K8s: handle multiple versions of the same group in standalone mode (#93199)

pkg/services/apiserver/builder/common.go

@@ -5,7 +5,6 @@ import (
 
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
-	"k8s.io/apimachinery/pkg/runtime/serializer"
 	"k8s.io/apiserver/pkg/authorization/authorizer"
 	"k8s.io/apiserver/pkg/registry/generic"
 	genericapiserver "k8s.io/apiserver/pkg/server"
@@ -24,13 +23,19 @@ type APIGroupBuilder interface {
 	// Add the kinds to the server scheme
 	InstallSchema(scheme *runtime.Scheme) error
 
-	// Build the group+version behavior
-	GetAPIGroupInfo(
+	// UpdateAPIGroupInfo used to be a getter until we ran into the issue
+	// where separate API Group Info for the same group (different versions) aren't handled well by
+	// the InstallAPIGroup facility of genericapiserver. Also, we can only ever call InstallAPIGroup
+	// once on the genericapiserver per group, or we run into double registration startup errors.
+	//
+	// The caller should share the apiGroupInfo passed into this function across builder versions of the same group.
+	// UpdateAPIGroupInfo builds the group+version behavior updating the passed in apiGroupInfo in place
+	UpdateAPIGroupInfo(
+		apiGroupInfo *genericapiserver.APIGroupInfo,
 		scheme *runtime.Scheme,
-		codecs serializer.CodecFactory,
 		optsGetter generic.RESTOptionsGetter,
-		dualWrite grafanarest.DualWriteBuilder,
-	) (*genericapiserver.APIGroupInfo, error)
+		dualWriteBuilder grafanarest.DualWriteBuilder,
+	) error
 
 	// Get OpenAPI definitions
 	GetOpenAPIDefinitions() common.GetOpenAPIDefinitions

pkg/services/apiserver/builder/helper.go

@@ -210,18 +210,33 @@ func InstallAPIs(
 		}
 	}
 
+	// NOTE: we build a map structure by version only for the purposes of InstallAPIGroup
+	// in other places, working with a flat []APIGroupBuilder list is much nicer
+	buildersGroupMap := make(map[string][]APIGroupBuilder, 0)
 	for _, b := range builders {
-		g, err := b.GetAPIGroupInfo(scheme, codecs, optsGetter, dualWrite)
-		if err != nil {
-			return err
+		group := b.GetGroupVersion().Group
+		if _, ok := buildersGroupMap[group]; !ok {
+			buildersGroupMap[group] = make([]APIGroupBuilder, 0)
 		}
-		if g == nil || len(g.PrioritizedVersions) < 1 {
-			continue
+		buildersGroupMap[group] = append(buildersGroupMap[group], b)
+	}
+
+	for group, buildersForGroup := range buildersGroupMap {
+		g := genericapiserver.NewDefaultAPIGroupInfo(group, scheme, metav1.ParameterCodec, codecs)
+		for _, b := range buildersForGroup {
+			if err := b.UpdateAPIGroupInfo(&g, scheme, optsGetter, dualWrite); err != nil {
+				return err
+			}
+			if len(g.PrioritizedVersions) < 1 {
+				continue
+			}
 		}
-		err = server.InstallAPIGroup(g)
+
+		err := server.InstallAPIGroup(&g)
 		if err != nil {
 			return err
 		}
 	}
+
 	return nil
 }