Added container option for kernel import

internal/app/wwctl/kernel/imprt/main.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 
+	"github.com/hpcng/warewulf/internal/pkg/container"
 	"github.com/hpcng/warewulf/internal/pkg/kernel"
 	"github.com/hpcng/warewulf/internal/pkg/node"
 	"github.com/hpcng/warewulf/internal/pkg/warewulfd"
@@ -14,6 +15,15 @@ import (
 func CobraRunE(cmd *cobra.Command, args []string) error {
 
 	for _, arg := range args {
+		// Checking if container flag was set, then overwriting OptRoot
+		if OptContainer != "" {
+			if container.ValidSource(OptContainer) == true {
+				OptRoot = container.RootFsDir(OptContainer)
+			} else {
+				wwlog.Printf(wwlog.ERROR, " %s is not a valid container", OptContainer)
+				os.Exit(1)
+			}
+		}
 		output, err := kernel.Build(arg, OptRoot)
 		if err != nil {
 			wwlog.Printf(wwlog.ERROR, "Failed building kernel: %s\n", err)

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

@@ -13,10 +13,11 @@ var (
 		RunE: CobraRunE,
 		Args: cobra.MinimumNArgs(1),
 	}
-	BuildAll   bool
-	ByNode     bool
-	SetDefault bool
-	OptRoot    string
+	BuildAll     bool
+	ByNode       bool
+	SetDefault   bool
+	OptRoot      string
+	OptContainer string
 )
 
 func init() {
@@ -24,6 +25,7 @@ func init() {
 	baseCmd.PersistentFlags().BoolVarP(&ByNode, "node", "n", false, "Build overlay for a particular node(s)")
 	baseCmd.PersistentFlags().BoolVar(&SetDefault, "setdefault", false, "Set this kernel for the default profile")
 	baseCmd.PersistentFlags().StringVarP(&OptRoot, "root", "r", "/", "Import kernel from root (chroot) directory")
+	baseCmd.PersistentFlags().StringVarP(&OptContainer, "container", "c", "", "Import kernel from container")
 }
 
 // GetRootCommand returns the root cobra.Command for the application.