at any time through the Config.V and
+// Config.VModule API.
+func NewLogger(c *Config) logr.Logger {
+	return logr.New(&tlogger{
+		values: nil,
+		config: c,
+	})
+}
+
+type tlogger struct {
+	callDepth int
+
+	// hasPrefix is true if the first entry in values is the special
+	// nameKey key/value. Such an entry gets added and later updated in
+	// WithName.
+	hasPrefix bool
+
+	values []interface{}
+	groups string
+	config *Config
+}
+
+func (l *tlogger) Init(info logr.RuntimeInfo) {
+	l.callDepth = info.CallDepth
+}
+
+func (l *tlogger) WithCallDepth(depth int) logr.LogSink {
+	newLogger := *l
+	newLogger.callDepth += depth
+	return &newLogger
+}
+
+func (l *tlogger) Enabled(level int) bool {
+	return l.config.vstate.Enabled(verbosity.Level(level), 1+l.callDepth)
+}
+
+func (l *tlogger) Info(_ int, msg string, kvList ...interface{}) {
+	l.print(nil, severity.InfoLog, msg, kvList)
+}
+
+func (l *tlogger) Error(err error, msg string, kvList ...interface{}) {
+	l.print(err, severity.ErrorLog, msg, kvList)
+}
+
+func (l *tlogger) print(err error, s severity.Severity, msg string, kvList []interface{}) {
+	var file string
+	var line int
+	var now time.Time
+	if l.config.co.withHeader {
+		// Determine caller.
+		// +1 for this frame, +1 for Info/Error.
+		skip := l.callDepth + 2
+		file, line = l.config.co.unwind(skip)
+		if file == "" {
+			file = "???"
+			line = 1
+		} else if slash := strings.LastIndex(file, "/"); slash >= 0 {
+			file = file[slash+1:]
+		}
+		now = time.Now()
+	}
+	l.printWithInfos(file, line, now, err, s, msg, kvList)
+}
+
+func runtimeBacktrace(skip int) (string, int) {
+	_, file, line, ok := runtime.Caller(skip + 1)
+	if !ok {
+		return "", 0
+	}
+	return file, line
+}
+
+func (l *tlogger) printWithInfos(file string, line int, now time.Time, err error, s severity.Severity, msg string, kvList []interface{}) {
+	// The message is always quoted, even if it contains line breaks.
+	// If developers want multi-line output, they should use a small, fixed
+	// message and put the multi-line output into a value.
+	qMsg := make([]byte, 0, 1024)
+	qMsg = strconv.AppendQuote(qMsg, msg)
+
+	// Only create a new buffer if we don't have one cached.
+	b := buffer.GetBuffer()
+	defer buffer.PutBuffer(b)
+
+	if l.config.co.withHeader {
+		// Format header.
+		if l.config.co.fixedTime != nil {
+			now = *l.config.co.fixedTime
+		}
+		b.FormatHeader(s, file, line, now)
+	}
+
+	b.Write(qMsg)
+
+	var errKV []interface{}
+	if err != nil {
+		errKV = []interface{}{"err", err}
+	}
+	serialize.FormatKVs(&b.Buffer, errKV, l.values, kvList)
+	if b.Len() == 0 || b.Bytes()[b.Len()-1] != '\n' {
+		b.WriteByte('\n')
+	}
+	_, _ = l.config.co.output.Write(b.Bytes())
+}
+
+func (l *tlogger) WriteKlogBuffer(data []byte) {
+	_, _ = l.config.co.output.Write(data)
+}
+
+// WithName returns a new logr.Logger with the specified name appended.  klogr
+// uses '/' characters to separate name elements.  Callers should not pass '/'
+// in the provided name string, but this library does not actually enforce that.
+func (l *tlogger) WithName(name string) logr.LogSink {
+	clone := *l
+	if l.hasPrefix {
+		// Copy slice and modify value. No length checks and type
+		// assertions are needed because hasPrefix is only true if the
+		// first two elements exist and are key/value strings.
+		v := make([]interface{}, 0, len(l.values))
+		v = append(v, l.values...)
+		prefix, _ := v[1].(string)
+		v[1] = prefix + "." + name
+		clone.values = v
+	} else {
+		// Preprend new key/value pair.
+		v := make([]interface{}, 0, 2+len(l.values))
+		v = append(v, nameKey, name)
+		v = append(v, l.values...)
+		clone.values = v
+		clone.hasPrefix = true
+	}
+	return &clone
+}
+
+func (l *tlogger) WithValues(kvList ...interface{}) logr.LogSink {
+	clone := *l
+	clone.values = serialize.WithValues(l.values, kvList)
+	return &clone
+}
+
+// KlogBufferWriter is implemented by the textlogger LogSink.
+type KlogBufferWriter interface {
+	// WriteKlogBuffer takes a pre-formatted buffer prepared by klog and
+	// writes it unchanged to the output stream. Can be used with
+	// klog.WriteKlogBuffer when setting a logger through
+	// klog.SetLoggerWithOptions.
+	WriteKlogBuffer([]byte)
+}
+
+var _ logr.LogSink = &tlogger{}
+var _ logr.CallDepthLogSink = &tlogger{}
+var _ KlogBufferWriter = &tlogger{}
@@ -0,0 +1,52 @@
+//go:build go1.21
+// +build go1.21
+
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package textlogger
+
+import (
+	"context"
+	"log/slog"
+
+	"github.com/go-logr/logr"
+
+	"k8s.io/klog/v2/internal/serialize"
+	"k8s.io/klog/v2/internal/sloghandler"
+)
+
+func (l *tlogger) Handle(ctx context.Context, record slog.Record) error {
+	return sloghandler.Handle(ctx, record, l.groups, l.printWithInfos)
+}
+
+func (l *tlogger) WithAttrs(attrs []slog.Attr) logr.SlogSink {
+	clone := *l
+	clone.values = serialize.WithValues(l.values, sloghandler.Attrs2KVList(l.groups, attrs))
+	return &clone
+}
+
+func (l *tlogger) WithGroup(name string) logr.SlogSink {
+	clone := *l
+	if clone.groups != "" {
+		clone.groups += "." + name
+	} else {
+		clone.groups = name
+	}
+	return &clone
+}
+
+var _ logr.SlogSink = &tlogger{}