Add delete image-policy and refactor

This adds a command for deleting ImagePolicy objects. Since the
control flow for the command needs only a runtime.Object (and a name
for the type), it can be factored out.

I have made the argument (field in the deleteCommand struct) an
interface `objectContainer`, through which the command code gets a
`runtime.Object` to deserialise into (and delete). It could be simply
a `runtime.Object` here; however things like `getCommand` require
other methods, so it's convenient to have an interface for it.

Signed-off-by: Michael Bridgen <michael@weave.works>

cmd/flux/delete_auto_imagerepository.go

@@ -17,14 +17,8 @@ limitations under the License.
 package main
 
 import (
-	"context"
-	"fmt"
-
-	"github.com/manifoldco/promptui"
 	"github.com/spf13/cobra"
-	"k8s.io/apimachinery/pkg/types"
 
-	"github.com/fluxcd/flux2/internal/utils"
 	imagev1 "github.com/fluxcd/image-reflector-controller/api/v1alpha1"
 )
 
@@ -35,54 +29,12 @@ var deleteImageRepositoryCmd = &cobra.Command{
 	Example: `  # Delete an image repository
   flux delete auto image-repository alpine
 `,
-	RunE: deleteImageRepositoryRun,
+	RunE: deleteCommand{
+		humanKind: "image repository",
+		container: genericContainer{&imagev1.ImageRepository{}},
+	}.run,
 }
 
 func init() {
 	deleteAutoCmd.AddCommand(deleteImageRepositoryCmd)
 }
-
-func deleteImageRepositoryRun(cmd *cobra.Command, args []string) error {
-	if len(args) < 1 {
-		return fmt.Errorf("image repository name is required")
-	}
-	name := args[0]
-
-	ctx, cancel := context.WithTimeout(context.Background(), timeout)
-	defer cancel()
-
-	kubeClient, err := utils.KubeClient(kubeconfig, kubecontext)
-	if err != nil {
-		return err
-	}
-
-	namespacedName := types.NamespacedName{
-		Namespace: namespace,
-		Name:      name,
-	}
-
-	var repo imagev1.ImageRepository
-	err = kubeClient.Get(ctx, namespacedName, &repo)
-	if err != nil {
-		return err
-	}
-
-	if !deleteSilent {
-		prompt := promptui.Prompt{
-			Label:     "Are you sure you want to delete this image repository",
-			IsConfirm: true,
-		}
-		if _, err := prompt.Run(); err != nil {
-			return fmt.Errorf("aborting")
-		}
-	}
-
-	logger.Actionf("deleting image repository %s in %s namespace", name, namespace)
-	err = kubeClient.Delete(ctx, &repo)
-	if err != nil {
-		return err
-	}
-	logger.Successf("image repository deleted")
-
-	return nil
-}