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

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 SpanIDFromHex 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:
  - SpanIDFromHex

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:sha256:525e0bc1c942ed3f3251d379d22868b6dd1fbc1533e29f146c4962b064c3ec96","contract":["SpanIDFromHex parses a valid 16-character lowercase hex string into a valid SpanID","SpanID formats back to the expected lowercase hex string via String","SpanIDFromHex returns an error for hex strings not equal to 16 characters","SpanIDFromHex returns an error for strings containing invalid hex or uppercase characters","SpanIDFromHex returns an error for an all-zero hex string"],"goal":"verify SpanIDFromHex 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":["SpanIDFromHex"]},"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":["SpanIDFromHex"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.22

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

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

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=

package main

import (
	"fmt"
	"os"

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

func main() {
	hexID := "00f067aa0ba902b7"
	spanID, err := trace.SpanIDFromHex(hexID)
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to parse span ID from hex: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("SpanID: %s (valid: %t)\n", spanID.String(), spanID.IsValid())

	invalidHex := "not-a-valid-hex"
	_, err = trace.SpanIDFromHex(invalidHex)
	if err != nil {
		fmt.Printf("Expected error for %q: %v\n", invalidHex, err)
	}
}

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

package main

import (
	"bytes"
	"fmt"
	"os"

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

func main() {
	// 1. SpanIDFromHex parses a valid 16-character lowercase hex string into a valid SpanID
	validHex := "00f067aa0ba902b7"
	expectedBytes := [8]byte{0x00, 0xf0, 0x67, 0xaa, 0x0b, 0xa9, 0x02, 0xb7}
	sid, err := trace.SpanIDFromHex(validHex)
	if err != nil {
		fmt.Fprintf(os.Stderr, "expected nil error for valid hex, got: %v\n", err)
		os.Exit(1)
	}
	if !sid.IsValid() {
		fmt.Fprintf(os.Stderr, "expected sid.IsValid() to be true for %s\n", validHex)
		os.Exit(1)
	}
	if !bytes.Equal(sid[:], expectedBytes[:]) {
		fmt.Fprintf(os.Stderr, "expected bytes %v, got %v\n", expectedBytes, sid[:])
		os.Exit(1)
	}

	// 2. SpanID formats back to the expected lowercase hex string via String
	if got := sid.String(); got != validHex {
		fmt.Fprintf(os.Stderr, "expected String() %q, got %q\n", validHex, got)
		os.Exit(1)
	}

	// 3. SpanIDFromHex returns an error for hex strings not equal to 16 characters
	invalidLengths := []string{
		"",
		"00f067aa",
		"00f067aa0ba902",
		"00f067aa0ba902b",
		"00f067aa0ba902b78",
		"00f067aa0ba902b789abcdef",
	}
	for _, hexStr := range invalidLengths {
		invalidSID, err := trace.SpanIDFromHex(hexStr)
		if err == nil {
			fmt.Fprintf(os.Stderr, "expected error for length %d (%q), got nil\n", len(hexStr), hexStr)
			os.Exit(1)
		}
		if invalidSID.IsValid() {
			fmt.Fprintf(os.Stderr, "expected invalid SpanID for length %d (%q)\n", len(hexStr), hexStr)
			os.Exit(1)
		}
	}

	// 4. SpanIDFromHex returns an error for strings containing invalid hex or uppercase characters
	invalidChars := []string{
		"00f067aa0ba902bg",
		"00f067aa0ba902b-",
		"00f067aa 0ba902b",
		"00F067AA0BA902B7",
		"00f067aa0ba902B7",
	}
	for _, hexStr := range invalidChars {
		invalidSID, err := trace.SpanIDFromHex(hexStr)
		if err == nil {
			fmt.Fprintf(os.Stderr, "expected error for invalid/uppercase chars %q, got nil\n", hexStr)
			os.Exit(1)
		}
		if invalidSID.IsValid() {
			fmt.Fprintf(os.Stderr, "expected invalid SpanID for %q\n", hexStr)
			os.Exit(1)
		}
	}

	// 5. SpanIDFromHex returns an error for an all-zero hex string
	zeroHex := "0000000000000000"
	zeroSID, err := trace.SpanIDFromHex(zeroHex)
	if err == nil {
		fmt.Fprintf(os.Stderr, "expected error for all-zero hex string %q, got nil\n", zeroHex)
		os.Exit(1)
	}
	if zeroSID.IsValid() {
		fmt.Fprintf(os.Stderr, "expected IsValid() to be false for all-zero hex string\n")
		os.Exit(1)
	}
}