mockkubeapiserver: Refactor storage to be pluggable

This helps if we want e.g. to capture all the objects easily.

mockkubeapiserver/apiserver.go

@@ -22,31 +22,47 @@ import (
 	"strings"
 
 	"k8s.io/klog/v2"
+	"sigs.k8s.io/kubebuilder-declarative-pattern/mockkubeapiserver/hooks"
+	"sigs.k8s.io/kubebuilder-declarative-pattern/mockkubeapiserver/storage"
+	"sigs.k8s.io/kubebuilder-declarative-pattern/mockkubeapiserver/storage/memorystorage"
 )
 
-func NewMockKubeAPIServer(addr string) (*MockKubeAPIServer, error) {
+func NewMockKubeAPIServer(addr string, options ...Option) (*MockKubeAPIServer, error) {
 	s := &MockKubeAPIServer{}
 	if addr == "" {
 		addr = ":http"
 	}
 
 	s.httpServer = &http.Server{Addr: addr, Handler: s}
 
-	var err error
+	for _, option := range options {
+		if err := option(s); err != nil {
+			return nil, err
+		}
+	}
 
-	s.storage, err = NewMemoryStorage(NewTestClock(), NewTestUIDGenerator())
-	if err != nil {
-		return nil, err
+	// If storage wasn't set with an option, default to memory storage
+	if s.storage == nil {
+		storage, err := memorystorage.NewMemoryStorage(storage.NewTestClock(), storage.NewTestUIDGenerator())
+		if err != nil {
+			return nil, err
+		}
+		s.storage = storage
 	}
 
+	// These hooks mock behaviour that would otherwise require full controllers
+	s.storage.AddStorageHook(&hooks.CRDHook{})
+	s.storage.AddStorageHook(&hooks.NamespaceHook{})
+	s.storage.AddStorageHook(&hooks.DeploymentHook{})
+
 	return s, nil
 }
 
 type MockKubeAPIServer struct {
 	httpServer *http.Server
 	listener   net.Listener
 
-	storage *MemoryStorage
+	storage storage.Storage
 
 	hooks []Hook
 }
@@ -337,3 +353,13 @@ func (s *MockKubeAPIServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
 	}
 }
+
+type Option func(config *MockKubeAPIServer) error
+
+// WithStorage is an Option that allows specifying the storage implementation.
+func WithStorage(storage storage.Storage) Option {
+	return func(config *MockKubeAPIServer) error {
+		config.storage = storage
+		return nil
+	}
+}

mockkubeapiserver/deleteresource.go

@@ -44,7 +44,7 @@ func (req *deleteResource) Run(ctx context.Context, s *MockKubeAPIServer) error
 		return fmt.Errorf("unexpected subresource on delete %q", req.SubResource)
 	}
 
-	deletedObject, err := s.storage.DeleteObject(ctx, resource, id)
+	deletedObject, err := resource.DeleteObject(ctx, id)
 	if err != nil {
 		return err
 	}

mockkubeapiserver/getresource.go

@@ -52,7 +52,7 @@ func (req *getResource) Run(ctx context.Context, s *MockKubeAPIServer) error {
 
 	id := types.NamespacedName{Namespace: req.Namespace, Name: req.Name}
 
-	object, found, err := s.storage.GetObject(ctx, resource, id)
+	object, found, err := resource.GetObject(ctx, id)
 	if err != nil {
 		return err
 	}

mockkubeapiserver/hooks/crd.go

@@ -0,0 +1,38 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package hooks
+
+import (
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/klog/v2"
+	"sigs.k8s.io/kubebuilder-declarative-pattern/mockkubeapiserver/storage"
+)
+
+// CRDHook implements functionality for CRD objects (the definitions themselves, not instances of CRDs)
+type CRDHook struct {
+	storage storage.Storage
+}
+
+func (s *CRDHook) OnWatchEvent(ev *storage.WatchEvent) {
+	switch ev.GroupKind() {
+	case schema.GroupKind{Group: "apiextensions.k8s.io", Kind: "CustomResourceDefinition"}:
+		// When a CRD is created, we notify the storage layer so it can store instances of the CRD
+		if err := s.storage.UpdateCRD(ev); err != nil {
+			klog.Warningf("crd change was invalid: %v", err)
+		}
+	}
+}