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

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 TraceState 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:
  - TraceState

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:deaaea08efdfca7a58863cbba8df763e28daa20df50c95c423252056679b549c","contract":["ParseTraceState parses valid W3C tracestate string into TraceState","ParseTraceState returns an error for invalid tracestate string","TraceState.Get returns value for existing member and empty string for non-existent key","TraceState.Insert adds new member and moves updated member to the front","TraceState.Delete removes member by key","TraceState.Len returns member count and String returns serialized W3C tracestate string"],"goal":"verify TraceState 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":["TraceState"]},"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":["TraceState"],"verifierAdapter":"golang@1"}

module example.com/sample

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=

{
  "schemaVersion": 1,
  "goal": "verify TraceState 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": [
    "TraceState"
  ]
}

package main

import (
	"fmt"
	"os"

	"example.com/sample"
	"go.opentelemetry.io/otel/trace"
)

func main() {
	// Assertion 1: ParseTraceState parses valid W3C tracestate string into TraceState
	raw := "congo=t61rcWkgMzE,rojo=00f067aa0ba902b7"
	ts, err := trace.ParseTraceState(raw)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: ParseTraceState failed on valid input: %v\n", err)
		os.Exit(1)
	}
	if ts.Len() != 2 {
		fmt.Fprintf(os.Stderr, "FAIL: expected Len == 2, got %d\n", ts.Len())
		os.Exit(1)
	}

	// Assertion 2: ParseTraceState returns an error for invalid tracestate string
	invalidRaw := "invalid key with spaces=value"
	if _, err := trace.ParseTraceState(invalidRaw); err == nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected error for invalid tracestate string, got nil\n")
		os.Exit(1)
	}

	// Assertion 3: TraceState.Get returns value for existing member and empty string for non-existent key
	if val := ts.Get("congo"); val != "t61rcWkgMzE" {
		fmt.Fprintf(os.Stderr, "FAIL: Get('congo') expected 't61rcWkgMzE', got %q\n", val)
		os.Exit(1)
	}
	if val := ts.Get("rojo"); val != "00f067aa0ba902b7" {
		fmt.Fprintf(os.Stderr, "FAIL: Get('rojo') expected '00f067aa0ba902b7', got %q\n", val)
		os.Exit(1)
	}
	if val := ts.Get("nonexistent"); val != "" {
		fmt.Fprintf(os.Stderr, "FAIL: Get('nonexistent') expected empty string, got %q\n", val)
		os.Exit(1)
	}

	// Assertion 4: TraceState.Insert adds new member and moves updated member to the front
	tsAdded, err := ts.Insert("vendor", "value123")
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: Insert new member failed: %v\n", err)
		os.Exit(1)
	}
	if tsAdded.Len() != 3 {
		fmt.Fprintf(os.Stderr, "FAIL: expected Len == 3 after insert, got %d\n", tsAdded.Len())
		os.Exit(1)
	}
	if tsAdded.String() != "vendor=value123,congo=t61rcWkgMzE,rojo=00f067aa0ba902b7" {
		fmt.Fprintf(os.Stderr, "FAIL: unexpected String after new insert: %s\n", tsAdded.String())
		os.Exit(1)
	}

	// Update existing key moves to front
	tsUpdated, err := tsAdded.Insert("rojo", "newvalue")
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: Insert update member failed: %v\n", err)
		os.Exit(1)
	}
	if tsUpdated.Len() != 3 {
		fmt.Fprintf(os.Stderr, "FAIL: expected Len == 3 after update, got %d\n", tsUpdated.Len())
		os.Exit(1)
	}
	if tsUpdated.String() != "rojo=newvalue,vendor=value123,congo=t61rcWkgMzE" {
		fmt.Fprintf(os.Stderr, "FAIL: unexpected String after update (expected front): %s\n", tsUpdated.String())
		os.Exit(1)
	}

	// Assertion 5: TraceState.Delete removes member by key
	tsDeleted := tsUpdated.Delete("vendor")
	if tsDeleted.Len() != 2 {
		fmt.Fprintf(os.Stderr, "FAIL: expected Len == 2 after delete, got %d\n", tsDeleted.Len())
		os.Exit(1)
	}
	if val := tsDeleted.Get("vendor"); val != "" {
		fmt.Fprintf(os.Stderr, "FAIL: expected empty string for deleted key 'vendor', got %q\n", val)
		os.Exit(1)
	}
	if tsDeleted.String() != "rojo=newvalue,congo=t61rcWkgMzE" {
		fmt.Fprintf(os.Stderr, "FAIL: unexpected String after delete: %s\n", tsDeleted.String())
		os.Exit(1)
	}

	// Assertion 6: TraceState.Len returns member count and String returns serialized W3C tracestate string
	mgr, err := sample.NewTraceStateManager("alpha=1,beta=2")
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: NewTraceStateManager failed: %v\n", err)
		os.Exit(1)
	}
	if mgr.Count() != 2 {
		fmt.Fprintf(os.Stderr, "FAIL: Count mismatch: got %d, want 2\n", mgr.Count())
		os.Exit(1)
	}
	if mgr.Header() != "alpha=1,beta=2" {
		fmt.Fprintf(os.Stderr, "FAIL: Header mismatch: got %q, want 'alpha=1,beta=2'\n", mgr.Header())
		os.Exit(1)
	}

	fmt.Println("PASS: TraceState contract passed")
}

package sample

import (
	"fmt"

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

// TraceStateManager wraps trace.TraceState to demonstrate safe member manipulation.
type TraceStateManager struct {
	state trace.TraceState
}

// NewTraceStateManager parses a W3C tracestate string into a TraceStateManager.
func NewTraceStateManager(raw string) (*TraceStateManager, error) {
	ts, err := trace.ParseTraceState(raw)
	if err != nil {
		return nil, fmt.Errorf("failed to parse trace state: %w", err)
	}
	return &TraceStateManager{state: ts}, nil
}

// State returns the current trace.TraceState.
func (m *TraceStateManager) State() trace.TraceState {
	return m.state
}

// Get returns the value associated with key.
func (m *TraceStateManager) Get(key string) string {
	return m.state.Get(key)
}

// Set adds a new entry or updates an existing entry, placing it at the front.
func (m *TraceStateManager) Set(key, value string) error {
	updated, err := m.state.Insert(key, value)
	if err != nil {
		return fmt.Errorf("failed to insert trace state entry: %w", err)
	}
	m.state = updated
	return nil
}

// Delete removes an entry by key from the trace state.
func (m *TraceStateManager) Delete(key string) {
	m.state = m.state.Delete(key)
}

// Header returns the W3C serialized tracestate string.
func (m *TraceStateManager) Header() string {
	return m.state.String()
}

// Count returns the number of list-members in the trace state.
func (m *TraceStateManager) Count() int {
	return m.state.Len()
}