go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp v1.43.0: WithAggregationSelector

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 WithAggregationSelector in pkg:golang/go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp@v1.43.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp@v1.43.0
Demonstrate these symbols/APIs:
  - WithAggregationSelector
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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:e6f7c55e919e37b2fbdb5671e3d0a42971f184081c5036d460477d65e6966854","contract":["otlpmetrichttp.WithAggregationSelector configures custom aggregation selector for metric instruments","exporter.Aggregation returns the configured Aggregation for instrument kinds","MeterProvider flushes recorded metrics through configured exporter to HTTP endpoint","meterProvider.Shutdown cleanly stops the exporter and flushes pending metrics"],"goal":"verify WithAggregationSelector in pkg:golang/go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp@v1.43.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp@v1.43.0"],"schemaVersion":1,"symbols":["WithAggregationSelector"]},"contractCommand":["go","run","-p","1","./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/exporters/otlp/otlpmetric/otlpmetrichttp@v1.43.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp@v1.43.0","symbols":["WithAggregationSelector"],"verifierAdapter":"golang@1"}

package sample

import (
	"context"
	"fmt"

	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
)

// CustomAggregationSelector returns a custom aggregation strategy based on instrument kind.
// For histogram instruments, it specifies explicit bucket boundaries.
// For observable counters, it drops the metric aggregation.
// For all other instruments, it falls back to the default SDK aggregation.
func CustomAggregationSelector(kind sdkmetric.InstrumentKind) sdkmetric.Aggregation {
	switch kind {
	case sdkmetric.InstrumentKindHistogram:
		return sdkmetric.AggregationExplicitBucketHistogram{
			Boundaries: []float64{0.5, 2.0, 10.0},
			NoMinMax:   false,
		}
	case sdkmetric.InstrumentKindObservableCounter:
		return sdkmetric.AggregationDrop{}
	default:
		return sdkmetric.DefaultAggregationSelector(kind)
	}
}

// NewConfiguredExporter creates an OTLP HTTP metric exporter with a custom AggregationSelector and endpoint.
func NewConfiguredExporter(ctx context.Context, endpoint string, selector sdkmetric.AggregationSelector) (*sdkmetric.MeterProvider, *otlpmetrichttp.Exporter, error) {
	opts := []otlpmetrichttp.Option{
		otlpmetrichttp.WithEndpoint(endpoint),
		otlpmetrichttp.WithInsecure(),
		otlpmetrichttp.WithAggregationSelector(selector),
	}

	exporter, err := otlpmetrichttp.New(ctx, opts...)
	if err != nil {
		return nil, nil, fmt.Errorf("failed to create otlpmetrichttp exporter: %w", err)
	}

	reader := sdkmetric.NewPeriodicReader(exporter)
	meterProvider := sdkmetric.NewMeterProvider(
		sdkmetric.WithReader(reader),
	)

	return meterProvider, exporter, nil
}

module sample

go 1.26.6

require (
	go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp v1.43.0
	go.opentelemetry.io/otel/metric v1.43.0
	go.opentelemetry.io/otel/sdk/metric v1.43.0
)

require (
	github.com/cenkalti/backoff/v5 v5.0.3 // indirect
	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
	github.com/grpc-ecosystem/grpc-gateway/v2 v2.28.0 // indirect
	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
	go.opentelemetry.io/otel v1.43.0 // indirect
	go.opentelemetry.io/otel/sdk v1.43.0 // indirect
	go.opentelemetry.io/otel/trace v1.43.0 // indirect
	go.opentelemetry.io/proto/otlp v1.10.0 // indirect
	golang.org/x/net v0.52.0 // indirect
	golang.org/x/sys v0.42.0 // indirect
	golang.org/x/text v0.35.0 // indirect
	google.golang.org/genproto/googleapis/api v0.0.0-20260401024825-9d38bb4040a9 // indirect
	google.golang.org/genproto/googleapis/rpc v0.0.0-20260401024825-9d38bb4040a9 // indirect
	google.golang.org/grpc v1.80.0 // indirect
	google.golang.org/protobuf v1.36.11 // indirect
)

github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=
github.com/cenkalti/backoff/v5 v5.0.3/go.mod h1:rkhZdG3JZukswDf7f0cwqPNk4K0sa+F97BxZthm/crw=
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/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
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/grpc-ecosystem/grpc-gateway/v2 v2.28.0 h1:HWRh5R2+9EifMyIHV7ZV+MIZqgz+PMpZ14Jynv3O2Zs=
github.com/grpc-ecosystem/grpc-gateway/v2 v2.28.0/go.mod h1:JfhWUomR1baixubs02l85lZYYOm7LV6om4ceouMv45c=
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 v1.43.0 h1:mYIM03dnh5zfN7HautFE4ieIig9amkNANT+xcVxAj9I=
go.opentelemetry.io/otel v1.43.0/go.mod h1:JuG+u74mvjvcm8vj8pI5XiHy1zDeoCS2LB1spIq7Ay0=
go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp v1.43.0 h1:w1K+pCJoPpQifuVpsKamUdn9U0zM3xUziVOqsGksUrY=
go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp v1.43.0/go.mod h1:HBy4BjzgVE8139ieRI75oXm3EcDN+6GhD88JT1Kjvxg=
go.opentelemetry.io/otel/metric v1.43.0 h1:d7638QeInOnuwOONPp4JAOGfbCEpYb+K6DVWvdxGzgM=
go.opentelemetry.io/otel/metric v1.43.0/go.mod h1:RDnPtIxvqlgO8GRW18W6Z/4P462ldprJtfxHxyKd2PY=
go.opentelemetry.io/otel/sdk v1.43.0 h1:pi5mE86i5rTeLXqoF/hhiBtUNcrAGHLKQdhg4h4V9Dg=
go.opentelemetry.io/otel/sdk v1.43.0/go.mod h1:P+IkVU3iWukmiit/Yf9AWvpyRDlUeBaRg6Y+C58QHzg=
go.opentelemetry.io/otel/sdk/metric v1.43.0 h1:S88dyqXjJkuBNLeMcVPRFXpRw2fuwdvfCGLEo89fDkw=
go.opentelemetry.io/otel/sdk/metric v1.43.0/go.mod h1:C/RJtwSEJ5hzTiUz5pXF1kILHStzb9zFlIEe85bhj6A=
go.opentelemetry.io/otel/trace v1.43.0 h1:BkNrHpup+4k4w+ZZ86CZoHHEkohws8AY+WTX09nk+3A=
go.opentelemetry.io/otel/trace v1.43.0/go.mod h1:/QJhyVBUUswCphDVxq+8mld+AvhXZLhe+8WVFxiFff0=
go.opentelemetry.io/proto/otlp v1.10.0 h1:IQRWgT5srOCYfiWnpqUYz9CVmbO8bFmKcwYxpuCSL2g=
go.opentelemetry.io/proto/otlp v1.10.0/go.mod h1:/CV4QoCR/S9yaPj8utp3lvQPoqMtxXdzn7ozvvozVqk=
golang.org/x/net v0.52.0 h1:He/TN1l0e4mmR3QqHMT2Xab3Aj3L9qjbhRm78/6jrW0=
golang.org/x/net v0.52.0/go.mod h1:R1MAz7uMZxVMualyPXb+VaqGSa3LIaUqk0eEt3w36Sw=
golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
golang.org/x/text v0.35.0 h1:JOVx6vVDFokkpaq1AEptVzLTpDe9KGpj5tR4/X+ybL8=
golang.org/x/text v0.35.0/go.mod h1:khi/HExzZJ2pGnjenulevKNX1W67CUy0AsXcNubPGCA=
gonum.org/v1/gonum v0.17.0 h1:VbpOemQlsSMrYmn7T2OUvQ4dqxQXU+ouZFQsZOx50z4=
gonum.org/v1/gonum v0.17.0/go.mod h1:El3tOrEuMpv2UdMrbNlKEh9vd86bmQ6vqIcDwxEOc1E=
google.golang.org/genproto/googleapis/api v0.0.0-20260401024825-9d38bb4040a9 h1:VPWxll4HlMw1Vs/qXtN7BvhZqsS9cdAittCNvVENElA=
google.golang.org/genproto/googleapis/api v0.0.0-20260401024825-9d38bb4040a9/go.mod h1:7QBABkRtR8z+TEnmXTqIqwJLlzrZKVfAUm7tY3yGv0M=
google.golang.org/genproto/googleapis/rpc v0.0.0-20260401024825-9d38bb4040a9 h1:m8qni9SQFH0tJc1X0vmnpw/0t+AImlSvp30sEupozUg=
google.golang.org/genproto/googleapis/rpc v0.0.0-20260401024825-9d38bb4040a9/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
google.golang.org/grpc v1.80.0 h1:Xr6m2WmWZLETvUNvIUmeD5OAagMw3FiKmMlTdViWsHM=
google.golang.org/grpc v1.80.0/go.mod h1:ho/dLnxwi3EDJA4Zghp7k2Ec1+c2jqup0bFkw07bwF4=
google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

{
  "schemaVersion": 1,
  "goal": "verify WithAggregationSelector in pkg:golang/go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp@v1.43.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp@v1.43.0"
  ],
  "symbols": [
    "WithAggregationSelector"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

package main

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"reflect"
	"sync/atomic"
	"time"

	"sample"

	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
)

func main() {
	var requestCount int64
	var payloadReceived bool

	// Start a local offline mock HTTP server to receive OTLP export requests
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		atomic.AddInt64(&requestCount, 1)
		bodyBytes, err := io.ReadAll(r.Body)
		_ = r.Body.Close()
		if err == nil && len(bodyBytes) > 0 {
			payloadReceived = true
		}

		w.Header().Set("Content-Type", "application/x-protobuf")
		w.WriteHeader(http.StatusOK)
	}))
	defer server.Close()

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	endpoint := server.Listener.Addr().String()

	// 1. Verify otlpmetrichttp.WithAggregationSelector configures the custom aggregation selector on the exporter
	meterProvider, exporter, err := sample.NewConfiguredExporter(
		ctx,
		endpoint,
		sample.CustomAggregationSelector,
	)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Contract failure: failed to create configured exporter: %v\n", err)
		os.Exit(1)
	}
	if exporter == nil {
		fmt.Fprintf(os.Stderr, "Contract failure: exporter is nil\n")
		os.Exit(1)
	}

	// 2. Verify exporter.Aggregation returns the configured Aggregation for instrument kinds
	histAgg := exporter.Aggregation(sdkmetric.InstrumentKindHistogram)
	expectedHistAgg := sdkmetric.AggregationExplicitBucketHistogram{
		Boundaries: []float64{0.5, 2.0, 10.0},
		NoMinMax:   false,
	}
	if !reflect.DeepEqual(histAgg, expectedHistAgg) {
		fmt.Fprintf(os.Stderr, "Contract failure: expected histogram aggregation %+v, got %+v\n", expectedHistAgg, histAgg)
		os.Exit(1)
	}

	dropAgg := exporter.Aggregation(sdkmetric.InstrumentKindObservableCounter)
	if _, ok := dropAgg.(sdkmetric.AggregationDrop); !ok {
		fmt.Fprintf(os.Stderr, "Contract failure: expected AggregationDrop for ObservableCounter, got %+v\n", dropAgg)
		os.Exit(1)
	}

	defaultCounterAgg := exporter.Aggregation(sdkmetric.InstrumentKindCounter)
	expectedCounterAgg := sdkmetric.DefaultAggregationSelector(sdkmetric.InstrumentKindCounter)
	if !reflect.DeepEqual(defaultCounterAgg, expectedCounterAgg) {
		fmt.Fprintf(os.Stderr, "Contract failure: expected default counter aggregation %+v, got %+v\n", expectedCounterAgg, defaultCounterAgg)
		os.Exit(1)
	}

	// 3. Verify direct creation with otlpmetrichttp.WithAggregationSelector option
	directExporter, err := otlpmetrichttp.New(
		ctx,
		otlpmetrichttp.WithEndpoint(endpoint),
		otlpmetrichttp.WithInsecure(),
		otlpmetrichttp.WithAggregationSelector(func(kind sdkmetric.InstrumentKind) sdkmetric.Aggregation {
			return sdkmetric.AggregationDrop{}
		}),
	)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Contract failure: direct exporter creation failed: %v\n", err)
		os.Exit(1)
	}
	if directDrop := directExporter.Aggregation(sdkmetric.InstrumentKindHistogram); directDrop != (sdkmetric.AggregationDrop{}) {
		fmt.Fprintf(os.Stderr, "Contract failure: expected AggregationDrop from direct exporter, got %+v\n", directDrop)
		os.Exit(1)
	}

	// 4. Record metrics using MeterProvider and verify export and flush work cleanly
	meter := meterProvider.Meter("contract-test-meter")
	histogram, err := meter.Float64Histogram("test_duration_seconds")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Contract failure: failed to create histogram: %v\n", err)
		os.Exit(1)
	}
	histogram.Record(ctx, 1.25)

	counter, err := meter.Int64Counter("test_events_total")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Contract failure: failed to create counter: %v\n", err)
		os.Exit(1)
	}
	counter.Add(ctx, 1)

	// Shutdown the MeterProvider to flush pending metric records through the exporter
	if err := meterProvider.Shutdown(ctx); err != nil {
		fmt.Fprintf(os.Stderr, "Contract failure: MeterProvider shutdown failed: %v\n", err)
		os.Exit(1)
	}

	if atomic.LoadInt64(&requestCount) == 0 || !payloadReceived {
		fmt.Fprintf(os.Stderr, "Contract failure: expected HTTP export payload was not received by endpoint\n")
		os.Exit(1)
	}

	fmt.Println("PASS: otlpmetrichttp.WithAggregationSelector verified successfully")
}