prometheus exporter convert instrumentation scope to otel_scope_info …

…metric (#3357)

* prometheus exporter convert instrumentation scope to otel_scope_info metric

Signed-off-by: Ziqi Zhao <zhaoziqi9146@gmail.com>

* fix for commits

Signed-off-by: Ziqi Zhao <zhaoziqi9146@gmail.com>

* fix for ci failed

Signed-off-by: Ziqi Zhao <zhaoziqi9146@gmail.com>

* add multi scopes test

Signed-off-by: Ziqi Zhao <zhaoziqi9146@gmail.com>

* fix ci failed

Signed-off-by: Ziqi Zhao <zhaoziqi9146@gmail.com>

Signed-off-by: Ziqi Zhao <zhaoziqi9146@gmail.com>

CHANGELOG.md

@@ -12,6 +12,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 - The `WithView` `Option` is added to the `go.opentelemetry.io/otel/sdk/metric` package.
    This option is used to configure the view(s) a `MeterProvider` will use for all `Reader`s that are registered with it. (#3387)
+- Add Instrumentation Scope and Version as info metric and label in Prometheus exporter.
+  This can be disabled using the `WithoutScopeInfo()` option added to that package.(#3273, #3357)
 
 ### Changed
 

exporters/prometheus/config.go

@@ -26,6 +26,7 @@ type config struct {
 	disableTargetInfo bool
 	withoutUnits      bool
 	aggregation       metric.AggregationSelector
+	disableScopeInfo  bool
 }
 
 // newConfig creates a validated config configured with options.
@@ -105,3 +106,13 @@ func WithoutUnits() Option {
 		return cfg
 	})
 }
+
+// WithoutScopeInfo configures the Exporter to not export the otel_scope_info metric.
+// If not specified, the Exporter will create a otel_scope_info metric containing
+// the metrics' Instrumentation Scope, and also add labels about Instrumentation Scope to all metric points.
+func WithoutScopeInfo() Option {
+	return optionFunc(func(cfg config) config {
+		cfg.disableScopeInfo = true
+		return cfg
+	})
+}

exporters/prometheus/exporter.go

@@ -28,6 +28,7 @@ import (
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/metric/unit"
+	"go.opentelemetry.io/otel/sdk/instrumentation"
 	"go.opentelemetry.io/otel/sdk/metric"
 	"go.opentelemetry.io/otel/sdk/metric/metricdata"
 	"go.opentelemetry.io/otel/sdk/resource"
@@ -36,8 +37,13 @@ import (
 const (
 	targetInfoMetricName  = "target_info"
 	targetInfoDescription = "Target metadata"
+
+	scopeInfoMetricName  = "otel_scope_info"
+	scopeInfoDescription = "Instrumentation Scope metadata"
 )
 
+var scopeInfoKeys = [2]string{"otel_scope_name", "otel_scope_version"}
+
 // Exporter is a Prometheus Exporter that embeds the OTel metric.Reader
 // interface for easy instantiation with a MeterProvider.
 type Exporter struct {
@@ -53,7 +59,9 @@ type collector struct {
 	disableTargetInfo    bool
 	withoutUnits         bool
 	targetInfo           prometheus.Metric
+	disableScopeInfo     bool
 	createTargetInfoOnce sync.Once
+	scopeInfos           map[instrumentation.Scope]prometheus.Metric
 }
 
 // prometheus counters MUST have a _total suffix:
@@ -73,6 +81,8 @@ func New(opts ...Option) (*Exporter, error) {
 		reader:            reader,
 		disableTargetInfo: cfg.disableTargetInfo,
 		withoutUnits:      cfg.withoutUnits,
+		disableScopeInfo:  cfg.disableScopeInfo,
+		scopeInfos:        make(map[instrumentation.Scope]prometheus.Metric),
 	}
 
 	if err := cfg.registerer.Register(collector); err != nil {
@@ -118,28 +128,46 @@ func (c *collector) Collect(ch chan<- prometheus.Metric) {
 	if !c.disableTargetInfo {
 		ch <- c.targetInfo
 	}
+
 	for _, scopeMetrics := range metrics.ScopeMetrics {
+		var keys, values [2]string
+
+		if !c.disableScopeInfo {
+			scopeInfo, ok := c.scopeInfos[scopeMetrics.Scope]
+			if !ok {
+				scopeInfo, err = createScopeInfoMetric(scopeMetrics.Scope)
+				if err != nil {
+					otel.Handle(err)
+				}
+				c.scopeInfos[scopeMetrics.Scope] = scopeInfo
+			}
+			ch <- scopeInfo
+			keys = scopeInfoKeys
+			values = [2]string{scopeMetrics.Scope.Name, scopeMetrics.Scope.Version}
+		}
+
 		for _, m := range scopeMetrics.Metrics {
 			switch v := m.Data.(type) {
 			case metricdata.Histogram:
-				addHistogramMetric(ch, v, m, c.getName(m))
+				addHistogramMetric(ch, v, m, keys, values, c.getName(m))
 			case metricdata.Sum[int64]:
-				addSumMetric(ch, v, m, c.getName(m))
+				addSumMetric(ch, v, m, keys, values, c.getName(m))
 			case metricdata.Sum[float64]:
-				addSumMetric(ch, v, m, c.getName(m))
+				addSumMetric(ch, v, m, keys, values, c.getName(m))
 			case metricdata.Gauge[int64]:
-				addGaugeMetric(ch, v, m, c.getName(m))
+				addGaugeMetric(ch, v, m, keys, values, c.getName(m))
 			case metricdata.Gauge[float64]:
-				addGaugeMetric(ch, v, m, c.getName(m))
+				addGaugeMetric(ch, v, m, keys, values, c.getName(m))
 			}
 		}
 	}
 }
 
-func addHistogramMetric(ch chan<- prometheus.Metric, histogram metricdata.Histogram, m metricdata.Metrics, name string) {
+func addHistogramMetric(ch chan<- prometheus.Metric, histogram metricdata.Histogram, m metricdata.Metrics, ks, vs [2]string, name string) {
 	// TODO(https://github.com/open-telemetry/opentelemetry-go/issues/3163): support exemplars
 	for _, dp := range histogram.DataPoints {
-		keys, values := getAttrs(dp.Attributes)
+		keys, values := getAttrs(dp.Attributes, ks, vs)
+
 		desc := prometheus.NewDesc(name, m.Description, keys, nil)
 		buckets := make(map[float64]uint64, len(dp.Bounds))
 
@@ -157,7 +185,7 @@ func addHistogramMetric(ch chan<- prometheus.Metric, histogram metricdata.Histog
 	}
 }
 
-func addSumMetric[N int64 | float64](ch chan<- prometheus.Metric, sum metricdata.Sum[N], m metricdata.Metrics, name string) {
+func addSumMetric[N int64 | float64](ch chan<- prometheus.Metric, sum metricdata.Sum[N], m metricdata.Metrics, ks, vs [2]string, name string) {
 	valueType := prometheus.CounterValue
 	if !sum.IsMonotonic {
 		valueType = prometheus.GaugeValue
@@ -167,7 +195,8 @@ func addSumMetric[N int64 | float64](ch chan<- prometheus.Metric, sum metricdata
 		name += counterSuffix
 	}
 	for _, dp := range sum.DataPoints {
-		keys, values := getAttrs(dp.Attributes)
+		keys, values := getAttrs(dp.Attributes, ks, vs)
+
 		desc := prometheus.NewDesc(name, m.Description, keys, nil)
 		m, err := prometheus.NewConstMetric(desc, valueType, float64(dp.Value), values...)
 		if err != nil {
@@ -178,9 +207,10 @@ func addSumMetric[N int64 | float64](ch chan<- prometheus.Metric, sum metricdata
 	}
 }
 
-func addGaugeMetric[N int64 | float64](ch chan<- prometheus.Metric, gauge metricdata.Gauge[N], m metricdata.Metrics, name string) {
+func addGaugeMetric[N int64 | float64](ch chan<- prometheus.Metric, gauge metricdata.Gauge[N], m metricdata.Metrics, ks, vs [2]string, name string) {
 	for _, dp := range gauge.DataPoints {
-		keys, values := getAttrs(dp.Attributes)
+		keys, values := getAttrs(dp.Attributes, ks, vs)
+
 		desc := prometheus.NewDesc(name, m.Description, keys, nil)
 		m, err := prometheus.NewConstMetric(desc, prometheus.GaugeValue, float64(dp.Value), values...)
 		if err != nil {
@@ -194,7 +224,7 @@ func addGaugeMetric[N int64 | float64](ch chan<- prometheus.Metric, gauge metric
 // getAttrs parses the attribute.Set to two lists of matching Prometheus-style
 // keys and values. It sanitizes invalid characters and handles duplicate keys
 // (due to sanitization) by sorting and concatenating the values following the spec.
-func getAttrs(attrs attribute.Set) ([]string, []string) {
+func getAttrs(attrs attribute.Set, ks, vs [2]string) ([]string, []string) {
 	keysMap := make(map[string][]string)
 	itr := attrs.Iter()
 	for itr.Next() {
@@ -217,15 +247,26 @@ func getAttrs(attrs attribute.Set) ([]string, []string) {
 		})
 		values = append(values, strings.Join(vals, ";"))
 	}
+
+	if ks[0] != "" {
+		keys = append(keys, ks[:]...)
+		values = append(values, vs[:]...)
+	}
 	return keys, values
 }
 
 func (c *collector) createInfoMetric(name, description string, res *resource.Resource) (prometheus.Metric, error) {
-	keys, values := getAttrs(*res.Set())
+	keys, values := getAttrs(*res.Set(), [2]string{}, [2]string{})
 	desc := prometheus.NewDesc(name, description, keys, nil)
 	return prometheus.NewConstMetric(desc, prometheus.GaugeValue, float64(1), values...)
 }
 
+func createScopeInfoMetric(scope instrumentation.Scope) (prometheus.Metric, error) {
+	keys := scopeInfoKeys[:]
+	desc := prometheus.NewDesc(scopeInfoMetricName, scopeInfoDescription, keys, nil)
+	return prometheus.NewConstMetric(desc, prometheus.GaugeValue, float64(1), scope.Name, scope.Version)
+}
+
 func sanitizeRune(r rune) rune {
 	if unicode.IsLetter(r) || unicode.IsDigit(r) || r == ':' || r == '_' {
 		return r

exporters/prometheus/exporter_test.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
 	"go.opentelemetry.io/otel/attribute"
@@ -221,6 +222,44 @@ func TestPrometheusExporter(t *testing.T) {
 				counter.Add(ctx, 9, attrs...)
 			},
 		},
+		{
+			name:         "without scope_info",
+			options:      []Option{WithoutScopeInfo()},
+			expectedFile: "testdata/without_scope_info.txt",
+			recordMetrics: func(ctx context.Context, meter otelmetric.Meter) {
+				attrs := []attribute.KeyValue{
+					attribute.Key("A").String("B"),
+					attribute.Key("C").String("D"),
+				}
+				gauge, err := meter.SyncInt64().UpDownCounter(
+					"bar",
+					instrument.WithDescription("a fun little gauge"),
+					instrument.WithUnit(unit.Dimensionless),
+				)
+				require.NoError(t, err)
+				gauge.Add(ctx, 2, attrs...)
+				gauge.Add(ctx, -1, attrs...)
+			},
+		},
+		{
+			name:         "without scope_info and target_info",
+			options:      []Option{WithoutScopeInfo(), WithoutTargetInfo()},
+			expectedFile: "testdata/without_scope_and_target_info.txt",
+			recordMetrics: func(ctx context.Context, meter otelmetric.Meter) {
+				attrs := []attribute.KeyValue{
+					attribute.Key("A").String("B"),
+					attribute.Key("C").String("D"),
+				}
+				counter, err := meter.SyncInt64().Counter(
+					"bar",
+					instrument.WithDescription("a fun little counter"),
+					instrument.WithUnit(unit.Bytes),
+				)
+				require.NoError(t, err)
+				counter.Add(ctx, 2, attrs...)
+				counter.Add(ctx, 1, attrs...)
+			},
+		},
 	}
 
 	for _, tc := range testCases {
@@ -263,7 +302,10 @@ func TestPrometheusExporter(t *testing.T) {
 				metric.WithReader(exporter),
 				metric.WithView(customBucketsView, defaultView),
 			)
-			meter := provider.Meter("testmeter")
+			meter := provider.Meter(
+				"testmeter",
+				otelmetric.WithInstrumentationVersion("v0.1.0"),
+			)
 
 			tc.recordMetrics(ctx, meter)
 
@@ -306,3 +348,48 @@ func TestSantitizeName(t *testing.T) {
 		require.Equalf(t, test.want, sanitizeName(test.input), "input: %q", test.input)
 	}
 }
+
+func TestMultiScopes(t *testing.T) {
+	ctx := context.Background()
+	registry := prometheus.NewRegistry()
+	exporter, err := New(WithRegisterer(registry))
+	require.NoError(t, err)
+
+	res, err := resource.New(ctx,
+		// always specify service.name because the default depends on the running OS
+		resource.WithAttributes(semconv.ServiceNameKey.String("prometheus_test")),
+		// Overwrite the semconv.TelemetrySDKVersionKey value so we don't need to update every version
+		resource.WithAttributes(semconv.TelemetrySDKVersionKey.String("latest")),
+	)
+	require.NoError(t, err)
+	res, err = resource.Merge(resource.Default(), res)
+	require.NoError(t, err)
+
+	provider := metric.NewMeterProvider(
+		metric.WithReader(exporter),
+		metric.WithResource(res),
+	)
+
+	fooCounter, err := provider.Meter("meterfoo", otelmetric.WithInstrumentationVersion("v0.1.0")).
+		SyncInt64().Counter(
+		"foo",
+		instrument.WithUnit(unit.Milliseconds),
+		instrument.WithDescription("meter foo counter"))
+	assert.NoError(t, err)
+	fooCounter.Add(ctx, 100, attribute.String("type", "foo"))
+
+	barCounter, err := provider.Meter("meterbar", otelmetric.WithInstrumentationVersion("v0.1.0")).
+		SyncInt64().Counter(
+		"bar",
+		instrument.WithUnit(unit.Milliseconds),
+		instrument.WithDescription("meter bar counter"))
+	assert.NoError(t, err)
+	barCounter.Add(ctx, 200, attribute.String("type", "bar"))
+
+	file, err := os.Open("testdata/multi_scopes.txt")
+	require.NoError(t, err)
+	t.Cleanup(func() { require.NoError(t, file.Close()) })
+
+	err = testutil.GatherAndCompare(registry, file)
+	require.NoError(t, err)
+}

exporters/prometheus/testdata/counter.txt

@@ -1,7 +1,10 @@
 # HELP foo_milliseconds_total a simple counter
 # TYPE foo_milliseconds_total counter
-foo_milliseconds_total{A="B",C="D",E="true",F="42"} 24.3
-foo_milliseconds_total{A="D",C="B",E="true",F="42"} 5
+foo_milliseconds_total{A="B",C="D",E="true",F="42",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 24.3
+foo_milliseconds_total{A="D",C="B",E="true",F="42",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 5
+# HELP otel_scope_info Instrumentation Scope metadata
+# TYPE otel_scope_info gauge
+otel_scope_info{otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 1
 # HELP target_info Target metadata
 # TYPE target_info gauge
 target_info{service_name="prometheus_test",telemetry_sdk_language="go",telemetry_sdk_name="opentelemetry",telemetry_sdk_version="latest"} 1

exporters/prometheus/testdata/custom_resource.txt

@@ -1,6 +1,9 @@
 # HELP foo_total a simple counter
 # TYPE foo_total counter
-foo_total{A="B",C="D",E="true",F="42"} 24.3
+foo_total{A="B",C="D",E="true",F="42",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 24.3
+# HELP otel_scope_info Instrumentation Scope metadata
+# TYPE otel_scope_info gauge
+otel_scope_info{otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 1
 # HELP target_info Target metadata
 # TYPE target_info gauge
 target_info{A="B",C="D",service_name="prometheus_test",telemetry_sdk_language="go",telemetry_sdk_name="opentelemetry",telemetry_sdk_version="latest"} 1

exporters/prometheus/testdata/empty_resource.txt

@@ -1,6 +1,9 @@
 # HELP foo_total a simple counter
 # TYPE foo_total counter
-foo_total{A="B",C="D",E="true",F="42"} 24.3
+foo_total{A="B",C="D",E="true",F="42",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 24.3
+# HELP otel_scope_info Instrumentation Scope metadata
+# TYPE otel_scope_info gauge
+otel_scope_info{otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 1
 # HELP target_info Target metadata
 # TYPE target_info gauge
 target_info 1

exporters/prometheus/testdata/gauge.txt

@@ -1,6 +1,9 @@
 # HELP bar_ratio a fun little gauge
 # TYPE bar_ratio gauge
-bar_ratio{A="B",C="D"} .75
+bar_ratio{A="B",C="D",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} .75
+# HELP otel_scope_info Instrumentation Scope metadata
+# TYPE otel_scope_info gauge
+otel_scope_info{otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 1
 # HELP target_info Target metadata
 # TYPE target_info gauge
 target_info{service_name="prometheus_test",telemetry_sdk_language="go",telemetry_sdk_name="opentelemetry",telemetry_sdk_version="latest"} 1

exporters/prometheus/testdata/histogram.txt

@@ -1,18 +1,21 @@
 # HELP histogram_baz_bytes a very nice histogram
 # TYPE histogram_baz_bytes histogram
-histogram_baz_bytes_bucket{A="B",C="D",le="0"} 0
-histogram_baz_bytes_bucket{A="B",C="D",le="5"} 0
-histogram_baz_bytes_bucket{A="B",C="D",le="10"} 1
-histogram_baz_bytes_bucket{A="B",C="D",le="25"} 2
-histogram_baz_bytes_bucket{A="B",C="D",le="50"} 2
-histogram_baz_bytes_bucket{A="B",C="D",le="75"} 2
-histogram_baz_bytes_bucket{A="B",C="D",le="100"} 2
-histogram_baz_bytes_bucket{A="B",C="D",le="250"} 4
-histogram_baz_bytes_bucket{A="B",C="D",le="500"} 4
-histogram_baz_bytes_bucket{A="B",C="D",le="1000"} 4
-histogram_baz_bytes_bucket{A="B",C="D",le="+Inf"} 4
-histogram_baz_bytes_sum{A="B",C="D"} 236
-histogram_baz_bytes_count{A="B",C="D"} 4
+histogram_baz_bytes_bucket{A="B",C="D",le="0",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 0
+histogram_baz_bytes_bucket{A="B",C="D",le="5",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 0
+histogram_baz_bytes_bucket{A="B",C="D",le="10",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 1
+histogram_baz_bytes_bucket{A="B",C="D",le="25",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 2
+histogram_baz_bytes_bucket{A="B",C="D",le="50",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 2
+histogram_baz_bytes_bucket{A="B",C="D",le="75",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 2
+histogram_baz_bytes_bucket{A="B",C="D",le="100",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 2
+histogram_baz_bytes_bucket{A="B",C="D",le="250",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 4
+histogram_baz_bytes_bucket{A="B",C="D",le="500",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 4
+histogram_baz_bytes_bucket{A="B",C="D",le="1000",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 4
+histogram_baz_bytes_bucket{A="B",C="D",le="+Inf",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 4
+histogram_baz_bytes_sum{A="B",C="D",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 236
+histogram_baz_bytes_count{A="B",C="D",otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 4
+# HELP otel_scope_info Instrumentation Scope metadata
+# TYPE otel_scope_info gauge
+otel_scope_info{otel_scope_name="testmeter",otel_scope_version="v0.1.0"} 1
 # HELP target_info Target metadata
 # TYPE target_info gauge
 target_info{service_name="prometheus_test",telemetry_sdk_language="go",telemetry_sdk_name="opentelemetry",telemetry_sdk_version="latest"} 1