enable preparer interface to pre operations

pkg/commands/publisher.go

@@ -41,6 +41,12 @@ func publishImages(ctx context.Context, importpaths []string, pub publish.Interf
 			return nil, fmt.Errorf("importpath %q is not supported: %w", importpath, err)
 		}
 
+		if ppub, ok := pub.(publish.Preparer); ok {
+			if err := ppub.Prepare(ctx, importpath); err != nil {
+				return nil, fmt.Errorf("error preparing publisher: %w", err)
+			}
+		}
+
 		img, err := b.Build(ctx, importpath)
 		if err != nil {
 			return nil, fmt.Errorf("error building %q: %w", importpath, err)

pkg/publish/default.go

@@ -260,3 +260,25 @@ func (d *defalt) Publish(ctx context.Context, br build.Result, s string) (name.R
 func (d *defalt) Close() error {
 	return nil
 }
+
+// Prepare implements publish.Preparer
+func (d *defalt) Prepare(ctx context.Context, s string) error {
+	var no []name.Option
+	if d.insecure {
+		no = append(no, name.Insecure)
+	}
+
+	for _, tagName := range d.tags {
+		tag, err := name.NewTag(fmt.Sprintf("%s:%s", d.namer(d.base, s), tagName), no...)
+		if err != nil {
+			return err
+		}
+
+		if err := remote.CheckPushPermission(tag, d.keychain, d.t); err != nil {
+			return err
+		}
+	}
+
+	return nil
+
+}

pkg/publish/multi.go

@@ -58,3 +58,15 @@ func (p *multiPublisher) Close() (err error) {
 	}
 	return
 }
+
+// Prepare implements publish.Preparer.
+func (p *multiPublisher) Prepare(ctx context.Context, s string) (err error) {
+	for _, pub := range p.publishers {
+		if ppub, ok := pub.(Preparer); ok {
+			if perr := ppub.Prepare(ctx, s); perr != nil {
+				err = perr
+			}
+		}
+	}
+	return
+}

pkg/publish/publish.go

@@ -21,6 +21,10 @@ import (
 	"github.com/google/ko/pkg/build"
 )
 
+type Preparer interface {
+	Prepare(context.Context, string) error
+}
+
 // Interface abstracts different methods for publishing images.
 type Interface interface {
 	// Publish uploads the given build.Result to a registry incorporating the