go.opentelemetry.io/otel/trace v1.37.0: SpanStartOption

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/trace.SpanStartOption in pkg:golang/go.opentelemetry.io/otel/trace@v1.37.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/trace@v1.37.0
Demonstrate these symbols/APIs:
  - go.opentelemetry.io/otel/trace.SpanStartOption

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:sha256:806d6727bd3334aa98e396d1388e4716cd44c48554d4b3e4a4746aa3e83681a2","contract":["SpanStartOption configures SpanKind on SpanConfig via WithSpanKind","SpanStartOption configures Attributes on SpanConfig via WithAttributes","SpanStartOption configures Timestamp on SpanConfig via WithTimestamp","SpanStartOption configures NewRoot on SpanConfig via WithNewRoot","Tracer Start creates active span using SpanStartOption configurations"],"goal":"verify go.opentelemetry.io/otel/trace.SpanStartOption in pkg:golang/go.opentelemetry.io/otel/trace@v1.37.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/trace@v1.37.0"],"schemaVersion":1,"symbols":["go.opentelemetry.io/otel/trace.SpanStartOption"]},"contractCommand":["go","test","./..."],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","moduleSystem":"go.mod","os":"linux","osVersionBucket":"24","packageManager":"go","runtime":"go","runtimeVersion":"1.26","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.opentelemetry.io/otel/trace@v1.37.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/trace@v1.37.0","symbols":["go.opentelemetry.io/otel/trace.SpanStartOption"],"verifierAdapter":"golang@1"}

module example.com/otel-trace-spanstartoption

go 1.26.6

require (
	go.opentelemetry.io/otel v1.37.0
	go.opentelemetry.io/otel/trace v1.37.0
)

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/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
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/otel v1.37.0 h1:9zhNfelUvx0KBfu/gb+ZgeAfAgtWrfHJZcAqFC228wQ=
go.opentelemetry.io/otel v1.37.0/go.mod h1:ehE/umFRLnuLa/vSccNq9oS1ErUlkkK71gMcN34UG8I=
go.opentelemetry.io/otel/trace v1.37.0 h1:HLdcFNbRQBE2imdSEgm/kwqmQj1Or1l/7bW6mxVK7z4=
go.opentelemetry.io/otel/trace v1.37.0/go.mod h1:TlgrlQ+PtQO5XFerSPUYG0JSgGyryXewPGyayAWSBS0=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package sample

import (
	"context"
	"time"

	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/trace"
	"go.opentelemetry.io/otel/trace/noop"
)

// BuildSpanStartOptions creates a slice of SpanStartOption configuring kind, attributes, timestamp, and root status.
func BuildSpanStartOptions(kind trace.SpanKind, attrs []attribute.KeyValue, startTime time.Time, newRoot bool) []trace.SpanStartOption {
	var opts []trace.SpanStartOption
	if kind != trace.SpanKindUnspecified {
		opts = append(opts, trace.WithSpanKind(kind))
	}
	if len(attrs) > 0 {
		opts = append(opts, trace.WithAttributes(attrs...))
	}
	if !startTime.IsZero() {
		opts = append(opts, trace.WithTimestamp(startTime))
	}
	if newRoot {
		opts = append(opts, trace.WithNewRoot())
	}
	return opts
}

// ConfigFromOptions evaluates a list of SpanStartOption and returns the resulting SpanConfig.
func ConfigFromOptions(opts ...trace.SpanStartOption) trace.SpanConfig {
	return trace.NewSpanStartConfig(opts...)
}

// StartSpanWithConfiguredOptions starts a span on the provided tracer using the given SpanStartOption slice.
func StartSpanWithConfiguredOptions(ctx context.Context, tr trace.Tracer, name string, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
	if tr == nil {
		tr = noop.NewTracerProvider().Tracer("example.com/noop")
	}
	return tr.Start(ctx, name, opts...)
}

{
  "schemaVersion": 1,
  "goal": "verify go.opentelemetry.io/otel/trace.SpanStartOption in pkg:golang/go.opentelemetry.io/otel/trace@v1.37.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/trace@v1.37.0"
  ],
  "symbols": [
    "go.opentelemetry.io/otel/trace.SpanStartOption"
  ]
}

package test

import (
	"context"
	"testing"
	"time"

	sample "example.com/otel-trace-spanstartoption"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/trace"
	"go.opentelemetry.io/otel/trace/noop"
)

func TestSpanStartOptionContract(t *testing.T) {
	ctx := context.Background()

	// 1. SpanStartOption configures SpanKind on SpanConfig via WithSpanKind
	wantKind := trace.SpanKindServer
	var optKind trace.SpanStartOption = trace.WithSpanKind(wantKind)
	cfgKind := sample.ConfigFromOptions(optKind)
	if gotKind := cfgKind.SpanKind(); gotKind != wantKind {
		t.Fatalf("SpanKind mismatch: got %v, want %v", gotKind, wantKind)
	}

	// 2. SpanStartOption configures Attributes on SpanConfig via WithAttributes
	wantAttr := attribute.String("component", "gateway")
	var optAttr trace.SpanStartOption = trace.WithAttributes(wantAttr)
	cfgAttr := sample.ConfigFromOptions(optAttr)
	attrs := cfgAttr.Attributes()
	if len(attrs) != 1 || attrs[0].Key != wantAttr.Key || attrs[0].Value.AsString() != wantAttr.Value.AsString() {
		t.Fatalf("Attributes mismatch: got %v, want [%v]", attrs, wantAttr)
	}

	// 3. SpanStartOption configures Timestamp on SpanConfig via WithTimestamp
	fixedTime := time.Date(2026, 1, 1, 12, 0, 0, 0, time.UTC)
	var optTime trace.SpanStartOption = trace.WithTimestamp(fixedTime)
	cfgTime := sample.ConfigFromOptions(optTime)
	if gotTime := cfgTime.Timestamp(); !gotTime.Equal(fixedTime) {
		t.Fatalf("Timestamp mismatch: got %v, want %v", gotTime, fixedTime)
	}

	// 4. SpanStartOption configures NewRoot on SpanConfig via WithNewRoot
	var optRoot trace.SpanStartOption = trace.WithNewRoot()
	cfgRoot := sample.ConfigFromOptions(optRoot)
	if !cfgRoot.NewRoot() {
		t.Fatalf("NewRoot mismatch: got false, want true")
	}

	// 5. Tracer Start creates active span using SpanStartOption configurations
	tp := noop.NewTracerProvider()
	tr := tp.Tracer("example.com/test-tracer")
	combinedOpts := sample.BuildSpanStartOptions(
		trace.SpanKindClient,
		[]attribute.KeyValue{attribute.String("test.key", "test.value")},
		fixedTime,
		true,
	)
	spanCtx, span := sample.StartSpanWithConfiguredOptions(ctx, tr, "test-span", combinedOpts...)
	if span == nil {
		t.Fatal("expected non-nil span from StartSpanWithConfiguredOptions")
	}
	defer span.End()

	if spanCtx == nil {
		t.Fatal("expected non-nil context from StartSpanWithConfiguredOptions")
	}
}