go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.61.0: NewHandler

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 pkg:golang/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp@v0.61.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp@v0.61.0

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:d42ab8bd6979ee8334cb4d70a609dd82309630f7681def51bb1dca68bb171b4f","contract":["otelhttp.NewHandler wraps an http.Handler to create OpenTelemetry trace spans for incoming HTTP requests"],"goal":"verify pkg:golang/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp@v0.61.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp@v0.61.0"],"schemaVersion":1,"symbols":["otelhttp.NewHandler"]},"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/contrib/instrumentation/net/http/otelhttp@v0.61.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp@v0.61.0","symbols":["otelhttp.NewHandler"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require (
	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.61.0
	go.opentelemetry.io/otel/sdk v1.36.0
	go.opentelemetry.io/otel/trace v1.36.0
)

require (
	github.com/felixge/httpsnoop v1.0.4 // indirect
	github.com/go-logr/logr v1.4.2 // indirect
	github.com/go-logr/stdr v1.2.2 // indirect
	github.com/google/uuid v1.6.0 // indirect
	go.opentelemetry.io/auto/sdk v1.1.0 // indirect
	go.opentelemetry.io/otel v1.36.0 // indirect
	go.opentelemetry.io/otel/metric v1.36.0 // indirect
	golang.org/x/sys v0.33.0 // indirect
)

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/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
github.com/go-logr/logr v1.4.2/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 v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
go.opentelemetry.io/auto/sdk v1.1.0 h1:cH53jehLUN6UFLY71z+NDOiNJqDdPRaXzTel0sJySYA=
go.opentelemetry.io/auto/sdk v1.1.0/go.mod h1:3wSPjt5PWp2RhlCcmmOial7AvC4DQqZb7a7wCow3W8A=
go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.61.0 h1:F7Jx+6hwnZ41NSFTO5q4LYDtJRXBf2PD0rNBkeB/lus=
go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.61.0/go.mod h1:UHB22Z8QsdRDrnAtX4PntOl36ajSxcdUMt1sF7Y6E7Q=
go.opentelemetry.io/otel v1.36.0 h1:UumtzIklRBY6cI/lllNZlALOF5nNIzJVb16APdvgTXg=
go.opentelemetry.io/otel v1.36.0/go.mod h1:/TcFMXYjyRNh8khOAO9ybYkqaDBb/70aVwkNML4pP8E=
go.opentelemetry.io/otel/metric v1.36.0 h1:MoWPKVhQvJ+eeXWHFBOPoBOi20jh6Iq2CcCREuTYufE=
go.opentelemetry.io/otel/metric v1.36.0/go.mod h1:zC7Ks+yeyJt4xig9DEw9kuUFe5C3zLbVjV2PzT6qzbs=
go.opentelemetry.io/otel/sdk v1.36.0 h1:b6SYIuLRs88ztox4EyrvRti80uXIFy+Sqzoh9kFULbs=
go.opentelemetry.io/otel/sdk v1.36.0/go.mod h1:+lC+mTgD+MUWfjJubi2vvXWcVxyr9rmlshZni72pXeY=
go.opentelemetry.io/otel/sdk/metric v1.36.0 h1:r0ntwwGosWGaa0CrSt8cuNuTcccMXERFwHX4dThiPis=
go.opentelemetry.io/otel/sdk/metric v1.36.0/go.mod h1:qTNOhFDfKRwX0yXOqJYegL5WRaW376QbB7P4Pb0qva4=
go.opentelemetry.io/otel/trace v1.36.0 h1:ahxWNuqZjpdiFAyrIoQ4GIiAIhxAunQR6MUoKrsNd4w=
go.opentelemetry.io/otel/trace v1.36.0/go.mod h1:gQ+OnDZzrybY4k4seLzPAWNwVBBVlF2szhehOBB/tGA=
go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
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"
	"net/http"
	"net/http/httptest"

	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
	"go.opentelemetry.io/otel/sdk/trace/tracetest"
	"go.opentelemetry.io/otel/trace"
)

func setupTracer() (*sdktrace.TracerProvider, *tracetest.InMemoryExporter) {
	exporter := tracetest.NewInMemoryExporter()
	tp := sdktrace.NewTracerProvider(
		sdktrace.WithSyncer(exporter),
	)
	return tp, exporter
}

func main() {
	tp, exporter := setupTracer()
	defer func() {
		_ = tp.Shutdown(context.Background())
	}()

	innerHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		span := trace.SpanFromContext(r.Context())
		if span.SpanContext().IsValid() {
			w.Header().Set("X-Trace-ID", span.SpanContext().TraceID().String())
		}
		w.WriteHeader(http.StatusOK)
		_, _ = w.Write([]byte("Hello from instrumented handler"))
	})

	handler := otelhttp.NewHandler(
		innerHandler,
		"demo-handler",
		otelhttp.WithTracerProvider(tp),
	)

	req := httptest.NewRequest(http.MethodGet, "/hello", nil)
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)

	fmt.Printf("Status: %d\n", rec.Code)
	fmt.Printf("Body: %s\n", rec.Body.String())
	fmt.Printf("Recorded %d span(s)\n", len(exporter.GetSpans()))
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp@v0.61.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp@v0.61.0"
  ],
  "symbols": [
    "otelhttp.NewHandler"
  ]
}

package main

import (
	"context"
	"fmt"
	"net/http"
	"net/http/httptest"
	"os"

	"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
	"go.opentelemetry.io/otel/sdk/trace/tracetest"
	"go.opentelemetry.io/otel/trace"
)

func main() {
	exporter := tracetest.NewInMemoryExporter()
	tp := sdktrace.NewTracerProvider(
		sdktrace.WithSyncer(exporter),
	)
	defer func() {
		_ = tp.Shutdown(context.Background())
	}()

	// Contract: otelhttp.NewHandler wraps an http.Handler to create OpenTelemetry trace spans for incoming HTTP requests
	{
		exporter.Reset()
		innerHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			span := trace.SpanFromContext(r.Context())
			if !span.SpanContext().IsValid() {
				fmt.Fprintln(os.Stderr, "FAIL: expected valid span in request context")
				os.Exit(1)
			}
			w.WriteHeader(http.StatusOK)
			_, _ = w.Write([]byte("handler response"))
		})

		handler := otelhttp.NewHandler(innerHandler, "server-handler-operation", otelhttp.WithTracerProvider(tp))

		req := httptest.NewRequest(http.MethodGet, "/api/data", nil)
		rec := httptest.NewRecorder()
		handler.ServeHTTP(rec, req)

		if rec.Code != http.StatusOK {
			fmt.Fprintf(os.Stderr, "FAIL: expected status 200, got %d\n", rec.Code)
			os.Exit(1)
		}
		if rec.Body.String() != "handler response" {
			fmt.Fprintf(os.Stderr, "FAIL: expected body 'handler response', got '%s'\n", rec.Body.String())
			os.Exit(1)
		}

		spans := exporter.GetSpans()
		if len(spans) != 1 {
			fmt.Fprintf(os.Stderr, "FAIL: expected 1 span, got %d\n", len(spans))
			os.Exit(1)
		}
		if spans[0].Name != "server-handler-operation" {
			fmt.Fprintf(os.Stderr, "FAIL: expected span name 'server-handler-operation', got '%s'\n", spans[0].Name)
			os.Exit(1)
		}
	}

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