error message every 10 minutes about managing the server certificate about acme-dns HOT 8 OPEN

From 003a56d677fe0cf621ea92fc9446cf45a199e277 Mon Sep 17 00:00:00 2001
From: Philipp Kolberg <[email protected]>
Date: Wed, 29 Nov 2023 22:43:49 +0100
Subject: [PATCH] Fix certmagic cache handling

---
 pkg/api/api.go | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/pkg/api/api.go b/pkg/api/api.go
index 9fc96f6..bd75129 100644
--- a/pkg/api/api.go
+++ b/pkg/api/api.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto/tls"
 	"net/http"
+	"sync"
 
 	"github.com/acme-dns/acme-dns/pkg/acmedns"
 
@@ -14,10 +15,12 @@ import (
 )
 
 type AcmednsAPI struct {
-	Config  *acmedns.AcmeDnsConfig
-	DB      acmedns.AcmednsDB
-	Logger  *zap.SugaredLogger
-	errChan chan error
+	Config  	 *acmedns.AcmeDnsConfig
+	DB      	 acmedns.AcmednsDB
+	Logger  	 *zap.SugaredLogger
+	errChan 	 chan error
+	magicCache   *certmagic.Cache
+	magicCacheMu sync.Mutex
 }
 
 func Init(config *acmedns.AcmeDnsConfig, db acmedns.AcmednsDB, logger *zap.SugaredLogger, errChan chan error) AcmednsAPI {
@@ -137,12 +140,17 @@ func (a *AcmednsAPI) setupTLS(dnsservers []acmedns.AcmednsNS) *certmagic.Config
 	magicConf.Logger = a.Logger.Desugar()
 	magicConf.Storage = &storage
 	magicConf.DefaultServerName = a.Config.General.Domain
-	magicCache := certmagic.NewCache(certmagic.CacheOptions{
-		GetConfigForCert: func(cert certmagic.Certificate) (*certmagic.Config, error) {
-			return &magicConf, nil
-		},
-		Logger: a.Logger.Desugar(),
-	})
-	magic := certmagic.New(magicCache, magicConf)
+	a.magicCacheMu.Lock()
+	if a.magicCache == nil {
+		a.magicCache = certmagic.NewCache(certmagic.CacheOptions{
+			GetConfigForCert: func(cert certmagic.Certificate) (*certmagic.Config, error) {
+				return a.setupTLS(dnsservers), nil
+			},
+			Logger: a.Logger.Desugar(),
+		})
+	}
+	certCache := a.magicCache
+	a.magicCacheMu.Unlock()
+	magic := certmagic.New(certCache, magicConf)
 	return magic
 }
-- 
2.39.3 (Apple Git-145)

Apr 08 20:13:32 vmanager9064 acme-dns[16782]: 1.7126072127843883e+09        info        maintenance        started background certificate maintenance        {"cache": "0xc000026800"}
Apr 08 20:13:32 vmanager9064 acme-dns[16782]: 1.7126072127844315e+09        info        maintenance        started background certificate maintenance        {"cache": "0xc000026880"}
...
Apr 08 20:43:32 vmanager9064 acme-dns[16782]: 1.712609012784654e+09        error        maintenance        unable to get configuration to manage certificate; unable to renew        {"identifiers": ["<snip>"], "error": "config returned for certificate [<snip>] is not nil and points to different cache; got 0xc000026800, expected 0xc000026880 (this one)"}