go.opentelemetry.io/proto/otlp v1.9.0: v1.Gauge

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify go.opentelemetry.io/proto/otlp/metrics/v1.Gauge in pkg:golang/go.opentelemetry.io/proto/otlp@v1.9.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/proto/otlp@v1.9.0
Demonstrate these symbols/APIs:
  - go.opentelemetry.io/proto/otlp/metrics/v1.Gauge

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:36a925b22ffb2588dd3bcd714dec361d4bb787f60c64d267f45c22879aee26f7","contract":["Gauge GetDataPoints returns empty slice when initialized without data points","Gauge holds NumberDataPoints recording floating point measurements with timestamps","Gauge holds NumberDataPoints recording integer measurements with key-value attributes","Metric GetData returns Metric_Gauge wrapper and GetGauge provides underlying Gauge","Metric GetGauge returns nil when metric contains non-gauge data","Gauge Reset clears all recorded data points","Gauge marshals and unmarshals with protobuf binary wire format preserving data points"],"goal":"verify go.opentelemetry.io/proto/otlp/metrics/v1.Gauge in pkg:golang/go.opentelemetry.io/proto/otlp@v1.9.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/proto/otlp@v1.9.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/proto/otlp/metrics/v1.Gauge"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.opentelemetry.io/proto/otlp@v1.9.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/proto/otlp@v1.9.0","symbols":["go.opentelemetry.io/proto/otlp/metrics/v1.Gauge"],"verifierAdapter":"golang@1"}

module sample

go 1.23.0

require (
	go.opentelemetry.io/proto/otlp v1.9.0
	google.golang.org/protobuf v1.36.10
)

github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
go.opentelemetry.io/proto/otlp v1.9.0 h1:l706jCMITVouPOqEnii2fIAuO3IVGBRPV5ICjceRb/A=
go.opentelemetry.io/proto/otlp v1.9.0/go.mod h1:xE+Cx5E/eEHw+ISFkwPLwCZefwVjY+pqKg1qcK03+/4=
google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=

package main

import (
	"fmt"
	"time"

	v1 "go.opentelemetry.io/proto/otlp/common/v1"
	metricspb "go.opentelemetry.io/proto/otlp/metrics/v1"
)

func main() {
	// Create a NumberDataPoint representing a gauge observation
	point := &metricspb.NumberDataPoint{
		TimeUnixNano: uint64(time.Now().UnixNano()),
		Value: &metricspb.NumberDataPoint_AsDouble{
			AsDouble: 42.5,
		},
		Attributes: []*v1.KeyValue{
			{
				Key: "device_id",
				Value: &v1.AnyValue{
					Value: &v1.AnyValue_StringValue{StringValue: "sensor-01"},
				},
			},
		},
	}

	// Construct Gauge with data points
	gauge := &metricspb.Gauge{
		DataPoints: []*metricspb.NumberDataPoint{point},
	}

	// Wrap Gauge in Metric
	metric := &metricspb.Metric{
		Name:        "temperature_celsius",
		Description: "Current temperature reading in Celsius",
		Unit:        "Cel",
		Data: &metricspb.Metric_Gauge{
			Gauge: gauge,
		},
	}

	fmt.Printf("Metric: %s, DataPoints count: %d\n", metric.GetName(), len(metric.GetGauge().GetDataPoints()))
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/proto/otlp/metrics/v1.Gauge in pkg:golang/go.opentelemetry.io/proto/otlp@v1.9.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/proto/otlp@v1.9.0"
  ],
  "symbols": [
    "go.opentelemetry.io/proto/otlp/metrics/v1.Gauge"
  ]
}

package main

import (
	"fmt"
	"os"

	v1 "go.opentelemetry.io/proto/otlp/common/v1"
	metricspb "go.opentelemetry.io/proto/otlp/metrics/v1"
	"google.golang.org/protobuf/proto"
)

func main() {
	// 1. Gauge GetDataPoints returns empty slice when initialized without data points
	emptyGauge := &metricspb.Gauge{}
	if pts := emptyGauge.GetDataPoints(); len(pts) != 0 {
		fmt.Fprintf(os.Stderr, "assertion 1 failed: expected 0 points, got %d\n", len(pts))
		os.Exit(1)
	}

	// 2. Gauge holds NumberDataPoints recording floating point measurements with timestamps
	dpDouble := &metricspb.NumberDataPoint{
		TimeUnixNano: 1725540000000000000,
		Value: &metricspb.NumberDataPoint_AsDouble{
			AsDouble: 73.5,
		},
	}
	gaugeWithDouble := &metricspb.Gauge{
		DataPoints: []*metricspb.NumberDataPoint{dpDouble},
	}
	if len(gaugeWithDouble.GetDataPoints()) != 1 {
		fmt.Fprintf(os.Stderr, "assertion 2 failed: expected 1 point\n")
		os.Exit(1)
	}
	if gaugeWithDouble.GetDataPoints()[0].GetAsDouble() != 73.5 {
		fmt.Fprintf(os.Stderr, "assertion 2 failed: expected 73.5, got %f\n", gaugeWithDouble.GetDataPoints()[0].GetAsDouble())
		os.Exit(1)
	}
	if gaugeWithDouble.GetDataPoints()[0].GetTimeUnixNano() != 1725540000000000000 {
		fmt.Fprintf(os.Stderr, "assertion 2 failed: timestamp mismatch\n")
		os.Exit(1)
	}

	// 3. Gauge holds NumberDataPoints recording integer measurements with key-value attributes
	dpInt := &metricspb.NumberDataPoint{
		TimeUnixNano: 1725540001000000000,
		Value: &metricspb.NumberDataPoint_AsInt{
			AsInt: 42,
		},
		Attributes: []*v1.KeyValue{
			{
				Key: "host",
				Value: &v1.AnyValue{
					Value: &v1.AnyValue_StringValue{StringValue: "server-01"},
				},
			},
		},
	}
	gaugeWithInt := &metricspb.Gauge{
		DataPoints: []*metricspb.NumberDataPoint{dpInt},
	}
	if gaugeWithInt.GetDataPoints()[0].GetAsInt() != 42 {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: expected int 42, got %d\n", gaugeWithInt.GetDataPoints()[0].GetAsInt())
		os.Exit(1)
	}
	if len(gaugeWithInt.GetDataPoints()[0].GetAttributes()) != 1 || gaugeWithInt.GetDataPoints()[0].GetAttributes()[0].GetKey() != "host" {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: attribute mismatch\n")
		os.Exit(1)
	}

	// 4. Metric GetData returns Metric_Gauge wrapper and GetGauge provides underlying Gauge
	metric := &metricspb.Metric{
		Name:        "memory_usage_bytes",
		Description: "Current memory usage in bytes",
		Unit:        "By",
		Data: &metricspb.Metric_Gauge{
			Gauge: gaugeWithDouble,
		},
	}
	if metric.GetGauge() == nil {
		fmt.Fprintf(os.Stderr, "assertion 4 failed: Metric.GetGauge returned nil\n")
		os.Exit(1)
	}
	if metric.GetGauge().GetDataPoints()[0].GetAsDouble() != 73.5 {
		fmt.Fprintf(os.Stderr, "assertion 4 failed: metric gauge data point mismatch\n")
		os.Exit(1)
	}
	if _, ok := metric.GetData().(*metricspb.Metric_Gauge); !ok {
		fmt.Fprintf(os.Stderr, "assertion 4 failed: Metric.GetData is not *Metric_Gauge\n")
		os.Exit(1)
	}

	// 5. Metric GetGauge returns nil when metric contains non-gauge data
	sumMetric := &metricspb.Metric{
		Name: "requests_total",
		Data: &metricspb.Metric_Sum{
			Sum: &metricspb.Sum{},
		},
	}
	if sumMetric.GetGauge() != nil {
		fmt.Fprintf(os.Stderr, "assertion 5 failed: Metric.GetGauge should return nil for Sum data\n")
		os.Exit(1)
	}

	// 6. Gauge Reset clears all recorded data points
	gaugeToReset := &metricspb.Gauge{
		DataPoints: []*metricspb.NumberDataPoint{dpDouble, dpInt},
	}
	gaugeToReset.Reset()
	if len(gaugeToReset.GetDataPoints()) != 0 {
		fmt.Fprintf(os.Stderr, "assertion 6 failed: Reset did not clear data points\n")
		os.Exit(1)
	}

	// 7. Gauge marshals and unmarshals with protobuf binary wire format preserving data points
	origGauge := &metricspb.Gauge{
		DataPoints: []*metricspb.NumberDataPoint{dpDouble, dpInt},
	}
	data, err := proto.Marshal(origGauge)
	if err != nil {
		fmt.Fprintf(os.Stderr, "assertion 7 failed: proto.Marshal error: %v\n", err)
		os.Exit(1)
	}
	deserializedGauge := &metricspb.Gauge{}
	if err := proto.Unmarshal(data, deserializedGauge); err != nil {
		fmt.Fprintf(os.Stderr, "assertion 7 failed: proto.Unmarshal error: %v\n", err)
		os.Exit(1)
	}
	if len(deserializedGauge.GetDataPoints()) != 2 {
		fmt.Fprintf(os.Stderr, "assertion 7 failed: expected 2 points, got %d\n", len(deserializedGauge.GetDataPoints()))
		os.Exit(1)
	}
	if deserializedGauge.GetDataPoints()[0].GetAsDouble() != 73.5 {
		fmt.Fprintf(os.Stderr, "assertion 7 failed: double value mismatch after roundtrip\n")
		os.Exit(1)
	}
	if deserializedGauge.GetDataPoints()[1].GetAsInt() != 42 {
		fmt.Fprintf(os.Stderr, "assertion 7 failed: int value mismatch after roundtrip\n")
		os.Exit(1)
	}

	fmt.Println("All contract assertions passed.")
}