cmd/ctrld: add "start --no-cd" flag to disable cd mode

cmd/ctrld/cli.go

@@ -37,7 +37,13 @@ import (
 	"github.com/Control-D-Inc/ctrld/internal/router"
 )
 
-const selfCheckFQDN = "verify.controld.com"
+const (
+	selfCheckFQDN      = "verify.controld.com"
+	cdModeConfigHeader = `# AUTO-GENERATED VIA CD FLAG - DO NOT MODIFY
+# TO DISABLE AUTO-GENERATION RUN: ctrld service start --no-cd
+
+`
+)
 
 var (
 	version = "dev"
@@ -240,6 +246,7 @@ func initCLI() {
 	runCmd.Flags().StringVarP(&logPath, "log", "", "", "Path to log file")
 	runCmd.Flags().IntVarP(&cacheSize, "cache_size", "", 0, "Enable cache with size items")
 	runCmd.Flags().StringVarP(&cdUID, "cd", "", "", "Control D resolver uid")
+	runCmd.Flags().BoolVarP(&noCD, "no-cd", "", false, `Disable cd mode, the same effect with --cd=""`)
 	runCmd.Flags().StringVarP(&homedir, "homedir", "", "", "")
 	_ = runCmd.Flags().MarkHidden("homedir")
 	runCmd.Flags().StringVarP(&iface, "iface", "", "", `Update DNS setting for iface, "auto" means the default interface gateway`)
@@ -292,6 +299,12 @@ func initCLI() {
 			initLogging()
 			cfg.Service.LogPath = logPath
 
+			if noCD {
+				cdUID = ""
+				if err := writeConfigFile(); err != nil {
+					log.Fatalf("failed to overwrite config file with --no-cd: %v", err)
+				}
+			}
 			processCDFlags()
 
 			// Explicitly passing config, so on system where home directory could not be obtained,
@@ -349,6 +362,7 @@ func initCLI() {
 	startCmd.Flags().StringVarP(&logPath, "log", "", "", "Path to log file")
 	startCmd.Flags().IntVarP(&cacheSize, "cache_size", "", 0, "Enable cache with size items")
 	startCmd.Flags().StringVarP(&cdUID, "cd", "", "", "Control D resolver uid")
+	startCmd.Flags().BoolVarP(&noCD, "no-cd", "", false, `Disable cd mode, the same effect with --cd=""`)
 	startCmd.Flags().StringVarP(&iface, "iface", "", "", `Update DNS setting for iface, "auto" means the default interface gateway`)
 	startCmd.Flags().BoolVarP(&setupRouter, "router", "", false, `setup for running on router platforms`)
 	_ = startCmd.Flags().MarkHidden("router")
@@ -565,7 +579,7 @@ func writeConfigFile() error {
 	}
 	defer f.Close()
 	if cdUID != "" {
-		if _, err := f.WriteString("# AUTO-GENERATED VIA CD FLAG - DO NOT MODIFY\n\n"); err != nil {
+		if _, err := f.WriteString(cdModeConfigHeader); err != nil {
 			return err
 		}
 	}

cmd/ctrld/main.go

@@ -27,6 +27,7 @@ var (
 	cfg               ctrld.Config
 	verbose           int
 	cdUID             string
+	noCD              bool
 	iface             string
 	ifaceStartStop    string
 	setupRouter       bool