Update module github.com/prometheus/common to v0.62.0 and fix tests (#6198)

Supersedes https://github.com/open-telemetry/opentelemetry-go/pull/6171

The update to prometheus/common changes the default escaping scheme to
NoEscaping. Use of underscores vs original UTF-8 is still determined by
content negotiation.

CHANGELOG.md

@@ -17,6 +17,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Add `EventName` and `SetEventName` to `Record` in `go.opentelemetry.io/otel/sdk/log`. (#6193)
 - Add `EventName` to `RecordFactory` in `go.opentelemetry.io/otel/sdk/log/logtest`. (#6193)
 
+### Changed
+
+- Update `github.com/prometheus/common` to v0.62.0., which changes the `NameValidationScheme` to `NoEscaping`. This allows metrics names to keep original delimiters (e.g. `.`), rather than replacing with underscores. This is controlled by the `Content-Type` header, or can be reverted by setting `NameValidationScheme` to `LegacyValidation` in `github.com/prometheus/common/model`. (#6198)
+
 <!-- Released section -->
 <!-- Don't change this section unless doing release -->
 

exporters/prometheus/config_test.go

@@ -133,7 +133,7 @@ func TestNewConfig(t *testing.T) {
 			},
 			wantConfig: config{
 				registerer: prometheus.DefaultRegisterer,
-				namespace:  "test_",
+				namespace:  "test/_",
 			},
 		},
 	}

exporters/prometheus/exporter.go

@@ -96,7 +96,7 @@ type collector struct {
 
 // prometheus counters MUST have a _total suffix by default:
 // https://github.com/open-telemetry/opentelemetry-specification/blob/v1.20.0/specification/compatibility/prometheus_and_openmetrics.md
-const counterSuffix = "_total"
+const counterSuffix = "total"
 
 // New returns a Prometheus Exporter.
 func New(opts ...Option) (*Exporter, error) {
@@ -368,38 +368,38 @@ func createScopeInfoMetric(scope instrumentation.Scope) (prometheus.Metric, erro
 
 var unitSuffixes = map[string]string{
 	// Time
-	"d":   "_days",
+	"d":   "days",
-	"h":   "_hours",
+	"h":   "hours",
-	"min": "_minutes",
+	"min": "minutes",
-	"s":   "_seconds",
+	"s":   "seconds",
-	"ms":  "_milliseconds",
+	"ms":  "milliseconds",
-	"us":  "_microseconds",
+	"us":  "microseconds",
-	"ns":  "_nanoseconds",
+	"ns":  "nanoseconds",
 
 	// Bytes
-	"By":   "_bytes",
+	"By":   "bytes",
-	"KiBy": "_kibibytes",
+	"KiBy": "kibibytes",
-	"MiBy": "_mebibytes",
+	"MiBy": "mebibytes",
-	"GiBy": "_gibibytes",
+	"GiBy": "gibibytes",
-	"TiBy": "_tibibytes",
+	"TiBy": "tibibytes",
-	"KBy":  "_kilobytes",
+	"KBy":  "kilobytes",
-	"MBy":  "_megabytes",
+	"MBy":  "megabytes",
-	"GBy":  "_gigabytes",
+	"GBy":  "gigabytes",
-	"TBy":  "_terabytes",
+	"TBy":  "terabytes",
 
 	// SI
-	"m": "_meters",
+	"m": "meters",
-	"V": "_volts",
+	"V": "volts",
-	"A": "_amperes",
+	"A": "amperes",
-	"J": "_joules",
+	"J": "joules",
-	"W": "_watts",
+	"W": "watts",
-	"g": "_grams",
+	"g": "grams",
 
 	// Misc
-	"Cel": "_celsius",
+	"Cel": "celsius",
-	"Hz":  "_hertz",
+	"Hz":  "hertz",
-	"1":   "_ratio",
+	"1":   "ratio",
-	"%":   "_percent",
+	"%":   "percent",
 }
 
 // getName returns the sanitized name, prefixed with the namespace and suffixed with unit.
@@ -414,19 +414,31 @@ func (c *collector) getName(m metricdata.Metrics, typ *dto.MetricType) string {
 		// Remove the _total suffix here, as we will re-add the total suffix
 		// later, and it needs to come after the unit suffix.
 		name = strings.TrimSuffix(name, counterSuffix)
+		// If the last character is an underscore, or would be converted to an underscore, trim it from the name.
+		// an underscore will be added back in later.
+		if convertsToUnderscore(rune(name[len(name)-1])) {
+			name = name[:len(name)-1]
+		}
 	}
 	if c.namespace != "" {
 		name = c.namespace + name
 	}
 	if suffix, ok := unitSuffixes[m.Unit]; ok && !c.withoutUnits && !strings.HasSuffix(name, suffix) {
-		name += suffix
+		name += "_" + suffix
 	}
 	if addCounterSuffix {
-		name += counterSuffix
+		name += "_" + counterSuffix
 	}
 	return name
 }
 
+// convertsToUnderscore returns true if the character would be converted to an
+// underscore when the escaping scheme is underscore escaping. This is meant to
+// capture any character that should be considered a "delimiter".
+func convertsToUnderscore(b rune) bool {
+	return !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == ':' || (b >= '0' && b <= '9'))
+}
+
 func (c *collector) metricType(m metricdata.Metrics) *dto.MetricType {
 	switch v := m.Data.(type) {
 	case metricdata.Histogram[int64], metricdata.Histogram[float64]:

exporters/prometheus/exporter_test.go

@@ -35,7 +35,7 @@ func TestPrometheusExporter(t *testing.T) {
 		recordMetrics       func(ctx context.Context, meter otelmetric.Meter)
 		options             []Option
 		expectedFile        string
-		enableUTF8          bool
+		disableUTF8         bool
 	}{
 		{
 			name:         "counter",
@@ -195,6 +195,7 @@ func TestPrometheusExporter(t *testing.T) {
 		{
 			name:         "sanitized attributes to labels",
 			expectedFile: "testdata/sanitized_labels.txt",
+			disableUTF8:  true,
 			options:      []Option{WithoutUnits()},
 			recordMetrics: func(ctx context.Context, meter otelmetric.Meter) {
 				opt := otelmetric.WithAttributes(
@@ -404,7 +405,6 @@ func TestPrometheusExporter(t *testing.T) {
 		{
 			name:         "counter utf-8",
 			expectedFile: "testdata/counter_utf8.txt",
-			enableUTF8:   true,
 			recordMetrics: func(ctx context.Context, meter otelmetric.Meter) {
 				opt := otelmetric.WithAttributes(
 					attribute.Key("A.G").String("B"),
@@ -471,11 +471,11 @@ func TestPrometheusExporter(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			if tc.enableUTF8 {
+			if tc.disableUTF8 {
-				model.NameValidationScheme = model.UTF8Validation
+				model.NameValidationScheme = model.LegacyValidation
 				defer func() {
 					// Reset to defaults
-					model.NameValidationScheme = model.LegacyValidation
+					model.NameValidationScheme = model.UTF8Validation
 				}()
 			}
 			ctx := context.Background()

exporters/prometheus/go.mod

@@ -5,7 +5,7 @@ go 1.22.0
 require (
 	github.com/prometheus/client_golang v1.20.5
 	github.com/prometheus/client_model v0.6.1
-	github.com/prometheus/common v0.61.0
+	github.com/prometheus/common v0.62.0
 	github.com/stretchr/testify v1.10.0
 	go.opentelemetry.io/otel v1.34.0
 	go.opentelemetry.io/otel/metric v1.34.0

exporters/prometheus/go.sum

@@ -29,8 +29,8 @@ github.com/prometheus/client_golang v1.20.5 h1:cxppBPuYhUnsO6yo/aoRol4L7q7UFfdm+
 github.com/prometheus/client_golang v1.20.5/go.mod h1:PIEt8X02hGcP8JWbeHyeZ53Y/jReSnHgO035n//V5WE=
 github.com/prometheus/client_model v0.6.1 h1:ZKSh/rekM+n3CeS952MLRAdFwIKqeY8b62p8ais2e9E=
 github.com/prometheus/client_model v0.6.1/go.mod h1:OrxVMOVHjw3lKMa8+x6HeMGkHMQyHDk9E3jmP2AmGiY=
-github.com/prometheus/common v0.61.0 h1:3gv/GThfX0cV2lpO7gkTUwZru38mxevy90Bj8YFSRQQ=
+github.com/prometheus/common v0.62.0 h1:xasJaQlnWAeyHdUBeGjXmutelfJHWMRr+Fg4QszZ2Io=
-github.com/prometheus/common v0.61.0/go.mod h1:zr29OCN/2BsJRaFwG8QOBr41D6kkchKbpeNH7pAjb/s=
+github.com/prometheus/common v0.62.0/go.mod h1:vyBcEuLSvWos9B1+CyL7JZ2up+uFzXhkqml0W5zIY1I=
 github.com/prometheus/procfs v0.15.1 h1:YagwOFzUgYfKKHX6Dr+sHT7km/hxC76UB0learggepc=
 github.com/prometheus/procfs v0.15.1/go.mod h1:fB45yRUv8NstnjriLhBQLuOUt+WW4BsoGhij/e3PBqk=
 github.com/rogpeppe/go-internal v1.13.1 h1:KvO1DLK/DRN07sQ1LQKScxyZJuNnedQ5/wKSR38lUII=

internal/tools/go.mod

@@ -147,7 +147,7 @@ require (
 	github.com/polyfloyd/go-errorlint v1.7.0 // indirect
 	github.com/prometheus/client_golang v1.20.5 // indirect
 	github.com/prometheus/client_model v0.6.1 // indirect
-	github.com/prometheus/common v0.61.0 // indirect
+	github.com/prometheus/common v0.62.0 // indirect
 	github.com/prometheus/procfs v0.15.1 // indirect
 	github.com/quasilyte/go-ruleguard v0.4.3-0.20240823090925-0fe6f58b47b1 // indirect
 	github.com/quasilyte/go-ruleguard/dsl v0.3.22 // indirect

internal/tools/go.sum

@@ -347,8 +347,8 @@ github.com/prometheus/client_golang v1.20.5 h1:cxppBPuYhUnsO6yo/aoRol4L7q7UFfdm+
 github.com/prometheus/client_golang v1.20.5/go.mod h1:PIEt8X02hGcP8JWbeHyeZ53Y/jReSnHgO035n//V5WE=
 github.com/prometheus/client_model v0.6.1 h1:ZKSh/rekM+n3CeS952MLRAdFwIKqeY8b62p8ais2e9E=
 github.com/prometheus/client_model v0.6.1/go.mod h1:OrxVMOVHjw3lKMa8+x6HeMGkHMQyHDk9E3jmP2AmGiY=
-github.com/prometheus/common v0.61.0 h1:3gv/GThfX0cV2lpO7gkTUwZru38mxevy90Bj8YFSRQQ=
+github.com/prometheus/common v0.62.0 h1:xasJaQlnWAeyHdUBeGjXmutelfJHWMRr+Fg4QszZ2Io=
-github.com/prometheus/common v0.61.0/go.mod h1:zr29OCN/2BsJRaFwG8QOBr41D6kkchKbpeNH7pAjb/s=
+github.com/prometheus/common v0.62.0/go.mod h1:vyBcEuLSvWos9B1+CyL7JZ2up+uFzXhkqml0W5zIY1I=
 github.com/prometheus/procfs v0.15.1 h1:YagwOFzUgYfKKHX6Dr+sHT7km/hxC76UB0learggepc=
 github.com/prometheus/procfs v0.15.1/go.mod h1:fB45yRUv8NstnjriLhBQLuOUt+WW4BsoGhij/e3PBqk=
 github.com/quasilyte/go-ruleguard v0.4.3-0.20240823090925-0fe6f58b47b1 h1:+Wl/0aFp0hpuHM3H//KMft64WQ1yX9LdJY64Qm/gFCo=