More idiomatic logging config

Update logging configuration to be more idiomatic for a Cobra
application

cmd/executor/cmd/root.go

@@ -39,13 +39,18 @@ import (
 )
 
 var (
-	opts  = &config.KanikoOptions{}
-	force bool
+	opts      = &config.KanikoOptions{}
+	force     bool
+	logLevel  string
+	logFormat string
 )
 
 func init() {
-	logging.AddFlags(RootCmd.PersistentFlags())
+	RootCmd.PersistentFlags().StringVarP(&logLevel, "verbosity", "v", logging.DefaultLevel, "Log level (debug, info, warn, error, fatal, panic")
+	RootCmd.PersistentFlags().StringVar(&logFormat, "log-format", logging.FormatColor, "Log format (text, color, json)")
+
 	RootCmd.PersistentFlags().BoolVarP(&force, "force", "", false, "Force building outside of a container")
+
 	addKanikoOptionsFlags()
 	addHiddenFlags(RootCmd)
 }
@@ -56,9 +61,11 @@ var RootCmd = &cobra.Command{
 	PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
 		if cmd.Use == "executor" {
 			resolveEnvironmentBuildArgs(opts.BuildArgs, os.Getenv)
-			if err := logging.Configure(); err != nil {
+
+			if err := logging.Configure(logLevel, logFormat); err != nil {
 				return err
 			}
+
 			if !opts.NoPush && len(opts.Destinations) == 0 {
 				return errors.New("You must provide --destination, or use --no-push")
 			}

cmd/warmer/cmd/root.go

@@ -29,21 +29,26 @@ import (
 )
 
 var (
-	opts = &config.WarmerOptions{}
+	opts      = &config.WarmerOptions{}
+	logLevel  string
+	logFormat string
 )
 
 func init() {
-	logging.AddFlags(RootCmd.PersistentFlags())
+	RootCmd.PersistentFlags().StringVarP(&logLevel, "verbosity", "v", logging.DefaultLevel, "Log level (debug, info, warn, error, fatal, panic")
+	RootCmd.PersistentFlags().StringVar(&logFormat, "log-format", logging.FormatColor, "Log format (text, color, json)")
+
 	addKanikoOptionsFlags()
 	addHiddenFlags()
 }
 
 var RootCmd = &cobra.Command{
 	Use: "cache warmer",
 	PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
-		if err := logging.Configure(); err != nil {
+		if err := logging.Configure(logLevel, logFormat); err != nil {
 			return err
 		}
+
 		if len(opts.Images) == 0 {
 			return errors.New("You must select at least one image to cache")
 		}

pkg/logging/logging.go

@@ -21,7 +21,6 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
-	"github.com/spf13/pflag"
 )
 
 const (
@@ -36,27 +35,16 @@ const (
 	FormatJSON = "json"
 )
 
-var (
-	logLevel  string
-	logFormat string
-)
-
-// AddFlags injects logging-related flags into the given FlagSet
-func AddFlags(fs *pflag.FlagSet) {
-	fs.StringVarP(&logLevel, "verbosity", "v", DefaultLevel, "Log level (debug, info, warn, error, fatal, panic")
-	fs.StringVar(&logFormat, "log-format", FormatColor, "Log format (text, color, json)")
-}
-
 // Configure sets the logrus logging level and formatter
-func Configure() error {
-	lvl, err := logrus.ParseLevel(logLevel)
+func Configure(level, format string) error {
+	lvl, err := logrus.ParseLevel(level)
 	if err != nil {
 		return errors.Wrap(err, "parsing log level")
 	}
 	logrus.SetLevel(lvl)
 
 	var formatter logrus.Formatter
-	switch logFormat {
+	switch format {
 	case FormatText:
 		formatter = &logrus.TextFormatter{
 			DisableColors: true,
@@ -68,7 +56,7 @@ func Configure() error {
 	case FormatJSON:
 		formatter = &logrus.JSONFormatter{}
 	default:
-		return fmt.Errorf("not a valid log format: %q. Please specify one of (text, color, json)", logFormat)
+		return fmt.Errorf("not a valid log format: %q. Please specify one of (text, color, json)", format)
 	}
 	logrus.SetFormatter(formatter)