3 files changed, 56 insertions, 41 deletions

diff --git a/caddyconfig/httpcaddyfile/directives.go b/caddyconfig/httpcaddyfile/directives.go
index ac401e1..1578772 100644
--- a/caddyconfig/httpcaddyfile/directives.go
+++ b/caddyconfig/httpcaddyfile/directives.go
@@ -120,6 +120,17 @@ func RegisterHandlerDirective(dir string, setupFunc UnmarshalHandlerFunc) {
 	})
 }
 
+// RegisterGlobalOption registers a unique global option opt with
+// an associated unmarshaling (setup) function. When the global
+// option opt is encountered in a Caddyfile, setupFunc will be
+// called to unmarshal its tokens.
+func RegisterGlobalOption(opt string, setupFunc UnmarshalGlobalFunc) {
+	if _, ok := registeredGlobalOptions[opt]; ok {
+		panic("global option " + opt + " already registered")
+	}
+	registeredGlobalOptions[opt] = setupFunc
+}
+
 // Helper is a type which helps setup a value from
 // Caddyfile tokens.
 type Helper struct {
@@ -454,6 +465,13 @@ type (
 	// for you. These are passed to a call to
 	// RegisterHandlerDirective.
 	UnmarshalHandlerFunc func(h Helper) (caddyhttp.MiddlewareHandler, error)
+
+	// UnmarshalGlobalFunc is a function which can unmarshal Caddyfile
+	// tokens into a global option config value using a Helper type.
+	// These are passed in a call to RegisterGlobalOption.
+	UnmarshalGlobalFunc func(d *caddyfile.Dispenser) (interface{}, error)
 )
 
 var registeredDirectives = make(map[string]UnmarshalFunc)
+
+var registeredGlobalOptions = make(map[string]UnmarshalGlobalFunc)
diff --git a/caddyconfig/httpcaddyfile/httptype.go b/caddyconfig/httpcaddyfile/httptype.go
index aacaf91..378289c 100644
--- a/caddyconfig/httpcaddyfile/httptype.go
+++ b/caddyconfig/httpcaddyfile/httptype.go
@@ -284,39 +284,18 @@ func (ServerType) evaluateGlobalOptionsBlock(serverBlocks []serverBlock, options
 		var val interface{}
 		var err error
 		disp := caddyfile.NewDispenser(segment)
-		switch dir {
-		case "debug":
-			val = true
-		case "http_port":
-			val, err = parseOptHTTPPort(disp)
-		case "https_port":
-			val, err = parseOptHTTPSPort(disp)
-		case "default_sni":
-			val, err = parseOptSingleString(disp)
-		case "order":
-			val, err = parseOptOrder(disp)
-		case "experimental_http3":
-			val, err = parseOptExperimentalHTTP3(disp)
-		case "storage":
-			val, err = parseOptStorage(disp)
-		case "acme_ca", "acme_dns", "acme_ca_root":
-			val, err = parseOptSingleString(disp)
-		case "email":
-			val, err = parseOptSingleString(disp)
-		case "admin":
-			val, err = parseOptAdmin(disp)
-		case "on_demand_tls":
-			val, err = parseOptOnDemand(disp)
-		case "local_certs":
-			val = true
-		case "key_type":
-			val, err = parseOptSingleString(disp)
-		default:
-			return nil, fmt.Errorf("unrecognized parameter name: %s", dir)
+
+		dirFunc, ok := registeredGlobalOptions[dir]
+		if !ok {
+			tkn := segment[0]
+			return nil, fmt.Errorf("%s:%d: unrecognized global option: %s", tkn.File, tkn.Line, dir)
 		}
+
+		val, err = dirFunc(disp)
 		if err != nil {
-			return nil, fmt.Errorf("%s: %v", dir, err)
+			return nil, fmt.Errorf("parsing caddyfile tokens for '%s': %v", dir, err)
 		}
+
 		options[dir] = val
 	}
 
diff --git a/caddyconfig/httpcaddyfile/options.go b/caddyconfig/httpcaddyfile/options.go
index 2ab73b2..de288db 100644
--- a/caddyconfig/httpcaddyfile/options.go
+++ b/caddyconfig/httpcaddyfile/options.go
@@ -23,7 +23,29 @@ import (
 	"github.com/caddyserver/caddy/v2/modules/caddytls"
 )
 
-func parseOptHTTPPort(d *caddyfile.Dispenser) (int, error) {
+func init() {
+	RegisterGlobalOption("debug", parseOptTrue)
+	RegisterGlobalOption("http_port", parseOptHTTPPort)
+	RegisterGlobalOption("https_port", parseOptHTTPSPort)
+	RegisterGlobalOption("default_sni", parseOptSingleString)
+	RegisterGlobalOption("order", parseOptOrder)
+	RegisterGlobalOption("experimental_http3", parseOptTrue)
+	RegisterGlobalOption("storage", parseOptStorage)
+	RegisterGlobalOption("acme_ca", parseOptSingleString)
+	RegisterGlobalOption("acme_dns", parseOptSingleString)
+	RegisterGlobalOption("acme_ca_root", parseOptSingleString)
+	RegisterGlobalOption("email", parseOptSingleString)
+	RegisterGlobalOption("admin", parseOptAdmin)
+	RegisterGlobalOption("on_demand_tls", parseOptOnDemand)
+	RegisterGlobalOption("local_certs", parseOptTrue)
+	RegisterGlobalOption("key_type", parseOptSingleString)
+}
+
+func parseOptTrue(d *caddyfile.Dispenser) (interface{}, error) {
+	return true, nil
+}
+
+func parseOptHTTPPort(d *caddyfile.Dispenser) (interface{}, error) {
 	var httpPort int
 	for d.Next() {
 		var httpPortStr string
@@ -39,7 +61,7 @@ func parseOptHTTPPort(d *caddyfile.Dispenser) (int, error) {
 	return httpPort, nil
 }
 
-func parseOptHTTPSPort(d *caddyfile.Dispenser) (int, error) {
+func parseOptHTTPSPort(d *caddyfile.Dispenser) (interface{}, error) {
 	var httpsPort int
 	for d.Next() {
 		var httpsPortStr string
@@ -55,11 +77,7 @@ func parseOptHTTPSPort(d *caddyfile.Dispenser) (int, error) {
 	return httpsPort, nil
 }
 
-func parseOptExperimentalHTTP3(d *caddyfile.Dispenser) (bool, error) {
-	return true, nil
-}
-
-func parseOptOrder(d *caddyfile.Dispenser) ([]string, error) {
+func parseOptOrder(d *caddyfile.Dispenser) (interface{}, error) {
 	newOrder := directiveOrder
 
 	for d.Next() {
@@ -135,7 +153,7 @@ func parseOptOrder(d *caddyfile.Dispenser) ([]string, error) {
 	return newOrder, nil
 }
 
-func parseOptStorage(d *caddyfile.Dispenser) (caddy.StorageConverter, error) {
+func parseOptStorage(d *caddyfile.Dispenser) (interface{}, error) {
 	if !d.Next() { // consume option name
 		return nil, d.ArgErr()
 	}
@@ -162,7 +180,7 @@ func parseOptStorage(d *caddyfile.Dispenser) (caddy.StorageConverter, error) {
 	return storage, nil
 }
 
-func parseOptSingleString(d *caddyfile.Dispenser) (string, error) {
+func parseOptSingleString(d *caddyfile.Dispenser) (interface{}, error) {
 	d.Next() // consume parameter name
 	if !d.Next() {
 		return "", d.ArgErr()
@@ -174,7 +192,7 @@ func parseOptSingleString(d *caddyfile.Dispenser) (string, error) {
 	return val, nil
 }
 
-func parseOptAdmin(d *caddyfile.Dispenser) (string, error) {
+func parseOptAdmin(d *caddyfile.Dispenser) (interface{}, error) {
 	if d.Next() {
 		var listenAddress string
 		if !d.AllArgs(&listenAddress) {
@@ -188,7 +206,7 @@ func parseOptAdmin(d *caddyfile.Dispenser) (string, error) {
 	return "", nil
 }
 
-func parseOptOnDemand(d *caddyfile.Dispenser) (*caddytls.OnDemandConfig, error) {
+func parseOptOnDemand(d *caddyfile.Dispenser) (interface{}, error) {
 	var ond *caddytls.OnDemandConfig
 	for d.Next() {
 		if d.NextArg() {