go.opentelemetry.io/otel/trace v1.24.0: ParseTraceState

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 ParseTraceState in pkg:golang/go.opentelemetry.io/otel/trace@v1.24.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.opentelemetry.io/otel/trace@v1.24.0
Demonstrate these symbols/APIs:
  - ParseTraceState

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:sha256:4a647ba1ef38376f3cf0655739b8469412db6144283c344c1d6bf1c86bece864","contract":["ParseTraceState parses empty string into an empty TraceState with zero length","ParseTraceState parses valid comma-separated key-value pairs into list-members","ParseTraceState parses multi-tenant vendor keys containing @ symbol","ParseTraceState trims optional whitespace surrounding list-members","ParseTraceState returns an error when list-member syntax or key format is invalid","ParseTraceState returns an error when duplicate keys are present"],"goal":"verify ParseTraceState in pkg:golang/go.opentelemetry.io/otel/trace@v1.24.0","kind":"HOW","packages":["pkg:golang/go.opentelemetry.io/otel/trace@v1.24.0"],"schemaVersion":1,"symbols":["ParseTraceState"]},"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/trace@v1.24.0"],"schemaVersion":1,"subject":"pkg:golang/go.opentelemetry.io/otel/trace@v1.24.0","symbols":["ParseTraceState"],"verifierAdapter":"golang@1"}

module example.com/otel-tracestate

go 1.26.6

require go.opentelemetry.io/otel/trace v1.24.0

require go.opentelemetry.io/otel v1.24.0 // 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/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
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 v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
go.opentelemetry.io/otel v1.24.0 h1:0LAOdjNmQeSTzGBzduGe/rU4tZhMwL5rWgtp9Ku5Jfo=
go.opentelemetry.io/otel v1.24.0/go.mod h1:W7b9Ozg4nkF5tWI5zsXkaKKDjdVjpD4oAt9Qi/MArHo=
go.opentelemetry.io/otel/trace v1.24.0 h1:CsKnnL4dUAr/0llH9FKuc698G04IrpWV0MQA/Y1YELI=
go.opentelemetry.io/otel/trace v1.24.0/go.mod h1:HPc3Xr/cOApsBI154IU0OI0HJexz+aw5uPdbs3UCjNU=
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"
	"os"

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

func main() {
	raw := "vendor1=opaqueValue,vendor2@tenant=123"
	ts, err := trace.ParseTraceState(raw)
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to parse tracestate: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("Parsed TraceState with %d entries:\n", ts.Len())
	fmt.Printf("  vendor1: %s\n", ts.Get("vendor1"))
	fmt.Printf("  vendor2@tenant: %s\n", ts.Get("vendor2@tenant"))
	fmt.Printf("Serialized TraceState: %s\n", ts.String())
}

{
  "schemaVersion": 1,
  "goal": "verify ParseTraceState in pkg:golang/go.opentelemetry.io/otel/trace@v1.24.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.opentelemetry.io/otel/trace@v1.24.0"
  ],
  "symbols": [
    "ParseTraceState"
  ]
}

package main

import (
	"fmt"
	"os"

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

func main() {
	// 1. ParseTraceState parses empty string into an empty TraceState with zero length
	tsEmpty, err := trace.ParseTraceState("")
	if err != nil {
		fmt.Fprintf(os.Stderr, "expected nil error for empty string, got: %v\n", err)
		os.Exit(1)
	}
	if tsEmpty.Len() != 0 {
		fmt.Fprintf(os.Stderr, "expected len 0 for empty string, got %d\n", tsEmpty.Len())
		os.Exit(1)
	}
	if tsEmpty.String() != "" {
		fmt.Fprintf(os.Stderr, "expected empty string serialization, got %q\n", tsEmpty.String())
		os.Exit(1)
	}
	if tsEmpty.Get("any") != "" {
		fmt.Fprintf(os.Stderr, "expected empty get for missing key, got %q\n", tsEmpty.Get("any"))
		os.Exit(1)
	}

	// 2. ParseTraceState parses valid comma-separated key-value pairs into list-members
	tsSimple, err := trace.ParseTraceState("rojo=1,congo=2")
	if err != nil {
		fmt.Fprintf(os.Stderr, "expected nil error for valid pairs, got: %v\n", err)
		os.Exit(1)
	}
	if tsSimple.Len() != 2 {
		fmt.Fprintf(os.Stderr, "expected len 2, got %d\n", tsSimple.Len())
		os.Exit(1)
	}
	if got := tsSimple.Get("rojo"); got != "1" {
		fmt.Fprintf(os.Stderr, "expected rojo=1, got %q\n", got)
		os.Exit(1)
	}
	if got := tsSimple.Get("congo"); got != "2" {
		fmt.Fprintf(os.Stderr, "expected congo=2, got %q\n", got)
		os.Exit(1)
	}
	if got := tsSimple.String(); got != "rojo=1,congo=2" {
		fmt.Fprintf(os.Stderr, "expected serialized rojo=1,congo=2, got %q\n", got)
		os.Exit(1)
	}

	// 3. ParseTraceState parses multi-tenant vendor keys containing @ symbol
	tsVendor, err := trace.ParseTraceState("tenant1@vendor=abc,tenant2@vendor=xyz")
	if err != nil {
		fmt.Fprintf(os.Stderr, "expected nil error for multi-tenant keys, got: %v\n", err)
		os.Exit(1)
	}
	if tsVendor.Len() != 2 {
		fmt.Fprintf(os.Stderr, "expected len 2 for vendor keys, got %d\n", tsVendor.Len())
		os.Exit(1)
	}
	if got := tsVendor.Get("tenant1@vendor"); got != "abc" {
		fmt.Fprintf(os.Stderr, "expected tenant1@vendor=abc, got %q\n", got)
		os.Exit(1)
	}
	if got := tsVendor.Get("tenant2@vendor"); got != "xyz" {
		fmt.Fprintf(os.Stderr, "expected tenant2@vendor=xyz, got %q\n", got)
		os.Exit(1)
	}

	// 4. ParseTraceState trims optional whitespace surrounding list-members
	tsSpaces, err := trace.ParseTraceState("k1=v1 , k2=v2\t,  k3=v3")
	if err != nil {
		fmt.Fprintf(os.Stderr, "expected nil error for spaced members, got: %v\n", err)
		os.Exit(1)
	}
	if tsSpaces.Len() != 3 {
		fmt.Fprintf(os.Stderr, "expected len 3, got %d\n", tsSpaces.Len())
		os.Exit(1)
	}
	if got := tsSpaces.String(); got != "k1=v1,k2=v2,k3=v3" {
		fmt.Fprintf(os.Stderr, "expected trimmed serialization k1=v1,k2=v2,k3=v3, got %q\n", got)
		os.Exit(1)
	}

	// 5. ParseTraceState returns an error when list-member syntax or key format is invalid
	invalidInputs := []string{
		"INVALID=val",
		"=val",
		"key=",
		"key",
		"k@invalid@v=1",
	}
	for _, inv := range invalidInputs {
		if _, err := trace.ParseTraceState(inv); err == nil {
			fmt.Fprintf(os.Stderr, "expected error for invalid input %q, got nil\n", inv)
			os.Exit(1)
		}
	}

	// 6. ParseTraceState returns an error when duplicate keys are present
	if _, err := trace.ParseTraceState("duplicate=1,duplicate=2"); err == nil {
		fmt.Fprintf(os.Stderr, "expected error for duplicate keys, got nil\n")
		os.Exit(1)
	}

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