root: add --quiet option for disabling logging

With the leveled logger in place, it's also interesting to the user to
disable any sort of logging, thus only the usual output from the commands
are printed, no other additional information. It's useful for scripting
any wrappers around lab.

Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>

cmd/root.go

@@ -111,16 +111,23 @@ func init() {
 	RootCmd.Flags().Bool("version", false, "Show the lab version")
 	RootCmd.PersistentFlags().Bool("no-pager", false, "Do not pipe output into a pager")
 	RootCmd.PersistentFlags().Bool("debug", false, "Enable debug logging level")
+	RootCmd.PersistentFlags().Bool("quiet", false, "Turn off any sort of logging. Only command output is printed")
 
 	// We need to set the logger level before any other piece of code is
 	// called, thus we make sure we don't lose any debug message, but for
 	// that we need to parse the args from command input.
 	err := RootCmd.ParseFlags(os.Args[1:])
 	// Handle the err != nil case later
 	if err == nil {
-		debugLogLevel, _ := RootCmd.Flags().GetBool("debug")
-		if debugLogLevel {
+		debugLogger, _ := RootCmd.Flags().GetBool("debug")
+		quietLogger, _ := RootCmd.Flags().GetBool("quiet")
+		if debugLogger && quietLogger {
+			log.Fatal("option --debug cannot be combined with --quiet")
+		}
+		if debugLogger {
 			log.SetLogLevel(logger.LOG_DEBUG)
+		} else if quietLogger {
+			log.SetLogLevel(logger.LOG_NONE)
 		}
 	}
 }

internal/logger/logger.go

@@ -13,7 +13,8 @@ import (
 
 // Logger levels available
 const (
-	LOG_ERROR = iota
+	LOG_NONE = iota
+	LOG_ERROR
 	LOG_INFO
 	LOG_DEBUG
 )
@@ -53,9 +54,9 @@ func GetInstance() *logger {
 }
 
 // SetLogLevel set the level of the internal logger.
-// Allowed values are LOG_{ERROR,INFO,DEBUG}.
+// Allowed values are LOG_{ERROR,INFO,DEBUG,NONE}.
 func (l *logger) SetLogLevel(level int) error {
-	if !(level >= LOG_ERROR && level <= LOG_DEBUG) {
+	if !(level >= LOG_NONE && level <= LOG_DEBUG) {
 		return errors.New("invalid log level")
 	}
 	l.level = level