feat(controlplane): filter referrer discovery by project name and version

app/cli/pkg/action/referrer_discover.go

@@ -67,6 +67,9 @@ func NewReferrerDiscoverPublicIndex(cfg *ActionsOpts) *ReferrerDiscoverPublic {
 	return &ReferrerDiscoverPublic{cfg}
 }
 
+// Run calls the deprecated public shared index RPC, kept for backwards compatibility.
+//
+//nolint:staticcheck // the RPC is deprecated but still supported
 func (action *ReferrerDiscoverPublic) Run(ctx context.Context, digest, kind string, p *PaginationOpts) (*ReferrerDiscoverResult, error) {
 	client := pb.NewReferrerServiceClient(action.cfg.CPConnection)
 	resp, err := client.DiscoverPublicShared(ctx, &pb.DiscoverPublicSharedRequest{

app/controlplane/api/controlplane/v1/referrer.proto

@@ -36,7 +36,9 @@ service ReferrerService {
     };
   }
   // DiscoverPublicShared returns the referrer item for a given digest in the public shared index
+  // Deprecated: the public shared index is being retired.
   rpc DiscoverPublicShared(DiscoverPublicSharedRequest) returns (DiscoverPublicSharedResponse) {
+    option deprecated = true;
     option (google.api.http) = {get: "/discover/shared/{digest}"};
     option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_operation) = {
       summary: "Discover public shared referrer"
@@ -60,6 +62,21 @@ message ReferrerServiceDiscoverPrivateRequest {
   string kind = 2;
   // Pagination options for the references list
   CursorPaginationRequest pagination = 3;
+  // ProjectName optionally scopes the discovery to a project by name.
+  // Must be set together with project_version.
+  string project_name = 4;
+  // ProjectVersion optionally scopes the discovery to a project version (by name, e.g. v1.2.0).
+  // The referrer and its references are confined to this project version.
+  // Must be set together with project_name.
+  string project_version = 5;
+
+  // project_name and project_version must be provided together: a version name is unique only
+  // within a project, and a project name on its own would not scope the discovery.
+  option (buf.validate.message).cel = {
+    id: "discover_project_version_dependency"
+    expression: "(this.project_name == '') == (this.project_version == '')"
+    message: "project_name and project_version must be set together"
+  };
 
   option (grpc.gateway.protoc_gen_openapiv2.options.openapiv2_schema) = {
     json_schema: {
@@ -70,7 +87,10 @@ message ReferrerServiceDiscoverPrivateRequest {
 }
 
 // DiscoverPublicSharedRequest is the request for the DiscoverPublicShared method
+// Deprecated: the public shared index is being retired.
 message DiscoverPublicSharedRequest {
+  option deprecated = true;
+
   // Digest is the unique identifier of the referrer to discover
   string digest = 1 [(buf.validate.field).string = {min_len: 1}];
   // Kind is the optional type of referrer, i.e CONTAINER_IMAGE, GIT_HEAD, ...