add config option for control URL

also return any replacer errors, and remove app nil check since we
always check prior to calling these config funcs.

Closes #22

Co-authored-by: ChibangLW <ich@leonlenzen.de>
Signed-off-by: Will Norris <will@tailscale.com>

app.go

@@ -22,6 +22,9 @@ type App struct {
 	// DefaultAuthKey is the default auth key to use for Tailscale if no other auth key is specified.
 	DefaultAuthKey string `json:"auth_key,omitempty" caddy:"namespace=tailscale.auth_key"`
 
+	// ControlURL specifies the default control URL to use for nodes.
+	ControlURL string `json:"control_url,omitempty" caddy:"namespace=tailscale.control_url"`
+
 	// Ephemeral specifies whether Tailscale nodes should be registered as ephemeral.
 	Ephemeral bool `json:"ephemeral,omitempty" caddy:"namespace=tailscale.ephemeral"`
 
@@ -38,6 +41,9 @@ type Node struct {
 	// AuthKey is the Tailscale auth key used to register the node.
 	AuthKey string `json:"auth_key,omitempty" caddy:"namespace=auth_key"`
 
+	// ControlURL specifies the control URL to use for the node.
+	ControlURL string `json:"control_url,omitempty" caddy:"namespace=tailscale.control_url"`
+
 	// Ephemeral specifies whether the node should be registered as ephemeral.
 	Ephemeral bool `json:"ephemeral,omitempty" caddy:"namespace=tailscale.ephemeral"`
 
@@ -82,6 +88,11 @@ func parseAppConfig(d *caddyfile.Dispenser, _ any) (any, error) {
 				return nil, d.ArgErr()
 			}
 			app.DefaultAuthKey = d.Val()
+		case "control_url":
+			if !d.NextArg() {
+				return nil, d.ArgErr()
+			}
+			app.ControlURL = d.Val()
 		case "ephemeral":
 			app.Ephemeral = true
 		default:
@@ -119,6 +130,11 @@ func parseNodeConfig(d *caddyfile.Dispenser) (Node, error) {
 				return node, segment.ArgErr()
 			}
 			node.AuthKey = segment.Val()
+		case "control_url":
+			if !segment.NextArg() {
+				return node, segment.ArgErr()
+			}
+			node.ControlURL = segment.Val()
 		case "ephemeral":
 			node.Ephemeral = true
 		default:

module.go

@@ -111,7 +111,10 @@ func getNode(ctx caddy.Context, name string) (*tailscaleNode, error) {
 		}
 
 		if s.AuthKey, err = getAuthKey(name, app); err != nil {
-			app.logger.Warn("error parsing auth key", zap.Error(err))
+			return nil, err
+		}
+		if s.ControlURL, err = getControlURL(name, app); err != nil {
+			return nil, err
 		}
 
 		if name != "" {
@@ -142,10 +145,6 @@ func getNode(ctx caddy.Context, name string) (*tailscaleNode, error) {
 var repl = caddy.NewReplacer()
 
 func getAuthKey(name string, app *App) (string, error) {
-	if app == nil {
-		return "", nil
-	}
-
 	if node, ok := app.Nodes[name]; ok {
 		if node.AuthKey != "" {
 			return repl.ReplaceOrErr(node.AuthKey, true, true)
@@ -167,14 +166,19 @@ func getAuthKey(name string, app *App) (string, error) {
 	return os.Getenv("TS_AUTHKEY"), nil
 }
 
-func getEphemeral(name string, app *App) bool {
-	if app == nil {
-		return false
+func getControlURL(name string, app *App) (string, error) {
+	if node, ok := app.Nodes[name]; ok {
+		if node.ControlURL != "" {
+			return repl.ReplaceOrErr(node.ControlURL, true, true)
+		}
 	}
+	return repl.ReplaceOrErr(app.ControlURL, true, true)
+}
+
+func getEphemeral(name string, app *App) bool {
 	if node, ok := app.Nodes[name]; ok {
 		return node.Ephemeral
 	}
-
 	return app.Ephemeral
 }