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/delete/main.go

@@ -1,81 +1,20 @@
 package delete
 
 import (
-	"fmt"
-	"os"
-	"path"
-
 	"github.com/spf13/cobra"
 	"github.com/warewulf/warewulf/internal/pkg/overlay"
-	"github.com/warewulf/warewulf/internal/pkg/util"
-	"github.com/warewulf/warewulf/internal/pkg/wwlog"
 )
 
 func CobraRunE(cmd *cobra.Command, args []string) error {
-	var fileName string
-
-	overlayName := args[0]
 
+	fileName := ""
 	if len(args) == 2 {
 		fileName = args[1]
 	}
 
-	overlay_ := overlay.GetOverlay(overlayName)
-	if overlay_.IsDistributionOverlay() {
-		return fmt.Errorf("distribution overlay can't deleted")
+	myOverlay, err := overlay.GetOverlay(args[0])
+	if err != nil {
+		return err
 	}
-	if !overlay_.Exists() {
-		return fmt.Errorf("overlay does not exist: %s", overlayName)
-	}
-
-	if fileName == "" {
-		if Force {
-			err := os.RemoveAll(overlay_.Path())
-			if err != nil {
-				return fmt.Errorf("failed deleting overlay: %w", err)
-			}
-		} else {
-			err := os.Remove(overlay_.Path())
-			if err != nil {
-				return fmt.Errorf("failed deleting overlay: %w", err)
-			}
-		}
-		wwlog.Info("Deleted overlay: %s\n", args[0])
-
-	} else {
-		removePath := overlay_.File(fileName)
-
-		if !(util.IsDir(removePath) || util.IsFile(removePath)) {
-			return fmt.Errorf("path to remove doesn't exist in overlay: %s", removePath)
-		}
-
-		if Force {
-			err := os.RemoveAll(removePath)
-			if err != nil {
-				return fmt.Errorf("failed deleting file from overlay: %s:%s", overlayName, removePath)
-			}
-		} else {
-			err := os.Remove(removePath)
-			if err != nil {
-				return fmt.Errorf("failed deleting overlay: %s:%s", overlayName, removePath)
-			}
-		}
-
-		if Parents {
-			// Cleanup any empty directories left behind...
-			i := path.Dir(removePath)
-			for i != overlay_.Rootfs() {
-				wwlog.Debug("Evaluating directory to remove: %s", i)
-				err := os.Remove(i)
-				if err != nil {
-					break
-				}
-
-				wwlog.Verbose("Removed empty directory: %s", i)
-				i = path.Dir(i)
-			}
-		}
-	}
-
-	return nil
+	return myOverlay.DeleteFile(fileName, Force, Parents)
 }