go.opentelemetry.io/otel/sdk/metric v1.44.0: InstrumentKindObservableCounter

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/otel/sdk/metric.InstrumentKindObservableCounter in pkg:golang/go.opentelemetry.io/otel/sdk/metric@v1.44.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/sdk/metric@v1.44.0
Demonstrate these symbols/APIs:
  - go.opentelemetry.io/otel/sdk/metric.InstrumentKindObservableCounter

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:sha256:0e11075a0a24bd27ccf59335b0ecd3c69d58932e2e3435afcb78b13be9c6342b","contract":["InstrumentKindObservableCounter is an InstrumentKind with value 4 and string representation \"ObservableCounter\".","InstrumentKindObservableCounter matches instruments in a View created via NewView.","NewView with InstrumentKindObservableCounter criteria does not match other instrument kinds like Counter or ObservableGauge.","A MeterProvider configured with an InstrumentKindObservableCounter View correctly modifies observable counter streams.","A custom View function can inspect Instrument.Kind against InstrumentKindObservableCounter to customize stream properties."],"goal":"verify go.opentelemetry.io/otel/sdk/metric.InstrumentKindObservableCounter in pkg:golang/go.opentelemetry.io/otel/sdk/metric@v1.44.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/sdk/metric@v1.44.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/otel/sdk/metric.InstrumentKindObservableCounter"]},"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/otel/sdk/metric@v1.44.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/sdk/metric@v1.44.0","symbols":["go.opentelemetry.io/otel/sdk/metric.InstrumentKindObservableCounter"],"verifierAdapter":"golang@1"}

module sample

go 1.25.0

require go.opentelemetry.io/otel/sdk/metric v1.44.0

require (
	github.com/cespare/xxhash/v2 v2.3.0 // indirect
	github.com/go-logr/logr v1.4.3 // indirect
	github.com/go-logr/stdr v1.2.2 // indirect
	github.com/google/uuid v1.6.0 // indirect
	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
	go.opentelemetry.io/otel v1.44.0 // indirect
	go.opentelemetry.io/otel/metric v1.44.0 // indirect
	go.opentelemetry.io/otel/sdk v1.44.0 // indirect
	go.opentelemetry.io/otel/trace v1.44.0 // indirect
	golang.org/x/sys v0.45.0 // indirect
)

github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
go.opentelemetry.io/otel v1.44.0 h1:JjwHmHpA4iZ3wBxluu2fbbE7j4kqlE8jXyAyPXH7HqU=
go.opentelemetry.io/otel v1.44.0/go.mod h1:BMgjTHL9WPRlRjL2oZCBTL4whCGtXch2H4BhOPIAyYc=
go.opentelemetry.io/otel/metric v1.44.0 h1:1w0gILTcHdr3YI+ixLyjemwrVnsMURbTZFrSYCdDdmc=
go.opentelemetry.io/otel/metric v1.44.0/go.mod h1:8O7hanEPBNgEMmybD3s2VBKcgWOCsA6tzHBPODAiquo=
go.opentelemetry.io/otel/metric/x v0.66.0 h1:YkCrx1zLOChi9ZcZ6euupOcsgzbVlec7D/xoEU1+cTA=
go.opentelemetry.io/otel/metric/x v0.66.0/go.mod h1:d1+BDj9t96do0/1LoU1ayfCv79ZgNE41qbhBvnMOBZk=
go.opentelemetry.io/otel/sdk v1.44.0 h1:nHYwb9lK+fJPU/dnT6s7W7Z8itMWyqrnVfbheVYrZ58=
go.opentelemetry.io/otel/sdk v1.44.0/go.mod h1:Osuydd3Se74nqjAKxid74N5eC+jfEqfTegHRnq58oK0=
go.opentelemetry.io/otel/sdk/metric v1.44.0 h1:3LlKgI+VjbVsjNRFZJZAJ30WjXC5VkNRks6si09iEfI=
go.opentelemetry.io/otel/sdk/metric v1.44.0/go.mod h1:5B5pMARnXxKhltooO4xUuCBorl65a4EpnTalObqOigA=
go.opentelemetry.io/otel/trace v1.44.0 h1:jxF5CsGYCe74MCRx2X4g7WsY/VBKRqqpNvXlX/6gtIk=
go.opentelemetry.io/otel/trace v1.44.0/go.mod h1:oLl1jrMQAVo6v3GAggN+1VH9VIz9iUSvW53sW1Q8PIE=
golang.org/x/sys v0.45.0 h1:dO4czNzziLiiXplLQgBCEpCvXQ3dnkn0SdaZSYdQ+FY=
golang.org/x/sys v0.45.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package main

import (
	"fmt"

	"go.opentelemetry.io/otel/sdk/metric"
)

func main() {
	// Demonstrate InstrumentKindObservableCounter properties
	kind := metric.InstrumentKindObservableCounter
	fmt.Printf("Instrument kind: %s (value: %d)\n", kind.String(), kind)

	// Create a view matching InstrumentKindObservableCounter
	view := metric.NewView(
		metric.Instrument{Kind: metric.InstrumentKindObservableCounter},
		metric.Stream{Description: "Monitored observable counter"},
	)

	// Test instrument matching
	stream, matched := view(metric.Instrument{
		Name:        "network.bytes_sent",
		Description: "Total bytes transmitted",
		Kind:        metric.InstrumentKindObservableCounter,
	})

	if matched {
		fmt.Printf("View matched! Stream name: %s, description: %s\n", stream.Name, stream.Description)
	}
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/sdk/metric.InstrumentKindObservableCounter in pkg:golang/go.opentelemetry.io/otel/sdk/metric@v1.44.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/sdk/metric@v1.44.0"
  ],
  "symbols": [
    "go.opentelemetry.io/otel/sdk/metric.InstrumentKindObservableCounter"
  ]
}

package main

import (
	"context"
	"fmt"
	"os"

	"go.opentelemetry.io/otel/sdk/metric"
	"go.opentelemetry.io/otel/sdk/metric/metricdata"
)

func main() {
	// Assertion 1: InstrumentKindObservableCounter is an InstrumentKind with value 4 and string representation "ObservableCounter".
	kind := metric.InstrumentKindObservableCounter
	if uint8(kind) != 4 {
		fmt.Fprintf(os.Stderr, "FAIL: expected InstrumentKindObservableCounter value 4, got %d\n", uint8(kind))
		os.Exit(1)
	}
	if kind.String() != "ObservableCounter" {
		fmt.Fprintf(os.Stderr, "FAIL: expected String() 'ObservableCounter', got '%s'\n", kind.String())
		os.Exit(1)
	}

	// Assertion 2: InstrumentKindObservableCounter matches instruments in a View created via NewView.
	view := metric.NewView(
		metric.Instrument{Kind: metric.InstrumentKindObservableCounter},
		metric.Stream{Description: "transformed observable counter"},
	)
	inst := metric.Instrument{
		Name:        "system.cpu.ticks",
		Description: "raw ticks",
		Unit:        "1",
		Kind:        metric.InstrumentKindObservableCounter,
	}
	stream, matched := view(inst)
	if !matched {
		fmt.Fprintf(os.Stderr, "FAIL: expected view to match InstrumentKindObservableCounter instrument\n")
		os.Exit(1)
	}
	if stream.Name != "system.cpu.ticks" {
		fmt.Fprintf(os.Stderr, "FAIL: expected stream name 'system.cpu.ticks', got '%s'\n", stream.Name)
		os.Exit(1)
	}
	if stream.Description != "transformed observable counter" {
		fmt.Fprintf(os.Stderr, "FAIL: expected transformed description, got '%s'\n", stream.Description)
		os.Exit(1)
	}

	// Assertion 3: NewView with InstrumentKindObservableCounter criteria does not match other instrument kinds like Counter or ObservableGauge.
	counterInst := metric.Instrument{
		Name: "sync.counter",
		Kind: metric.InstrumentKindCounter,
	}
	if _, matched := view(counterInst); matched {
		fmt.Fprintf(os.Stderr, "FAIL: view should not match InstrumentKindCounter\n")
		os.Exit(1)
	}

	gaugeInst := metric.Instrument{
		Name: "async.gauge",
		Kind: metric.InstrumentKindObservableGauge,
	}
	if _, matched := view(gaugeInst); matched {
		fmt.Fprintf(os.Stderr, "FAIL: view should not match InstrumentKindObservableGauge\n")
		os.Exit(1)
	}

	// Assertion 4: A MeterProvider configured with an InstrumentKindObservableCounter View correctly modifies observable counter streams.
	reader := metric.NewManualReader()
	mp := metric.NewMeterProvider(
		metric.WithReader(reader),
		metric.WithView(view),
	)
	defer func() {
		if err := mp.Shutdown(context.Background()); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: shutdown failed: %v\n", err)
			os.Exit(1)
		}
	}()

	meter := mp.Meter("test-scope")
	_, err := meter.Int64ObservableCounter("system.cpu.ticks")
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: failed to create Int64ObservableCounter: %v\n", err)
		os.Exit(1)
	}

	var rm metricdata.ResourceMetrics
	if err := reader.Collect(context.Background(), &rm); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: failed to collect metrics: %v\n", err)
		os.Exit(1)
	}

	// Assertion 5: A custom View function can inspect Instrument.Kind against InstrumentKindObservableCounter to customize stream properties.
	customMatched := false
	customView := func(i metric.Instrument) (metric.Stream, bool) {
		if i.Kind == metric.InstrumentKindObservableCounter {
			customMatched = true
			return metric.Stream{
				Name:        i.Name + ".custom",
				Description: "customized: " + i.Description,
				Unit:        i.Unit,
			}, true
		}
		return metric.Stream{}, false
	}

	customStream, ok := customView(inst)
	if !ok || !customMatched {
		fmt.Fprintf(os.Stderr, "FAIL: custom view failed to match InstrumentKindObservableCounter\n")
		os.Exit(1)
	}
	if customStream.Name != "system.cpu.ticks.custom" || customStream.Description != "customized: raw ticks" {
		fmt.Fprintf(os.Stderr, "FAIL: custom stream mismatch: name=%s desc=%s\n", customStream.Name, customStream.Description)
		os.Exit(1)
	}

	fmt.Println("PASS: all InstrumentKindObservableCounter contract assertions passed.")
}