feat: add image data context (#12175)

pkg/imagedataloader/context.go

@@ -0,0 +1,60 @@
+package imagedataloader
+
+import (
+	"context"
+
+	k8scorev1 "k8s.io/client-go/kubernetes/typed/core/v1"
+)
+
+type imageContext struct {
+	f    Fetcher
+	list map[string]*ImageData
+}
+
+// ImageContext stores a list of imagedata, it lives as long as
+// the admission request. Get request for images either returned a prefetched image or
+// fetches it from the registry. It is used to share image data for a policy across policies
+type ImageContext interface {
+	AddImages(ctx context.Context, images []string, opts ...Option) error
+	Get(ctx context.Context, image string, opts ...Option) (*ImageData, error)
+}
+
+func NewImageContext(lister k8scorev1.SecretInterface, opts ...Option) (ImageContext, error) {
+	idl, err := New(lister, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return &imageContext{
+		f:    idl,
+		list: make(map[string]*ImageData),
+	}, nil
+}
+
+func (idc *imageContext) AddImages(ctx context.Context, images []string, opts ...Option) error {
+	for _, img := range images {
+		if _, found := idc.list[img]; found {
+			continue
+		}
+
+		data, err := idc.f.FetchImageData(ctx, img, opts...)
+		if err != nil {
+			return err
+		}
+		idc.list[img] = data
+	}
+	return nil
+}
+
+func (idc *imageContext) Get(ctx context.Context, image string, opts ...Option) (*ImageData, error) {
+	if data, found := idc.list[image]; found {
+		return data, nil
+	}
+
+	data, err := idc.f.FetchImageData(ctx, image, opts...)
+	if err != nil {
+		return nil, err
+	}
+	idc.list[image] = data
+
+	return data, nil
+}