Move filtered registry search out of image service

SearchRegistryForImages does not make sense as part of the image
service interface. The implementation just wraps the search API of the
registry service to filter the results client-side. It has nothing to do
with local image storage, and the implementation of search does not need
to change when changing which backend (graph driver vs. containerd
snapshotter) is used for local image storage.

Filtering of the search results is an implementation detail: the
consumer of the results does not care which actor does the filtering so
long as the results are filtered as requested. Move filtering into the
exported API of the registry service to hide the implementation details.
Only one thing---the registry service implementation---would need to
change in order to support server-side filtering of search results if
Docker Hub or other registry servers were to add support for it to their
APIs.

Use a fake registry server in the search unit tests to avoid having to
mock out the registry API client.

Signed-off-by: Cory Snider <csnider@mirantis.com>

3 files changed, 9 insertions, 4 deletions

diff --git a/api/server/router/image/backend.go b/api/server/router/image/backend.go
index d4558fd0dd..6dcee6f100 100644
--- a/api/server/router/image/backend.go
+++ b/api/server/router/image/backend.go
@@ -39,5 +39,8 @@ type importExportBackend interface {
 type registryBackend interface {
 	PullImage(ctx context.Context, image, tag string, platform *specs.Platform, metaHeaders map[string][]string, authConfig *registry.AuthConfig, outStream io.Writer) error
 	PushImage(ctx context.Context, image, tag string, metaHeaders map[string][]string, authConfig *registry.AuthConfig, outStream io.Writer) error
-	SearchRegistryForImages(ctx context.Context, searchFilters filters.Args, term string, limit int, authConfig *registry.AuthConfig, metaHeaders map[string][]string) (*registry.SearchResults, error)
+}
+
+type Searcher interface {
+	Search(ctx context.Context, searchFilters filters.Args, term string, limit int, authConfig *registry.AuthConfig, metaHeaders map[string][]string) ([]registry.SearchResult, error)
 }
diff --git a/api/server/router/image/image.go b/api/server/router/image/image.go
index 70750d09af..7dd1eabf44 100644
--- a/api/server/router/image/image.go
+++ b/api/server/router/image/image.go
@@ -10,6 +10,7 @@ import (
 // imageRouter is a router to talk with the image controller
 type imageRouter struct {
 	backend          Backend
+	searcher         Searcher
 	referenceBackend reference.Store
 	imageStore       image.Store
 	layerStore       layer.Store
@@ -17,9 +18,10 @@ type imageRouter struct {
 }
 
 // NewRouter initializes a new image router
-func NewRouter(backend Backend, referenceBackend reference.Store, imageStore image.Store, layerStore layer.Store) router.Router {
+func NewRouter(backend Backend, searcher Searcher, referenceBackend reference.Store, imageStore image.Store, layerStore layer.Store) router.Router {
 	ir := &imageRouter{
 		backend:          backend,
+		searcher:         searcher,
 		referenceBackend: referenceBackend,
 		imageStore:       imageStore,
 		layerStore:       layerStore,
diff --git a/api/server/router/image/image_routes.go b/api/server/router/image/image_routes.go
index 5e0cbac315..3140a663ab 100644
--- a/api/server/router/image/image_routes.go
+++ b/api/server/router/image/image_routes.go
@@ -415,11 +415,11 @@ func (ir *imageRouter) getImagesSearch(ctx context.Context, w http.ResponseWrite
 	// For a search it is not an error if no auth was given. Ignore invalid
 	// AuthConfig to increase compatibility with the existing API.
 	authConfig, _ := registry.DecodeAuthConfig(r.Header.Get(registry.AuthHeader))
-	query, err := ir.backend.SearchRegistryForImages(ctx, searchFilters, r.Form.Get("term"), limit, authConfig, headers)
+	res, err := ir.searcher.Search(ctx, searchFilters, r.Form.Get("term"), limit, authConfig, headers)
 	if err != nil {
 		return err
 	}
-	return httputils.WriteJSON(w, http.StatusOK, query.Results)
+	return httputils.WriteJSON(w, http.StatusOK, res)
 }
 
 func (ir *imageRouter) postImagesPrune(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {