github.com/caddyserver/certmagic v0.25.3: Cache

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/caddyserver/certmagic.Cache in pkg:golang/github.com/caddyserver/certmagic@v0.25.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/caddyserver/certmagic@v0.25.3
Demonstrate these symbols/APIs:
  - github.com/caddyserver/certmagic.Cache

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.

package sample

import (
	"time"

	"github.com/caddyserver/certmagic"
	"go.uber.org/zap"
)

// NewCustomCache creates and returns an initialized *certmagic.Cache with custom options.
func NewCustomCache(capacity int, renewInterval, ocspInterval time.Duration, logger *zap.Logger) *certmagic.Cache {
	if logger == nil {
		logger = zap.NewNop()
	}

	var cache *certmagic.Cache
	cache = certmagic.NewCache(certmagic.CacheOptions{
		GetConfigForCert: func(cert certmagic.Certificate) (*certmagic.Config, error) {
			return certmagic.New(cache, certmagic.Config{
				Logger: logger,
			}), nil
		},
		RenewCheckInterval: renewInterval,
		OCSPCheckInterval:  ocspInterval,
		Capacity:           capacity,
		Logger:             logger,
	})

	return cache
}

{"case":{"caseId":"case:sha256:f34eabd7c87a64fbdef635c9725bfa82d88831ff9b8926986aa9678f8c79b805","contract":["certmagic.NewCache panics if GetConfigForCert is not set in CacheOptions","certmagic.NewCache returns a valid Cache instance when GetConfigForCert is configured","Cache.SetOptions panics when GetConfigForCert callback is nil","Cache.AllMatchingCertificates retrieves certificates matching exact SAN names and wildcard domains","Cache.Remove deletes certificates by hash and clears lookup indexes","Cache.Stop cleanly terminates background maintenance"],"goal":"verify github.com/caddyserver/certmagic.Cache in pkg:golang/github.com/caddyserver/certmagic@v0.25.3","kind":"HOW","packages":["pkg:golang/github.com/caddyserver/certmagic@v0.25.3"],"schemaVersion":1,"symbols":["github.com/caddyserver/certmagic.Cache"]},"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/caddyserver/certmagic@v0.25.3"],"schemaVersion":1,"subject":"pkg:golang/github.com/caddyserver/certmagic@v0.25.3","symbols":["github.com/caddyserver/certmagic.Cache"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require (
	github.com/caddyserver/certmagic v0.25.3
	go.uber.org/zap v1.27.1
)

require (
	github.com/caddyserver/zerossl v0.1.5 // indirect
	github.com/klauspost/cpuid/v2 v2.3.0 // indirect
	github.com/libdns/libdns v1.1.1 // indirect
	github.com/mholt/acmez/v3 v3.1.6 // indirect
	github.com/miekg/dns v1.1.72 // indirect
	github.com/zeebo/blake3 v0.2.4 // indirect
	go.uber.org/multierr v1.11.0 // indirect
	go.uber.org/zap/exp v0.3.0 // indirect
	golang.org/x/crypto v0.50.0 // indirect
	golang.org/x/mod v0.35.0 // indirect
	golang.org/x/net v0.53.0 // indirect
	golang.org/x/sync v0.20.0 // indirect
	golang.org/x/sys v0.43.0 // indirect
	golang.org/x/text v0.36.0 // indirect
	golang.org/x/tools v0.44.0 // indirect
)

code.pfad.fr/check v1.1.0 h1:GWvjdzhSEgHvEHe2uJujDcpmZoySKuHQNrZMfzfO0bE=
code.pfad.fr/check v1.1.0/go.mod h1:NiUH13DtYsb7xp5wll0U4SXx7KhXQVCtRgdC96IPfoM=
github.com/caddyserver/certmagic v0.25.3 h1:mGf5ba8F7xA4c5jfDZZbK2buY1VEkbnwpMDixaju94A=
github.com/caddyserver/certmagic v0.25.3/go.mod h1:YVs43D5+H/Dckt4bTga1KSO/xYfFBfVZainGDywYPAA=
github.com/caddyserver/zerossl v0.1.5 h1:dkvOjBAEEtY6LIGAHei7sw2UgqSD6TrWweXpV7lvEvE=
github.com/caddyserver/zerossl v0.1.5/go.mod h1:CxA0acn7oEGO6//4rtrRjYgEoa4MFw/XofZnrYwGqG4=
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/go-jose/go-jose/v4 v4.1.3 h1:CVLmWDhDVRa6Mi/IgCgaopNosCaHz7zrMeF9MlZRkrs=
github.com/go-jose/go-jose/v4 v4.1.3/go.mod h1:x4oUasVrzR7071A4TnHLGSPpNOm2a21K9Kf04k1rs08=
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/klauspost/cpuid/v2 v2.3.0 h1:S4CRMLnYUhGeDFDqkGriYKdfoFlDnMtqTiI/sFzhA9Y=
github.com/klauspost/cpuid/v2 v2.3.0/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
github.com/letsencrypt/challtestsrv v1.4.2 h1:0ON3ldMhZyWlfVNYYpFuWRTmZNnyfiL9Hh5YzC3JVwU=
github.com/letsencrypt/challtestsrv v1.4.2/go.mod h1:GhqMqcSoeGpYd5zX5TgwA6er/1MbWzx/o7yuuVya+Wk=
github.com/letsencrypt/pebble/v2 v2.10.0 h1:Wq6gYXlsY6ubqI3hhxsTzdyotvfdjFBxuwYqCLCnj/U=
github.com/letsencrypt/pebble/v2 v2.10.0/go.mod h1:Sk8cmUIPcIdv2nINo+9PB4L+ZBhzY+F9A1a/h/xmWiQ=
github.com/libdns/libdns v1.1.1 h1:wPrHrXILoSHKWJKGd0EiAVmiJbFShguILTg9leS/P/U=
github.com/libdns/libdns v1.1.1/go.mod h1:4Bj9+5CQiNMVGf87wjX4CY3HQJypUHRuLvlsfsZqLWQ=
github.com/mholt/acmez/v3 v3.1.6 h1:eGVQNObP0pBN4sxqrXeg7MYqTOWyoiYpQqITVWlrevk=
github.com/mholt/acmez/v3 v3.1.6/go.mod h1:5nTPosTGosLxF3+LU4ygbgMRFDhbAVpqMI4+a4aHLBY=
github.com/miekg/dns v1.1.72 h1:vhmr+TF2A3tuoGNkLDFK9zi36F2LS+hKTRW0Uf8kbzI=
github.com/miekg/dns v1.1.72/go.mod h1:+EuEPhdHOsfk6Wk5TT2CzssZdqkmFhf8r+aVyDEToIs=
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 v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
github.com/zeebo/assert v1.1.0 h1:hU1L1vLTHsnO8x8c9KAR5GmM5QscxHg5RNU5z5qbUWY=
github.com/zeebo/assert v1.1.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN/wJ0=
github.com/zeebo/blake3 v0.2.4 h1:KYQPkhpRtcqh0ssGYcKLG1JYvddkEA8QwCM/yBqhaZI=
github.com/zeebo/blake3 v0.2.4/go.mod h1:7eeQ6d2iXWRGF6npfaxl2CU+xy2Fjo2gxeyZGCRUjcE=
github.com/zeebo/pcg v1.0.1 h1:lyqfGeWiv4ahac6ttHs+I5hwtH/+1mrhlCtVNQM2kHo=
github.com/zeebo/pcg v1.0.1/go.mod h1:09F0S9iiKrwn9rlI5yjLkmrug154/YRW6KnnXVDM/l4=
go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=
go.uber.org/multierr v1.11.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
go.uber.org/zap v1.27.1 h1:08RqriUEv8+ArZRYSTXy1LeBScaMpVSTBhCeaZYfMYc=
go.uber.org/zap v1.27.1/go.mod h1:GB2qFLM7cTU87MWRP2mPIjqfIDnGu+VIO4V/SdhGo2E=
go.uber.org/zap/exp v0.3.0 h1:6JYzdifzYkGmTdRR59oYH+Ng7k49H9qVpWwNSsGJj3U=
go.uber.org/zap/exp v0.3.0/go.mod h1:5I384qq7XGxYyByIhHm6jg5CHkGY0nsTfbDLgDDlgJQ=
golang.org/x/crypto v0.50.0 h1:zO47/JPrL6vsNkINmLoo/PH1gcxpls50DNogFvB5ZGI=
golang.org/x/crypto v0.50.0/go.mod h1:3muZ7vA7PBCE6xgPX7nkzzjiUq87kRItoJQM1Yo8S+Q=
golang.org/x/mod v0.35.0 h1:Ww1D637e6Pg+Zb2KrWfHQUnH2dQRLBQyAtpr/haaJeM=
golang.org/x/mod v0.35.0/go.mod h1:+GwiRhIInF8wPm+4AoT6L0FA1QWAad3OMdTRx4tFYlU=
golang.org/x/net v0.53.0 h1:d+qAbo5L0orcWAr0a9JweQpjXF19LMXJE8Ey7hwOdUA=
golang.org/x/net v0.53.0/go.mod h1:JvMuJH7rrdiCfbeHoo3fCQU24Lf5JJwT9W3sJFulfgs=
golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
golang.org/x/sys v0.43.0 h1:Rlag2XtaFTxp19wS8MXlJwTvoh8ArU6ezoyFsMyCTNI=
golang.org/x/sys v0.43.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
golang.org/x/text v0.36.0 h1:JfKh3XmcRPqZPKevfXVpI1wXPTqbkE5f7JA92a55Yxg=
golang.org/x/text v0.36.0/go.mod h1:NIdBknypM8iqVmPiuco0Dh6P5Jcdk8lJL0CUebqK164=
golang.org/x/tools v0.44.0 h1:UP4ajHPIcuMjT1GqzDWRlalUEoY+uzoZKnhOjbIPD2c=
golang.org/x/tools v0.44.0/go.mod h1:KA0AfVErSdxRZIsOVipbv3rQhVXTnlU6UhKxHd1seDI=
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 github.com/caddyserver/certmagic.Cache in pkg:golang/github.com/caddyserver/certmagic@v0.25.3",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/caddyserver/certmagic@v0.25.3"
  ],
  "symbols": [
    "github.com/caddyserver/certmagic.Cache"
  ]
}

package main

import (
	"context"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"crypto/tls"
	"crypto/x509"
	"crypto/x509/pkix"
	"fmt"
	"math/big"
	"os"
	"time"

	"sample"

	"github.com/caddyserver/certmagic"
	"go.uber.org/zap"
)

func generateTestCert(domain string) (tls.Certificate, error) {
	priv, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	if err != nil {
		return tls.Certificate{}, err
	}
	template := x509.Certificate{
		SerialNumber: big.NewInt(1),
		Subject: pkix.Name{
			CommonName: domain,
		},
		DNSNames:  []string{domain},
		NotBefore: time.Now().Add(-1 * time.Hour),
		NotAfter:  time.Now().Add(24 * time.Hour),
	}
	derBytes, err := x509.CreateCertificate(rand.Reader, &template, &template, &priv.PublicKey, priv)
	if err != nil {
		return tls.Certificate{}, err
	}
	return tls.Certificate{
		Certificate: [][]byte{derBytes},
		PrivateKey:  priv,
	}, nil
}

func main() {
	// 1. certmagic.NewCache panics if GetConfigForCert is not set in CacheOptions
	panicked := false
	func() {
		defer func() {
			if r := recover(); r != nil {
				panicked = true
			}
		}()
		certmagic.NewCache(certmagic.CacheOptions{Logger: zap.NewNop()})
	}()
	if !panicked {
		fmt.Fprintln(os.Stderr, "FAIL: expected NewCache to panic when GetConfigForCert is nil")
		os.Exit(1)
	}
	fmt.Println("PASS: certmagic.NewCache panics if GetConfigForCert is not set")

	// 2. certmagic.NewCache returns a valid Cache instance when GetConfigForCert is configured
	cache := sample.NewCustomCache(100, 10*time.Minute, 10*time.Minute, zap.NewNop())
	if cache == nil {
		fmt.Fprintln(os.Stderr, "FAIL: expected valid non-nil Cache from NewCustomCache")
		os.Exit(1)
	}
	fmt.Println("PASS: certmagic.NewCache returns a valid Cache instance")

	// 3. Cache.SetOptions panics when GetConfigForCert callback is nil
	panicked = false
	func() {
		defer func() {
			if r := recover(); r != nil {
				panicked = true
			}
		}()
		cache.SetOptions(certmagic.CacheOptions{Logger: zap.NewNop()})
	}()
	if !panicked {
		fmt.Fprintln(os.Stderr, "FAIL: expected SetOptions to panic when GetConfigForCert is nil")
		os.Exit(1)
	}
	fmt.Println("PASS: Cache.SetOptions panics when GetConfigForCert callback is nil")

	// 4. Cache.AllMatchingCertificates retrieves certificates matching exact SAN names and wildcard domains
	cfg := certmagic.New(cache, certmagic.Config{
		Logger: zap.NewNop(),
	})

	exactCert, err := generateTestCert("example.com")
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: generateTestCert(example.com): %v\n", err)
		os.Exit(1)
	}
	exactHash, err := cfg.CacheUnmanagedTLSCertificate(context.Background(), exactCert, nil)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: CacheUnmanagedTLSCertificate(example.com): %v\n", err)
		os.Exit(1)
	}

	wildcardCert, err := generateTestCert("*.example.com")
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: generateTestCert(*.example.com): %v\n", err)
		os.Exit(1)
	}
	wildcardHash, err := cfg.CacheUnmanagedTLSCertificate(context.Background(), wildcardCert, nil)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: CacheUnmanagedTLSCertificate(*.example.com): %v\n", err)
		os.Exit(1)
	}

	exactMatches := cache.AllMatchingCertificates("example.com")
	if len(exactMatches) == 0 || exactMatches[0].Hash() != exactHash {
		fmt.Fprintln(os.Stderr, "FAIL: AllMatchingCertificates failed to match exact SAN")
		os.Exit(1)
	}

	subMatches := cache.AllMatchingCertificates("sub.example.com")
	foundWildcard := false
	for _, m := range subMatches {
		if m.Hash() == wildcardHash {
			foundWildcard = true
			break
		}
	}
	if !foundWildcard {
		fmt.Fprintln(os.Stderr, "FAIL: AllMatchingCertificates failed to match wildcard domain")
		os.Exit(1)
	}

	unmatched := cache.AllMatchingCertificates("unrelated.org")
	if len(unmatched) != 0 {
		fmt.Fprintln(os.Stderr, "FAIL: AllMatchingCertificates unexpectedly matched unrelated domain")
		os.Exit(1)
	}
	fmt.Println("PASS: Cache.AllMatchingCertificates retrieves exact and wildcard matches")

	// 5. Cache.Remove deletes certificates by hash and clears lookup indexes
	cache.Remove([]string{exactHash})
	afterExactRemove := cache.AllMatchingCertificates("example.com")
	if len(afterExactRemove) != 0 {
		fmt.Fprintln(os.Stderr, "FAIL: expected zero matches for example.com after Remove")
		os.Exit(1)
	}
	cache.Remove([]string{wildcardHash})
	afterWildcardRemove := cache.AllMatchingCertificates("sub.example.com")
	if len(afterWildcardRemove) != 0 {
		fmt.Fprintln(os.Stderr, "FAIL: expected zero matches for sub.example.com after Remove")
		os.Exit(1)
	}
	fmt.Println("PASS: Cache.Remove unloads certificates and clears lookup indexes")

	// 6. Cache.Stop cleanly terminates background maintenance
	cache.Stop()
	fmt.Println("PASS: Cache.Stop cleanly terminates background maintenance")

	fmt.Println("All certmagic.Cache contract tests passed.")
}