[Fix] Fix prometheus label value is not valid utf 8 cause api timeout (#7128)

## Which problem is this PR solving?
- Example: Resolves #2944

## Description of the changes
- Use `hist.GetMetricWithLabelValues` instead of `hist.WithLabelValues`
to avoid the panic 'Label value is not valid UTF-8' and receive instead
of that empty counter/gauge/timer/histogram.

## How was this change tested?
- Four new tests were added to ensure the system remains stable when it
receives an invalid label.

## Checklist
- [x] I have read
https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
- [x] I have signed all commits
- [x] I have added unit tests for the new functionality
- [x] I have run lint and test steps successfully
  - for `jaeger`: `make lint test`
  - for `jaeger-ui`: `npm run lint` and `npm run test`

---------

Signed-off-by: Ilia Petrov <[email protected]>
Signed-off-by: Yuri Shkuro <[email protected]>
Co-authored-by: Yuri Shkuro <[email protected]>

Author: iypetrov

internal/jptrace/utf8.go

@@ -0,0 +1,15 @@
+// Copyright (c) 2025 The Jaeger Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package jptrace
+
+import (
+	"golang.org/x/text/runes"
+	"golang.org/x/text/transform"
+)
+
+func SanitizeUTF8(input string) (string, error) {
+	t := transform.Chain(runes.ReplaceIllFormed(), transform.Nop)
+	sanitized, _, err := transform.String(t, input)
+	return sanitized, err
+}

internal/jptrace/utf8_test.go

@@ -0,0 +1,63 @@
+// Copyright (c) 2025 The Jaeger Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package jptrace
+
+import (
+	"testing"
+	"unicode/utf8"
+)
+
+func TestSanitizeUTF8(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  string
+	}{
+		{
+			name:  "Valid ASCII",
+			input: "Hello, world!",
+			want:  "Hello, world!",
+		},
+		{
+			name:  "Valid UTF-8 multibyte",
+			input: "こんにちは世界",
+			want:  "こんにちは世界",
+		},
+		{
+			name:  "Valid Emoji",
+			input: "😃🚀🔥",
+			want:  "😃🚀🔥",
+		},
+		{
+			name:  "String with replacement rune",
+			input: string([]byte{0xff, 0xfe, 0xfd}),
+			want:  "���",
+		},
+		{
+			name:  "Mixed valid and invalid",
+			input: "Good\xffMorning",
+			want:  "Good�Morning",
+		},
+		{
+			name:  "Empty string",
+			input: "",
+			want:  "",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			sanitized, err := SanitizeUTF8(tt.input)
+			if err != nil {
+				t.Errorf("SanitizeUTF8 failed: %v", err)
+			}
+			if !utf8.ValidString(sanitized) {
+				t.Errorf("SanitizeUTF8 returned invalid UTF-8 string: %s, want %s", sanitized, tt.want)
+			}
+			if sanitized != tt.want {
+				t.Errorf("SanitizeUTF8 gave not correct output: %s, want %s", sanitized, tt.want)
+			}
+		})
+	}
+}

internal/metrics/prometheus/factory.go

@@ -129,8 +129,14 @@ func (f *Factory) Counter(options metrics.Options) metrics.Counter {
 		Help: help,
 	}
 	cv := f.cache.getOrMakeCounterVec(opts, labelNames)
+	labelValues := f.tagsAsLabelValues(labelNames, tags)
+	metric, err := cv.GetMetricWithLabelValues(labelValues...)
+	if err != nil {
+		return metrics.NullCounter
+	}
+
 	return &counter{
-		counter: cv.WithLabelValues(f.tagsAsLabelValues(labelNames, tags)...),
+		counter: metric,
 	}
 }
 
@@ -148,8 +154,13 @@ func (f *Factory) Gauge(options metrics.Options) metrics.Gauge {
 		Help: help,
 	}
 	gv := f.cache.getOrMakeGaugeVec(opts, labelNames)
+	labelValues := f.tagsAsLabelValues(labelNames, tags)
+	metric, err := gv.GetMetricWithLabelValues(labelValues...)
+	if err != nil {
+		return metrics.NullGauge
+	}
 	return &gauge{
-		gauge: gv.WithLabelValues(f.tagsAsLabelValues(labelNames, tags)...),
+		gauge: metric,
 	}
 }
 
@@ -169,8 +180,13 @@ func (f *Factory) Timer(options metrics.TimerOptions) metrics.Timer {
 		Buckets: buckets,
 	}
 	hv := f.cache.getOrMakeHistogramVec(opts, labelNames)
+	labelValues := f.tagsAsLabelValues(labelNames, tags)
+	metric, err := hv.GetMetricWithLabelValues(labelValues...)
+	if err != nil {
+		return metrics.NullTimer
+	}
 	return &timer{
-		histogram: hv.WithLabelValues(f.tagsAsLabelValues(labelNames, tags)...),
+		histogram: metric,
 	}
 }
 
@@ -198,8 +214,14 @@ func (f *Factory) Histogram(options metrics.HistogramOptions) metrics.Histogram
 		Buckets: buckets,
 	}
 	hv := f.cache.getOrMakeHistogramVec(opts, labelNames)
+	labelValues := f.tagsAsLabelValues(labelNames, tags)
+	metric, err := hv.GetMetricWithLabelValues(labelValues...)
+	if err != nil {
+		return metrics.NullHistogram
+	}
+
 	return &histogram{
-		histogram: hv.WithLabelValues(f.tagsAsLabelValues(labelNames, tags)...),
+		histogram: metric,
 	}
 }
 

internal/metrics/prometheus/factory_test.go

@@ -96,6 +96,18 @@ func TestCounterDefaultHelp(t *testing.T) {
 	assert.Equal(t, "rodriguez", snapshot[0].GetHelp())
 }
 
+func TestCounterNotValidLabel(t *testing.T) {
+	registry := prometheus.NewPedanticRegistry()
+	f1 := promMetrics.New(
+		promMetrics.WithRegisterer(registry),
+	)
+	c1 := f1.Counter(metrics.Options{
+		Name: "ilia",
+		Tags: map[string]string{"x": "label__3d\x85_this_will_panic-repro"},
+	})
+	assert.Equal(t, c1, metrics.NullCounter, "Expected NullCounter, got %v", c1)
+}
+
 func TestGauge(t *testing.T) {
 	registry := prometheus.NewPedanticRegistry()
 	f1 := promMetrics.New(promMetrics.WithRegisterer(registry))
@@ -153,6 +165,18 @@ func TestGaugeDefaultHelp(t *testing.T) {
 	assert.Equal(t, "rodriguez", snapshot[0].GetHelp())
 }
 
+func TestGaugeNotValidLabel(t *testing.T) {
+	registry := prometheus.NewPedanticRegistry()
+	f1 := promMetrics.New(
+		promMetrics.WithRegisterer(registry),
+	)
+	c1 := f1.Gauge(metrics.Options{
+		Name: "ilia",
+		Tags: map[string]string{"x": "label__3d\x85_this_will_panic-repro"},
+	})
+	assert.Equal(t, c1, metrics.NullGauge, "Expected NullGauge, got %v", c1)
+}
+
 func TestTimer(t *testing.T) {
 	registry := prometheus.NewPedanticRegistry()
 	f1 := promMetrics.New(promMetrics.WithRegisterer(registry))
@@ -232,6 +256,18 @@ func TestTimerDefaultHelp(t *testing.T) {
 	assert.Equal(t, "rodriguez", snapshot[0].GetHelp())
 }
 
+func TestTimerNotValidLabel(t *testing.T) {
+	registry := prometheus.NewPedanticRegistry()
+	f1 := promMetrics.New(
+		promMetrics.WithRegisterer(registry),
+	)
+	c1 := f1.Timer(metrics.TimerOptions{
+		Name: "ilia",
+		Tags: map[string]string{"x": "label__3d\x85_this_will_panic-repro"},
+	})
+	assert.Equal(t, c1, metrics.NullTimer, "Expected NullTimer, got %v", c1)
+}
+
 func TestTimerCustomBuckets(t *testing.T) {
 	registry := prometheus.NewPedanticRegistry()
 	f1 := promMetrics.New(promMetrics.WithRegisterer(registry), promMetrics.WithBuckets([]float64{1.5}))
@@ -374,6 +410,18 @@ func TestHistogramCustomBuckets(t *testing.T) {
 	assert.Len(t, m1.GetHistogram().GetBucket(), 1)
 }
 
+func TestHistogramNotValidLabel(t *testing.T) {
+	registry := prometheus.NewPedanticRegistry()
+	f1 := promMetrics.New(
+		promMetrics.WithRegisterer(registry),
+	)
+	c1 := f1.Histogram(metrics.HistogramOptions{
+		Name: "ilia",
+		Tags: map[string]string{"x": "label__3d\x85_this_will_panic-repro"},
+	})
+	assert.Equal(t, c1, metrics.NullHistogram, "Expected NullHistogram, got %v", c1)
+}
+
 func TestHistogramDefaultBuckets(t *testing.T) {
 	registry := prometheus.NewPedanticRegistry()
 	f1 := promMetrics.New(promMetrics.WithRegisterer(registry), promMetrics.WithBuckets([]float64{1.5}))