Add histogram to telemetrygen (open-telemetry#36322)

shivanthzen · mx-psi · zeck-ops · commit ec6c212775cd · 2025-04-22T09:37:52.000-05:00
#### Description Generates simple histograms using telemetrygen  #### Link to tracking issue Fixes  #### Testing Test with a local otel collector with debug output ``` bin/telemetrygen metrics --metrics 5 --otlp-http --otlp-endpoint "localhost:4318" --metric-type Histogram --otlp-insecure ``` Output from debug Exporter: ``` Resource SchemaURL: https://opentelemetry.io/schemas/1.13.0 ScopeMetrics #0 ScopeMetrics SchemaURL: InstrumentationScope Metric #0 Descriptor: -> Name: gen -> Description: -> Unit: -> DataType: Histogram -> AggregationTemporality: Cumulative HistogramDataPoints #0 StartTimestamp: 2024-11-13 16:22:50.633365 +0000 UTC Timestamp: 2024-11-13 16:22:51.633367 +0000 UTC Count: 0 Sum: 0.000000 ExplicitBounds #0: 0.000000 ExplicitBounds open-telemetry#1: 1.000000 ExplicitBounds open-telemetry#2: 2.000000 ExplicitBounds open-telemetry#3: 3.000000 ExplicitBounds open-telemetry#4: 4.000000 Buckets #0, Count: 0 Buckets open-telemetry#1, Count: 0 Buckets open-telemetry#2, Count: 0 Buckets open-telemetry#3, Count: 0 Buckets open-telemetry#4, Count: 0 ResourceMetrics open-telemetry#1 Resource SchemaURL: https://opentelemetry.io/schemas/1.13.0 ScopeMetrics #0 ScopeMetrics SchemaURL: InstrumentationScope Metric #0 Descriptor: -> Name: gen -> Description: -> Unit: -> DataType: Histogram -> AggregationTemporality: Cumulative HistogramDataPoints #0 StartTimestamp: 2024-11-13 16:22:50.639942 +0000 UTC Timestamp: 2024-11-13 16:22:51.639942 +0000 UTC Count: 1 Sum: 1.000000 ExplicitBounds #0: 0.000000 ExplicitBounds open-telemetry#1: 1.000000 ExplicitBounds open-telemetry#2: 2.000000 ExplicitBounds open-telemetry#3: 3.000000 ExplicitBounds open-telemetry#4: 4.000000 Buckets #0, Count: 0 Buckets open-telemetry#1, Count: 1 Buckets open-telemetry#2, Count: 0 Buckets open-telemetry#3, Count: 0 Buckets open-telemetry#4, Count: 0 ResourceMetrics open-telemetry#2 Resource SchemaURL: https://opentelemetry.io/schemas/1.13.0 ScopeMetrics #0 ScopeMetrics SchemaURL: InstrumentationScope Metric #0 Descriptor: -> Name: gen -> Description: -> Unit: -> DataType: Histogram -> AggregationTemporality: Cumulative HistogramDataPoints #0 StartTimestamp: 2024-11-13 16:22:50.6404 +0000 UTC Timestamp: 2024-11-13 16:22:51.640401 +0000 UTC Count: 2 Sum: 4.000000 ExplicitBounds #0: 0.000000 ExplicitBounds open-telemetry#1: 1.000000 ExplicitBounds open-telemetry#2: 2.000000 ExplicitBounds open-telemetry#3: 3.000000 ExplicitBounds open-telemetry#4: 4.000000 Buckets #0, Count: 0 Buckets open-telemetry#1, Count: 1 Buckets open-telemetry#2, Count: 0 Buckets open-telemetry#3, Count: 1 Buckets open-telemetry#4, Count: 0 ResourceMetrics open-telemetry#3 Resource SchemaURL: https://opentelemetry.io/schemas/1.13.0 ScopeMetrics #0 ScopeMetrics SchemaURL: InstrumentationScope Metric #0 Descriptor: -> Name: gen -> Description: -> Unit: -> DataType: Histogram -> AggregationTemporality: Cumulative HistogramDataPoints #0 StartTimestamp: 2024-11-13 16:22:50.640729 +0000 UTC Timestamp: 2024-11-13 16:22:51.640729 +0000 UTC Count: 3 Sum: 3.000000 ExplicitBounds #0: 0.000000 ExplicitBounds open-telemetry#1: 1.000000 ExplicitBounds open-telemetry#2: 2.000000 ExplicitBounds open-telemetry#3: 3.000000 ExplicitBounds open-telemetry#4: 4.000000 Buckets #0, Count: 1 Buckets open-telemetry#1, Count: 1 Buckets open-telemetry#2, Count: 1 Buckets open-telemetry#3, Count: 0 Buckets open-telemetry#4, Count: 0 ResourceMetrics open-telemetry#4 Resource SchemaURL: https://opentelemetry.io/schemas/1.13.0 ScopeMetrics #0 ScopeMetrics SchemaURL: InstrumentationScope Metric #0 Descriptor: -> Name: gen -> Description: -> Unit: -> DataType: Histogram -> AggregationTemporality: Cumulative HistogramDataPoints #0 StartTimestamp: 2024-11-13 16:22:50.641073 +0000 UTC Timestamp: 2024-11-13 16:22:51.641073 +0000 UTC Count: 4 Sum: 12.000000 ExplicitBounds #0: 0.000000 ExplicitBounds open-telemetry#1: 1.000000 ExplicitBounds open-telemetry#2: 2.000000 ExplicitBounds open-telemetry#3: 3.000000 ExplicitBounds open-telemetry#4: 4.000000 Buckets #0, Count: 0 Buckets open-telemetry#1, Count: 0 Buckets open-telemetry#2, Count: 1 Buckets open-telemetry#3, Count: 2 Buckets open-telemetry#4, Count: 1 {"kind": "exporter", "data_type": "metrics", "name": "debug"} ```  #### Documentation  --------- Co-authored-by: Pablo Baeyens <pbaeyens31+github@gmail.com>
diff --git a/.chloggen/telemetrygen.yaml b/.chloggen/telemetrygen.yaml
@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: cmd/telemetrygen
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Introduce support for generating histograms in telemetrygen
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [36322]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]
diff --git a/cmd/telemetrygen/internal/metrics/metrics_types.go b/cmd/telemetrygen/internal/metrics/metrics_types.go
@@ -10,8 +10,9 @@ import (
 type metricType string
 
 const (
-	metricTypeGauge = "Gauge"
-	metricTypeSum   = "Sum"
+	metricTypeGauge     = "Gauge"
+	metricTypeSum       = "Sum"
+	metricTypeHistogram = "Histogram"
 )
 
 // String is used both by fmt.Print and by Cobra in help text
@@ -22,11 +23,11 @@ func (e *metricType) String() string {
 // Set must have pointer receiver so it doesn't change the value of a copy
 func (e *metricType) Set(v string) error {
 	switch v {
-	case "Gauge", "Sum":
+	case "Gauge", "Sum", "Histogram":
 		*e = metricType(v)
 		return nil
 	default:
-		return errors.New(`must be one of "Gauge" or "Sum"`)
+		return errors.New(`must be one of "Gauge", "Sum", "Histogram"`)
 	}
 }
 
diff --git a/cmd/telemetrygen/internal/metrics/worker.go b/cmd/telemetrygen/internal/metrics/worker.go
@@ -30,6 +30,52 @@ type worker struct {
 	index          int                          // worker index
 }
 
+var histogramBucketSamples = []struct {
+	bucketCounts []uint64
+	sum          int64
+}{
+	{
+		[]uint64{0, 0, 1, 0, 0, 0, 3, 4, 1, 1, 0, 0, 0, 0, 0},
+		3940,
+	},
+	{
+		[]uint64{0, 0, 0, 0, 0, 0, 2, 4, 4, 0, 0, 0, 0, 0, 0},
+		4455,
+	},
+	{
+		[]uint64{0, 0, 0, 0, 0, 0, 1, 4, 3, 2, 0, 0, 0, 0, 0},
+		5337,
+	},
+	{
+		[]uint64{0, 0, 1, 0, 1, 0, 2, 2, 1, 3, 0, 0, 0, 0, 0},
+		4477,
+	},
+	{
+		[]uint64{0, 0, 0, 0, 0, 1, 3, 2, 2, 2, 0, 0, 0, 0, 0},
+		4670,
+	},
+	{
+		[]uint64{0, 0, 0, 1, 1, 0, 1, 1, 1, 5, 0, 0, 0, 0, 0},
+		5670,
+	},
+	{
+		[]uint64{0, 0, 0, 0, 0, 2, 1, 1, 4, 2, 0, 0, 0, 0, 0},
+		5091,
+	},
+	{
+		[]uint64{0, 0, 2, 0, 0, 0, 2, 4, 1, 1, 0, 0, 0, 0, 0},
+		3420,
+	},
+	{
+		[]uint64{0, 0, 0, 0, 0, 0, 1, 3, 2, 4, 0, 0, 0, 0, 0},
+		5917,
+	},
+	{
+		[]uint64{0, 0, 1, 0, 1, 0, 0, 4, 4, 0, 0, 0, 0, 0, 0},
+		3988,
+	},
+}
+
 func (w worker) simulateMetrics(res *resource.Resource, exporterFunc func() (sdkmetric.Exporter, error), signalAttrs []attribute.KeyValue) {
 	limiter := rate.NewLimiter(w.limitPerSecond, 1)
 
@@ -82,6 +128,29 @@ func (w worker) simulateMetrics(res *resource.Resource, exporterFunc func() (sdk
 					},
 				},
 			})
+		case metricTypeHistogram:
+			iteration := uint64(i) % 10
+			sum := histogramBucketSamples[iteration].sum
+			bucketCounts := histogramBucketSamples[iteration].bucketCounts
+			metrics = append(metrics, metricdata.Metrics{
+				Name: w.metricName,
+				Data: metricdata.Histogram[int64]{
+					Temporality: metricdata.CumulativeTemporality,
+					DataPoints: []metricdata.HistogramDataPoint[int64]{
+						{
+							StartTime:  time.Now().Add(-1 * time.Second),
+							Time:       time.Now(),
+							Attributes: attribute.NewSet(signalAttrs...),
+							Exemplars:  w.exemplars,
+							Count:      iteration,
+							Sum:        sum,
+							// Bounds from https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/sdk.md#explicit-bucket-histogram-aggregation
+							Bounds:       []float64{0, 5, 10, 25, 50, 75, 100, 250, 500, 750, 1000, 2500, 5000, 7500, 10000},
+							BucketCounts: bucketCounts,
+						},
+					},
+				},
+			})
 		default:
 			w.logger.Fatal("unknown metric type")
 		}
