github.com/googleapis/enterprise-certificate-proxy v0.3.20: client.ErrCredUnavailable

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 github.com/googleapis/enterprise-certificate-proxy/client.ErrCredUnavailable in pkg:golang/github.com/googleapis/enterprise-certificate-proxy@v0.3.20
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/googleapis/enterprise-certificate-proxy@v0.3.20
Demonstrate these symbols/APIs:
  - github.com/googleapis/enterprise-certificate-proxy/client.ErrCredUnavailable

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:dc2c0e2570e4e8d56337d3162703965c0cd92f801a07ca5f25cfae0656f1bb9c","contract":["client.ErrCredUnavailable is a sentinel error indicating enterprise certificate credentials are unavailable","client.Cred returns client.ErrCredUnavailable when the configuration file does not exist","client.Cred returns client.ErrCredUnavailable when the configuration specifies an empty signer binary path","errors.Is matches client.ErrCredUnavailable when wrapped in an error chain"],"goal":"verify github.com/googleapis/enterprise-certificate-proxy/client.ErrCredUnavailable in pkg:golang/github.com/googleapis/enterprise-certificate-proxy@v0.3.20","kind":"HOW","packages":["pkg:golang/github.com/googleapis/enterprise-certificate-proxy@v0.3.20"],"schemaVersion":1,"symbols":["github.com/googleapis/enterprise-certificate-proxy/client.ErrCredUnavailable"]},"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/github.com/googleapis/enterprise-certificate-proxy@v0.3.20"],"schemaVersion":1,"subject":"pkg:golang/github.com/googleapis/enterprise-certificate-proxy@v0.3.20","symbols":["github.com/googleapis/enterprise-certificate-proxy/client.ErrCredUnavailable"],"verifierAdapter":"golang@1"}

module sample

go 1.25.0

require github.com/googleapis/enterprise-certificate-proxy v0.3.20

github.com/googleapis/enterprise-certificate-proxy v0.3.20 h1:t/xL64VUoN69MuMRQuJETqYGOw4Z9mSRJK9epIEtwFk=
github.com/googleapis/enterprise-certificate-proxy v0.3.20/go.mod h1:L3D/IQExI6LqEjBdXcZQ1WluSgigQmSwBboFstVPM4w=

package main

import (
	"errors"
	"fmt"

	"github.com/googleapis/enterprise-certificate-proxy/client"
)

func main() {
	// Attempt to load credentials from a non-existent configuration path
	_, err := client.Cred("non_existent_config.json")
	if errors.Is(err, client.ErrCredUnavailable) {
		fmt.Printf("Received expected sentinel error: %v\n", err)
	} else if err != nil {
		fmt.Printf("Unexpected error: %v\n", err)
	} else {
		fmt.Println("Unexpected success loading credentials")
	}
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/googleapis/enterprise-certificate-proxy/client.ErrCredUnavailable in pkg:golang/github.com/googleapis/enterprise-certificate-proxy@v0.3.20",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/googleapis/enterprise-certificate-proxy@v0.3.20"
  ],
  "symbols": [
    "github.com/googleapis/enterprise-certificate-proxy/client.ErrCredUnavailable"
  ]
}

package main

import (
	"errors"
	"fmt"
	"os"
	"path/filepath"

	"github.com/googleapis/enterprise-certificate-proxy/client"
)

func main() {
	if err := runContract(); err != nil {
		fmt.Fprintf(os.Stderr, "Contract verification failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("All enterprise-certificate-proxy ErrCredUnavailable contract assertions passed successfully.")
}

func runContract() error {
	tempDir, err := os.MkdirTemp("", "ecp-contract-*")
	if err != nil {
		return fmt.Errorf("failed to create temp directory: %w", err)
	}
	defer os.RemoveAll(tempDir)

	// 1. client.ErrCredUnavailable is a sentinel error indicating enterprise certificate credentials are unavailable
	if client.ErrCredUnavailable == nil {
		return fmt.Errorf("assertion 1 failed: client.ErrCredUnavailable is nil")
	}
	if client.ErrCredUnavailable.Error() != "cred is unavailable" {
		return fmt.Errorf("assertion 1 failed: expected error string 'cred is unavailable', got %q", client.ErrCredUnavailable.Error())
	}

	// 2. client.Cred returns client.ErrCredUnavailable when the configuration file does not exist
	nonExistentPath := filepath.Join(tempDir, "does_not_exist.json")
	_, err = client.Cred(nonExistentPath)
	if !errors.Is(err, client.ErrCredUnavailable) {
		return fmt.Errorf("assertion 2 failed: expected client.ErrCredUnavailable, got %v", err)
	}

	// 3. client.Cred returns client.ErrCredUnavailable when the configuration specifies an empty signer binary path
	emptySignerConfig := filepath.Join(tempDir, "empty_signer.json")
	if err := os.WriteFile(emptySignerConfig, []byte(`{"libs":{"ecp":""}}`), 0600); err != nil {
		return fmt.Errorf("failed to write empty signer config: %w", err)
	}
	_, err = client.Cred(emptySignerConfig)
	if !errors.Is(err, client.ErrCredUnavailable) {
		return fmt.Errorf("assertion 3 failed: expected client.ErrCredUnavailable, got %v", err)
	}

	// 4. errors.Is matches client.ErrCredUnavailable when wrapped in an error chain
	wrappedErr := fmt.Errorf("credential init failure: %w", client.ErrCredUnavailable)
	if !errors.Is(wrappedErr, client.ErrCredUnavailable) {
		return fmt.Errorf("assertion 4 failed: wrapped error was not matched by errors.Is")
	}

	return nil
}