go.opentelemetry.io/contrib/bridges/prometheus v0.68.0: bridge Prometheus metrics into OpenTelemetry using NewMetricProducer

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: bridge Prometheus metrics into OpenTelemetry using NewMetricProducer
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/contrib/bridges/prometheus@v0.68.0
Demonstrate these symbols/APIs:
  - NewMetricProducer
Required runtime conditions:
  - ecosystem: golang
  - language: go
  - packageManager: go@1.26.6
  - runtime: go@1.26.6

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:eec495a59650e7761c199e24f78510afac68cbc4457cc5d6114f9889c063cf7e","contract":["NewMetricProducer returns an OpenTelemetry metric.Producer initialized with default options","NewMetricProducer with WithGatherer bridges Prometheus counter metrics into OpenTelemetry ResourceMetrics","NewMetricProducer with WithGatherer bridges Prometheus gauge metrics into OpenTelemetry ResourceMetrics"],"goal":"bridge Prometheus metrics into OpenTelemetry using NewMetricProducer","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/contrib/bridges/prometheus@v0.68.0"],"schemaVersion":1,"symbols":["NewMetricProducer"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.opentelemetry.io/contrib/bridges/prometheus@v0.68.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/contrib/bridges/prometheus@v0.68.0","symbols":["NewMetricProducer"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.25.0

require (
	github.com/prometheus/client_golang v1.23.2
	go.opentelemetry.io/contrib/bridges/prometheus v0.68.0
	go.opentelemetry.io/otel/sdk/metric v1.43.0
)

require (
	github.com/beorn7/perks v1.0.1 // 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/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
	github.com/prometheus/client_model v0.6.2 // indirect
	github.com/prometheus/common v0.67.5 // indirect
	github.com/prometheus/procfs v0.20.1 // indirect
	go.opentelemetry.io/auto/sdk v1.2.1 // indirect
	go.opentelemetry.io/otel v1.43.0 // indirect
	go.opentelemetry.io/otel/metric v1.43.0 // indirect
	go.opentelemetry.io/otel/sdk v1.43.0 // indirect
	go.opentelemetry.io/otel/trace v1.43.0 // indirect
	go.yaml.in/yaml/v2 v2.4.4 // indirect
	golang.org/x/sys v0.42.0 // indirect
	google.golang.org/protobuf v1.36.11 // indirect
)

github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
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/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
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/prometheus/client_golang v1.23.2 h1:Je96obch5RDVy3FDMndoUsjAhG5Edi49h0RJWRi/o0o=
github.com/prometheus/client_golang v1.23.2/go.mod h1:Tb1a6LWHB3/SPIzCoaDXI4I8UHKeFTEQ1YCr+0Gyqmg=
github.com/prometheus/client_model v0.6.2 h1:oBsgwpGs7iVziMvrGhE53c/GrLUsZdHnqNwqPLxwZyk=
github.com/prometheus/client_model v0.6.2/go.mod h1:y3m2F6Gdpfy6Ut/GBsUqTWZqCUvMVzSfMLjcu6wAwpE=
github.com/prometheus/common v0.67.5 h1:pIgK94WWlQt1WLwAC5j2ynLaBRDiinoAb86HZHTUGI4=
github.com/prometheus/common v0.67.5/go.mod h1:SjE/0MzDEEAyrdr5Gqc6G+sXI67maCxzaT3A2+HqjUw=
github.com/prometheus/procfs v0.20.1 h1:XwbrGOIplXW/AU3YhIhLODXMJYyC1isLFfYCsTEycfc=
github.com/prometheus/procfs v0.20.1/go.mod h1:o9EMBZGRyvDrSPH1RqdxhojkuXstoe4UlK79eF5TGGo=
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/contrib/bridges/prometheus v0.68.0 h1:w3zlHYETbDwXyWHZlyyR58ZC39XGi8rAhkBgUgJ9d5w=
go.opentelemetry.io/contrib/bridges/prometheus v0.68.0/go.mod h1:GR/mClR2nn7vE8RLwxKjoBNg+QtgdDhRzxVa93koy5o=
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/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.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
go.yaml.in/yaml/v2 v2.4.4 h1:tuyd0P+2Ont/d6e2rl3be67goVK4R6deVxCUX5vyPaQ=
go.yaml.in/yaml/v2 v2.4.4/go.mod h1:gMZqIpDtDqOfM0uNfy0SkpRhvUryYH0Z6wdMYcacYXQ=
golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
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=

package main

import (
	"context"
	"fmt"
	"log"

	prombridge "go.opentelemetry.io/contrib/bridges/prometheus"
	"github.com/prometheus/client_golang/prometheus"
	otelmetric "go.opentelemetry.io/otel/sdk/metric"
	"go.opentelemetry.io/otel/sdk/metric/metricdata"
)

func main() {
	ctx := context.Background()

	// 1. Create a custom Prometheus registry and register metrics
	registry := prometheus.NewRegistry()

	counter := prometheus.NewCounter(prometheus.CounterOpts{
		Name: "sample_requests_total",
		Help: "Total number of sample requests",
	})
	if err := registry.Register(counter); err != nil {
		log.Fatalf("failed to register prometheus counter: %v", err)
	}
	counter.Add(100)

	// 2. Create the OpenTelemetry metric producer bridge from Prometheus
	producer := prombridge.NewMetricProducer(prombridge.WithGatherer(registry))

	// 3. Attach producer to OpenTelemetry reader and provider
	reader := otelmetric.NewManualReader(otelmetric.WithProducer(producer))
	meterProvider := otelmetric.NewMeterProvider(otelmetric.WithReader(reader))
	defer func() {
		if err := meterProvider.Shutdown(ctx); err != nil {
			log.Fatalf("failed to shut down meter provider: %v", err)
		}
	}()

	// 4. Collect metrics through the OpenTelemetry pipeline
	var rm metricdata.ResourceMetrics
	if err := reader.Collect(ctx, &rm); err != nil {
		log.Fatalf("failed to collect metrics: %v", err)
	}

	// 5. Inspect the bridged metrics
	for _, sm := range rm.ScopeMetrics {
		for _, m := range sm.Metrics {
			fmt.Printf("Collected metric: %s\n", m.Name)
		}
	}

	fmt.Println("Successfully bridged Prometheus metrics to OpenTelemetry")
}

{
  "schemaVersion": 1,
  "goal": "bridge Prometheus metrics into OpenTelemetry using NewMetricProducer",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/contrib/bridges/prometheus@v0.68.0"
  ],
  "symbols": [
    "NewMetricProducer"
  ],
  "runtimeConditions": {
    "ecosystem": "golang",
    "language": "go",
    "packageManager": "go@1.26.6",
    "runtime": "go@1.26.6"
  }
}

package main

import (
	"context"
	"fmt"
	"os"

	prombridge "go.opentelemetry.io/contrib/bridges/prometheus"
	"github.com/prometheus/client_golang/prometheus"
	otelmetric "go.opentelemetry.io/otel/sdk/metric"
	"go.opentelemetry.io/otel/sdk/metric/metricdata"
)

func main() {
	ctx := context.Background()

	// Contract 1: NewMetricProducer returns an OpenTelemetry metric.Producer initialized with default options
	defaultProducer := prombridge.NewMetricProducer()
	if defaultProducer == nil {
		fmt.Fprintf(os.Stderr, "contract 1 failed: NewMetricProducer returned nil\n")
		os.Exit(1)
	}

	// Contract 2: NewMetricProducer with WithGatherer bridges Prometheus counter metrics into OpenTelemetry ResourceMetrics
	reg := prometheus.NewRegistry()
	counter := prometheus.NewCounter(prometheus.CounterOpts{
		Name: "sample_requests_total",
		Help: "Total number of sample requests",
	})
	if err := reg.Register(counter); err != nil {
		fmt.Fprintf(os.Stderr, "contract 2 failed: failed to register counter: %v\n", err)
		os.Exit(1)
	}
	counter.Add(100)

	producer := prombridge.NewMetricProducer(prombridge.WithGatherer(reg))
	if producer == nil {
		fmt.Fprintf(os.Stderr, "contract 2 failed: NewMetricProducer with custom gatherer returned nil\n")
		os.Exit(1)
	}

	reader := otelmetric.NewManualReader(otelmetric.WithProducer(producer))
	mp := otelmetric.NewMeterProvider(otelmetric.WithReader(reader))
	defer mp.Shutdown(ctx)

	var rm metricdata.ResourceMetrics
	if err := reader.Collect(ctx, &rm); err != nil {
		fmt.Fprintf(os.Stderr, "contract 2 failed: reader.Collect error: %v\n", err)
		os.Exit(1)
	}

	var counterFound bool
	for _, sm := range rm.ScopeMetrics {
		for _, m := range sm.Metrics {
			if m.Name == "sample_requests_total" {
				if sum, ok := m.Data.(metricdata.Sum[float64]); ok {
					if len(sum.DataPoints) > 0 && sum.DataPoints[0].Value == 100 {
						counterFound = true
					}
				}
			}
		}
	}
	if !counterFound {
		fmt.Fprintf(os.Stderr, "contract 2 failed: metric sample_requests_total with value 100 not found\n")
		os.Exit(1)
	}

	// Contract 3: NewMetricProducer with WithGatherer bridges Prometheus gauge metrics into OpenTelemetry ResourceMetrics
	gauge := prometheus.NewGauge(prometheus.GaugeOpts{
		Name: "sample_temperature_celsius",
		Help: "Current temperature",
	})
	if err := reg.Register(gauge); err != nil {
		fmt.Fprintf(os.Stderr, "contract 3 failed: failed to register gauge: %v\n", err)
		os.Exit(1)
	}
	gauge.Set(24.5)

	var rm2 metricdata.ResourceMetrics
	if err := reader.Collect(ctx, &rm2); err != nil {
		fmt.Fprintf(os.Stderr, "contract 3 failed: reader.Collect error: %v\n", err)
		os.Exit(1)
	}

	var gaugeFound bool
	for _, sm := range rm2.ScopeMetrics {
		for _, m := range sm.Metrics {
			if m.Name == "sample_temperature_celsius" {
				if g, ok := m.Data.(metricdata.Gauge[float64]); ok {
					if len(g.DataPoints) > 0 && g.DataPoints[0].Value == 24.5 {
						gaugeFound = true
					}
				}
			}
		}
	}
	if !gaugeFound {
		fmt.Fprintf(os.Stderr, "contract 3 failed: metric sample_temperature_celsius with value 24.5 not found\n")
		os.Exit(1)
	}

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