fix a bug when replacing existing containers

Signed-off-by: jason yang <jasonyangshadow@gmail.com>

internal/app/wwctl/container/imprt/root.go

@@ -1,6 +1,9 @@
 package imprt
 
-import "github.com/spf13/cobra"
+import (
+	"github.com/hpcng/warewulf/internal/pkg/wwlog"
+	"github.com/spf13/cobra"
+)
 
 var (
 	baseCmd = &cobra.Command{
@@ -19,6 +22,11 @@ Imported containers are used to create bootable VNFS images.`,
 		Example: "wwctl container import docker://ghcr.io/hpcng/warewulf-rockylinux:8 rockylinux-8",
 		RunE:    CobraRunE,
 		Args:    cobra.MinimumNArgs(1),
+		PreRun: func(cmd *cobra.Command, args []string) {
+			if SetForce && SetUpdate {
+				wwlog.Warn("Both --force and --update flags are set, will ignore --update flag")
+			}
+		},
 	}
 	SetForce   bool
 	SetUpdate  bool

internal/pkg/api/container/container.go

@@ -175,21 +175,23 @@ func ContainerImport(cip *wwapiv1.ContainerImportParameter) (containerName strin
 	containerName = cip.Name
 	fullPath := container.SourceDir(cip.Name)
 
+	// container already exists and should be removed first
+	if util.IsDir(fullPath) && cip.Force {
+		wwlog.Info("Overwriting existing VNFS")
+		err = os.RemoveAll(fullPath)
+		if err != nil {
+			wwlog.ErrorExc(err, "")
+			return
+		}
+	}
+
 	if util.IsDir(fullPath) {
-		if cip.Force {
-			wwlog.Info("Overwriting existing VNFS")
-			err = os.RemoveAll(fullPath)
-			if err != nil {
-				wwlog.ErrorExc(err, "")
-				return
-			}
-		} else if cip.Update {
-			wwlog.Info("Updating existing VNFS")
-		} else {
+		if !cip.Update {
 			err = fmt.Errorf("VNFS Name exists, specify --force, --update, or choose a different name: %s", cip.Name)
 			wwlog.Error(err.Error())
 			return
 		}
+		wwlog.Info("Updating existing VNFS")
 	} else if strings.HasPrefix(cip.Source, "docker://") || strings.HasPrefix(cip.Source, "docker-daemon://") ||
 		strings.HasPrefix(cip.Source, "file://") || util.IsFile(cip.Source) {
 		var sCtx *types.SystemContext