caddyfile: Add renewal_window_ratio global option and tls subdirective (#7473)

* caddyfile: Add renewal_window_ratio global option

Adds support for configuring the TLS certificate renewal window ratio
directly in the Caddyfile global options block. This allows users to
customize when certificates should be renewed without needing to use
JSON configuration.

Example usage:
    {
        renewal_window_ratio 0.1666
    }

Fixes #7467

* caddyfile: Add renewal_window_ratio to tls directive and tests

Adds support for renewal_window_ratio in the tls directive (not just
global options) and adds caddyfile adapt tests for both the global
option and tls directive.

* fix: inherit global renewal_window_ratio in site policies

* fix: correct test expected output for policy consolidation

* fix: properly inherit global renewal_window_ratio without removing other code

caddyconfig/httpcaddyfile/builtins.go

@@ -113,6 +113,7 @@ func parseBind(h Helper) ([]ConfigValue, error) {
 //	    issuer                        <module_name> [...]
 //	    get_certificate               <module_name> [...]
 //	    insecure_secrets_log          <log_file>
+//	    renewal_window_ratio          <ratio>
 //	}
 func parseTLS(h Helper) ([]ConfigValue, error) {
 	h.Next() // consume directive name
@@ -129,6 +130,7 @@ func parseTLS(h Helper) ([]ConfigValue, error) {
 	var onDemand bool
 	var reusePrivateKeys bool
 	var forceAutomate bool
+	var renewalWindowRatio float64
 
 	// Track which DNS challenge options are set
 	var dnsOptionsSet []string
@@ -473,6 +475,20 @@ func parseTLS(h Helper) ([]ConfigValue, error) {
 			}
 			cp.InsecureSecretsLog = h.Val()
 
+		case "renewal_window_ratio":
+			arg := h.RemainingArgs()
+			if len(arg) != 1 {
+				return nil, h.ArgErr()
+			}
+			ratio, err := strconv.ParseFloat(arg[0], 64)
+			if err != nil {
+				return nil, h.Errf("parsing renewal_window_ratio: %v", err)
+			}
+			if ratio <= 0 || ratio >= 1 {
+				return nil, h.Errf("renewal_window_ratio must be between 0 and 1 (exclusive)")
+			}
+			renewalWindowRatio = ratio
+
 		default:
 			return nil, h.Errf("unknown subdirective: %s", h.Val())
 		}
@@ -597,6 +613,14 @@ func parseTLS(h Helper) ([]ConfigValue, error) {
 		})
 	}
 
+	// renewal window ratio
+	if renewalWindowRatio > 0 {
+		configVals = append(configVals, ConfigValue{
+			Class: "tls.renewal_window_ratio",
+			Value: renewalWindowRatio,
+		})
+	}
+
 	// if enabled, the names in the site addresses will be
 	// added to the automation policies
 	if forceAutomate {

caddyconfig/httpcaddyfile/options.go

@@ -65,6 +65,7 @@ func init() {
 	RegisterGlobalOption("persist_config", parseOptPersistConfig)
 	RegisterGlobalOption("dns", parseOptDNS)
 	RegisterGlobalOption("ech", parseOptECH)
+	RegisterGlobalOption("renewal_window_ratio", parseOptRenewalWindowRatio)
 }
 
 func parseOptTrue(d *caddyfile.Dispenser, _ any) (any, error) { return true, nil }
@@ -624,3 +625,22 @@ func parseOptECH(d *caddyfile.Dispenser, _ any) (any, error) {
 
 	return ech, nil
 }
+
+func parseOptRenewalWindowRatio(d *caddyfile.Dispenser, _ any) (any, error) {
+	d.Next() // consume option name
+	if !d.Next() {
+		return 0, d.ArgErr()
+	}
+	val := d.Val()
+	ratio, err := strconv.ParseFloat(val, 64)
+	if err != nil {
+		return 0, d.Errf("parsing renewal_window_ratio: %v", err)
+	}
+	if ratio <= 0 || ratio >= 1 {
+		return 0, d.Errf("renewal_window_ratio must be between 0 and 1 (exclusive)")
+	}
+	if d.Next() {
+		return 0, d.ArgErr()
+	}
+	return ratio, nil
+}

caddyconfig/httpcaddyfile/tlsapp.go

@@ -143,6 +143,12 @@ func (st ServerType) buildTLSApp(
 				ap.KeyType = keyTypeVals[0].Value.(string)
 			}
 
+			if renewalWindowRatioVals, ok := sblock.pile["tls.renewal_window_ratio"]; ok {
+				ap.RenewalWindowRatio = renewalWindowRatioVals[0].Value.(float64)
+			} else if globalRenewalWindowRatio, ok := options["renewal_window_ratio"]; ok {
+				ap.RenewalWindowRatio = globalRenewalWindowRatio.(float64)
+			}
+
 			// certificate issuers
 			if issuerVals, ok := sblock.pile["tls.cert_issuer"]; ok {
 				var issuers []certmagic.Issuer
@@ -607,7 +613,8 @@ func newBaseAutomationPolicy(
 	_, hasLocalCerts := options["local_certs"]
 	keyType, hasKeyType := options["key_type"]
 	ocspStapling, hasOCSPStapling := options["ocsp_stapling"]
-	hasGlobalAutomationOpts := hasIssuers || hasLocalCerts || hasKeyType || hasOCSPStapling
+	renewalWindowRatio, hasRenewalWindowRatio := options["renewal_window_ratio"]
+	hasGlobalAutomationOpts := hasIssuers || hasLocalCerts || hasKeyType || hasOCSPStapling || hasRenewalWindowRatio
 
 	globalACMECA := options["acme_ca"]
 	globalACMECARoot := options["acme_ca_root"]
@@ -654,6 +661,10 @@ func newBaseAutomationPolicy(
 		ap.OCSPOverrides = ocspConfig.ResponderOverrides
 	}
 
+	if hasRenewalWindowRatio {
+		ap.RenewalWindowRatio = renewalWindowRatio.(float64)
+	}
+
 	return ap, nil
 }
 

caddytest/integration/caddyfile_adapt/renewal_window_ratio_global.caddyfiletest

@@ -0,0 +1,41 @@
+{
+	renewal_window_ratio 0.1666
+}
+
+example.com {
+}
+----------
+{
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":443"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"host": [
+										"example.com"
+									]
+								}
+							],
+							"terminal": true
+						}
+					]
+				}
+			}
+		},
+		"tls": {
+			"automation": {
+				"policies": [
+					{
+						"renewal_window_ratio": 0.1666
+					}
+				]
+			}
+		}
+	}
+}

caddytest/integration/caddyfile_adapt/renewal_window_ratio_tls_directive.caddyfiletest

@@ -0,0 +1,63 @@
+{
+	renewal_window_ratio 0.1666
+}
+
+a.example.com {
+	tls {
+		renewal_window_ratio 0.25
+	}
+}
+
+b.example.com {
+}
+----------
+{
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":443"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"host": [
+										"a.example.com"
+									]
+								}
+							],
+							"terminal": true
+						},
+						{
+							"match": [
+								{
+									"host": [
+										"b.example.com"
+									]
+								}
+							],
+							"terminal": true
+						}
+					]
+				}
+			}
+		},
+		"tls": {
+			"automation": {
+				"policies": [
+					{
+						"subjects": [
+							"a.example.com"
+						],
+						"renewal_window_ratio": 0.25
+					},
+					{
+						"renewal_window_ratio": 0.1666
+					}
+				]
+			}
+		}
+	}
+}