refactored overlay class

overlay.GetOverlay(name) returns now an error if the overlay doesn't
exist. This is the most canonical way to act if there is no overlay.

internal/app/wwctl/overlay/list/root.go

@@ -5,28 +5,29 @@ import (
 	"github.com/warewulf/warewulf/internal/app/wwctl/completions"
 )
 
-var (
-	baseCmd = &cobra.Command{
+// Holds the variables which are needed in CobraRunE
+type variables struct {
+	ListContents bool
+	ListLong     bool
+	ShowPath     bool
+}
+
+// GetCommand returns the root cobra.Command for the application.
+func GetCommand() *cobra.Command {
+	vars := variables{}
+	baseCmd := &cobra.Command{
 		DisableFlagsInUseLine: true,
 		Use:                   "list [OPTIONS] OVERLAY_NAME",
 		Short:                 "List Warewulf Overlays and files",
 		Long:                  "This command displays information about all Warewulf overlays or the specified\nOVERLAY_NAME. It also supports listing overlay content information.",
-		RunE:                  CobraRunE,
+		RunE:                  CobraRunE(&vars),
 		Aliases:               []string{"ls"},
 		ValidArgsFunction:     completions.Overlays,
 		Args:                  cobra.ArbitraryArgs,
 	}
-	ListContents bool
-	ListLong     bool
-)
+	baseCmd.PersistentFlags().BoolVarP(&vars.ListContents, "all", "a", false, "List the contents of overlays")
+	baseCmd.PersistentFlags().BoolVarP(&vars.ListLong, "long", "l", false, "List 'long' of all overlay contents")
+	baseCmd.PersistentFlags().BoolVarP(&vars.ShowPath, "path", "p", false, "Show the absolute path to the overlay")
 
-func init() {
-	baseCmd.PersistentFlags().BoolVarP(&ListContents, "all", "a", false, "List the contents of overlays")
-	baseCmd.PersistentFlags().BoolVarP(&ListLong, "long", "l", false, "List 'long' of all overlay contents")
-
-}
-
-// GetRootCommand returns the root cobra.Command for the application.
-func GetCommand() *cobra.Command {
 	return baseCmd
 }